Amend f6890ed mostly to please static analyzers.

# Conflicts:
#	backends/imgui_impl_glfw.cpp
#	backends/imgui_impl_sdl2.cpp
#	backends/imgui_impl_sdl3.cpp
#	docs/CHANGELOG.txt
#	examples/example_glfw_metal/main.mm
#	examples/example_glfw_opengl2/main.cpp
#	examples/example_glfw_vulkan/main.cpp
#	examples/example_win32_opengl3/main.cpp
#	examples/example_win32_vulkan/main.cpp
#	imgui.h

.github/ISSUE_TEMPLATE/issue_template.yml

@@ -4,7 +4,7 @@ body:
   - type: markdown
     attributes:
       value: |
-        FOR FIRST-TIME USERS ISSUES COMPILING/LINKING/RUNNING or LOADING FONTS, please use [GitHub Discussions](https://github.com/ocornut/imgui/discussions)
+        FOR FIRST-TIME USERS ISSUES COMPILING/LINKING/RUNNING, please use [GitHub Discussions](https://github.com/ocornut/imgui/discussions)
         For anything else: **we are happy to use 'GitHub Issues' for many types of open-ended questions**. We are encouraging 'Issues' becoming a large, centralized, tagged, cross-referenced database of Dear ImGui contents.
 
         Be mindful that messages are being sent to the e-mail box of "Watching" users. Try to proof-read your messages before sending them. Edits are not seen by those users.

.github/pull_request_template.md

@@ -2,5 +2,7 @@
 
 1. PLEASE CAREFULLY READ: [Contributing Guidelines](https://github.com/ocornut/imgui/blob/master/docs/CONTRIBUTING.md)
 
-2. Clear this template before submitting your PR.
+2. Make sure you're using a special branch just for this pull request. (Sometimes people unknowingly use a default branch, then later update that branch, which updates the pull request with the other changes if it hasn't been merged yet.)
+
+3. Clear this template before submitting your PR.
 

.github/workflows/build.yml

@@ -17,31 +17,46 @@ on:
 
 jobs:
   Windows:
-    runs-on: windows-2019
+    runs-on: windows-2025
     env:
-      VS_PATH: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\
-      MSBUILD_PATH: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\
+      VS_PATH: C:\Program Files\Microsoft Visual Studio\2022\Enterprise\
+      MSBUILD_PATH: C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\
     steps:
       - uses: actions/checkout@v4
 
       - name: Install Dependencies
         shell: powershell
         run: |
-          Invoke-WebRequest -Uri "https://www.libsdl.org/release/SDL2-devel-2.26.3-VC.zip" -OutFile "SDL2-devel-2.26.3-VC.zip"
-          Expand-Archive -Path SDL2-devel-2.26.3-VC.zip
-          echo "SDL2_DIR=$(pwd)\SDL2-devel-2.26.3-VC\SDL2-2.26.3\" >>${env:GITHUB_ENV}
+          Invoke-WebRequest -Uri "https://www.libsdl.org/release/SDL2-devel-2.32.8-VC.zip" -OutFile "SDL2-devel-2.32.8-VC.zip"
+          Expand-Archive -Path SDL2-devel-2.32.8-VC.zip
+          echo "SDL2_DIR=$(pwd)\SDL2-devel-2.32.8-VC\SDL2-2.32.8\" >>${env:GITHUB_ENV}
 
-          Invoke-WebRequest -Uri "https://github.com/ocornut/imgui/files/3789205/vulkan-sdk-1.1.121.2.zip" -OutFile vulkan-sdk-1.1.121.2.zip
-          Expand-Archive -Path vulkan-sdk-1.1.121.2.zip
-          echo "VULKAN_SDK=$(pwd)\vulkan-sdk-1.1.121.2\" >>${env:GITHUB_ENV}
+          Invoke-WebRequest -Uri "https://www.libsdl.org/release/SDL3-devel-3.2.18-VC.zip" -OutFile "SDL3-devel-3.2.18-VC.zip"
+          Expand-Archive -Path SDL3-devel-3.2.18-VC.zip
+          echo "SDL3_DIR=$(pwd)\SDL3-devel-3.2.18-VC\SDL3-3.2.18\" >>${env:GITHUB_ENV}
+
+          # VulkanSDK (retrieve minimal bits of the SDK from git)
+          $vulkanVersion = "1.4.326"
+          # 1. Get the vulkan headers, we will treat that folder as the sdk folder to avoid having to copy headers around
+          Invoke-WebRequest -Uri "https://github.com/KhronosGroup/Vulkan-Headers/archive/refs/tags/v$($vulkanVersion).zip" -OutFile Vulkan-Headers-$($vulkanVersion).zip
+          Expand-Archive -Path Vulkan-Headers-$($vulkanVersion).zip
+          echo "VULKAN_SDK=$(pwd)\Vulkan-Headers-$($vulkanVersion)\Vulkan-Headers-$($vulkanVersion)" >>${env:GITHUB_ENV}
+          # 2. Get and build the vulkan loader source code (UPDATE_DEPS=On will make it automatically fetch its dependencies)
+          Invoke-WebRequest -Uri "https://github.com/KhronosGroup/Vulkan-Loader/archive/refs/tags/v$($vulkanVersion).zip" -OutFile Vulkan-Loader-$($vulkanVersion).zip
+          Expand-Archive -Path Vulkan-Loader-$($vulkanVersion).zip
+          cmake -S Vulkan-Loader-$($vulkanVersion)\Vulkan-Loader-$($vulkanVersion) -B VulkanLoader-build -D UPDATE_DEPS=On
+          cmake --build VulkanLoader-build
+          # 3. Copy the built lib/dll to the expected place
+          mkdir Vulkan-Headers-$($vulkanVersion)\Vulkan-Headers-$($vulkanVersion)\Lib
+          copy VulkanLoader-build\loader\Debug\vulkan-1.* Vulkan-Headers-$($vulkanVersion)\Vulkan-Headers-$($vulkanVersion)\Lib\
 
       - name: Fix Projects
         shell: powershell
         run: |
           # CI workers do not supporter older Visual Studio versions. Fix projects to target newer available version.
           gci -recurse -filter "*.vcxproj" | ForEach-Object {
-            (Get-Content $_.FullName) -Replace "<PlatformToolset>v\d{3}</PlatformToolset>","<PlatformToolset>v142</PlatformToolset>" | Set-Content -Path $_.FullName
-            (Get-Content $_.FullName) -Replace "<WindowsTargetPlatformVersion>[\d\.]+</WindowsTargetPlatformVersion>","<WindowsTargetPlatformVersion>10.0.18362.0</WindowsTargetPlatformVersion>" | Set-Content -Path $_.FullName
+            (Get-Content $_.FullName) -Replace "<PlatformToolset>v\d{3}</PlatformToolset>","<PlatformToolset>v143</PlatformToolset>" | Set-Content -Path $_.FullName
+            (Get-Content $_.FullName) -Replace "<WindowsTargetPlatformVersion>[\d\.]+</WindowsTargetPlatformVersion>",'<WindowsTargetPlatformVersion>$(LatestTargetPlatformVersion)</WindowsTargetPlatformVersion>' | Set-Content -Path $_.FullName
           }
 
       # Not using matrix here because it would inflate job count too much. Check out and setup is done for every job and that makes build times way too long.
@@ -51,15 +66,11 @@ jobs:
       - name: Build example_null (mingw 64-bit, as DLL)
         shell: bash
         run: |
-          echo '#ifdef _EXPORT'                                  >  example_single_file.cpp
-          echo '#  define IMGUI_API __declspec(dllexport)'       >> example_single_file.cpp
-          echo '#else'                                           >> example_single_file.cpp
-          echo '#  define IMGUI_API __declspec(dllimport)'       >> example_single_file.cpp
-          echo '#endif'                                          >> example_single_file.cpp
+          echo '#define IMGUI_API __declspec(dllexport)'         >  example_single_file.cpp
           echo '#define IMGUI_IMPLEMENTATION'                    >> example_single_file.cpp
           echo '#include "misc/single_file/imgui_single_file.h"' >> example_single_file.cpp
-          g++ -I. -Wall -Wformat -D_EXPORT -shared -o libimgui.dll -Wl,--out-implib,libimgui.a example_single_file.cpp -limm32
-          g++ -I. -Wall -Wformat -o example_null.exe examples/example_null/main.cpp -L. -limgui
+          g++ -I. -Wall -Wformat -shared -o libimgui.dll -Wl,--out-implib,libimgui.a example_single_file.cpp -limm32
+          g++ -I. -Wall -Wformat -DIMGUI_API='__declspec(dllimport)' -o example_null.exe examples/example_null/main.cpp -L. -limgui
           rm -f example_null.exe libimgui.* example_single_file.*
 
       - name: Build example_null (extra warnings, msvc 64-bit)
@@ -99,20 +110,19 @@ jobs:
         run: |
           call "%VS_PATH%\VC\Auxiliary\Build\vcvars64.bat"
 
-          echo #ifdef _EXPORT                                  >  example_single_file.cpp
-          echo #  define IMGUI_API __declspec(dllexport)       >> example_single_file.cpp
-          echo #else                                           >> example_single_file.cpp
-          echo #  define IMGUI_API __declspec(dllimport)       >> example_single_file.cpp
-          echo #endif                                          >> example_single_file.cpp
+          echo #define IMGUI_API __declspec(dllexport)         >  example_single_file.cpp
           echo #define IMGUI_IMPLEMENTATION                    >> example_single_file.cpp
           echo #include "misc/single_file/imgui_single_file.h" >> example_single_file.cpp
 
-          cl.exe /D_USRDLL /D_WINDLL /D_EXPORT /I. example_single_file.cpp /LD /FeImGui.dll /link
-          cl.exe /I. ImGui.lib /Feexample_null.exe examples/example_null/main.cpp
+          cl.exe /D_USRDLL /D_WINDLL /I. example_single_file.cpp /LD /FeImGui.dll /link
+          cl.exe /DIMGUI_API=__declspec(dllimport) /I. ImGui.lib /Feexample_null.exe examples/example_null/main.cpp
 
+      # Win64 examples are more frequently compilted than the Win32 examples.
+      # More of the Win32 examples requires 'workflow_run' to reduce waste.
       - name: Build Win32 example_glfw_opengl2
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_glfw_opengl2/example_glfw_opengl2.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
 
       - name: Build Win32 example_glfw_opengl3
         shell: cmd
@@ -148,77 +158,116 @@ jobs:
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_directx11/example_sdl2_directx11.vcxproj /p:Platform=Win32 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
+      - name: Build Win32 example_sdl3_opengl3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_opengl3/example_sdl3_opengl3.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+
+      - name: Build Win32 example_sdl3_sdlgpu3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_sdlgpu3/example_sdl3_sdlgpu3.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
+
+      - name: Build Win32 example_sdl3_sdlrenderer3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_sdlrenderer3/example_sdl3_sdlrenderer3.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
+
+      - name: Build Win32 example_sdl3_vulkan
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_vulkan/example_sdl3_vulkan.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
+
       - name: Build Win32 example_win32_directx9
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx9/example_win32_directx9.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
 
       - name: Build Win32 example_win32_directx10
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx10/example_win32_directx10.vcxproj /p:Platform=Win32 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
 
       - name: Build Win32 example_win32_directx11
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx11/example_win32_directx11.vcxproj /p:Platform=Win32 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_glfw_opengl2
+      # Windows 64-bits
+      - name: Build Win64 example_glfw_opengl2
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_glfw_opengl2/example_glfw_opengl2.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_glfw_opengl3
+      - name: Build Win64 example_glfw_opengl3
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_glfw_opengl3/example_glfw_opengl3.vcxproj /p:Platform=x64 /p:Configuration=Release'
 
-      - name: Build x64 example_glfw_vulkan
+      - name: Build Win64 example_glfw_vulkan
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_glfw_vulkan/example_glfw_vulkan.vcxproj /p:Platform=x64 /p:Configuration=Release'
 
-      - name: Build x64 example_sdl2_sdlrenderer2
+      - name: Build Win64 example_sdl2_sdlrenderer2
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_sdlrenderer2/example_sdl2_sdlrenderer2.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_sdl2_vulkan
+      - name: Build Win64 example_sdl2_vulkan
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_vulkan/example_sdl2_vulkan.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_sdl2_opengl2
+      - name: Build Win64 example_sdl2_opengl2
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_opengl2/example_sdl2_opengl2.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_sdl2_opengl3
+      - name: Build Win64 example_sdl2_opengl3
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_opengl3/example_sdl2_opengl3.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_sdl2_directx11
+      - name: Build Win64 example_sdl2_directx11
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl2_directx11/example_sdl2_directx11.vcxproj /p:Platform=x64 /p:Configuration=Release'
 
-      - name: Build x64 example_win32_directx9
+      - name: Build Win64 example_sdl3_opengl3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_opengl3/example_sdl3_opengl3.vcxproj /p:Platform=x64 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
+
+      - name: Build Win64 example_sdl3_sdlgpu3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_sdlgpu3/example_sdl3_sdlgpu3.vcxproj /p:Platform=x64 /p:Configuration=Release'
+
+      - name: Build Win64 example_sdl3_sdlrenderer3
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_sdlrenderer3/example_sdl3_sdlrenderer3.vcxproj /p:Platform=x64 /p:Configuration=Release'
+
+      - name: Build Win64 example_sdl3_vulkan
+        shell: cmd
+        run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_sdl3_vulkan/example_sdl3_vulkan.vcxproj /p:Platform=x64 /p:Configuration=Release'
+        if: github.event_name == 'workflow_run'
+
+      - name: Build Win64 example_win32_directx9
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx9/example_win32_directx9.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_win32_directx10
+      - name: Build Win64 example_win32_directx10
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx10/example_win32_directx10.vcxproj /p:Platform=x64 /p:Configuration=Release'
         if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_win32_directx11
+      - name: Build Win64 example_win32_directx11
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx11/example_win32_directx11.vcxproj /p:Platform=x64 /p:Configuration=Release'
-        if: github.event_name == 'workflow_run'
 
-      - name: Build x64 example_win32_directx12
+      - name: Build Win64 example_win32_directx12
         shell: cmd
         run: '"%MSBUILD_PATH%\MSBuild.exe" examples/example_win32_directx12/example_win32_directx12.vcxproj /p:Platform=x64 /p:Configuration=Release'
 
   Linux:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
 
@@ -441,7 +490,7 @@ jobs:
 
     - name: Install Dependencies
       run: |
-        brew install glfw3 sdl2
+        brew install glfw3 sdl2 sdl3
 
     - name: Build example_null (extra warnings, clang 64-bit)
       run: make -C examples/example_null WITH_EXTRA_WARNINGS=1
@@ -499,6 +548,9 @@ jobs:
     - name: Build example_sdl2_opengl3
       run: make -C examples/example_sdl2_opengl3
 
+    - name: Build example_sdl3_opengl3
+      run: make -C examples/example_sdl3_opengl3
+
     - name: Build example_apple_metal
       run: xcodebuild -project examples/example_apple_metal/example_apple_metal.xcodeproj -target example_apple_metal_macos
 
@@ -506,7 +558,7 @@ jobs:
       run: xcodebuild -project examples/example_apple_opengl2/example_apple_opengl2.xcodeproj -target example_osx_opengl2
 
   iOS:
-    runs-on: macos-latest
+    runs-on: macos-14
     steps:
     - uses: actions/checkout@v4
 
@@ -516,7 +568,7 @@ jobs:
         xcodebuild -project examples/example_apple_metal/example_apple_metal.xcodeproj -target example_apple_metal_ios CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO
 
   Emscripten:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
 
@@ -557,7 +609,7 @@ jobs:
         cmake --build build
 
   Android:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
 

.github/workflows/static-analysis.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   PVS-Studio:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with:
@@ -42,5 +42,5 @@ jobs:
           fi
           cd examples/example_null
           pvs-studio-analyzer trace -- make WITH_EXTRA_WARNINGS=1
-          pvs-studio-analyzer analyze -e ../../imstb_rectpack.h -e ../../imstb_textedit.h -e ../../imstb_truetype.h -l ../../pvs-studio.lic -o pvs-studio.log
+          pvs-studio-analyzer analyze --disableLicenseExpirationCheck -e ../../imstb_rectpack.h -e ../../imstb_textedit.h -e ../../imstb_truetype.h -l ../../pvs-studio.lic -o pvs-studio.log
           plog-converter -a 'GA:1,2;OP:1' -d V1071 -t errorfile -w pvs-studio.log

.gitignore

@@ -29,12 +29,14 @@ ipch
 ## Getting files created in JSON/Schemas/Catalog/ from a VS2022 update
 JSON/
 
-## Commonly used CMake directories
+## Commonly used CMake directories & CMake CPM cache
 build*/
+.cache
 
-## Xcode artifacts
+## Xcode & macOS artifacts
 project.xcworkspace
 xcuserdata
+examples/*/*.dSYM
 
 ## Emscripten artifacts
 examples/*.o.tmp
@@ -53,12 +55,21 @@ cmake-build-*
 .vscode
 
 ## Unix executables from our example Makefiles
+examples/example_apple_metal/example_apple_metal
+examples/example_apple_opengl2/example_apple_opengl2
 examples/example_glfw_metal/example_glfw_metal
 examples/example_glfw_opengl2/example_glfw_opengl2
 examples/example_glfw_opengl3/example_glfw_opengl3
+examples/example_glfw_vulkan/example_glfw_vulkan
 examples/example_glut_opengl2/example_glut_opengl2
 examples/example_null/example_null
 examples/example_sdl2_metal/example_sdl2_metal
 examples/example_sdl2_opengl2/example_sdl2_opengl2
 examples/example_sdl2_opengl3/example_sdl2_opengl3
-examples/example_sdl2_sdlrenderer/example_sdl2_sdlrenderer
+examples/example_sdl2_sdlrenderer2/example_sdl2_sdlrenderer2
+examples/example_sdl2_vulkan/example_sdl2_vulkan
+examples/example_sdl3_metal/example_sdl3_metal
+examples/example_sdl3_opengl3/example_sdl3_opengl3
+examples/example_sdl3_sdlgpu3/example_sdl3_sdlgpu3
+examples/example_sdl3_sdlrenderer3/example_sdl3_sdlrenderer3
+examples/example_sdl3_vulkan/example_sdl3_vulkan

backends/imgui_impl_allegro5.cpp

@@ -2,13 +2,15 @@
 // (Info: Allegro 5 is a cross-platform general purpose library for handling windows, inputs, graphics, etc.)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ALLEGRO_BITMAP*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ALLEGRO_BITMAP*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy ALLEGRO_KEY_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Clipboard support (from Allegro 5.1.12).
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 // Missing features or Issues:
-//  [ ] Renderer: The renderer is suboptimal as we need to convert vertices manually.
+//  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -20,6 +22,10 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-08-12: Inputs: fixed missing support for ImGuiKey_PrintScreen under Windows, as raw Allegro 5 does not receive it.
+//  2025-08-12: Added ImGui_ImplAllegro5_SetDisplay() function to change current ALLEGRO_DISPLAY, as Allegro applications often need to do that.
+//  2025-07-07: Fixed texture update broken on some platforms where ALLEGRO_LOCK_WRITEONLY needed all texels to be rewritten.
+//  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLGPU3_CreateFontsTexture() and ImGui_ImplSDLGPU3_DestroyFontsTexture().
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-01-06: Avoid calling al_set_mouse_cursor() repeatedly since it appears to leak on on X11 (#8256).
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
@@ -137,6 +143,13 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
     if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplAllegro5_UpdateTexture(tex);
+
     // Backup Allegro state that will be modified
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
     ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
@@ -150,10 +163,8 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplAllegro5_SetupRenderState(draw_data);
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
-
         ImVector<ImDrawVertAllegro>& vertices = bd->BufVertices;
 #if ALLEGRO_HAS_DRAW_INDEXED_PRIM
         vertices.resize(draw_list->VtxBuffer.Size);
@@ -232,43 +243,7 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
 
 bool ImGui_ImplAllegro5_CreateDeviceObjects()
 {
-    // Build texture atlas
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
-    ImGuiIO& io = ImGui::GetIO();
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
-
-    // Create texture
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    int flags = al_get_new_bitmap_flags();
-    int fmt = al_get_new_bitmap_format();
-    al_set_new_bitmap_flags(ALLEGRO_MEMORY_BITMAP | ALLEGRO_MIN_LINEAR | ALLEGRO_MAG_LINEAR);
-    al_set_new_bitmap_format(ALLEGRO_PIXEL_FORMAT_ABGR_8888_LE);
-    ALLEGRO_BITMAP* img = al_create_bitmap(width, height);
-    al_set_new_bitmap_flags(flags);
-    al_set_new_bitmap_format(fmt);
-    if (!img)
-        return false;
-
-    ALLEGRO_LOCKED_REGION* locked_img = al_lock_bitmap(img, al_get_bitmap_format(img), ALLEGRO_LOCK_WRITEONLY);
-    if (!locked_img)
-    {
-        al_destroy_bitmap(img);
-        return false;
-    }
-    memcpy(locked_img->data, pixels, sizeof(int) * width * height);
-    al_unlock_bitmap(img);
-
-    // Convert software texture to hardware texture.
-    ALLEGRO_BITMAP* cloned_img = al_clone_bitmap(img);
-    al_destroy_bitmap(img);
-    if (!cloned_img)
-        return false;
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)cloned_img);
-    bd->Texture = cloned_img;
 
     // Create an invisible mouse cursor
     // Because al_hide_mouse_cursor() seems to mess up with the actual inputs..
@@ -279,16 +254,82 @@ bool ImGui_ImplAllegro5_CreateDeviceObjects()
     return true;
 }
 
+void ImGui_ImplAllegro5_UpdateTexture(ImTextureData* tex)
+{
+    if (tex->Status == ImTextureStatus_WantCreate)
+    {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // Create texture
+        // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+        const int new_bitmap_flags = al_get_new_bitmap_flags();
+        int new_bitmap_format = al_get_new_bitmap_format();
+        al_set_new_bitmap_flags(ALLEGRO_MEMORY_BITMAP | ALLEGRO_MIN_LINEAR | ALLEGRO_MAG_LINEAR);
+        al_set_new_bitmap_format(ALLEGRO_PIXEL_FORMAT_ABGR_8888_LE);
+        ALLEGRO_BITMAP* cpu_bitmap = al_create_bitmap(tex->Width, tex->Height);
+        IM_ASSERT(cpu_bitmap != nullptr && "Backend failed to create texture!");
+
+        // Upload pixels
+        ALLEGRO_LOCKED_REGION* locked_region = al_lock_bitmap(cpu_bitmap, al_get_bitmap_format(cpu_bitmap), ALLEGRO_LOCK_WRITEONLY);
+        IM_ASSERT(locked_region != nullptr && "Backend failed to create texture!");
+        memcpy(locked_region->data, tex->GetPixels(), tex->GetSizeInBytes());
+        al_unlock_bitmap(cpu_bitmap);
+
+        // Convert software texture to hardware texture.
+        al_set_new_bitmap_flags(ALLEGRO_VIDEO_BITMAP);
+        al_set_new_bitmap_format(ALLEGRO_PIXEL_FORMAT_ANY_32_WITH_ALPHA);
+        ALLEGRO_BITMAP* gpu_bitmap = al_clone_bitmap(cpu_bitmap);
+        al_destroy_bitmap(cpu_bitmap);
+        IM_ASSERT(gpu_bitmap != nullptr && "Backend failed to create texture!");
+
+        al_set_new_bitmap_flags(new_bitmap_flags);
+        al_set_new_bitmap_format(new_bitmap_format);
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)gpu_bitmap);
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        ImTextureRect r = tex->UpdateRect; // Bounding box encompassing all individual updates
+        ALLEGRO_BITMAP* gpu_bitmap = (ALLEGRO_BITMAP*)(intptr_t)tex->TexID;
+        ALLEGRO_LOCKED_REGION* locked_region = al_lock_bitmap_region(gpu_bitmap, r.x, r.y, r.w, r.h, al_get_bitmap_format(gpu_bitmap), ALLEGRO_LOCK_WRITEONLY);
+        IM_ASSERT(locked_region && "Backend failed to update texture!");
+        for (int y = 0; y < r.h; y++)
+            memcpy((unsigned char*)locked_region->data + locked_region->pitch * y, tex->GetPixelsAt(r.x, r.y + y), r.w * tex->BytesPerPixel); // dst, src, block pitch
+        al_unlock_bitmap(gpu_bitmap);
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        ALLEGRO_BITMAP* backend_tex = (ALLEGRO_BITMAP*)(intptr_t)tex->TexID;
+        if (backend_tex)
+            al_destroy_bitmap(backend_tex);
+
+        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
+    }
+}
+
 void ImGui_ImplAllegro5_InvalidateDeviceObjects()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
-    if (bd->Texture)
-    {
-        io.Fonts->SetTexID(0);
-        al_destroy_bitmap(bd->Texture);
-        bd->Texture = nullptr;
-    }
+
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+        {
+            tex->SetStatus(ImTextureStatus_WantDestroy);
+            ImGui_ImplAllegro5_UpdateTexture(tex);
+        }
+
+    // Destroy mouse cursor
     if (bd->MouseCursorInvisible)
     {
         al_destroy_mouse_cursor(bd->MouseCursorInvisible);
@@ -439,21 +480,11 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
     io.BackendPlatformUserData = (void*)bd;
     io.BackendPlatformName = io.BackendRendererName = "imgui_impl_allegro5";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;       // We can honor GetMouseCursor() values (optional)
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
 
-    bd->Display = display;
     bd->LastCursor = ALLEGRO_SYSTEM_MOUSE_CURSOR_NONE;
 
-    // Create custom vertex declaration.
-    // Unfortunately Allegro doesn't support 32-bit packed colors so we have to convert them to 4 floats.
-    // We still use a custom declaration to use 'ALLEGRO_PRIM_TEX_COORD' instead of 'ALLEGRO_PRIM_TEX_COORD_PIXEL' else we can't do a reliable conversion.
-    ALLEGRO_VERTEX_ELEMENT elems[] =
-    {
-        { ALLEGRO_PRIM_POSITION, ALLEGRO_PRIM_FLOAT_2, offsetof(ImDrawVertAllegro, pos) },
-        { ALLEGRO_PRIM_TEX_COORD, ALLEGRO_PRIM_FLOAT_2, offsetof(ImDrawVertAllegro, uv) },
-        { ALLEGRO_PRIM_COLOR_ATTR, 0, offsetof(ImDrawVertAllegro, col) },
-        { 0, 0, 0 }
-    };
-    bd->VertexDecl = al_create_vertex_decl(elems, sizeof(ImDrawVertAllegro));
+    ImGui_ImplAllegro5_SetDisplay(display);
 
 #if ALLEGRO_HAS_CLIPBOARD
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
@@ -478,10 +509,37 @@ void ImGui_ImplAllegro5_Shutdown()
 
     io.BackendPlatformName = io.BackendRendererName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_HasMouseCursors;
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_RendererHasTextures);
     IM_DELETE(bd);
 }
 
+void ImGui_ImplAllegro5_SetDisplay(ALLEGRO_DISPLAY* display)
+{
+    ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
+    bd->Display = display;
+
+    if (bd->VertexDecl)
+    {
+        al_destroy_vertex_decl(bd->VertexDecl);
+        bd->VertexDecl = NULL;
+    }
+
+    if (bd->Display && !bd->VertexDecl)
+    {
+        // Create custom vertex declaration.
+        // Unfortunately Allegro doesn't support 32-bits packed colors so we have to convert them to 4 floats.
+        // We still use a custom declaration to use 'ALLEGRO_PRIM_TEX_COORD' instead of 'ALLEGRO_PRIM_TEX_COORD_PIXEL' else we can't do a reliable conversion.
+        ALLEGRO_VERTEX_ELEMENT elems[] =
+        {
+            { ALLEGRO_PRIM_POSITION, ALLEGRO_PRIM_FLOAT_2, offsetof(ImDrawVertAllegro, pos) },
+            { ALLEGRO_PRIM_TEX_COORD, ALLEGRO_PRIM_FLOAT_2, offsetof(ImDrawVertAllegro, uv) },
+            { ALLEGRO_PRIM_COLOR_ATTR, 0, offsetof(ImDrawVertAllegro, col) },
+            { 0, 0, 0 }
+        };
+        bd->VertexDecl = al_create_vertex_decl(elems, sizeof(ImDrawVertAllegro));
+    }
+}
+
 // ev->keyboard.modifiers seems always zero so using that...
 static void ImGui_ImplAllegro5_UpdateKeyModifiers()
 {
@@ -608,12 +666,11 @@ void ImGui_ImplAllegro5_NewFrame()
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplAllegro5_Init()?");
 
-    if (!bd->Texture)
+    if (!bd->MouseCursorInvisible)
         ImGui_ImplAllegro5_CreateDeviceObjects();
 
-    ImGuiIO& io = ImGui::GetIO();
-
     // Setup display size (every frame to accommodate for window resizing)
+    ImGuiIO& io = ImGui::GetIO();
     int w, h;
     w = al_get_display_width(bd->Display);
     h = al_get_display_height(bd->Display);
@@ -624,6 +681,11 @@ void ImGui_ImplAllegro5_NewFrame()
     io.DeltaTime = bd->Time > 0.0 ? (float)(current_time - bd->Time) : (float)(1.0f / 60.0f);
     bd->Time = current_time;
 
+    // Allegro 5 doesn't receive PrintScreen under Windows
+#ifdef _WIN32
+    io.AddKeyEvent(ImGuiKey_PrintScreen, (::GetAsyncKeyState(VK_SNAPSHOT) & 0x8000) != 0);
+#endif
+
     // Setup mouse cursor shape
     ImGui_ImplAllegro5_UpdateMouseCursor();
 }

backends/imgui_impl_allegro5.h

@@ -2,13 +2,15 @@
 // (Info: Allegro 5 is a cross-platform general purpose library for handling windows, inputs, graphics, etc.)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ALLEGRO_BITMAP*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ALLEGRO_BITMAP*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy ALLEGRO_KEY_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Clipboard support (from Allegro 5.1.12).
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 // Missing features or Issues:
 //  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -31,9 +33,13 @@ IMGUI_IMPL_API void     ImGui_ImplAllegro5_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplAllegro5_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data);
 IMGUI_IMPL_API bool     ImGui_ImplAllegro5_ProcessEvent(ALLEGRO_EVENT* event);
+IMGUI_IMPL_API void     ImGui_ImplAllegro5_SetDisplay(ALLEGRO_DISPLAY* display);
 
 // Use if you want to reset your rendering device without losing Dear ImGui state.
 IMGUI_IMPL_API bool     ImGui_ImplAllegro5_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplAllegro5_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplAllegro5_UpdateTexture(ImTextureData* tex);
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_android.cpp

@@ -6,8 +6,9 @@
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen/Pen.
 // Missing features or Issues:
 //  [ ] Platform: Clipboard support.
-//  [ ] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [ ] Platform: Gamepad support.
 //  [ ] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'. FIXME: Check if this is even possible with Android.
+//  [ ] Platform: Multi-viewport support (multiple windows). Not meaningful on Android.
 // Important:
 //  - Consider using SDL or GLFW backend on Android, which will be more full-featured than this.
 //  - FIXME: On-screen keyboard currently needs to be enabled by the application (see examples/ and issue #3446)

backends/imgui_impl_android.h

@@ -6,8 +6,9 @@
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen/Pen.
 // Missing features or Issues:
 //  [ ] Platform: Clipboard support.
-//  [ ] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [ ] Platform: Gamepad support.
 //  [ ] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'. FIXME: Check if this is even possible with Android.
+//  [ ] Platform: Multi-viewport support (multiple windows). Not meaningful on Android.
 // Important:
 //  - Consider using SDL or GLFW backend on Android, which will be more full-featured than this.
 //  - FIXME: On-screen keyboard currently needs to be enabled by the application (see examples/ and issue #3446)

backends/imgui_impl_dx10.cpp

@@ -2,8 +2,10 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -15,6 +17,9 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-11: DirectX10: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
+//  2025-05-07: DirectX10: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
 //  2025-01-06: DirectX10: Expose selected render state in ImGui_ImplDX10_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
 //  2024-10-07: DirectX10: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -47,7 +52,19 @@
 #pragma comment(lib, "d3dcompiler") // Automatically link with d3dcompiler.lib as we are using D3DCompile() below.
 #endif
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wold-style-cast"         // warning: use of old-style cast                            // yes, they are more terse.
+#pragma clang diagnostic ignored "-Wsign-conversion"        // warning: implicit conversion changes signedness
+#endif
+
 // DirectX10 data
+struct ImGui_ImplDX10_Texture
+{
+    ID3D10Texture2D*            pTexture;
+    ID3D10ShaderResourceView*   pTextureView;
+};
+
 struct ImGui_ImplDX10_Data
 {
     ID3D10Device*               pd3dDevice;
@@ -58,8 +75,7 @@ struct ImGui_ImplDX10_Data
     ID3D10InputLayout*          pInputLayout;
     ID3D10Buffer*               pVertexConstantBuffer;
     ID3D10PixelShader*          pPixelShader;
-    ID3D10SamplerState*         pFontSampler;
-    ID3D10ShaderResourceView*   pFontTextureView;
+    ID3D10SamplerState*         pTexSamplerLinear;
     ID3D10RasterizerState*      pRasterizerState;
     ID3D10BlendState*           pBlendState;
     ID3D10DepthStencilState*    pDepthStencilState;
@@ -81,6 +97,10 @@ static ImGui_ImplDX10_Data* ImGui_ImplDX10_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX10_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX10_InitMultiViewportSupport();
+static void ImGui_ImplDX10_ShutdownMultiViewportSupport();
+
 // Functions
 static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device* device)
 {
@@ -88,8 +108,8 @@ static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device*
 
     // Setup viewport
     D3D10_VIEWPORT vp = {};
-    vp.Width = (UINT)draw_data->DisplaySize.x;
-    vp.Height = (UINT)draw_data->DisplaySize.y;
+    vp.Width = (UINT)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    vp.Height = (UINT)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -126,7 +146,7 @@ static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device*
     device->VSSetShader(bd->pVertexShader);
     device->VSSetConstantBuffers(0, 1, &bd->pVertexConstantBuffer);
     device->PSSetShader(bd->pPixelShader);
-    device->PSSetSamplers(0, 1, &bd->pFontSampler);
+    device->PSSetSamplers(0, 1, &bd->pTexSamplerLinear);
     device->GSSetShader(nullptr);
 
     // Setup render state
@@ -146,6 +166,13 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
     ID3D10Device* device = bd->pd3dDevice;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplDX10_UpdateTexture(tex);
+
     // Create and grow vertex/index buffers if needed
     if (!bd->pVB || bd->VertexBufferSize < draw_data->TotalVtxCount)
     {
@@ -179,9 +206,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImDrawIdx* idx_dst = nullptr;
     bd->pVB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&vtx_dst);
     bd->pIB->Map(D3D10_MAP_WRITE_DISCARD, 0, (void**)&idx_dst);
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -237,7 +263,7 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     ImGui_ImplDX10_RenderState render_state;
     render_state.Device = bd->pd3dDevice;
-    render_state.SamplerDefault = bd->pFontSampler;
+    render_state.SamplerDefault = bd->pTexSamplerLinear;
     render_state.VertexConstantBuffer = bd->pVertexConstantBuffer;
     platform_io.Renderer_RenderState = &render_state;
 
@@ -246,9 +272,9 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    ImVec2 clip_scale = draw_data->FramebufferScale;
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
@@ -264,8 +290,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 
@@ -302,21 +328,39 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     device->IASetInputLayout(old.InputLayout); if (old.InputLayout) old.InputLayout->Release();
 }
 
-static void ImGui_ImplDX10_CreateFontsTexture()
+static void ImGui_ImplDX10_DestroyTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
-    ImGuiIO& io = ImGui::GetIO();
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
+    ImGui_ImplDX10_Texture* backend_tex = (ImGui_ImplDX10_Texture*)tex->BackendUserData;
+    if (backend_tex == nullptr)
+        return;
+    IM_ASSERT(backend_tex->pTextureView == (ID3D10ShaderResourceView*)(intptr_t)tex->TexID);
+    backend_tex->pTexture->Release();
+    backend_tex->pTextureView->Release();
+    IM_DELETE(backend_tex);
 
-    // Upload texture to graphics system
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+    tex->BackendUserData = nullptr;
+}
+
+void ImGui_ImplDX10_UpdateTexture(ImTextureData* tex)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        unsigned int* pixels = (unsigned int*)tex->GetPixels();
+        ImGui_ImplDX10_Texture* backend_tex = IM_NEW(ImGui_ImplDX10_Texture)();
+
+        // Create texture
         D3D10_TEXTURE2D_DESC desc;
         ZeroMemory(&desc, sizeof(desc));
-        desc.Width = width;
-        desc.Height = height;
+        desc.Width = (UINT)tex->Width;
+        desc.Height = (UINT)tex->Height;
         desc.MipLevels = 1;
         desc.ArraySize = 1;
         desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
@@ -325,13 +369,12 @@ static void ImGui_ImplDX10_CreateFontsTexture()
         desc.BindFlags = D3D10_BIND_SHADER_RESOURCE;
         desc.CPUAccessFlags = 0;
 
-        ID3D10Texture2D* pTexture = nullptr;
         D3D10_SUBRESOURCE_DATA subResource;
         subResource.pSysMem = pixels;
         subResource.SysMemPitch = desc.Width * 4;
         subResource.SysMemSlicePitch = 0;
-        bd->pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
-        IM_ASSERT(pTexture != nullptr);
+        bd->pd3dDevice->CreateTexture2D(&desc, &subResource, &backend_tex->pTexture);
+        IM_ASSERT(backend_tex->pTexture != nullptr && "Backend failed to create texture!");
 
         // Create texture view
         D3D10_SHADER_RESOURCE_VIEW_DESC srv_desc;
@@ -340,23 +383,29 @@ static void ImGui_ImplDX10_CreateFontsTexture()
         srv_desc.ViewDimension = D3D10_SRV_DIMENSION_TEXTURE2D;
         srv_desc.Texture2D.MipLevels = desc.MipLevels;
         srv_desc.Texture2D.MostDetailedMip = 0;
-        bd->pd3dDevice->CreateShaderResourceView(pTexture, &srv_desc, &bd->pFontTextureView);
-        pTexture->Release();
+        bd->pd3dDevice->CreateShaderResourceView(backend_tex->pTexture, &srv_desc, &backend_tex->pTextureView);
+        IM_ASSERT(backend_tex->pTextureView != nullptr && "Backend failed to create texture!");
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)backend_tex->pTextureView);
+        tex->SetStatus(ImTextureStatus_OK);
+        tex->BackendUserData = backend_tex;
     }
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)bd->pFontTextureView);
-}
-
-static void ImGui_ImplDX10_DestroyFontsTexture()
-{
-    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
-    if (bd->pFontTextureView)
+    else if (tex->Status == ImTextureStatus_WantUpdates)
     {
-        bd->pFontTextureView->Release();
-        bd->pFontTextureView = nullptr;
-        ImGui::GetIO().Fonts->SetTexID(0); // We copied bd->pFontTextureView to io.Fonts->TexID so let's clear that as well.
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        ImGui_ImplDX10_Texture* backend_tex = (ImGui_ImplDX10_Texture*)tex->BackendUserData;
+        IM_ASSERT(backend_tex->pTextureView == (ID3D10ShaderResourceView*)(intptr_t)tex->TexID);
+        for (ImTextureRect& r : tex->Updates)
+        {
+            D3D10_BOX box = { (UINT)r.x, (UINT)r.y, (UINT)0, (UINT)(r.x + r.w), (UINT)(r.y + r.h), (UINT)1 };
+            bd->pd3dDevice->UpdateSubresource(backend_tex->pTexture, 0, &box, tex->GetPixelsAt(r.x, r.y), (UINT)tex->GetPitch(), 0);
+        }
+        tex->SetStatus(ImTextureStatus_OK);
     }
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+        ImGui_ImplDX10_DestroyTexture(tex);
 }
 
 bool    ImGui_ImplDX10_CreateDeviceObjects()
@@ -364,8 +413,7 @@ bool    ImGui_ImplDX10_CreateDeviceObjects()
     ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
     if (!bd->pd3dDevice)
         return false;
-    if (bd->pFontSampler)
-        ImGui_ImplDX10_InvalidateDeviceObjects();
+    ImGui_ImplDX10_InvalidateDeviceObjects();
 
     // By using D3DCompile() from <d3dcompiler.h> / d3dcompiler.lib, we introduce a dependency to a given version of d3dcompiler_XX.dll (see D3DCOMPILER_DLL_A)
     // If you would like to use this DX10 sample code but remove this dependency you can:
@@ -521,11 +569,9 @@ bool    ImGui_ImplDX10_CreateDeviceObjects()
         desc.ComparisonFunc = D3D10_COMPARISON_ALWAYS;
         desc.MinLOD = 0.f;
         desc.MaxLOD = 0.f;
-        bd->pd3dDevice->CreateSamplerState(&desc, &bd->pFontSampler);
+        bd->pd3dDevice->CreateSamplerState(&desc, &bd->pTexSamplerLinear);
     }
 
-    ImGui_ImplDX10_CreateFontsTexture();
-
     return true;
 }
 
@@ -535,9 +581,11 @@ void    ImGui_ImplDX10_InvalidateDeviceObjects()
     if (!bd->pd3dDevice)
         return;
 
-    ImGui_ImplDX10_DestroyFontsTexture();
-
-    if (bd->pFontSampler)           { bd->pFontSampler->Release(); bd->pFontSampler = nullptr; }
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplDX10_DestroyTexture(tex);
+    if (bd->pTexSamplerLinear)      { bd->pTexSamplerLinear->Release(); bd->pTexSamplerLinear = nullptr; }
     if (bd->pIB)                    { bd->pIB->Release(); bd->pIB = nullptr; }
     if (bd->pVB)                    { bd->pVB->Release(); bd->pVB = nullptr; }
     if (bd->pBlendState)            { bd->pBlendState->Release(); bd->pBlendState = nullptr; }
@@ -560,6 +608,11 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_dx10";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = D3D10_REQ_TEXTURE2D_U_OR_V_DIMENSION;
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -576,6 +629,8 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
     if (pDXGIAdapter) pDXGIAdapter->Release();
     bd->pd3dDevice->AddRef();
 
+    ImGui_ImplDX10_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -585,12 +640,13 @@ void ImGui_ImplDX10_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX10_ShutdownMultiViewportSupport();
     ImGui_ImplDX10_InvalidateDeviceObjects();
     if (bd->pFactory) { bd->pFactory->Release(); }
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -600,7 +656,131 @@ void ImGui_ImplDX10_NewFrame()
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX10_Init()?");
 
     if (!bd->pVertexShader)
-        ImGui_ImplDX10_CreateDeviceObjects();
+        if (!ImGui_ImplDX10_CreateDeviceObjects())
+            IM_ASSERT(0 && "ImGui_ImplDX10_CreateDeviceObjects() failed!");
+}
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX10_ViewportData
+{
+    IDXGISwapChain*         SwapChain;
+    ID3D10RenderTargetView* RTView;
+
+    ImGui_ImplDX10_ViewportData()   { SwapChain = nullptr; RTView = nullptr; }
+    ~ImGui_ImplDX10_ViewportData()  { IM_ASSERT(SwapChain == nullptr && RTView == nullptr); }
+};
+
+static void ImGui_ImplDX10_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = IM_NEW(ImGui_ImplDX10_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    // Create swap chain
+    DXGI_SWAP_CHAIN_DESC sd;
+    ZeroMemory(&sd, sizeof(sd));
+    sd.BufferDesc.Width = (UINT)viewport->Size.x;
+    sd.BufferDesc.Height = (UINT)viewport->Size.y;
+    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+    sd.SampleDesc.Count = 1;
+    sd.SampleDesc.Quality = 0;
+    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd.BufferCount = 1;
+    sd.OutputWindow = hwnd;
+    sd.Windowed = TRUE;
+    sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
+    sd.Flags = 0;
+
+    IM_ASSERT(vd->SwapChain == nullptr && vd->RTView == nullptr);
+    bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+
+    // Create the render target
+    if (vd->SwapChain)
+    {
+        ID3D10Texture2D* pBackBuffer;
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX10_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 here since we didn't create the data for it.
+    if (ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        if (vd->RTView)
+            vd->RTView->Release();
+        vd->RTView = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX10_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    if (vd->RTView)
+    {
+        vd->RTView->Release();
+        vd->RTView = nullptr;
+    }
+    if (vd->SwapChain)
+    {
+        ID3D10Texture2D* pBackBuffer = nullptr;
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, DXGI_FORMAT_UNKNOWN, 0);
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        if (pBackBuffer == nullptr) { fprintf(stderr, "ImGui_ImplDX10_SetWindowSize() failed creating buffers.\n"); return; }
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX10_RenderViewport(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    bd->pd3dDevice->OMSetRenderTargets(1, &vd->RTView, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        bd->pd3dDevice->ClearRenderTargetView(vd->RTView, (float*)&clear_color);
+    ImGui_ImplDX10_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplDX10_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX10_ViewportData* vd = (ImGui_ImplDX10_ViewportData*)viewport->RendererUserData;
+    vd->SwapChain->Present(0, 0); // Present without vsync
+}
+
+void ImGui_ImplDX10_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX10_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX10_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX10_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX10_RenderViewport;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX10_SwapBuffers;
+}
+
+void ImGui_ImplDX10_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_dx10.h

@@ -2,8 +2,10 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -31,6 +33,9 @@ IMGUI_IMPL_API void     ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data);
 IMGUI_IMPL_API bool     ImGui_ImplDX10_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplDX10_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplDX10_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplDX10_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_dx11.cpp

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -16,6 +18,10 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-11: DirectX11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
+//  2025-05-07: DirectX11: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
+//  2025-02-24: [Docking] Added undocumented ImGui_ImplDX11_SetSwapChainDescs() to configure swap chain creation for secondary viewports.
 //  2025-01-06: DirectX11: Expose VertexConstantBuffer in ImGui_ImplDX11_RenderState. Reset projection matrix in ImDrawCallback_ResetRenderState handler.
 //  2024-10-07: DirectX11: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-10-07: DirectX11: Expose selected render state in ImGui_ImplDX11_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
@@ -49,7 +55,19 @@
 #pragma comment(lib, "d3dcompiler") // Automatically link with d3dcompiler.lib as we are using D3DCompile() below.
 #endif
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wold-style-cast"         // warning: use of old-style cast                            // yes, they are more terse.
+#pragma clang diagnostic ignored "-Wsign-conversion"        // warning: implicit conversion changes signedness
+#endif
+
 // DirectX11 data
+struct ImGui_ImplDX11_Texture
+{
+    ID3D11Texture2D*            pTexture;
+    ID3D11ShaderResourceView*   pTextureView;
+};
+
 struct ImGui_ImplDX11_Data
 {
     ID3D11Device*               pd3dDevice;
@@ -61,13 +79,13 @@ struct ImGui_ImplDX11_Data
     ID3D11InputLayout*          pInputLayout;
     ID3D11Buffer*               pVertexConstantBuffer;
     ID3D11PixelShader*          pPixelShader;
-    ID3D11SamplerState*         pFontSampler;
-    ID3D11ShaderResourceView*   pFontTextureView;
+    ID3D11SamplerState*         pTexSamplerLinear;
     ID3D11RasterizerState*      pRasterizerState;
     ID3D11BlendState*           pBlendState;
     ID3D11DepthStencilState*    pDepthStencilState;
     int                         VertexBufferSize;
     int                         IndexBufferSize;
+    ImVector<DXGI_SWAP_CHAIN_DESC> SwapChainDescsForViewports;
 
     ImGui_ImplDX11_Data()       { memset((void*)this, 0, sizeof(*this)); VertexBufferSize = 5000; IndexBufferSize = 10000; }
 };
@@ -84,15 +102,19 @@ static ImGui_ImplDX11_Data* ImGui_ImplDX11_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX11_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX11_InitMultiViewportSupport();
+static void ImGui_ImplDX11_ShutdownMultiViewportSupport();
+
 // Functions
-static void ImGui_ImplDX11_SetupRenderState(ImDrawData* draw_data, ID3D11DeviceContext* device_ctx)
+static void ImGui_ImplDX11_SetupRenderState(const ImDrawData* draw_data, ID3D11DeviceContext* device_ctx)
 {
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
 
     // Setup viewport
     D3D11_VIEWPORT vp = {};
-    vp.Width = draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
+    vp.Width = draw_data->DisplaySize.x * draw_data->FramebufferScale.x;
+    vp.Height = draw_data->DisplaySize.y * draw_data->FramebufferScale.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -129,7 +151,7 @@ static void ImGui_ImplDX11_SetupRenderState(ImDrawData* draw_data, ID3D11DeviceC
     device_ctx->VSSetShader(bd->pVertexShader, nullptr, 0);
     device_ctx->VSSetConstantBuffers(0, 1, &bd->pVertexConstantBuffer);
     device_ctx->PSSetShader(bd->pPixelShader, nullptr, 0);
-    device_ctx->PSSetSamplers(0, 1, &bd->pFontSampler);
+    device_ctx->PSSetSamplers(0, 1, &bd->pTexSamplerLinear);
     device_ctx->GSSetShader(nullptr, nullptr, 0);
     device_ctx->HSSetShader(nullptr, nullptr, 0); // In theory we should backup and restore this as well.. very infrequently used..
     device_ctx->DSSetShader(nullptr, nullptr, 0); // In theory we should backup and restore this as well.. very infrequently used..
@@ -152,6 +174,13 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
     ID3D11DeviceContext* device = bd->pd3dDeviceContext;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplDX11_UpdateTexture(tex);
+
     // Create and grow vertex/index buffers if needed
     if (!bd->pVB || bd->VertexBufferSize < draw_data->TotalVtxCount)
     {
@@ -187,9 +216,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         return;
     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource.pData;
     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource.pData;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -251,7 +279,7 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX11_RenderState render_state;
     render_state.Device = bd->pd3dDevice;
     render_state.DeviceContext = bd->pd3dDeviceContext;
-    render_state.SamplerDefault = bd->pFontSampler;
+    render_state.SamplerDefault = bd->pTexSamplerLinear;
     render_state.VertexConstantBuffer = bd->pVertexConstantBuffer;
     platform_io.Renderer_RenderState = &render_state;
 
@@ -260,9 +288,9 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     int global_idx_offset = 0;
     int global_vtx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    ImVec2 clip_scale = draw_data->FramebufferScale;
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
@@ -278,8 +306,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 
@@ -318,21 +346,39 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     device->IASetInputLayout(old.InputLayout); if (old.InputLayout) old.InputLayout->Release();
 }
 
-static void ImGui_ImplDX11_CreateFontsTexture()
+static void ImGui_ImplDX11_DestroyTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
+    ImGui_ImplDX11_Texture* backend_tex = (ImGui_ImplDX11_Texture*)tex->BackendUserData;
+    if (backend_tex == nullptr)
+        return;
+    IM_ASSERT(backend_tex->pTextureView == (ID3D11ShaderResourceView*)(intptr_t)tex->TexID);
+    backend_tex->pTextureView->Release();
+    backend_tex->pTexture->Release();
+    IM_DELETE(backend_tex);
 
-    // Upload texture to graphics system
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+    tex->BackendUserData = nullptr;
+}
+
+void ImGui_ImplDX11_UpdateTexture(ImTextureData* tex)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        unsigned int* pixels = (unsigned int*)tex->GetPixels();
+        ImGui_ImplDX11_Texture* backend_tex = IM_NEW(ImGui_ImplDX11_Texture)();
+
+        // Create texture
         D3D11_TEXTURE2D_DESC desc;
         ZeroMemory(&desc, sizeof(desc));
-        desc.Width = width;
-        desc.Height = height;
+        desc.Width = (UINT)tex->Width;
+        desc.Height = (UINT)tex->Height;
         desc.MipLevels = 1;
         desc.ArraySize = 1;
         desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
@@ -340,14 +386,12 @@ static void ImGui_ImplDX11_CreateFontsTexture()
         desc.Usage = D3D11_USAGE_DEFAULT;
         desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
         desc.CPUAccessFlags = 0;
-
-        ID3D11Texture2D* pTexture = nullptr;
         D3D11_SUBRESOURCE_DATA subResource;
         subResource.pSysMem = pixels;
         subResource.SysMemPitch = desc.Width * 4;
         subResource.SysMemSlicePitch = 0;
-        bd->pd3dDevice->CreateTexture2D(&desc, &subResource, &pTexture);
-        IM_ASSERT(pTexture != nullptr);
+        bd->pd3dDevice->CreateTexture2D(&desc, &subResource, &backend_tex->pTexture);
+        IM_ASSERT(backend_tex->pTexture != nullptr && "Backend failed to create texture!");
 
         // Create texture view
         D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;
@@ -356,23 +400,29 @@ static void ImGui_ImplDX11_CreateFontsTexture()
         srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
         srvDesc.Texture2D.MipLevels = desc.MipLevels;
         srvDesc.Texture2D.MostDetailedMip = 0;
-        bd->pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, &bd->pFontTextureView);
-        pTexture->Release();
+        bd->pd3dDevice->CreateShaderResourceView(backend_tex->pTexture, &srvDesc, &backend_tex->pTextureView);
+        IM_ASSERT(backend_tex->pTextureView != nullptr && "Backend failed to create texture!");
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)backend_tex->pTextureView);
+        tex->SetStatus(ImTextureStatus_OK);
+        tex->BackendUserData = backend_tex;
     }
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)bd->pFontTextureView);
-}
-
-static void ImGui_ImplDX11_DestroyFontsTexture()
-{
-    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
-    if (bd->pFontTextureView)
+    else if (tex->Status == ImTextureStatus_WantUpdates)
     {
-        bd->pFontTextureView->Release();
-        bd->pFontTextureView = nullptr;
-        ImGui::GetIO().Fonts->SetTexID(0); // We copied data->pFontTextureView to io.Fonts->TexID so let's clear that as well.
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        ImGui_ImplDX11_Texture* backend_tex = (ImGui_ImplDX11_Texture*)tex->BackendUserData;
+        IM_ASSERT(backend_tex->pTextureView == (ID3D11ShaderResourceView*)(intptr_t)tex->TexID);
+        for (ImTextureRect& r : tex->Updates)
+        {
+            D3D11_BOX box = { (UINT)r.x, (UINT)r.y, (UINT)0, (UINT)(r.x + r.w), (UINT)(r.y + r .h), (UINT)1 };
+            bd->pd3dDeviceContext->UpdateSubresource(backend_tex->pTexture, 0, &box, tex->GetPixelsAt(r.x, r.y), (UINT)tex->GetPitch(), 0);
+        }
+        tex->SetStatus(ImTextureStatus_OK);
     }
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+        ImGui_ImplDX11_DestroyTexture(tex);
 }
 
 bool    ImGui_ImplDX11_CreateDeviceObjects()
@@ -380,8 +430,7 @@ bool    ImGui_ImplDX11_CreateDeviceObjects()
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
     if (!bd->pd3dDevice)
         return false;
-    if (bd->pFontSampler)
-        ImGui_ImplDX11_InvalidateDeviceObjects();
+    ImGui_ImplDX11_InvalidateDeviceObjects();
 
     // By using D3DCompile() from <d3dcompiler.h> / d3dcompiler.lib, we introduce a dependency to a given version of d3dcompiler_XX.dll (see D3DCOMPILER_DLL_A)
     // If you would like to use this DX11 sample code but remove this dependency you can:
@@ -537,11 +586,9 @@ bool    ImGui_ImplDX11_CreateDeviceObjects()
         desc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
         desc.MinLOD = 0.f;
         desc.MaxLOD = 0.f;
-        bd->pd3dDevice->CreateSamplerState(&desc, &bd->pFontSampler);
+        bd->pd3dDevice->CreateSamplerState(&desc, &bd->pTexSamplerLinear);
     }
 
-    ImGui_ImplDX11_CreateFontsTexture();
-
     return true;
 }
 
@@ -551,9 +598,12 @@ void    ImGui_ImplDX11_InvalidateDeviceObjects()
     if (!bd->pd3dDevice)
         return;
 
-    ImGui_ImplDX11_DestroyFontsTexture();
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplDX11_DestroyTexture(tex);
 
-    if (bd->pFontSampler)           { bd->pFontSampler->Release(); bd->pFontSampler = nullptr; }
+    if (bd->pTexSamplerLinear)    { bd->pTexSamplerLinear->Release(); bd->pTexSamplerLinear = nullptr; }
     if (bd->pIB)                    { bd->pIB->Release(); bd->pIB = nullptr; }
     if (bd->pVB)                    { bd->pVB->Release(); bd->pVB = nullptr; }
     if (bd->pBlendState)            { bd->pBlendState->Release(); bd->pBlendState = nullptr; }
@@ -576,6 +626,11 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_dx11";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION;
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -595,6 +650,8 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
     bd->pd3dDevice->AddRef();
     bd->pd3dDeviceContext->AddRef();
 
+    ImGui_ImplDX11_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -604,13 +661,14 @@ void ImGui_ImplDX11_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX11_ShutdownMultiViewportSupport();
     ImGui_ImplDX11_InvalidateDeviceObjects();
     if (bd->pFactory)             { bd->pFactory->Release(); }
     if (bd->pd3dDevice)           { bd->pd3dDevice->Release(); }
     if (bd->pd3dDeviceContext)    { bd->pd3dDeviceContext->Release(); }
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -619,8 +677,153 @@ void ImGui_ImplDX11_NewFrame()
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX11_Init()?");
 
-    if (!bd->pFontSampler)
-        ImGui_ImplDX11_CreateDeviceObjects();
+    if (!bd->pVertexShader)
+        if (!ImGui_ImplDX11_CreateDeviceObjects())
+            IM_ASSERT(0 && "ImGui_ImplDX11_CreateDeviceObjects() failed!");
+}
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX11_ViewportData
+{
+    IDXGISwapChain*                 SwapChain;
+    ID3D11RenderTargetView*         RTView;
+
+    ImGui_ImplDX11_ViewportData()   { SwapChain = nullptr; RTView = nullptr; }
+    ~ImGui_ImplDX11_ViewportData()  { IM_ASSERT(SwapChain == nullptr && RTView == nullptr); }
+};
+
+// Multi-Viewports: configure templates used when creating swapchains for secondary viewports. Will try them in order.
+// This is intentionally not declared in the .h file yet, so you will need to copy this declaration:
+void ImGui_ImplDX11_SetSwapChainDescs(const DXGI_SWAP_CHAIN_DESC* desc_templates, int desc_templates_count);
+void ImGui_ImplDX11_SetSwapChainDescs(const DXGI_SWAP_CHAIN_DESC* desc_templates, int desc_templates_count)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    bd->SwapChainDescsForViewports.resize(desc_templates_count);
+    memcpy(bd->SwapChainDescsForViewports.Data, desc_templates, sizeof(DXGI_SWAP_CHAIN_DESC));
+}
+
+static void ImGui_ImplDX11_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = IM_NEW(ImGui_ImplDX11_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+    IM_ASSERT(vd->SwapChain == nullptr && vd->RTView == nullptr);
+
+    // Create swap chain
+    HRESULT hr = DXGI_ERROR_UNSUPPORTED;
+    for (const DXGI_SWAP_CHAIN_DESC& sd_template : bd->SwapChainDescsForViewports)
+    {
+        IM_ASSERT(sd_template.BufferDesc.Width == 0 && sd_template.BufferDesc.Height == 0 && sd_template.OutputWindow == nullptr);
+        DXGI_SWAP_CHAIN_DESC sd = sd_template;
+        sd.BufferDesc.Width = (UINT)viewport->Size.x;
+        sd.BufferDesc.Height = (UINT)viewport->Size.y;
+        sd.OutputWindow = hwnd;
+        hr = bd->pFactory->CreateSwapChain(bd->pd3dDevice, &sd, &vd->SwapChain);
+        if (SUCCEEDED(hr))
+            break;
+    }
+    IM_ASSERT(SUCCEEDED(hr));
+
+    // Create the render target
+    if (vd->SwapChain != nullptr)
+    {
+        ID3D11Texture2D* pBackBuffer;
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX11_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == nullptr since we didn't create the data for it.
+    if (ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        if (vd->RTView)
+            vd->RTView->Release();
+        vd->RTView = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX11_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    if (vd->RTView)
+    {
+        vd->RTView->Release();
+        vd->RTView = nullptr;
+    }
+    if (vd->SwapChain)
+    {
+        ID3D11Texture2D* pBackBuffer = nullptr;
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, DXGI_FORMAT_UNKNOWN, 0);
+        vd->SwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer));
+        if (pBackBuffer == nullptr) { fprintf(stderr, "ImGui_ImplDX11_SetWindowSize() failed creating buffers.\n"); return; }
+        bd->pd3dDevice->CreateRenderTargetView(pBackBuffer, nullptr, &vd->RTView);
+        pBackBuffer->Release();
+    }
+}
+
+static void ImGui_ImplDX11_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    bd->pd3dDeviceContext->OMSetRenderTargets(1, &vd->RTView, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        bd->pd3dDeviceContext->ClearRenderTargetView(vd->RTView, (float*)&clear_color);
+    ImGui_ImplDX11_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplDX11_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX11_ViewportData* vd = (ImGui_ImplDX11_ViewportData*)viewport->RendererUserData;
+    vd->SwapChain->Present(0, 0); // Present without vsync
+}
+
+static void ImGui_ImplDX11_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX11_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX11_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX11_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX11_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX11_SwapBuffers;
+
+    // Default swapchain format
+    DXGI_SWAP_CHAIN_DESC sd;
+    ZeroMemory(&sd, sizeof(sd));
+    sd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+    sd.SampleDesc.Count = 1;
+    sd.SampleDesc.Quality = 0;
+    sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd.BufferCount = 1;
+    sd.Windowed = TRUE;
+    sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
+    sd.Flags = 0;
+    ImGui_ImplDX11_SetSwapChainDescs(&sd, 1);
+}
+
+static void ImGui_ImplDX11_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_dx11.h

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -33,6 +35,9 @@ IMGUI_IMPL_API void     ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data);
 IMGUI_IMPL_API bool     ImGui_ImplDX11_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplDX11_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplDX11_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplDX11_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_dx12.cpp

@@ -2,9 +2,12 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//      FIXME: The transition from removing a viewport and moving the window in an existing hosted viewport tends to flicker.
 
 // The aim of imgui_impl_dx12.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -19,6 +22,10 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-19: Fixed build on MinGW. (#8702, #4594)
+//  2025-06-11: DirectX12: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
+//  2025-05-07: DirectX12: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
 //  2025-02-24: DirectX12: Fixed an issue where ImGui_ImplDX12_Init() signature change from 2024-11-15 combined with change from 2025-01-15 made legacy ImGui_ImplDX12_Init() crash. (#8429)
 //  2025-01-15: DirectX12: Texture upload use the command queue provided in ImGui_ImplDX12_InitInfo instead of creating its own.
 //  2024-12-09: DirectX12: Let user specifies the DepthStencilView format by setting ImGui_ImplDX12_InitInfo::DSVFormat.
@@ -58,6 +65,15 @@
 #pragma comment(lib, "d3dcompiler") // Automatically link with d3dcompiler.lib as we are using D3DCompile() below.
 #endif
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wold-style-cast"         // warning: use of old-style cast                            // yes, they are more terse.
+#pragma clang diagnostic ignored "-Wsign-conversion"        // warning: implicit conversion changes signedness
+#endif
+
+// MinGW workaround, see #4594
+typedef decltype(D3D12SerializeRootSignature) *_PFN_D3D12_SERIALIZE_ROOT_SIGNATURE;
+
 // DirectX12 data
 struct ImGui_ImplDX12_RenderBuffers;
 
@@ -86,10 +102,9 @@ struct ImGui_ImplDX12_Data
     ImGui_ImplDX12_RenderBuffers* pFrameResources;
     UINT                        frameIndex;
 
-    ImGui_ImplDX12_Texture      FontTexture;
     bool                        LegacySingleDescriptorUsed;
 
-    ImGui_ImplDX12_Data()       { memset((void*)this, 0, sizeof(*this)); frameIndex = UINT_MAX; }
+    ImGui_ImplDX12_Data()       { memset((void*)this, 0, sizeof(*this)); }
 };
 
 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
@@ -108,11 +123,88 @@ struct ImGui_ImplDX12_RenderBuffers
     int                 VertexBufferSize;
 };
 
+// Buffers used for secondary viewports created by the multi-viewports systems
+struct ImGui_ImplDX12_FrameContext
+{
+    ID3D12CommandAllocator*         CommandAllocator;
+    ID3D12Resource*                 RenderTarget;
+    D3D12_CPU_DESCRIPTOR_HANDLE     RenderTargetCpuDescriptors;
+};
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+// Main viewport created by application will only use the Resources field.
+// Secondary viewports created by this backend will use all the fields (including Window fields),
+struct ImGui_ImplDX12_ViewportData
+{
+    // Window
+    ID3D12CommandQueue*             CommandQueue;
+    ID3D12GraphicsCommandList*      CommandList;
+    ID3D12DescriptorHeap*           RtvDescHeap;
+    IDXGISwapChain3*                SwapChain;
+    ID3D12Fence*                    Fence;
+    UINT64                          FenceSignaledValue;
+    HANDLE                          FenceEvent;
+    UINT                            NumFramesInFlight;
+    ImGui_ImplDX12_FrameContext*    FrameCtx;
+
+    // Render buffers
+    UINT                            FrameIndex;
+    ImGui_ImplDX12_RenderBuffers*   FrameRenderBuffers;
+
+    ImGui_ImplDX12_ViewportData(UINT num_frames_in_flight)
+    {
+        CommandQueue = nullptr;
+        CommandList = nullptr;
+        RtvDescHeap = nullptr;
+        SwapChain = nullptr;
+        Fence = nullptr;
+        FenceSignaledValue = 0;
+        FenceEvent = nullptr;
+        NumFramesInFlight = num_frames_in_flight;
+        FrameCtx = new ImGui_ImplDX12_FrameContext[NumFramesInFlight];
+        FrameIndex = UINT_MAX;
+        FrameRenderBuffers = new ImGui_ImplDX12_RenderBuffers[NumFramesInFlight];
+
+        for (UINT i = 0; i < NumFramesInFlight; ++i)
+        {
+            FrameCtx[i].CommandAllocator = nullptr;
+            FrameCtx[i].RenderTarget = nullptr;
+
+            // Create buffers with a default size (they will later be grown as needed)
+            FrameRenderBuffers[i].IndexBuffer = nullptr;
+            FrameRenderBuffers[i].VertexBuffer = nullptr;
+            FrameRenderBuffers[i].VertexBufferSize = 5000;
+            FrameRenderBuffers[i].IndexBufferSize = 10000;
+        }
+    }
+    ~ImGui_ImplDX12_ViewportData()
+    {
+        IM_ASSERT(CommandQueue == nullptr && CommandList == nullptr);
+        IM_ASSERT(RtvDescHeap == nullptr);
+        IM_ASSERT(SwapChain == nullptr);
+        IM_ASSERT(Fence == nullptr);
+        IM_ASSERT(FenceEvent == nullptr);
+
+        for (UINT i = 0; i < NumFramesInFlight; ++i)
+        {
+            IM_ASSERT(FrameCtx[i].CommandAllocator == nullptr && FrameCtx[i].RenderTarget == nullptr);
+            IM_ASSERT(FrameRenderBuffers[i].IndexBuffer == nullptr && FrameRenderBuffers[i].VertexBuffer == nullptr);
+        }
+
+        delete[] FrameCtx; FrameCtx = nullptr;
+        delete[] FrameRenderBuffers; FrameRenderBuffers = nullptr;
+    }
+};
+
 struct VERTEX_CONSTANT_BUFFER_DX12
 {
     float   mvp[4][4];
 };
 
+// Forward Declarations
+static void ImGui_ImplDX12_InitPlatformInterface();
+static void ImGui_ImplDX12_ShutdownPlatformInterface();
+
 // Functions
 static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12GraphicsCommandList* command_list, ImGui_ImplDX12_RenderBuffers* fr)
 {
@@ -138,8 +230,8 @@ static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12Graphic
 
     // Setup viewport
     D3D12_VIEWPORT vp = {};
-    vp.Width = draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
+    vp.Width = draw_data->DisplaySize.x * draw_data->FramebufferScale.x;
+    vp.Height = draw_data->DisplaySize.y * draw_data->FramebufferScale.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0.0f;
@@ -183,10 +275,18 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplDX12_UpdateTexture(tex);
+
     // FIXME: We are assuming that this only gets called once per frame!
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-    bd->frameIndex = bd->frameIndex + 1;
-    ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[bd->frameIndex % bd->numFramesInFlight];
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)draw_data->OwnerViewport->RendererUserData;
+    vd->FrameIndex++;
+    ImGui_ImplDX12_RenderBuffers* fr = &vd->FrameRenderBuffers[vd->FrameIndex % bd->numFramesInFlight];
 
     // Create and grow vertex/index buffers if needed
     if (fr->VertexBuffer == nullptr || fr->VertexBufferSize < draw_data->TotalVtxCount)
@@ -242,9 +342,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
         return;
     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource;
     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -274,9 +373,9 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    ImVec2 clip_scale = draw_data->FramebufferScale;
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
@@ -292,8 +391,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 
@@ -314,18 +413,39 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     platform_io.Renderer_RenderState = nullptr;
 }
 
-static void ImGui_ImplDX12_CreateFontsTexture()
+static void ImGui_ImplDX12_DestroyTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplDX12_Texture* backend_tex = (ImGui_ImplDX12_Texture*)tex->BackendUserData;
+    if (backend_tex == nullptr)
+        return;
+    IM_ASSERT(backend_tex->hFontSrvGpuDescHandle.ptr == (UINT64)tex->TexID);
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
+    bd->InitInfo.SrvDescriptorFreeFn(&bd->InitInfo, backend_tex->hFontSrvCpuDescHandle, backend_tex->hFontSrvGpuDescHandle);
+    SafeRelease(backend_tex->pTextureResource);
+    backend_tex->hFontSrvCpuDescHandle.ptr = 0;
+    backend_tex->hFontSrvGpuDescHandle.ptr = 0;
+    IM_DELETE(backend_tex);
 
-    // Upload texture to graphics system
-    ImGui_ImplDX12_Texture* font_tex = &bd->FontTexture;
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+    tex->BackendUserData = nullptr;
+}
+
+void ImGui_ImplDX12_UpdateTexture(ImTextureData* tex)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    bool need_barrier_before_copy = true; // Do we need a resource barrier before we copy new data in?
+
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        ImGui_ImplDX12_Texture* backend_tex = IM_NEW(ImGui_ImplDX12_Texture)();
+        bd->InitInfo.SrvDescriptorAllocFn(&bd->InitInfo, &backend_tex->hFontSrvCpuDescHandle, &backend_tex->hFontSrvGpuDescHandle); // Allocate a desctriptor handle
+
         D3D12_HEAP_PROPERTIES props = {};
         props.Type = D3D12_HEAP_TYPE_DEFAULT;
         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
@@ -335,8 +455,8 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         ZeroMemory(&desc, sizeof(desc));
         desc.Dimension = D3D12_RESOURCE_DIMENSION_TEXTURE2D;
         desc.Alignment = 0;
-        desc.Width = width;
-        desc.Height = height;
+        desc.Width = tex->Width;
+        desc.Height = tex->Height;
         desc.DepthOrArraySize = 1;
         desc.MipLevels = 1;
         desc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
@@ -349,8 +469,47 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         bd->pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc,
             D3D12_RESOURCE_STATE_COPY_DEST, nullptr, IID_PPV_ARGS(&pTexture));
 
-        UINT upload_pitch = (width * 4 + D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u) & ~(D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u);
-        UINT upload_size = height * upload_pitch;
+        // Create SRV
+        D3D12_SHADER_RESOURCE_VIEW_DESC srvDesc;
+        ZeroMemory(&srvDesc, sizeof(srvDesc));
+        srvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+        srvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
+        srvDesc.Texture2D.MipLevels = desc.MipLevels;
+        srvDesc.Texture2D.MostDetailedMip = 0;
+        srvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
+        bd->pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, backend_tex->hFontSrvCpuDescHandle);
+        SafeRelease(backend_tex->pTextureResource);
+        backend_tex->pTextureResource = pTexture;
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)backend_tex->hFontSrvGpuDescHandle.ptr);
+        tex->BackendUserData = backend_tex;
+        need_barrier_before_copy = false; // Because this is a newly-created texture it will be in D3D12_RESOURCE_STATE_COMMON and thus we don't need a barrier
+        // We don't set tex->Status to ImTextureStatus_OK to let the code fallthrough below.
+    }
+
+    if (tex->Status == ImTextureStatus_WantCreate || tex->Status == ImTextureStatus_WantUpdates)
+    {
+        ImGui_ImplDX12_Texture* backend_tex = (ImGui_ImplDX12_Texture*)tex->BackendUserData;
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // We could use the smaller rect on _WantCreate but using the full rect allows us to clear the texture.
+        // FIXME-OPT: Uploading single box even when using ImTextureStatus_WantUpdates. Could use tex->Updates[]
+        // - Copy all blocks contiguously in upload buffer.
+        // - Barrier before copy, submit all CopyTextureRegion(), barrier after copy.
+        const int upload_x = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.x;
+        const int upload_y = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.y;
+        const int upload_w = (tex->Status == ImTextureStatus_WantCreate) ? tex->Width : tex->UpdateRect.w;
+        const int upload_h = (tex->Status == ImTextureStatus_WantCreate) ? tex->Height : tex->UpdateRect.h;
+
+        // Update full texture or selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->UpdateRect but you can use tex->Updates[] to upload individual regions.
+        UINT upload_pitch_src = upload_w * tex->BytesPerPixel;
+        UINT upload_pitch_dst = (upload_pitch_src + D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u) & ~(D3D12_TEXTURE_DATA_PITCH_ALIGNMENT - 1u);
+        UINT upload_size = upload_pitch_dst * upload_h;
+
+        D3D12_RESOURCE_DESC desc;
+        ZeroMemory(&desc, sizeof(desc));
         desc.Dimension = D3D12_RESOURCE_DIMENSION_BUFFER;
         desc.Alignment = 0;
         desc.Width = upload_size;
@@ -363,47 +522,19 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         desc.Layout = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;
         desc.Flags = D3D12_RESOURCE_FLAG_NONE;
 
+        D3D12_HEAP_PROPERTIES props;
+        memset(&props, 0, sizeof(D3D12_HEAP_PROPERTIES));
         props.Type = D3D12_HEAP_TYPE_UPLOAD;
         props.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
         props.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
 
+        // FIXME-OPT: Can upload buffer be reused?
         ID3D12Resource* uploadBuffer = nullptr;
         HRESULT hr = bd->pd3dDevice->CreateCommittedResource(&props, D3D12_HEAP_FLAG_NONE, &desc,
             D3D12_RESOURCE_STATE_GENERIC_READ, nullptr, IID_PPV_ARGS(&uploadBuffer));
         IM_ASSERT(SUCCEEDED(hr));
 
-        void* mapped = nullptr;
-        D3D12_RANGE range = { 0, upload_size };
-        hr = uploadBuffer->Map(0, &range, &mapped);
-        IM_ASSERT(SUCCEEDED(hr));
-        for (int y = 0; y < height; y++)
-            memcpy((void*) ((uintptr_t) mapped + y * upload_pitch), pixels + y * width * 4, width * 4);
-        uploadBuffer->Unmap(0, &range);
-
-        D3D12_TEXTURE_COPY_LOCATION srcLocation = {};
-        D3D12_TEXTURE_COPY_LOCATION dstLocation = {};
-        {
-            srcLocation.pResource = uploadBuffer;
-            srcLocation.Type = D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT;
-            srcLocation.PlacedFootprint.Footprint.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
-            srcLocation.PlacedFootprint.Footprint.Width = width;
-            srcLocation.PlacedFootprint.Footprint.Height = height;
-            srcLocation.PlacedFootprint.Footprint.Depth = 1;
-            srcLocation.PlacedFootprint.Footprint.RowPitch = upload_pitch;
-
-            dstLocation.pResource = pTexture;
-            dstLocation.Type = D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX;
-            dstLocation.SubresourceIndex = 0;
-        }
-
-        D3D12_RESOURCE_BARRIER barrier = {};
-        barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
-        barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
-        barrier.Transition.pResource   = pTexture;
-        barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
-        barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_COPY_DEST;
-        barrier.Transition.StateAfter  = D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE;
-
+        // Create temporary command list and execute immediately
         ID3D12Fence* fence = nullptr;
         hr = bd->pd3dDevice->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&fence));
         IM_ASSERT(SUCCEEDED(hr));
@@ -411,16 +542,63 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         HANDLE event = ::CreateEvent(0, 0, 0, 0);
         IM_ASSERT(event != nullptr);
 
+        // FIXME-OPT: Create once and reuse?
         ID3D12CommandAllocator* cmdAlloc = nullptr;
         hr = bd->pd3dDevice->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&cmdAlloc));
         IM_ASSERT(SUCCEEDED(hr));
 
+        // FIXME-OPT: Can be use the one from user? (pass ID3D12GraphicsCommandList* to ImGui_ImplDX12_UpdateTextures)
         ID3D12GraphicsCommandList* cmdList = nullptr;
         hr = bd->pd3dDevice->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, cmdAlloc, nullptr, IID_PPV_ARGS(&cmdList));
         IM_ASSERT(SUCCEEDED(hr));
 
-        cmdList->CopyTextureRegion(&dstLocation, 0, 0, 0, &srcLocation, nullptr);
-        cmdList->ResourceBarrier(1, &barrier);
+        // Copy to upload buffer
+        void* mapped = nullptr;
+        D3D12_RANGE range = { 0, upload_size };
+        hr = uploadBuffer->Map(0, &range, &mapped);
+        IM_ASSERT(SUCCEEDED(hr));
+        for (int y = 0; y < upload_h; y++)
+            memcpy((void*)((uintptr_t)mapped + y * upload_pitch_dst), tex->GetPixelsAt(upload_x, upload_y + y), upload_pitch_src);
+        uploadBuffer->Unmap(0, &range);
+
+        if (need_barrier_before_copy)
+        {
+            D3D12_RESOURCE_BARRIER barrier = {};
+            barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
+            barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
+            barrier.Transition.pResource = backend_tex->pTextureResource;
+            barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
+            barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE;
+            barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_COPY_DEST;
+            cmdList->ResourceBarrier(1, &barrier);
+        }
+
+        D3D12_TEXTURE_COPY_LOCATION srcLocation = {};
+        D3D12_TEXTURE_COPY_LOCATION dstLocation = {};
+        {
+            srcLocation.pResource = uploadBuffer;
+            srcLocation.Type = D3D12_TEXTURE_COPY_TYPE_PLACED_FOOTPRINT;
+            srcLocation.PlacedFootprint.Footprint.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
+            srcLocation.PlacedFootprint.Footprint.Width = upload_w;
+            srcLocation.PlacedFootprint.Footprint.Height = upload_h;
+            srcLocation.PlacedFootprint.Footprint.Depth = 1;
+            srcLocation.PlacedFootprint.Footprint.RowPitch = upload_pitch_dst;
+            dstLocation.pResource = backend_tex->pTextureResource;
+            dstLocation.Type = D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX;
+            dstLocation.SubresourceIndex = 0;
+        }
+        cmdList->CopyTextureRegion(&dstLocation, upload_x, upload_y, 0, &srcLocation, nullptr);
+
+        {
+            D3D12_RESOURCE_BARRIER barrier = {};
+            barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
+            barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
+            barrier.Transition.pResource = backend_tex->pTextureResource;
+            barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
+            barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_COPY_DEST;
+            barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE;
+            cmdList->ResourceBarrier(1, &barrier);
+        }
 
         hr = cmdList->Close();
         IM_ASSERT(SUCCEEDED(hr));
@@ -430,6 +608,10 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         hr = cmdQueue->Signal(fence, 1);
         IM_ASSERT(SUCCEEDED(hr));
 
+        // FIXME-OPT: Suboptimal?
+        // - To remove this may need to create NumFramesInFlight x ImGui_ImplDX12_FrameContext in backend data (mimick docking version)
+        // - Store per-frame in flight: upload buffer?
+        // - Where do cmdList and cmdAlloc fit?
         fence->SetEventOnCompletion(1, event);
         ::WaitForSingleObject(event, INFINITE);
 
@@ -438,22 +620,11 @@ static void ImGui_ImplDX12_CreateFontsTexture()
         ::CloseHandle(event);
         fence->Release();
         uploadBuffer->Release();
-
-        // Create texture view
-        D3D12_SHADER_RESOURCE_VIEW_DESC srvDesc;
-        ZeroMemory(&srvDesc, sizeof(srvDesc));
-        srvDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
-        srvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
-        srvDesc.Texture2D.MipLevels = desc.MipLevels;
-        srvDesc.Texture2D.MostDetailedMip = 0;
-        srvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
-        bd->pd3dDevice->CreateShaderResourceView(pTexture, &srvDesc, font_tex->hFontSrvCpuDescHandle);
-        SafeRelease(font_tex->pTextureResource);
-        font_tex->pTextureResource = pTexture;
+        tex->SetStatus(ImTextureStatus_OK);
     }
 
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)font_tex->hFontSrvGpuDescHandle.ptr);
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames >= (int)bd->numFramesInFlight)
+        ImGui_ImplDX12_DestroyTexture(tex);
 }
 
 bool    ImGui_ImplDX12_CreateDeviceObjects()
@@ -487,26 +658,26 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
         param[1].ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
 
         // Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling.
-        D3D12_STATIC_SAMPLER_DESC staticSampler = {};
-        staticSampler.Filter = D3D12_FILTER_MIN_MAG_MIP_LINEAR;
-        staticSampler.AddressU = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
-        staticSampler.AddressV = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
-        staticSampler.AddressW = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
-        staticSampler.MipLODBias = 0.f;
-        staticSampler.MaxAnisotropy = 0;
-        staticSampler.ComparisonFunc = D3D12_COMPARISON_FUNC_ALWAYS;
-        staticSampler.BorderColor = D3D12_STATIC_BORDER_COLOR_TRANSPARENT_BLACK;
-        staticSampler.MinLOD = 0.f;
-        staticSampler.MaxLOD = 0.f;
-        staticSampler.ShaderRegister = 0;
-        staticSampler.RegisterSpace = 0;
-        staticSampler.ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
+        D3D12_STATIC_SAMPLER_DESC staticSampler[1] = {};
+        staticSampler[0].Filter = D3D12_FILTER_MIN_MAG_MIP_LINEAR;
+        staticSampler[0].AddressU = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
+        staticSampler[0].AddressV = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
+        staticSampler[0].AddressW = D3D12_TEXTURE_ADDRESS_MODE_CLAMP;
+        staticSampler[0].MipLODBias = 0.f;
+        staticSampler[0].MaxAnisotropy = 0;
+        staticSampler[0].ComparisonFunc = D3D12_COMPARISON_FUNC_ALWAYS;
+        staticSampler[0].BorderColor = D3D12_STATIC_BORDER_COLOR_TRANSPARENT_BLACK;
+        staticSampler[0].MinLOD = 0.f;
+        staticSampler[0].MaxLOD = D3D12_FLOAT32_MAX;
+        staticSampler[0].ShaderRegister = 0;
+        staticSampler[0].RegisterSpace = 0;
+        staticSampler[0].ShaderVisibility = D3D12_SHADER_VISIBILITY_PIXEL;
 
         D3D12_ROOT_SIGNATURE_DESC desc = {};
         desc.NumParameters = _countof(param);
         desc.pParameters = param;
         desc.NumStaticSamplers = 1;
-        desc.pStaticSamplers = &staticSampler;
+        desc.pStaticSamplers = &staticSampler[0];
         desc.Flags =
             D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT |
             D3D12_ROOT_SIGNATURE_FLAG_DENY_HULL_SHADER_ROOT_ACCESS |
@@ -535,7 +706,7 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
                 return false;
         }
 
-        PFN_D3D12_SERIALIZE_ROOT_SIGNATURE D3D12SerializeRootSignatureFn = (PFN_D3D12_SERIALIZE_ROOT_SIGNATURE)::GetProcAddress(d3d12_dll, "D3D12SerializeRootSignature");
+        _PFN_D3D12_SERIALIZE_ROOT_SIGNATURE D3D12SerializeRootSignatureFn = (_PFN_D3D12_SERIALIZE_ROOT_SIGNATURE)(void*)::GetProcAddress(d3d12_dll, "D3D12SerializeRootSignature");
         if (D3D12SerializeRootSignatureFn == nullptr)
             return false;
 
@@ -685,11 +856,16 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
     if (result_pipeline_state != S_OK)
         return false;
 
-    ImGui_ImplDX12_CreateFontsTexture();
-
     return true;
 }
 
+static void ImGui_ImplDX12_DestroyRenderBuffers(ImGui_ImplDX12_RenderBuffers* render_buffers)
+{
+    SafeRelease(render_buffers->IndexBuffer);
+    SafeRelease(render_buffers->VertexBuffer);
+    render_buffers->IndexBufferSize = render_buffers->VertexBufferSize = 0;
+}
+
 void    ImGui_ImplDX12_InvalidateDeviceObjects()
 {
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
@@ -702,21 +878,34 @@ void    ImGui_ImplDX12_InvalidateDeviceObjects()
     SafeRelease(bd->pRootSignature);
     SafeRelease(bd->pPipelineState);
 
-    // Free SRV descriptor used by texture
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplDX12_Texture* font_tex = &bd->FontTexture;
-    bd->InitInfo.SrvDescriptorFreeFn(&bd->InitInfo, font_tex->hFontSrvCpuDescHandle, font_tex->hFontSrvGpuDescHandle);
-    SafeRelease(font_tex->pTextureResource);
-    io.Fonts->SetTexID(0); // We copied bd->hFontSrvGpuDescHandle to io.Fonts->TexID so let's clear that as well.
-
-    for (UINT i = 0; i < bd->numFramesInFlight; i++)
-    {
-        ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[i];
-        SafeRelease(fr->IndexBuffer);
-        SafeRelease(fr->VertexBuffer);
-    }
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplDX12_DestroyTexture(tex);
 }
 
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+static void ImGui_ImplDX12_InitLegacySingleDescriptorMode(ImGui_ImplDX12_InitInfo* init_info)
+{
+    // Wrap legacy behavior of passing space for a single descriptor
+    IM_ASSERT(init_info->LegacySingleSrvCpuDescriptor.ptr != 0 && init_info->LegacySingleSrvGpuDescriptor.ptr != 0);
+    init_info->SrvDescriptorAllocFn = [](ImGui_ImplDX12_InitInfo*, D3D12_CPU_DESCRIPTOR_HANDLE* out_cpu_handle, D3D12_GPU_DESCRIPTOR_HANDLE* out_gpu_handle)
+    {
+        ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+        IM_ASSERT(bd->LegacySingleDescriptorUsed == false && "Only 1 simultaneous texture allowed with legacy ImGui_ImplDX12_Init() signature!");
+        *out_cpu_handle = bd->InitInfo.LegacySingleSrvCpuDescriptor;
+        *out_gpu_handle = bd->InitInfo.LegacySingleSrvGpuDescriptor;
+        bd->LegacySingleDescriptorUsed = true;
+    };
+    init_info->SrvDescriptorFreeFn = [](ImGui_ImplDX12_InitInfo*, D3D12_CPU_DESCRIPTOR_HANDLE, D3D12_GPU_DESCRIPTOR_HANDLE)
+    {
+        ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+        IM_ASSERT(bd->LegacySingleDescriptorUsed == true);
+        bd->LegacySingleDescriptorUsed = false;
+    };
+}
+#endif
+
 bool ImGui_ImplDX12_Init(ImGui_ImplDX12_InitInfo* init_info)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -739,44 +928,22 @@ bool ImGui_ImplDX12_Init(ImGui_ImplDX12_InitInfo* init_info)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_dx12";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX12_InitPlatformInterface();
+
+    // Create a dummy ImGui_ImplDX12_ViewportData holder for the main viewport,
+    // Since this is created and managed by the application, we will only use the ->Resources[] fields.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->RendererUserData = IM_NEW(ImGui_ImplDX12_ViewportData)(bd->numFramesInFlight);
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     if (init_info->SrvDescriptorAllocFn == nullptr)
-    {
-        // Wrap legacy behavior of passing space for a single descriptor
-        IM_ASSERT(init_info->LegacySingleSrvCpuDescriptor.ptr != 0 && init_info->LegacySingleSrvGpuDescriptor.ptr != 0);
-        init_info->SrvDescriptorAllocFn = [](ImGui_ImplDX12_InitInfo*, D3D12_CPU_DESCRIPTOR_HANDLE* out_cpu_handle, D3D12_GPU_DESCRIPTOR_HANDLE* out_gpu_handle)
-        {
-            ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-            IM_ASSERT(bd->LegacySingleDescriptorUsed == false && "Only 1 simultaneous texture allowed with legacy ImGui_ImplDX12_Init() signature!");
-            *out_cpu_handle = bd->InitInfo.LegacySingleSrvCpuDescriptor;
-            *out_gpu_handle = bd->InitInfo.LegacySingleSrvGpuDescriptor;
-            bd->LegacySingleDescriptorUsed = true;
-        };
-        init_info->SrvDescriptorFreeFn = [](ImGui_ImplDX12_InitInfo*, D3D12_CPU_DESCRIPTOR_HANDLE, D3D12_GPU_DESCRIPTOR_HANDLE)
-        {
-            ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-            IM_ASSERT(bd->LegacySingleDescriptorUsed == true);
-            bd->LegacySingleDescriptorUsed = false;
-        };
-    }
+        ImGui_ImplDX12_InitLegacySingleDescriptorMode(init_info);
 #endif
-
-    // Allocate 1 SRV descriptor for the font texture
     IM_ASSERT(init_info->SrvDescriptorAllocFn != nullptr && init_info->SrvDescriptorFreeFn != nullptr);
-    init_info->SrvDescriptorAllocFn(&bd->InitInfo, &bd->FontTexture.hFontSrvCpuDescHandle, &bd->FontTexture.hFontSrvGpuDescHandle);
-
-    // Create buffers with a default size (they will later be grown as needed)
-    bd->frameIndex = UINT_MAX;
-    bd->pFrameResources = new ImGui_ImplDX12_RenderBuffers[bd->numFramesInFlight];
-    for (int i = 0; i < (int)bd->numFramesInFlight; i++)
-    {
-        ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[i];
-        fr->IndexBuffer = nullptr;
-        fr->VertexBuffer = nullptr;
-        fr->IndexBufferSize = 10000;
-        fr->VertexBufferSize = 5000;
-    }
 
     return true;
 }
@@ -804,6 +971,9 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
     bool ret = ImGui_ImplDX12_Init(&init_info);
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
     bd->commandQueueOwned = true;
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasTextures; // Using legacy ImGui_ImplDX12_Init() call with 1 SRV descriptor we cannot support multiple textures.
+
     return ret;
 }
 #endif
@@ -814,13 +984,24 @@ void ImGui_ImplDX12_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    // Manually delete main viewport render resources in-case we haven't initialized for viewports
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    if (ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)main_viewport->RendererUserData)
+    {
+        // We could just call ImGui_ImplDX12_DestroyWindow(main_viewport) as a convenience but that would be misleading since we only use data->Resources[]
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+            ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+        IM_DELETE(vd);
+        main_viewport->RendererUserData = nullptr;
+    }
+
     // Clean up windows and device objects
+    ImGui_ImplDX12_ShutdownPlatformInterface();
     ImGui_ImplDX12_InvalidateDeviceObjects();
-    delete[] bd->pFrameResources;
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -830,7 +1011,248 @@ void ImGui_ImplDX12_NewFrame()
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX12_Init()?");
 
     if (!bd->pPipelineState)
-        ImGui_ImplDX12_CreateDeviceObjects();
+        if (!ImGui_ImplDX12_CreateDeviceObjects())
+            IM_ASSERT(0 && "ImGui_ImplDX12_CreateDeviceObjects() failed!");
+}
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplDX12_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = IM_NEW(ImGui_ImplDX12_ViewportData)(bd->numFramesInFlight);
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    vd->FrameIndex = UINT_MAX;
+
+    // Create command queue.
+    D3D12_COMMAND_QUEUE_DESC queue_desc = {};
+    queue_desc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
+    queue_desc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;
+
+    HRESULT res = S_OK;
+    res = bd->pd3dDevice->CreateCommandQueue(&queue_desc, IID_PPV_ARGS(&vd->CommandQueue));
+    IM_ASSERT(res == S_OK);
+
+    // Create command allocator.
+    for (UINT i = 0; i < bd->numFramesInFlight; ++i)
+    {
+        res = bd->pd3dDevice->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&vd->FrameCtx[i].CommandAllocator));
+        IM_ASSERT(res == S_OK);
+    }
+
+    // Create command list.
+    res = bd->pd3dDevice->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, vd->FrameCtx[0].CommandAllocator, nullptr, IID_PPV_ARGS(&vd->CommandList));
+    IM_ASSERT(res == S_OK);
+    vd->CommandList->Close();
+
+    // Create fence.
+    res = bd->pd3dDevice->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&vd->Fence));
+    IM_ASSERT(res == S_OK);
+
+    vd->FenceEvent = CreateEvent(nullptr, FALSE, FALSE, nullptr);
+    IM_ASSERT(vd->FenceEvent != nullptr);
+
+    // Create swap chain
+    // FIXME-VIEWPORT: May want to copy/inherit swap chain settings from the user/application.
+    DXGI_SWAP_CHAIN_DESC1 sd1;
+    ZeroMemory(&sd1, sizeof(sd1));
+    sd1.BufferCount = bd->numFramesInFlight;
+    sd1.Width = (UINT)viewport->Size.x;
+    sd1.Height = (UINT)viewport->Size.y;
+    sd1.Format = bd->RTVFormat;
+    sd1.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
+    sd1.SampleDesc.Count = 1;
+    sd1.SampleDesc.Quality = 0;
+    sd1.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
+    sd1.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
+    sd1.Scaling = DXGI_SCALING_NONE;
+    sd1.Stereo = FALSE;
+
+    IDXGIFactory4* dxgi_factory = nullptr;
+    res = ::CreateDXGIFactory1(IID_PPV_ARGS(&dxgi_factory));
+    IM_ASSERT(res == S_OK);
+
+    IDXGISwapChain1* swap_chain = nullptr;
+    res = dxgi_factory->CreateSwapChainForHwnd(vd->CommandQueue, hwnd, &sd1, nullptr, nullptr, &swap_chain);
+    IM_ASSERT(res == S_OK);
+
+    dxgi_factory->Release();
+
+    // Or swapChain.As(&mSwapChain)
+    IM_ASSERT(vd->SwapChain == nullptr);
+    swap_chain->QueryInterface(IID_PPV_ARGS(&vd->SwapChain));
+    swap_chain->Release();
+
+    // Create the render targets
+    if (vd->SwapChain)
+    {
+        D3D12_DESCRIPTOR_HEAP_DESC desc = {};
+        desc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
+        desc.NumDescriptors = bd->numFramesInFlight;
+        desc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
+        desc.NodeMask = 1;
+
+        HRESULT hr = bd->pd3dDevice->CreateDescriptorHeap(&desc, IID_PPV_ARGS(&vd->RtvDescHeap));
+        IM_ASSERT(hr == S_OK);
+
+        SIZE_T rtv_descriptor_size = bd->pd3dDevice->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
+        D3D12_CPU_DESCRIPTOR_HANDLE rtv_handle = vd->RtvDescHeap->GetCPUDescriptorHandleForHeapStart();
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            vd->FrameCtx[i].RenderTargetCpuDescriptors = rtv_handle;
+            rtv_handle.ptr += rtv_descriptor_size;
+        }
+
+        ID3D12Resource* back_buffer;
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            IM_ASSERT(vd->FrameCtx[i].RenderTarget == nullptr);
+            vd->SwapChain->GetBuffer(i, IID_PPV_ARGS(&back_buffer));
+            bd->pd3dDevice->CreateRenderTargetView(back_buffer, nullptr, vd->FrameCtx[i].RenderTargetCpuDescriptors);
+            vd->FrameCtx[i].RenderTarget = back_buffer;
+        }
+    }
+
+    for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+}
+
+static void ImGui_WaitForPendingOperations(ImGui_ImplDX12_ViewportData* vd)
+{
+    HRESULT hr = S_FALSE;
+    if (vd && vd->CommandQueue && vd->Fence && vd->FenceEvent)
+    {
+        hr = vd->CommandQueue->Signal(vd->Fence, ++vd->FenceSignaledValue);
+        IM_ASSERT(hr == S_OK);
+        ::WaitForSingleObject(vd->FenceEvent, 0); // Reset any forgotten waits
+        hr = vd->Fence->SetEventOnCompletion(vd->FenceSignaledValue, vd->FenceEvent);
+        IM_ASSERT(hr == S_OK);
+        ::WaitForSingleObject(vd->FenceEvent, INFINITE);
+    }
+}
+
+static void ImGui_ImplDX12_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    if (ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData)
+    {
+        ImGui_WaitForPendingOperations(vd);
+
+        SafeRelease(vd->CommandQueue);
+        SafeRelease(vd->CommandList);
+        SafeRelease(vd->SwapChain);
+        SafeRelease(vd->RtvDescHeap);
+        SafeRelease(vd->Fence);
+        ::CloseHandle(vd->FenceEvent);
+        vd->FenceEvent = nullptr;
+
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            SafeRelease(vd->FrameCtx[i].RenderTarget);
+            SafeRelease(vd->FrameCtx[i].CommandAllocator);
+            ImGui_ImplDX12_DestroyRenderBuffers(&vd->FrameRenderBuffers[i]);
+        }
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX12_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    ImGui_WaitForPendingOperations(vd);
+
+    for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        SafeRelease(vd->FrameCtx[i].RenderTarget);
+
+    if (vd->SwapChain)
+    {
+        ID3D12Resource* back_buffer = nullptr;
+        vd->SwapChain->ResizeBuffers(0, (UINT)size.x, (UINT)size.y, DXGI_FORMAT_UNKNOWN, 0);
+        for (UINT i = 0; i < bd->numFramesInFlight; i++)
+        {
+            vd->SwapChain->GetBuffer(i, IID_PPV_ARGS(&back_buffer));
+            bd->pd3dDevice->CreateRenderTargetView(back_buffer, nullptr, vd->FrameCtx[i].RenderTargetCpuDescriptors);
+            vd->FrameCtx[i].RenderTarget = back_buffer;
+        }
+    }
+}
+
+static void ImGui_ImplDX12_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    ImGui_ImplDX12_FrameContext* frame_context = &vd->FrameCtx[vd->FrameIndex % bd->numFramesInFlight];
+    UINT back_buffer_idx = vd->SwapChain->GetCurrentBackBufferIndex();
+
+    const ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+    D3D12_RESOURCE_BARRIER barrier = {};
+    barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
+    barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
+    barrier.Transition.pResource = vd->FrameCtx[back_buffer_idx].RenderTarget;
+    barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
+    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_PRESENT;
+    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_RENDER_TARGET;
+
+    // Draw
+    ID3D12GraphicsCommandList* cmd_list = vd->CommandList;
+
+    frame_context->CommandAllocator->Reset();
+    cmd_list->Reset(frame_context->CommandAllocator, nullptr);
+    cmd_list->ResourceBarrier(1, &barrier);
+    cmd_list->OMSetRenderTargets(1, &vd->FrameCtx[back_buffer_idx].RenderTargetCpuDescriptors, FALSE, nullptr);
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+        cmd_list->ClearRenderTargetView(vd->FrameCtx[back_buffer_idx].RenderTargetCpuDescriptors, (const float*)&clear_color, 0, nullptr);
+    cmd_list->SetDescriptorHeaps(1, &bd->pd3dSrvDescHeap);
+
+    ImGui_ImplDX12_RenderDrawData(viewport->DrawData, cmd_list);
+
+    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_RENDER_TARGET;
+    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_PRESENT;
+    cmd_list->ResourceBarrier(1, &barrier);
+    cmd_list->Close();
+
+    vd->CommandQueue->Wait(vd->Fence, vd->FenceSignaledValue);
+    vd->CommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&cmd_list);
+    vd->CommandQueue->Signal(vd->Fence, ++vd->FenceSignaledValue);
+}
+
+static void ImGui_ImplDX12_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX12_ViewportData* vd = (ImGui_ImplDX12_ViewportData*)viewport->RendererUserData;
+
+    vd->SwapChain->Present(0, 0);
+    while (vd->Fence->GetCompletedValue() < vd->FenceSignaledValue)
+        ::SwitchToThread();
+}
+
+void ImGui_ImplDX12_InitPlatformInterface()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX12_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX12_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX12_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX12_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX12_SwapBuffers;
+}
+
+void ImGui_ImplDX12_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_dx12.h

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_dx12.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -63,6 +65,9 @@ IMGUI_IMPL_API bool     ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames
 IMGUI_IMPL_API bool     ImGui_ImplDX12_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplDX12_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplDX12_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplDX12_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_dx9.cpp

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: IMGUI_USE_BGRA_PACKED_COLOR support, as this is the optimal color encoding for DirectX9.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -16,6 +18,8 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-11: DirectX9: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas.
 //  2024-10-07: DirectX9: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-02-12: DirectX9: Using RGBA format when supported by the driver to avoid CPU side conversion. (#6575)
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -44,13 +48,18 @@
 // DirectX
 #include <d3d9.h>
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wold-style-cast"         // warning: use of old-style cast                            // yes, they are more terse.
+#pragma clang diagnostic ignored "-Wsign-conversion"        // warning: implicit conversion changes signedness
+#endif
+
 // DirectX data
 struct ImGui_ImplDX9_Data
 {
     LPDIRECT3DDEVICE9           pd3dDevice;
     LPDIRECT3DVERTEXBUFFER9     pVB;
     LPDIRECT3DINDEXBUFFER9      pIB;
-    LPDIRECT3DTEXTURE9          FontTexture;
     int                         VertexBufferSize;
     int                         IndexBufferSize;
     bool                        HasRgbaSupport;
@@ -79,6 +88,12 @@ static ImGui_ImplDX9_Data* ImGui_ImplDX9_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX9_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX9_InitMultiViewportSupport();
+static void ImGui_ImplDX9_ShutdownMultiViewportSupport();
+static void ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
+static void ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows();
+
 // Functions
 static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
 {
@@ -163,6 +178,13 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     LPDIRECT3DDEVICE9 device = bd->pd3dDevice;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplDX9_UpdateTexture(tex);
+
     // Create and grow buffers if needed
     if (!bd->pVB || bd->VertexBufferSize < draw_data->TotalVtxCount)
     {
@@ -214,9 +236,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     // FIXME-OPT: This is a minor waste of resource, the ideal is to use imconfig.h and
     //  1) to avoid repacking colors:   #define IMGUI_USE_BGRA_PACKED_COLOR
     //  2) to avoid repacking vertices: #define IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT struct ImDrawVert { ImVec2 pos; float z; ImU32 col; ImVec2 uv; }
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_src = draw_list->VtxBuffer.Data;
         for (int i = 0; i < draw_list->VtxBuffer.Size; i++)
         {
@@ -246,9 +267,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
@@ -283,6 +303,11 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
         global_vtx_offset += draw_list->VtxBuffer.Size;
     }
 
+    // When using multi-viewports, it appears that there's an odd logic in DirectX9 which prevent subsequent windows
+    // from rendering until the first window submits at least one draw call, even once. That's our workaround. (see #2560)
+    if (global_vtx_offset == 0)
+        bd->pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 0, 0, 0);
+
     // Restore the DX9 transform
     device->SetTransform(D3DTS_WORLD, &last_world);
     device->SetTransform(D3DTS_VIEW, &last_view);
@@ -322,11 +347,18 @@ bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_dx9";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = 4096;
 
     bd->pd3dDevice = device;
     bd->pd3dDevice->AddRef();
     bd->HasRgbaSupport = ImGui_ImplDX9_CheckFormatSupport(bd->pd3dDevice, D3DFMT_A8B8G8R8);
 
+    ImGui_ImplDX9_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -336,16 +368,17 @@ void ImGui_ImplDX9_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX9_ShutdownMultiViewportSupport();
     ImGui_ImplDX9_InvalidateDeviceObjects();
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 // Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
-static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, ImU32* src, int src_pitch, ImU32* dst, int dst_pitch, int w, int h)
+static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, const ImU32* src, int src_pitch, ImU32* dst, int dst_pitch, int w, int h)
 {
 #ifndef IMGUI_USE_BGRA_PACKED_COLOR
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
@@ -356,8 +389,8 @@ static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, ImU32* src, int
 #endif
     for (int y = 0; y < h; y++)
     {
-        ImU32* src_p = (ImU32*)((unsigned char*)src + src_pitch * y);
-        ImU32* dst_p = (ImU32*)((unsigned char*)dst + dst_pitch * y);
+        const ImU32* src_p = (const ImU32*)(const void*)((const unsigned char*)src + src_pitch * y);
+        ImU32* dst_p = (ImU32*)(void*)((unsigned char*)dst + dst_pitch * y);
         if (convert_rgba_to_bgra)
             for (int x = w; x > 0; x--, src_p++, dst_p++) // Convert copy
                 *dst_p = IMGUI_COL_TO_DX9_ARGB(*src_p);
@@ -366,28 +399,61 @@ static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, ImU32* src, int
     }
 }
 
-static bool ImGui_ImplDX9_CreateFontsTexture()
+void ImGui_ImplDX9_UpdateTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
-    unsigned char* pixels;
-    int width, height, bytes_per_pixel;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &bytes_per_pixel);
 
-    // Upload texture to graphics system
-    bd->FontTexture = nullptr;
-    if (bd->pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, bd->HasRgbaSupport ? D3DFMT_A8B8G8R8 : D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &bd->FontTexture, nullptr) < 0)
-        return false;
-    D3DLOCKED_RECT tex_locked_rect;
-    if (bd->FontTexture->LockRect(0, &tex_locked_rect, nullptr, 0) != D3D_OK)
-        return false;
-    ImGui_ImplDX9_CopyTextureRegion(io.Fonts->TexPixelsUseColors, (ImU32*)pixels, width * bytes_per_pixel, (ImU32*)tex_locked_rect.pBits, (int)tex_locked_rect.Pitch, width, height);
-    bd->FontTexture->UnlockRect(0);
+    if (tex->Status == ImTextureStatus_WantCreate)
+    {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        LPDIRECT3DTEXTURE9 dx_tex = nullptr;
+        HRESULT hr = bd->pd3dDevice->CreateTexture(tex->Width, tex->Height, 1, D3DUSAGE_DYNAMIC, bd->HasRgbaSupport ? D3DFMT_A8B8G8R8 : D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &dx_tex, nullptr);
+        if (hr < 0)
+        {
+            IM_ASSERT(hr >= 0 && "Backend failed to create texture!");
+            return;
+        }
 
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)bd->FontTexture);
-    return true;
+        D3DLOCKED_RECT locked_rect;
+        if (dx_tex->LockRect(0, &locked_rect, nullptr, 0) == D3D_OK)
+        {
+            ImGui_ImplDX9_CopyTextureRegion(tex->UseColors, (ImU32*)tex->GetPixels(), tex->Width * 4, (ImU32*)locked_rect.pBits, (ImU32)locked_rect.Pitch, tex->Width, tex->Height);
+            dx_tex->UnlockRect(0);
+        }
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)dx_tex);
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        LPDIRECT3DTEXTURE9 backend_tex = (LPDIRECT3DTEXTURE9)(intptr_t)tex->TexID;
+        RECT update_rect = { (LONG)tex->UpdateRect.x, (LONG)tex->UpdateRect.y, (LONG)(tex->UpdateRect.x + tex->UpdateRect.w), (LONG)(tex->UpdateRect.y + tex->UpdateRect.h) };
+        D3DLOCKED_RECT locked_rect;
+        if (backend_tex->LockRect(0, &locked_rect, &update_rect, 0) == D3D_OK)
+            for (ImTextureRect& r : tex->Updates)
+                ImGui_ImplDX9_CopyTextureRegion(tex->UseColors, (ImU32*)tex->GetPixelsAt(r.x, r.y), tex->Width * 4,
+                    (ImU32*)locked_rect.pBits + (r.x - update_rect.left) + (r.y - update_rect.top) * (locked_rect.Pitch / 4), (int)locked_rect.Pitch, r.w, r.h);
+        backend_tex->UnlockRect(0);
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        LPDIRECT3DTEXTURE9 backend_tex = (LPDIRECT3DTEXTURE9)tex->TexID;
+        if (backend_tex == nullptr)
+            return;
+        IM_ASSERT(tex->TexID == (ImTextureID)(intptr_t)backend_tex);
+        backend_tex->Release();
+
+        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
+    }
 }
 
 bool ImGui_ImplDX9_CreateDeviceObjects()
@@ -395,8 +461,7 @@ bool ImGui_ImplDX9_CreateDeviceObjects()
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd || !bd->pd3dDevice)
         return false;
-    if (!ImGui_ImplDX9_CreateFontsTexture())
-        return false;
+    ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
     return true;
 }
 
@@ -405,18 +470,166 @@ void ImGui_ImplDX9_InvalidateDeviceObjects()
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     if (!bd || !bd->pd3dDevice)
         return;
+
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+        {
+            tex->SetStatus(ImTextureStatus_WantDestroy);
+            ImGui_ImplDX9_UpdateTexture(tex);
+        }
     if (bd->pVB) { bd->pVB->Release(); bd->pVB = nullptr; }
     if (bd->pIB) { bd->pIB->Release(); bd->pIB = nullptr; }
-    if (bd->FontTexture) { bd->FontTexture->Release(); bd->FontTexture = nullptr; ImGui::GetIO().Fonts->SetTexID(0); } // We copied bd->pFontTextureView to io.Fonts->TexID so let's clear that as well.
+    ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows();
 }
 
 void ImGui_ImplDX9_NewFrame()
 {
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX9_Init()?");
+    IM_UNUSED(bd);
+}
 
-    if (!bd->FontTexture)
-        ImGui_ImplDX9_CreateDeviceObjects();
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplDX9_ViewportData
+{
+    IDirect3DSwapChain9*    SwapChain;
+    D3DPRESENT_PARAMETERS   d3dpp;
+
+    ImGui_ImplDX9_ViewportData()  { SwapChain = nullptr; ZeroMemory(&d3dpp, sizeof(D3DPRESENT_PARAMETERS)); }
+    ~ImGui_ImplDX9_ViewportData() { IM_ASSERT(SwapChain == nullptr); }
+};
+
+static void ImGui_ImplDX9_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    ImGui_ImplDX9_ViewportData* vd = IM_NEW(ImGui_ImplDX9_ViewportData)();
+    viewport->RendererUserData = vd;
+
+    // PlatformHandleRaw should always be a HWND, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL's WindowID).
+    // Some backends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the HWND.
+    HWND hwnd = viewport->PlatformHandleRaw ? (HWND)viewport->PlatformHandleRaw : (HWND)viewport->PlatformHandle;
+    IM_ASSERT(hwnd != 0);
+
+    ZeroMemory(&vd->d3dpp, sizeof(D3DPRESENT_PARAMETERS));
+    vd->d3dpp.Windowed = TRUE;
+    vd->d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
+    vd->d3dpp.BackBufferWidth = (UINT)viewport->Size.x;
+    vd->d3dpp.BackBufferHeight = (UINT)viewport->Size.y;
+    vd->d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;
+    vd->d3dpp.hDeviceWindow = hwnd;
+    vd->d3dpp.EnableAutoDepthStencil = FALSE;
+    vd->d3dpp.AutoDepthStencilFormat = D3DFMT_D16;
+    vd->d3dpp.PresentationInterval = D3DPRESENT_INTERVAL_IMMEDIATE;   // Present without vsync
+
+    HRESULT hr = bd->pd3dDevice->CreateAdditionalSwapChain(&vd->d3dpp, &vd->SwapChain); IM_UNUSED(hr);
+    IM_ASSERT(hr == D3D_OK);
+    IM_ASSERT(vd->SwapChain != nullptr);
+}
+
+static void ImGui_ImplDX9_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    if (ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData)
+    {
+        if (vd->SwapChain)
+            vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        ZeroMemory(&vd->d3dpp, sizeof(D3DPRESENT_PARAMETERS));
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplDX9_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    if (vd->SwapChain)
+    {
+        vd->SwapChain->Release();
+        vd->SwapChain = nullptr;
+        vd->d3dpp.BackBufferWidth = (UINT)size.x;
+        vd->d3dpp.BackBufferHeight = (UINT)size.y;
+        HRESULT hr = bd->pd3dDevice->CreateAdditionalSwapChain(&vd->d3dpp, &vd->SwapChain); IM_UNUSED(hr);
+        IM_ASSERT(hr == D3D_OK);
+    }
+}
+
+static void ImGui_ImplDX9_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+
+    LPDIRECT3DSURFACE9 render_target = nullptr;
+    LPDIRECT3DSURFACE9 last_render_target = nullptr;
+    LPDIRECT3DSURFACE9 last_depth_stencil = nullptr;
+    vd->SwapChain->GetBackBuffer(0, D3DBACKBUFFER_TYPE_MONO, &render_target);
+    bd->pd3dDevice->GetRenderTarget(0, &last_render_target);
+    bd->pd3dDevice->GetDepthStencilSurface(&last_depth_stencil);
+    bd->pd3dDevice->SetRenderTarget(0, render_target);
+    bd->pd3dDevice->SetDepthStencilSurface(nullptr);
+
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+    {
+        D3DCOLOR clear_col_dx = D3DCOLOR_RGBA((int)(clear_color.x*255.0f), (int)(clear_color.y*255.0f), (int)(clear_color.z*255.0f), (int)(clear_color.w*255.0f));
+        bd->pd3dDevice->Clear(0, nullptr, D3DCLEAR_TARGET, clear_col_dx, 1.0f, 0);
+    }
+
+    ImGui_ImplDX9_RenderDrawData(viewport->DrawData);
+
+    // Restore render target
+    bd->pd3dDevice->SetRenderTarget(0, last_render_target);
+    bd->pd3dDevice->SetDepthStencilSurface(last_depth_stencil);
+    render_target->Release();
+    last_render_target->Release();
+    if (last_depth_stencil) last_depth_stencil->Release();
+}
+
+static void ImGui_ImplDX9_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplDX9_ViewportData* vd = (ImGui_ImplDX9_ViewportData*)viewport->RendererUserData;
+    HRESULT hr = vd->SwapChain->Present(nullptr, nullptr, vd->d3dpp.hDeviceWindow, nullptr, 0);
+    // Let main application handle D3DERR_DEVICELOST by resetting the device.
+    IM_ASSERT(SUCCEEDED(hr) || hr == D3DERR_DEVICELOST);
+}
+
+static void ImGui_ImplDX9_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplDX9_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplDX9_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplDX9_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplDX9_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplDX9_SwapBuffers;
+}
+
+static void ImGui_ImplDX9_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+static void ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (!platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplDX9_CreateWindow(platform_io.Viewports[i]);
+}
+
+static void ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplDX9_DestroyWindow(platform_io.Viewports[i]);
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_dx9.h

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. Win32)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: IMGUI_USE_BGRA_PACKED_COLOR support, as this is the optimal color encoding for DirectX9.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -30,4 +32,7 @@ IMGUI_IMPL_API void     ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data);
 IMGUI_IMPL_API bool     ImGui_ImplDX9_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplDX9_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplDX9_UpdateTexture(ImTextureData* tex);
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_glfw.h

@@ -1,6 +1,7 @@
 // dear imgui: Platform Backend for GLFW
 // This needs to be used along with a Renderer (e.g. OpenGL3, Vulkan, WebGPU..)
 // (Info: GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
+// (Requires: GLFW 3.1+. Prefer GLFW 3.3+ for full feature support.)
 
 // Implemented features:
 //  [X] Platform: Clipboard support.
@@ -8,9 +9,12 @@
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy GLFW_KEY_* values are obsolete since 1.87 and not supported since 1.91.5]
 //  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Resizing cursors requires GLFW 3.4+! Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Multiple Dear ImGui contexts support.
 // Missing features or Issues:
 //  [ ] Touch events are only correctly identified as Touch on Windows. This create issues with some interactions. GLFW doesn't provide a way to identify touch inputs from mouse inputs, we cannot call io.AddMouseSourceEvent() to identify the source. We provide a Windows-specific workaround.
 //  [ ] Missing ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress cursors.
+//  [ ] Multi-viewport: ParentViewportID not honored, and so io.ConfigViewportsNoDefaultParent has no effect (minor).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -62,5 +66,8 @@ IMGUI_IMPL_API void     ImGui_ImplGlfw_MonitorCallback(GLFWmonitor* monitor, int
 
 // GLFW helpers
 IMGUI_IMPL_API void     ImGui_ImplGlfw_Sleep(int milliseconds);
+IMGUI_IMPL_API float    ImGui_ImplGlfw_GetContentScaleForWindow(GLFWwindow* window);
+IMGUI_IMPL_API float    ImGui_ImplGlfw_GetContentScaleForMonitor(GLFWmonitor* monitor);
+
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_glut.cpp

@@ -13,6 +13,7 @@
 //  [ ] Platform: Missing mouse cursor shape/visibility support.
 //  [ ] Platform: Missing clipboard support (not supported by Glut).
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Platform: Missing multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_glut.h

@@ -13,6 +13,7 @@
 //  [ ] Platform: Missing mouse cursor shape/visibility support.
 //  [ ] Platform: Missing clipboard support (not supported by Glut).
 //  [ ] Platform: Missing gamepad support.
+//  [ ] Platform: Missing multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_metal.h

@@ -2,8 +2,10 @@
 // This needs to be used along with a Platform Backend (e.g. OSX)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'MTLTexture' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -35,11 +37,12 @@ IMGUI_IMPL_API void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData,
                                                    id<MTLRenderCommandEncoder> commandEncoder);
 
 // Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool ImGui_ImplMetal_CreateFontsTexture(id<MTLDevice> device);
-IMGUI_IMPL_API void ImGui_ImplMetal_DestroyFontsTexture();
 IMGUI_IMPL_API bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device);
 IMGUI_IMPL_API void ImGui_ImplMetal_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void ImGui_ImplMetal_UpdateTexture(ImTextureData* tex);
+
 #endif
 
 //-----------------------------------------------------------------------------
@@ -62,11 +65,12 @@ IMGUI_IMPL_API void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data,
                                                    MTL::RenderCommandEncoder* commandEncoder);
 
 // Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool ImGui_ImplMetal_CreateFontsTexture(MTL::Device* device);
-IMGUI_IMPL_API void ImGui_ImplMetal_DestroyFontsTexture();
 IMGUI_IMPL_API bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device);
 IMGUI_IMPL_API void ImGui_ImplMetal_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void ImGui_ImplMetal_UpdateTexture(ImTextureData* tex);
+
 #endif
 #endif
 

backends/imgui_impl_metal.mm

@@ -2,8 +2,10 @@
 // This needs to be used along with a Platform Backend (e.g. OSX)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'MTLTexture' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -15,8 +17,10 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Metal: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplMetal_CreateFontsTexture() and ImGui_ImplMetal_DestroyFontsTexture().
 //  2025-02-03: Metal: Crash fix. (#8367)
-//  2024-01-08: Metal: Fixed memory leaks when using metal-cpp (#8276, #8166) or when using multiple contexts (#7419).
+//  2025-01-08: Metal: Fixed memory leaks when using metal-cpp (#8276, #8166) or when using multiple contexts (#7419).
 //  2022-08-23: Metal: Update deprecated property 'sampleCount'->'rasterSampleCount'.
 //  2022-07-05: Metal: Add dispatch synchronization.
 //  2022-06-30: Metal: Use __bridge for ARC based systems.
@@ -40,6 +44,12 @@
 #import <time.h>
 #import <Metal/Metal.h>
 
+// Forward Declarations
+static void ImGui_ImplMetal_InitMultiViewportSupport();
+static void ImGui_ImplMetal_ShutdownMultiViewportSupport();
+static void ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows();
+static void ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows();
+
 #pragma mark - Support classes
 
 // A wrapper around a MTLBuffer object that knows the last time it was reused
@@ -59,6 +69,11 @@
 - (instancetype)initWithRenderPassDescriptor:(MTLRenderPassDescriptor*)renderPassDescriptor;
 @end
 
+@interface MetalTexture : NSObject
+@property (nonatomic, strong) id<MTLTexture> metalTexture;
+- (instancetype)initWithTexture:(id<MTLTexture>)metalTexture;
+@end
+
 // A singleton that stores long-lived objects that are needed by the Metal
 // renderer backend. Stores the render pipeline state cache and the default
 // font texture, and manages the reusable buffer cache.
@@ -67,7 +82,6 @@
 @property (nonatomic, strong) id<MTLDepthStencilState>      depthStencilState;
 @property (nonatomic, strong) FramebufferDescriptor*        framebufferDescriptor; // framebuffer descriptor for current frame; transient
 @property (nonatomic, strong) NSMutableDictionary*          renderPipelineStateCache; // pipeline cache; keyed on framebuffer descriptors
-@property (nonatomic, strong, nullable) id<MTLTexture>      fontTexture;
 @property (nonatomic, strong) NSMutableArray<MetalBuffer*>* bufferCache;
 @property (nonatomic, assign) double                        lastBufferCachePurge;
 - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLDevice>)device;
@@ -110,11 +124,6 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data,
 
 }
 
-bool ImGui_ImplMetal_CreateFontsTexture(MTL::Device* device)
-{
-    return ImGui_ImplMetal_CreateFontsTexture((__bridge id<MTLDevice>)(device));
-}
-
 bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
 {
     return ImGui_ImplMetal_CreateDeviceObjects((__bridge id<MTLDevice>)(device));
@@ -134,10 +143,14 @@ bool ImGui_ImplMetal_Init(id<MTLDevice> device)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_metal";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     bd->SharedMetalContext = [[MetalContext alloc] init];
     bd->SharedMetalContext.device = device;
 
+    ImGui_ImplMetal_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -146,13 +159,14 @@ void ImGui_ImplMetal_Shutdown()
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
     IM_UNUSED(bd);
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGui_ImplMetal_ShutdownMultiViewportSupport();
     ImGui_ImplMetal_DestroyDeviceObjects();
     ImGui_ImplMetal_DestroyBackendData();
 
     ImGuiIO& io = ImGui::GetIO();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
 }
 
 void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
@@ -168,7 +182,7 @@ void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
         ImGui_ImplMetal_CreateDeviceObjects(bd->SharedMetalContext.device);
 }
 
-static void ImGui_ImplMetal_SetupRenderState(ImDrawData* drawData, id<MTLCommandBuffer> commandBuffer,
+static void ImGui_ImplMetal_SetupRenderState(ImDrawData* draw_data, id<MTLCommandBuffer> commandBuffer,
     id<MTLRenderCommandEncoder> commandEncoder, id<MTLRenderPipelineState> renderPipelineState,
     MetalBuffer* vertexBuffer, size_t vertexBufferOffset)
 {
@@ -184,17 +198,17 @@ static void ImGui_ImplMetal_SetupRenderState(ImDrawData* drawData, id<MTLCommand
     {
         .originX = 0.0,
         .originY = 0.0,
-        .width = (double)(drawData->DisplaySize.x * drawData->FramebufferScale.x),
-        .height = (double)(drawData->DisplaySize.y * drawData->FramebufferScale.y),
+        .width = (double)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x),
+        .height = (double)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y),
         .znear = 0.0,
         .zfar = 1.0
     };
     [commandEncoder setViewport:viewport];
 
-    float L = drawData->DisplayPos.x;
-    float R = drawData->DisplayPos.x + drawData->DisplaySize.x;
-    float T = drawData->DisplayPos.y;
-    float B = drawData->DisplayPos.y + drawData->DisplaySize.y;
+    float L = draw_data->DisplayPos.x;
+    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
+    float T = draw_data->DisplayPos.y;
+    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
     float N = (float)viewport.znear;
     float F = (float)viewport.zfar;
     const float ortho_projection[4][4] =
@@ -213,17 +227,24 @@ static void ImGui_ImplMetal_SetupRenderState(ImDrawData* drawData, id<MTLCommand
 }
 
 // Metal Render function.
-void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder)
+void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data, id<MTLCommandBuffer> commandBuffer, id<MTLRenderCommandEncoder> commandEncoder)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
     MetalContext* ctx = bd->SharedMetalContext;
 
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-    int fb_width = (int)(drawData->DisplaySize.x * drawData->FramebufferScale.x);
-    int fb_height = (int)(drawData->DisplaySize.y * drawData->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || drawData->CmdListsCount == 0)
+    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
+    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdLists.Size == 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplMetal_UpdateTexture(tex);
+
     // Try to retrieve a render pipeline state that is compatible with the framebuffer config for this frame
     // The hit rate for this cache should be very near 100%.
     id<MTLRenderPipelineState> renderPipelineState = ctx.renderPipelineStateCache[ctx.framebufferDescriptor];
@@ -236,24 +257,22 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> c
         ctx.renderPipelineStateCache[ctx.framebufferDescriptor] = renderPipelineState;
     }
 
-    size_t vertexBufferLength = (size_t)drawData->TotalVtxCount * sizeof(ImDrawVert);
-    size_t indexBufferLength = (size_t)drawData->TotalIdxCount * sizeof(ImDrawIdx);
+    size_t vertexBufferLength = (size_t)draw_data->TotalVtxCount * sizeof(ImDrawVert);
+    size_t indexBufferLength = (size_t)draw_data->TotalIdxCount * sizeof(ImDrawIdx);
     MetalBuffer* vertexBuffer = [ctx dequeueReusableBufferOfLength:vertexBufferLength device:commandBuffer.device];
     MetalBuffer* indexBuffer = [ctx dequeueReusableBufferOfLength:indexBufferLength device:commandBuffer.device];
 
-    ImGui_ImplMetal_SetupRenderState(drawData, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, 0);
+    ImGui_ImplMetal_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, 0);
 
     // Will project scissor/clipping rectangles into framebuffer space
-    ImVec2 clip_off = drawData->DisplayPos;         // (0,0) unless using multi-viewports
-    ImVec2 clip_scale = drawData->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
+    ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
+    ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
     size_t vertexBufferOffset = 0;
     size_t indexBufferOffset = 0;
-    for (int n = 0; n < drawData->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = drawData->CmdLists[n];
-
         memcpy((char*)vertexBuffer.buffer.contents + vertexBufferOffset, draw_list->VtxBuffer.Data, (size_t)draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy((char*)indexBuffer.buffer.contents + indexBufferOffset, draw_list->IdxBuffer.Data, (size_t)draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
 
@@ -265,7 +284,7 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> c
                 // User callback, registered via ImDrawList::AddCallback()
                 // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
                 if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
-                    ImGui_ImplMetal_SetupRenderState(drawData, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, vertexBufferOffset);
+                    ImGui_ImplMetal_SetupRenderState(draw_data, commandBuffer, commandEncoder, renderPipelineState, vertexBuffer, vertexBufferOffset);
                 else
                     pcmd->UserCallback(draw_list, pcmd);
             }
@@ -325,42 +344,71 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> c
     }];
 }
 
-bool ImGui_ImplMetal_CreateFontsTexture(id<MTLDevice> device)
+static void ImGui_ImplMetal_DestroyTexture(ImTextureData* tex)
 {
-    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    ImGuiIO& io = ImGui::GetIO();
+    MetalTexture* backend_tex = (__bridge_transfer MetalTexture*)(tex->BackendUserData);
+    if (backend_tex == nullptr)
+        return;
+    IM_ASSERT(backend_tex.metalTexture == (__bridge id<MTLTexture>)(void*)(intptr_t)tex->TexID);
+    backend_tex.metalTexture = nil;
 
-    // We are retrieving and uploading the font atlas as a 4-channels RGBA texture here.
-    // In theory we could call GetTexDataAsAlpha8() and upload a 1-channel texture to save on memory access bandwidth.
-    // However, using a shader designed for 1-channel texture would make it less obvious to use the ImTextureID facility to render users own textures.
-    // You can make that change in your implementation.
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
-    MTLTextureDescriptor* textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm
-                                                                                                 width:(NSUInteger)width
-                                                                                                height:(NSUInteger)height
-                                                                                             mipmapped:NO];
-    textureDescriptor.usage = MTLTextureUsageShaderRead;
-#if TARGET_OS_OSX || TARGET_OS_MACCATALYST
-    textureDescriptor.storageMode = MTLStorageModeManaged;
-#else
-    textureDescriptor.storageMode = MTLStorageModeShared;
-#endif
-    id <MTLTexture> texture = [device newTextureWithDescriptor:textureDescriptor];
-    [texture replaceRegion:MTLRegionMake2D(0, 0, (NSUInteger)width, (NSUInteger)height) mipmapLevel:0 withBytes:pixels bytesPerRow:(NSUInteger)width * 4];
-    bd->SharedMetalContext.fontTexture = texture;
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)(__bridge void*)bd->SharedMetalContext.fontTexture); // ImTextureID == ImU64
-
-    return (bd->SharedMetalContext.fontTexture != nil);
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+    tex->BackendUserData = nullptr;
 }
 
-void ImGui_ImplMetal_DestroyFontsTexture()
+void ImGui_ImplMetal_UpdateTexture(ImTextureData* tex)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    ImGuiIO& io = ImGui::GetIO();
-    bd->SharedMetalContext.fontTexture = nil;
-    io.Fonts->SetTexID(0);
+    if (tex->Status == ImTextureStatus_WantCreate)
+    {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // We are retrieving and uploading the font atlas as a 4-channels RGBA texture here.
+        // In theory we could call GetTexDataAsAlpha8() and upload a 1-channel texture to save on memory access bandwidth.
+        // However, using a shader designed for 1-channel texture would make it less obvious to use the ImTextureID facility to render users own textures.
+        // You can make that change in your implementation.
+        MTLTextureDescriptor* textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm
+                                                                                                     width:(NSUInteger)tex->Width
+                                                                                                    height:(NSUInteger)tex->Height
+                                                                                                 mipmapped:NO];
+        textureDescriptor.usage = MTLTextureUsageShaderRead;
+    #if TARGET_OS_OSX || TARGET_OS_MACCATALYST
+        textureDescriptor.storageMode = MTLStorageModeManaged;
+    #else
+        textureDescriptor.storageMode = MTLStorageModeShared;
+    #endif
+        id <MTLTexture> texture = [bd->SharedMetalContext.device newTextureWithDescriptor:textureDescriptor];
+        [texture replaceRegion:MTLRegionMake2D(0, 0, (NSUInteger)tex->Width, (NSUInteger)tex->Height) mipmapLevel:0 withBytes:tex->Pixels bytesPerRow:(NSUInteger)tex->Width * 4];
+        MetalTexture* backend_tex = [[MetalTexture alloc] initWithTexture:texture];
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)texture);
+        tex->SetStatus(ImTextureStatus_OK);
+        tex->BackendUserData = (__bridge_retained void*)(backend_tex);
+    }
+    else if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        MetalTexture* backend_tex = (__bridge MetalTexture*)(tex->BackendUserData);
+        for (ImTextureRect& r : tex->Updates)
+        {
+            [backend_tex.metalTexture replaceRegion:MTLRegionMake2D((NSUInteger)r.x, (NSUInteger)r.y, (NSUInteger)r.w, (NSUInteger)r.h)
+                                        mipmapLevel:0
+                                          withBytes:tex->GetPixelsAt(r.x, r.y)
+                                        bytesPerRow:(NSUInteger)tex->Width * 4];
+        }
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+    {
+        ImGui_ImplMetal_DestroyTexture(tex);
+    }
 }
 
 bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device)
@@ -370,20 +418,171 @@ bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device)
     depthStencilDescriptor.depthWriteEnabled = NO;
     depthStencilDescriptor.depthCompareFunction = MTLCompareFunctionAlways;
     bd->SharedMetalContext.depthStencilState = [device newDepthStencilStateWithDescriptor:depthStencilDescriptor];
+    ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows();
 #ifdef IMGUI_IMPL_METAL_CPP
     [depthStencilDescriptor release];
 #endif
-    ImGui_ImplMetal_CreateFontsTexture(device);
+
     return true;
 }
 
 void ImGui_ImplMetal_DestroyDeviceObjects()
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    ImGui_ImplMetal_DestroyFontsTexture();
+
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplMetal_DestroyTexture(tex);
+
+    ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows();
     [bd->SharedMetalContext.renderPipelineStateCache removeAllObjects];
 }
 
+#pragma mark - Multi-viewport support
+
+#import <QuartzCore/CAMetalLayer.h>
+
+#if TARGET_OS_OSX
+#import <Cocoa/Cocoa.h>
+#endif
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the back-end to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+struct ImGuiViewportDataMetal
+{
+    CAMetalLayer*               MetalLayer;
+    id<MTLCommandQueue>         CommandQueue;
+    MTLRenderPassDescriptor*    RenderPassDescriptor;
+    void*                       Handle = nullptr;
+    bool                        FirstFrame = true;
+};
+
+static void ImGui_ImplMetal_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
+    ImGuiViewportDataMetal* data = IM_NEW(ImGuiViewportDataMetal)();
+    viewport->RendererUserData = data;
+
+    // PlatformHandleRaw should always be a NSWindow*, whereas PlatformHandle might be a higher-level handle (e.g. GLFWWindow*, SDL_Window*).
+    // Some back-ends will leave PlatformHandleRaw == 0, in which case we assume PlatformHandle will contain the NSWindow*.
+    void* handle = viewport->PlatformHandleRaw ? viewport->PlatformHandleRaw : viewport->PlatformHandle;
+    IM_ASSERT(handle != nullptr);
+
+    id<MTLDevice> device = bd->SharedMetalContext.device;
+    CAMetalLayer* layer = [CAMetalLayer layer];
+    layer.device = device;
+    layer.framebufferOnly = YES;
+    layer.pixelFormat = bd->SharedMetalContext.framebufferDescriptor.colorPixelFormat;
+#if TARGET_OS_OSX
+    NSWindow* window = (__bridge NSWindow*)handle;
+    NSView* view = window.contentView;
+    view.layer = layer;
+    view.wantsLayer = YES;
+#endif
+    data->MetalLayer = layer;
+    data->CommandQueue = [device newCommandQueue];
+    data->RenderPassDescriptor = [[MTLRenderPassDescriptor alloc] init];
+    data->Handle = handle;
+}
+
+static void ImGui_ImplMetal_DestroyWindow(ImGuiViewport* viewport)
+{
+    // The main viewport (owned by the application) will always have RendererUserData == 0 since we didn't create the data for it.
+    if (ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData)
+        IM_DELETE(data);
+    viewport->RendererUserData = nullptr;
+}
+
+inline static CGSize MakeScaledSize(CGSize size, CGFloat scale)
+{
+    return CGSizeMake(size.width * scale, size.height * scale);
+}
+
+static void ImGui_ImplMetal_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData;
+    data->MetalLayer.drawableSize = MakeScaledSize(CGSizeMake(size.x, size.y), viewport->DpiScale);
+}
+
+static void ImGui_ImplMetal_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGuiViewportDataMetal* data = (ImGuiViewportDataMetal*)viewport->RendererUserData;
+
+#if TARGET_OS_OSX
+    void* handle = viewport->PlatformHandleRaw ? viewport->PlatformHandleRaw : viewport->PlatformHandle;
+    NSWindow* window = (__bridge NSWindow*)handle;
+
+    // Always render the first frame, regardless of occlusionState, to avoid an initial flicker
+    if ((window.occlusionState & NSWindowOcclusionStateVisible) == 0 && !data->FirstFrame)
+    {
+        // Do not render windows which are completely occluded. Calling -[CAMetalLayer nextDrawable] will hang for
+        // approximately 1 second if the Metal layer is completely occluded.
+        return;
+    }
+    data->FirstFrame = false;
+
+    float fb_scale = (float)window.backingScaleFactor;
+    if (data->MetalLayer.contentsScale != fb_scale)
+    {
+        data->MetalLayer.contentsScale = fb_scale;
+        data->MetalLayer.drawableSize = MakeScaledSize(window.frame.size, fb_scale);
+    }
+#endif
+
+    id <CAMetalDrawable> drawable = [data->MetalLayer nextDrawable];
+    if (drawable == nil)
+        return;
+
+    MTLRenderPassDescriptor* renderPassDescriptor = data->RenderPassDescriptor;
+    renderPassDescriptor.colorAttachments[0].texture = drawable.texture;
+    renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(0, 0, 0, 0);
+    if ((viewport->Flags & ImGuiViewportFlags_NoRendererClear) == 0)
+        renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
+
+    id <MTLCommandBuffer> commandBuffer = [data->CommandQueue commandBuffer];
+    id <MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
+    ImGui_ImplMetal_RenderDrawData(viewport->DrawData, commandBuffer, renderEncoder);
+    [renderEncoder endEncoding];
+
+    [commandBuffer presentDrawable:drawable];
+    [commandBuffer commit];
+}
+
+static void ImGui_ImplMetal_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_CreateWindow = ImGui_ImplMetal_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplMetal_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplMetal_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplMetal_RenderWindow;
+}
+
+static void ImGui_ImplMetal_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+static void ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (!platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplMetal_CreateWindow(platform_io.Viewports[i]);
+}
+
+static void ImGui_ImplMetal_InvalidateDeviceObjectsForPlatformWindows()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int i = 1; i < platform_io.Viewports.Size; i++)
+        if (platform_io.Viewports[i]->RendererUserData)
+            ImGui_ImplMetal_DestroyWindow(platform_io.Viewports[i]);
+}
+
 #pragma mark - MetalBuffer implementation
 
 @implementation MetalBuffer
@@ -446,6 +645,18 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
 
 @end
 
+#pragma mark - MetalTexture implementation
+
+@implementation MetalTexture
+- (instancetype)initWithTexture:(id<MTLTexture>)metalTexture
+{
+    if ((self = [super init]))
+        self.metalTexture = metalTexture;
+    return self;
+}
+
+@end
+
 #pragma mark - MetalContext implementation
 
 @implementation MetalContext

backends/imgui_impl_opengl2.cpp

@@ -2,7 +2,9 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 // Missing features or Issues:
 //  [ ] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 
@@ -24,6 +26,9 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-07-15: OpenGL: Set GL_UNPACK_ALIGNMENT to 1 before updating textures. (#8802)
+//  2025-06-11: OpenGL: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplOpenGL2_CreateFontsTexture() and ImGui_ImplOpenGL2_DestroyFontsTexture().
 //  2024-10-07: OpenGL: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-06-28: OpenGL: ImGui_ImplOpenGL2_NewFrame() recreates font texture if it has been destroyed by ImGui_ImplOpenGL2_DestroyFontsTexture(). (#7748)
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -81,8 +86,6 @@
 // OpenGL data
 struct ImGui_ImplOpenGL2_Data
 {
-    GLuint       FontTexture;
-
     ImGui_ImplOpenGL2_Data() { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -93,6 +96,10 @@ static ImGui_ImplOpenGL2_Data* ImGui_ImplOpenGL2_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL2_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL2_InitMultiViewportSupport();
+static void ImGui_ImplOpenGL2_ShutdownMultiViewportSupport();
+
 // Functions
 bool    ImGui_ImplOpenGL2_Init()
 {
@@ -104,6 +111,10 @@ bool    ImGui_ImplOpenGL2_Init()
     ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_opengl2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;      // We can create multi-viewports on the Renderer side (optional)
+
+    ImGui_ImplOpenGL2_InitMultiViewportSupport();
 
     return true;
 }
@@ -114,9 +125,11 @@ void    ImGui_ImplOpenGL2_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplOpenGL2_ShutdownMultiViewportSupport();
     ImGui_ImplOpenGL2_DestroyDeviceObjects();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -124,11 +137,7 @@ void    ImGui_ImplOpenGL2_NewFrame()
 {
     ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplOpenGL2_Init()?");
-
-    if (!bd->FontTexture)
-        ImGui_ImplOpenGL2_CreateDeviceObjects();
-    if (!bd->FontTexture)
-        ImGui_ImplOpenGL2_CreateFontsTexture();
+    IM_UNUSED(bd);
 }
 
 static void ImGui_ImplOpenGL2_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height)
@@ -186,6 +195,13 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     if (fb_width == 0 || fb_height == 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplOpenGL2_UpdateTexture(tex);
+
     // Backup GL state
     GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
     GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
@@ -203,9 +219,8 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
         glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + offsetof(ImDrawVert, pos)));
@@ -259,57 +274,108 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, last_tex_env_mode);
 }
 
-bool ImGui_ImplOpenGL2_CreateFontsTexture()
+void ImGui_ImplOpenGL2_UpdateTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
-
-    // Upload texture to graphics system
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    GLint last_texture;
-    glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
-    glGenTextures(1, &bd->FontTexture);
-    glBindTexture(GL_TEXTURE_2D, bd->FontTexture);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
-    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
-
-    // Restore state
-    glBindTexture(GL_TEXTURE_2D, last_texture);
-
-    return true;
-}
-
-void ImGui_ImplOpenGL2_DestroyFontsTexture()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
-    if (bd->FontTexture)
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
-        glDeleteTextures(1, &bd->FontTexture);
-        io.Fonts->SetTexID(0);
-        bd->FontTexture = 0;
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        const void* pixels = tex->GetPixels();
+        GLuint gl_texture_id = 0;
+
+        // Upload texture to graphics system
+        // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+        GLint last_texture;
+        GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
+        GL_CALL(glGenTextures(1, &gl_texture_id));
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, gl_texture_id));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP));
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
+        GL_CALL(glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
+        GL_CALL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex->Width, tex->Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)gl_texture_id);
+        tex->SetStatus(ImTextureStatus_OK);
+
+        // Restore state
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, last_texture));
+    }
+    else if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        GLint last_texture;
+        GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
+
+        GLuint gl_tex_id = (GLuint)(intptr_t)tex->TexID;
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, gl_tex_id));
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, tex->Width));
+        GL_CALL(glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
+        for (ImTextureRect& r : tex->Updates)
+            GL_CALL(glTexSubImage2D(GL_TEXTURE_2D, 0, r.x, r.y, r.w, r.h, GL_RGBA, GL_UNSIGNED_BYTE, tex->GetPixelsAt(r.x, r.y)));
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, last_texture)); // Restore state
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        GLuint gl_tex_id = (GLuint)(intptr_t)tex->TexID;
+        glDeleteTextures(1, &gl_tex_id);
+
+        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
     }
 }
 
 bool    ImGui_ImplOpenGL2_CreateDeviceObjects()
 {
-    return ImGui_ImplOpenGL2_CreateFontsTexture();
+    return true;
 }
 
 void    ImGui_ImplOpenGL2_DestroyDeviceObjects()
 {
-    ImGui_ImplOpenGL2_DestroyFontsTexture();
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+        {
+            tex->SetStatus(ImTextureStatus_WantDestroy);
+            ImGui_ImplOpenGL2_UpdateTexture(tex);
+        }
+}
+
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplOpenGL2_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+    {
+        ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+    }
+    ImGui_ImplOpenGL2_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplOpenGL2_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL2_RenderWindow;
+}
+
+static void ImGui_ImplOpenGL2_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_opengl2.h

@@ -2,7 +2,9 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 // Missing features or Issues:
 //  [ ] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 
@@ -33,9 +35,10 @@ IMGUI_IMPL_API void     ImGui_ImplOpenGL2_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data);
 
 // Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool     ImGui_ImplOpenGL2_CreateFontsTexture();
-IMGUI_IMPL_API void     ImGui_ImplOpenGL2_DestroyFontsTexture();
 IMGUI_IMPL_API bool     ImGui_ImplOpenGL2_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL2_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplOpenGL2_UpdateTexture(ImTextureData* tex);
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_opengl3.cpp

@@ -4,8 +4,10 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [x] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset) [Desktop OpenGL only!]
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // About WebGL/ES:
 // - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
@@ -22,6 +24,11 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-07-22: OpenGL: Add and call embedded loader shutdown during ImGui_ImplOpenGL3_Shutdown() to facilitate multiple init/shutdown cycles in same process. (#8792)
+//  2025-07-15: OpenGL: Set GL_UNPACK_ALIGNMENT to 1 before updating textures (#8802) + restore non-WebGL/ES update path that doesn't require a CPU-side copy.
+//  2025-06-11: OpenGL: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplOpenGL3_CreateFontsTexture() and ImGui_ImplOpenGL3_DestroyFontsTexture().
+//  2025-06-04: OpenGL: Made GLES 3.20 contexts not access GL_CONTEXT_PROFILE_MASK nor GL_PRIMITIVE_RESTART. (#8664)
 //  2025-02-18: OpenGL: Lazily reinitialize embedded GL loader for when calling backend from e.g. other DLL boundaries. (#8406)
 //  2024-10-07: OpenGL: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-06-28: OpenGL: ImGui_ImplOpenGL3_NewFrame() recreates font texture if it has been destroyed by ImGui_ImplOpenGL3_DestroyFontsTexture(). (#7748)
@@ -230,7 +237,7 @@ struct ImGui_ImplOpenGL3_Data
     bool            GlProfileIsES3;
     bool            GlProfileIsCompat;
     GLint           GlProfileMask;
-    GLuint          FontTexture;
+    GLint           MaxTextureSize;
     GLuint          ShaderHandle;
     GLint           AttribLocationTex;       // Uniforms location
     GLint           AttribLocationProjMtx;
@@ -241,8 +248,10 @@ struct ImGui_ImplOpenGL3_Data
     GLsizeiptr      VertexBufferSize;
     GLsizeiptr      IndexBufferSize;
     bool            HasPolygonMode;
+    bool            HasBindSampler;
     bool            HasClipOrigin;
     bool            UseBufferSubData;
+    ImVector<char>  TempBuffer;
 
     ImGui_ImplOpenGL3_Data() { memset((void*)this, 0, sizeof(*this)); }
 };
@@ -254,6 +263,10 @@ static ImGui_ImplOpenGL3_Data* ImGui_ImplOpenGL3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL3_InitMultiViewportSupport();
+static void ImGui_ImplOpenGL3_ShutdownMultiViewportSupport();
+
 // OpenGL vertex attribute state (for ES 1.0 and ES 2.0 only)
 #ifndef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
 struct ImGui_ImplOpenGL3_VtxAttribState
@@ -325,11 +338,7 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     if (major == 0 && minor == 0)
         sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
     bd->GlVersion = (GLuint)(major * 100 + minor * 10);
-#if defined(GL_CONTEXT_PROFILE_MASK)
-    if (bd->GlVersion >= 320)
-        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
-    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
-#endif
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &bd->MaxTextureSize);
 
 #if defined(IMGUI_IMPL_OPENGL_ES3)
     bd->GlProfileIsES3 = true;
@@ -338,6 +347,12 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
         bd->GlProfileIsES3 = true;
 #endif
 
+#if defined(GL_CONTEXT_PROFILE_MASK)
+    if (!bd->GlProfileIsES3 && bd->GlVersion >= 320)
+        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
+    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
+#endif
+
     bd->UseBufferSubData = false;
     /*
     // Query vendor to enable glBufferSubData kludge
@@ -357,6 +372,11 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     if (bd->GlVersion >= 320)
         io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 #endif
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;      // We can create multi-viewports on the Renderer side (optional)
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = (int)bd->MaxTextureSize;
 
     // Store GLSL version string so we can refer to it later in case we recreate shaders.
     // Note: GLSL version is NOT the same as GL version. Leave this to nullptr if unsure.
@@ -384,6 +404,9 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     // Detect extensions we support
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
     bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
+#endif
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
+    bd->HasBindSampler = (bd->GlVersion >= 330 || bd->GlProfileIsES3);
 #endif
     bd->HasClipOrigin = (bd->GlVersion >= 450);
 #ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
@@ -397,6 +420,8 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     }
 #endif
 
+    ImGui_ImplOpenGL3_InitMultiViewportSupport();
+
     return true;
 }
 
@@ -406,11 +431,16 @@ void    ImGui_ImplOpenGL3_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplOpenGL3_ShutdownMultiViewportSupport();
     ImGui_ImplOpenGL3_DestroyDeviceObjects();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
+
+#ifdef IMGUI_IMPL_OPENGL_LOADER_IMGL3W
+    imgl3wShutdown();
+#endif
 }
 
 void    ImGui_ImplOpenGL3_NewFrame()
@@ -421,9 +451,8 @@ void    ImGui_ImplOpenGL3_NewFrame()
     ImGui_ImplOpenGL3_InitLoader(); // Lazily init loader if not already done for e.g. DLL boundaries.
 
     if (!bd->ShaderHandle)
-        ImGui_ImplOpenGL3_CreateDeviceObjects();
-    if (!bd->FontTexture)
-        ImGui_ImplOpenGL3_CreateFontsTexture();
+        if (!ImGui_ImplOpenGL3_CreateDeviceObjects())
+            IM_ASSERT(0 && "ImGui_ImplOpenGL3_CreateDeviceObjects() failed!");
 }
 
 static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
@@ -439,7 +468,7 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
     glDisable(GL_STENCIL_TEST);
     glEnable(GL_SCISSOR_TEST);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
-    if (bd->GlVersion >= 310)
+    if (!bd->GlProfileIsES3 && bd->GlVersion >= 310)
         glDisable(GL_PRIMITIVE_RESTART);
 #endif
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
@@ -480,7 +509,7 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
     glUniformMatrix4fv(bd->AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
 
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    if (bd->GlVersion >= 330 || bd->GlProfileIsES3)
+    if (bd->HasBindSampler)
         glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 and GL ES 3.0 may set that otherwise.
 #endif
 
@@ -515,13 +544,20 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplOpenGL3_UpdateTexture(tex);
+
     // Backup GL state
     GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
     glActiveTexture(GL_TEXTURE0);
     GLuint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, (GLint*)&last_program);
     GLuint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, (GLint*)&last_texture);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    GLuint last_sampler; if (bd->GlVersion >= 330 || bd->GlProfileIsES3) { glGetIntegerv(GL_SAMPLER_BINDING, (GLint*)&last_sampler); } else { last_sampler = 0; }
+    GLuint last_sampler; if (bd->HasBindSampler) { glGetIntegerv(GL_SAMPLER_BINDING, (GLint*)&last_sampler); } else { last_sampler = 0; }
 #endif
     GLuint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, (GLint*)&last_array_buffer);
 #ifndef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
@@ -551,7 +587,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     GLboolean last_enable_stencil_test = glIsEnabled(GL_STENCIL_TEST);
     GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
-    GLboolean last_enable_primitive_restart = (bd->GlVersion >= 310) ? glIsEnabled(GL_PRIMITIVE_RESTART) : GL_FALSE;
+    GLboolean last_enable_primitive_restart = (!bd->GlProfileIsES3 && bd->GlVersion >= 310) ? glIsEnabled(GL_PRIMITIVE_RESTART) : GL_FALSE;
 #endif
 
     // Setup desired GL state
@@ -568,10 +604,8 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
-
         // Upload vertex/index buffers
         // - OpenGL drivers are in a very sorry state nowadays....
         //   During 2021 we attempted to switch from glBufferData() to orphaning+glBufferSubData() following reports
@@ -648,7 +682,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     if (last_program == 0 || glIsProgram(last_program)) glUseProgram(last_program);
     glBindTexture(GL_TEXTURE_2D, last_texture);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    if (bd->GlVersion >= 330 || bd->GlProfileIsES3)
+    if (bd->HasBindSampler)
         glBindSampler(0, last_sampler);
 #endif
     glActiveTexture(last_active_texture);
@@ -670,7 +704,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     if (last_enable_stencil_test) glEnable(GL_STENCIL_TEST); else glDisable(GL_STENCIL_TEST);
     if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
-    if (bd->GlVersion >= 310) { if (last_enable_primitive_restart) glEnable(GL_PRIMITIVE_RESTART); else glDisable(GL_PRIMITIVE_RESTART); }
+    if (!bd->GlProfileIsES3 && bd->GlVersion >= 310) { if (last_enable_primitive_restart) glEnable(GL_PRIMITIVE_RESTART); else glDisable(GL_PRIMITIVE_RESTART); }
 #endif
 
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
@@ -683,50 +717,90 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     (void)bd; // Not all compilation paths use this
 }
 
-bool ImGui_ImplOpenGL3_CreateFontsTexture()
+static void ImGui_ImplOpenGL3_DestroyTexture(ImTextureData* tex)
 {
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+    GLuint gl_tex_id = (GLuint)(intptr_t)tex->TexID;
+    glDeleteTextures(1, &gl_tex_id);
 
-    // Build texture atlas
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
-
-    // Upload texture to graphics system
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    GLint last_texture;
-    GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
-    GL_CALL(glGenTextures(1, &bd->FontTexture));
-    GL_CALL(glBindTexture(GL_TEXTURE_2D, bd->FontTexture));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
-    GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
-#ifdef GL_UNPACK_ROW_LENGTH // Not on WebGL/ES
-    GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
-#endif
-    GL_CALL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
-
-    // Store identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
-
-    // Restore state
-    GL_CALL(glBindTexture(GL_TEXTURE_2D, last_texture));
-
-    return true;
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
 }
 
-void ImGui_ImplOpenGL3_DestroyFontsTexture()
+void ImGui_ImplOpenGL3_UpdateTexture(ImTextureData* tex)
 {
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    if (bd->FontTexture)
+    // FIXME: Consider backing up and restoring
+    if (tex->Status == ImTextureStatus_WantCreate || tex->Status == ImTextureStatus_WantUpdates)
     {
-        glDeleteTextures(1, &bd->FontTexture);
-        io.Fonts->SetTexID(0);
-        bd->FontTexture = 0;
+#ifdef GL_UNPACK_ROW_LENGTH // Not on WebGL/ES
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
+#endif
+#ifdef GL_UNPACK_ALIGNMENT
+        GL_CALL(glPixelStorei(GL_UNPACK_ALIGNMENT, 1));
+#endif
     }
+
+    if (tex->Status == ImTextureStatus_WantCreate)
+    {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        const void* pixels = tex->GetPixels();
+        GLuint gl_texture_id = 0;
+
+        // Upload texture to graphics system
+        // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+        GLint last_texture;
+        GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
+        GL_CALL(glGenTextures(1, &gl_texture_id));
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, gl_texture_id));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
+        GL_CALL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
+        GL_CALL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex->Width, tex->Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels));
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)gl_texture_id);
+        tex->SetStatus(ImTextureStatus_OK);
+
+        // Restore state
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, last_texture));
+    }
+    else if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        GLint last_texture;
+        GL_CALL(glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture));
+
+        GLuint gl_tex_id = (GLuint)(intptr_t)tex->TexID;
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, gl_tex_id));
+#if GL_UNPACK_ROW_LENGTH // Not on WebGL/ES
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, tex->Width));
+        for (ImTextureRect& r : tex->Updates)
+            GL_CALL(glTexSubImage2D(GL_TEXTURE_2D, 0, r.x, r.y, r.w, r.h, GL_RGBA, GL_UNSIGNED_BYTE, tex->GetPixelsAt(r.x, r.y)));
+        GL_CALL(glPixelStorei(GL_UNPACK_ROW_LENGTH, 0));
+#else
+        // GL ES doesn't have GL_UNPACK_ROW_LENGTH, so we need to (A) copy to a contiguous buffer or (B) upload line by line.
+        ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+        for (ImTextureRect& r : tex->Updates)
+        {
+            const int src_pitch = r.w * tex->BytesPerPixel;
+            bd->TempBuffer.resize(r.h * src_pitch);
+            char* out_p = bd->TempBuffer.Data;
+            for (int y = 0; y < r.h; y++, out_p += src_pitch)
+                memcpy(out_p, tex->GetPixelsAt(r.x, r.y + y), src_pitch);
+            IM_ASSERT(out_p == bd->TempBuffer.end());
+            GL_CALL(glTexSubImage2D(GL_TEXTURE_2D, 0, r.x, r.y, r.w, r.h, GL_RGBA, GL_UNSIGNED_BYTE, bd->TempBuffer.Data));
+        }
+#endif
+        tex->SetStatus(ImTextureStatus_OK);
+        GL_CALL(glBindTexture(GL_TEXTURE_2D, last_texture)); // Restore state
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+        ImGui_ImplOpenGL3_DestroyTexture(tex);
 }
 
 // If you get an error please report on github. You may try different GL context version or GLSL version. See GL<>GLSL version table at the top of this file.
@@ -918,21 +992,24 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     GL_CALL(vert_handle = glCreateShader(GL_VERTEX_SHADER));
     glShaderSource(vert_handle, 2, vertex_shader_with_version, nullptr);
     glCompileShader(vert_handle);
-    CheckShader(vert_handle, "vertex shader");
+    if (!CheckShader(vert_handle, "vertex shader"))
+        return false;
 
     const GLchar* fragment_shader_with_version[2] = { bd->GlslVersionString, fragment_shader };
     GLuint frag_handle;
     GL_CALL(frag_handle = glCreateShader(GL_FRAGMENT_SHADER));
     glShaderSource(frag_handle, 2, fragment_shader_with_version, nullptr);
     glCompileShader(frag_handle);
-    CheckShader(frag_handle, "fragment shader");
+    if (!CheckShader(frag_handle, "fragment shader"))
+        return false;
 
     // Link
     bd->ShaderHandle = glCreateProgram();
     glAttachShader(bd->ShaderHandle, vert_handle);
     glAttachShader(bd->ShaderHandle, frag_handle);
     glLinkProgram(bd->ShaderHandle);
-    CheckProgram(bd->ShaderHandle, "shader program");
+    if (!CheckProgram(bd->ShaderHandle, "shader program"))
+        return false;
 
     glDetachShader(bd->ShaderHandle, vert_handle);
     glDetachShader(bd->ShaderHandle, frag_handle);
@@ -949,8 +1026,6 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     glGenBuffers(1, &bd->VboHandle);
     glGenBuffers(1, &bd->ElementsHandle);
 
-    ImGui_ImplOpenGL3_CreateFontsTexture();
-
     // Restore modified GL state
     glBindTexture(GL_TEXTURE_2D, last_texture);
     glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
@@ -970,7 +1045,39 @@ void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
     if (bd->VboHandle)      { glDeleteBuffers(1, &bd->VboHandle); bd->VboHandle = 0; }
     if (bd->ElementsHandle) { glDeleteBuffers(1, &bd->ElementsHandle); bd->ElementsHandle = 0; }
     if (bd->ShaderHandle)   { glDeleteProgram(bd->ShaderHandle); bd->ShaderHandle = 0; }
-    ImGui_ImplOpenGL3_DestroyFontsTexture();
+
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplOpenGL3_DestroyTexture(tex);
+}
+
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplOpenGL3_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    if (!(viewport->Flags & ImGuiViewportFlags_NoRendererClear))
+    {
+        ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        glClear(GL_COLOR_BUFFER_BIT);
+    }
+    ImGui_ImplOpenGL3_RenderDrawData(viewport->DrawData);
+}
+
+static void ImGui_ImplOpenGL3_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL3_RenderWindow;
+}
+
+static void ImGui_ImplOpenGL3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_opengl3.h

@@ -4,8 +4,10 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [x] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset) [Desktop OpenGL only!]
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // About WebGL/ES:
 // - You need to '#define IMGUI_IMPL_OPENGL_ES2' or '#define IMGUI_IMPL_OPENGL_ES3' to use WebGL or OpenGL ES.
@@ -36,11 +38,12 @@ IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);
 
 // (Optional) Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateFontsTexture();
-IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyFontsTexture();
 IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplOpenGL3_UpdateTexture(ImTextureData* tex);
+
 // Configuration flags to add in your imconfig file:
 //#define IMGUI_IMPL_OPENGL_ES2     // Enable ES 2 (Auto-detected on Emscripten)
 //#define IMGUI_IMPL_OPENGL_ES3     // Enable ES 3 (Auto-detected on iOS/Android)

backends/imgui_impl_opengl3_loader.h

@@ -166,7 +166,9 @@ typedef khronos_uint8_t GLubyte;
 #define GL_SCISSOR_BOX                    0x0C10
 #define GL_SCISSOR_TEST                   0x0C11
 #define GL_UNPACK_ROW_LENGTH              0x0CF2
+#define GL_UNPACK_ALIGNMENT               0x0CF5
 #define GL_PACK_ALIGNMENT                 0x0D05
+#define GL_MAX_TEXTURE_SIZE               0x0D33
 #define GL_TEXTURE_2D                     0x0DE1
 #define GL_UNSIGNED_BYTE                  0x1401
 #define GL_UNSIGNED_SHORT                 0x1403
@@ -178,6 +180,7 @@ typedef khronos_uint8_t GLubyte;
 #define GL_RENDERER                       0x1F01
 #define GL_VERSION                        0x1F02
 #define GL_EXTENSIONS                     0x1F03
+#define GL_NEAREST                        0x2600
 #define GL_LINEAR                         0x2601
 #define GL_TEXTURE_MAG_FILTER             0x2800
 #define GL_TEXTURE_MIN_FILTER             0x2801
@@ -224,11 +227,13 @@ typedef khronos_float_t GLclampf;
 typedef double GLclampd;
 #define GL_TEXTURE_BINDING_2D             0x8069
 typedef void (APIENTRYP PFNGLDRAWELEMENTSPROC) (GLenum mode, GLsizei count, GLenum type, const void *indices);
+typedef void (APIENTRYP PFNGLTEXSUBIMAGE2DPROC) (GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void *pixels);
 typedef void (APIENTRYP PFNGLBINDTEXTUREPROC) (GLenum target, GLuint texture);
 typedef void (APIENTRYP PFNGLDELETETEXTURESPROC) (GLsizei n, const GLuint *textures);
 typedef void (APIENTRYP PFNGLGENTEXTURESPROC) (GLsizei n, GLuint *textures);
 #ifdef GL_GLEXT_PROTOTYPES
 GLAPI void APIENTRY glDrawElements (GLenum mode, GLsizei count, GLenum type, const void *indices);
+GLAPI void APIENTRY glTexSubImage2D (GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void *pixels);
 GLAPI void APIENTRY glBindTexture (GLenum target, GLuint texture);
 GLAPI void APIENTRY glDeleteTextures (GLsizei n, const GLuint *textures);
 GLAPI void APIENTRY glGenTextures (GLsizei n, GLuint *textures);
@@ -396,9 +401,15 @@ GLAPI void APIENTRY glDrawElementsBaseVertex (GLenum mode, GLsizei count, GLenum
 #ifndef GL_VERSION_3_3
 #define GL_VERSION_3_3 1
 #define GL_SAMPLER_BINDING                0x8919
+typedef void (APIENTRYP PFNGLGENSAMPLERSPROC) (GLsizei count, GLuint *samplers);
+typedef void (APIENTRYP PFNGLDELETESAMPLERSPROC) (GLsizei count, const GLuint *samplers);
 typedef void (APIENTRYP PFNGLBINDSAMPLERPROC) (GLuint unit, GLuint sampler);
+typedef void (APIENTRYP PFNGLSAMPLERPARAMETERIPROC) (GLuint sampler, GLenum pname, GLint param);
 #ifdef GL_GLEXT_PROTOTYPES
+GLAPI void APIENTRY glGenSamplers (GLsizei count, GLuint *samplers);
+GLAPI void APIENTRY glDeleteSamplers (GLsizei count, const GLuint *samplers);
 GLAPI void APIENTRY glBindSampler (GLuint unit, GLuint sampler);
+GLAPI void APIENTRY glSamplerParameteri (GLuint sampler, GLenum pname, GLint param);
 #endif
 #endif /* GL_VERSION_3_3 */
 #ifndef GL_VERSION_4_1
@@ -473,12 +484,13 @@ typedef GL3WglProc (*GL3WGetProcAddressProc)(const char *proc);
 /* gl3w api */
 GL3W_API int imgl3wInit(void);
 GL3W_API int imgl3wInit2(GL3WGetProcAddressProc proc);
+GL3W_API void imgl3wShutdown(void);
 GL3W_API int imgl3wIsSupported(int major, int minor);
 GL3W_API GL3WglProc imgl3wGetProcAddress(const char *proc);
 
 /* gl3w internal state */
 union ImGL3WProcs {
-    GL3WglProc ptr[59];
+    GL3WglProc ptr[63];
     struct {
         PFNGLACTIVETEXTUREPROC            ActiveTexture;
         PFNGLATTACHSHADERPROC             AttachShader;
@@ -498,6 +510,7 @@ union ImGL3WProcs {
         PFNGLCREATESHADERPROC             CreateShader;
         PFNGLDELETEBUFFERSPROC            DeleteBuffers;
         PFNGLDELETEPROGRAMPROC            DeleteProgram;
+        PFNGLDELETESAMPLERSPROC           DeleteSamplers;
         PFNGLDELETESHADERPROC             DeleteShader;
         PFNGLDELETETEXTURESPROC           DeleteTextures;
         PFNGLDELETEVERTEXARRAYSPROC       DeleteVertexArrays;
@@ -510,6 +523,7 @@ union ImGL3WProcs {
         PFNGLENABLEVERTEXATTRIBARRAYPROC  EnableVertexAttribArray;
         PFNGLFLUSHPROC                    Flush;
         PFNGLGENBUFFERSPROC               GenBuffers;
+        PFNGLGENSAMPLERSPROC              GenSamplers;
         PFNGLGENTEXTURESPROC              GenTextures;
         PFNGLGENVERTEXARRAYSPROC          GenVertexArrays;
         PFNGLGETATTRIBLOCATIONPROC        GetAttribLocation;
@@ -530,10 +544,12 @@ union ImGL3WProcs {
         PFNGLPIXELSTOREIPROC              PixelStorei;
         PFNGLPOLYGONMODEPROC              PolygonMode;
         PFNGLREADPIXELSPROC               ReadPixels;
+        PFNGLSAMPLERPARAMETERIPROC        SamplerParameteri;
         PFNGLSCISSORPROC                  Scissor;
         PFNGLSHADERSOURCEPROC             ShaderSource;
         PFNGLTEXIMAGE2DPROC               TexImage2D;
         PFNGLTEXPARAMETERIPROC            TexParameteri;
+        PFNGLTEXSUBIMAGE2DPROC            TexSubImage2D;
         PFNGLUNIFORM1IPROC                Uniform1i;
         PFNGLUNIFORMMATRIX4FVPROC         UniformMatrix4fv;
         PFNGLUSEPROGRAMPROC               UseProgram;
@@ -563,6 +579,7 @@ GL3W_API extern union ImGL3WProcs imgl3wProcs;
 #define glCreateShader                    imgl3wProcs.gl.CreateShader
 #define glDeleteBuffers                   imgl3wProcs.gl.DeleteBuffers
 #define glDeleteProgram                   imgl3wProcs.gl.DeleteProgram
+#define glDeleteSamplers                  imgl3wProcs.gl.DeleteSamplers
 #define glDeleteShader                    imgl3wProcs.gl.DeleteShader
 #define glDeleteTextures                  imgl3wProcs.gl.DeleteTextures
 #define glDeleteVertexArrays              imgl3wProcs.gl.DeleteVertexArrays
@@ -575,6 +592,7 @@ GL3W_API extern union ImGL3WProcs imgl3wProcs;
 #define glEnableVertexAttribArray         imgl3wProcs.gl.EnableVertexAttribArray
 #define glFlush                           imgl3wProcs.gl.Flush
 #define glGenBuffers                      imgl3wProcs.gl.GenBuffers
+#define glGenSamplers                     imgl3wProcs.gl.GenSamplers
 #define glGenTextures                     imgl3wProcs.gl.GenTextures
 #define glGenVertexArrays                 imgl3wProcs.gl.GenVertexArrays
 #define glGetAttribLocation               imgl3wProcs.gl.GetAttribLocation
@@ -595,10 +613,12 @@ GL3W_API extern union ImGL3WProcs imgl3wProcs;
 #define glPixelStorei                     imgl3wProcs.gl.PixelStorei
 #define glPolygonMode                     imgl3wProcs.gl.PolygonMode
 #define glReadPixels                      imgl3wProcs.gl.ReadPixels
+#define glSamplerParameteri               imgl3wProcs.gl.SamplerParameteri
 #define glScissor                         imgl3wProcs.gl.Scissor
 #define glShaderSource                    imgl3wProcs.gl.ShaderSource
 #define glTexImage2D                      imgl3wProcs.gl.TexImage2D
 #define glTexParameteri                   imgl3wProcs.gl.TexParameteri
+#define glTexSubImage2D                   imgl3wProcs.gl.TexSubImage2D
 #define glUniform1i                       imgl3wProcs.gl.Uniform1i
 #define glUniformMatrix4fv                imgl3wProcs.gl.UniformMatrix4fv
 #define glUseProgram                      imgl3wProcs.gl.UseProgram
@@ -626,7 +646,7 @@ extern "C" {
 #endif
 #include <windows.h>
 
-static HMODULE libgl;
+static HMODULE libgl = NULL;
 typedef PROC(__stdcall* GL3WglGetProcAddr)(LPCSTR);
 static GL3WglGetProcAddr wgl_get_proc_address;
 
@@ -639,7 +659,7 @@ static int open_libgl(void)
     return GL3W_OK;
 }
 
-static void close_libgl(void) { FreeLibrary(libgl); }
+static void close_libgl(void) { FreeLibrary(libgl); libgl = NULL; }
 static GL3WglProc get_proc(const char *proc)
 {
     GL3WglProc res;
@@ -651,7 +671,7 @@ static GL3WglProc get_proc(const char *proc)
 #elif defined(__APPLE__)
 #include <dlfcn.h>
 
-static void *libgl;
+static void *libgl = NULL;
 static int open_libgl(void)
 {
     libgl = dlopen("/System/Library/Frameworks/OpenGL.framework/OpenGL", RTLD_LAZY | RTLD_LOCAL);
@@ -660,7 +680,7 @@ static int open_libgl(void)
     return GL3W_OK;
 }
 
-static void close_libgl(void) { dlclose(libgl); }
+static void close_libgl(void) { dlclose(libgl); libgl = NULL; }
 
 static GL3WglProc get_proc(const char *proc)
 {
@@ -828,6 +848,11 @@ int imgl3wInit2(GL3WGetProcAddressProc proc)
     return parse_version();
 }
 
+void imgl3wShutdown(void)
+{
+    close_libgl();
+}
+
 int imgl3wIsSupported(int major, int minor)
 {
     if (major < 2)
@@ -858,6 +883,7 @@ static const char *proc_names[] = {
     "glCreateShader",
     "glDeleteBuffers",
     "glDeleteProgram",
+    "glDeleteSamplers",
     "glDeleteShader",
     "glDeleteTextures",
     "glDeleteVertexArrays",
@@ -870,6 +896,7 @@ static const char *proc_names[] = {
     "glEnableVertexAttribArray",
     "glFlush",
     "glGenBuffers",
+    "glGenSamplers",
     "glGenTextures",
     "glGenVertexArrays",
     "glGetAttribLocation",
@@ -890,10 +917,12 @@ static const char *proc_names[] = {
     "glPixelStorei",
     "glPolygonMode",
     "glReadPixels",
+    "glSamplerParameteri",
     "glScissor",
     "glShaderSource",
     "glTexImage2D",
     "glTexParameteri",
+    "glTexSubImage2D",
     "glUniform1i",
     "glUniformMatrix4fv",
     "glUseProgram",

backends/imgui_impl_osx.h

@@ -7,11 +7,13 @@
 //  [X] Platform: Clipboard support is part of core Dear ImGui (no specific code in this backend).
 //  [X] Platform: Mouse support. Can discriminate Mouse/Pen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy kVK_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
 // Missing features or Issues:
-//  [ ] Missing ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress cursors.
+//  [ ] Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] Multi-viewport: ParentViewportID not honored, and so io.ConfigViewportsNoDefaultParent has no effect (minor).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_osx.mm

@@ -7,11 +7,13 @@
 //  [X] Platform: Clipboard support is part of core Dear ImGui (no specific code in this backend).
 //  [X] Platform: Mouse support. Can discriminate Mouse/Pen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy kVK_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
 // Missing features or Issues:
-//  [ ] Missing ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress cursors.
+//  [ ] Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] Multi-viewport: ParentViewportID not honored, and so io.ConfigViewportsNoDefaultParent has no effect (minor).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -31,6 +33,12 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-07-08: [Docking] Fixed multi-viewport handling broken on 2025-06-02. (#8644, #8777)
+//  2025-06-27: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
+//  2025-06-12: ImGui_ImplOSX_HandleEvent() only process event for window containing our view. (#8644)
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-01-20: Removed notification observer when shutting down. (#8331)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
 //               - io.GetClipboardTextFn    -> platform_io.Platform_GetClipboardTextFn
@@ -99,6 +107,9 @@ static void                     ImGui_ImplOSX_DestroyBackendData()  { IM_DELETE(
 static inline CFTimeInterval    GetMachAbsoluteTimeInSeconds()      { return (CFTimeInterval)(double)(clock_gettime_nsec_np(CLOCK_UPTIME_RAW) / 1e9); }
 
 // Forward Declarations
+static void ImGui_ImplOSX_InitMultiViewportSupport();
+static void ImGui_ImplOSX_ShutdownMultiViewportSupport();
+static void ImGui_ImplOSX_UpdateMonitors();
 static void ImGui_ImplOSX_AddTrackingArea(NSView* _Nonnull view);
 static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
@@ -108,6 +119,7 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 + (id)_windowResizeNorthEastSouthWestCursor;
 + (id)_windowResizeNorthSouthCursor;
 + (id)_windowResizeEastWestCursor;
++ (id)busyButClickableCursor;
 @end
 
 /**
@@ -145,9 +157,25 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
     NSWindow* window = view.window;
     if (!window)
         return;
-    NSRect contentRect = [window contentRectForFrameRect:window.frame];
-    NSRect rect = NSMakeRect(_posX, contentRect.size.height - _posY, 0, 0);
-    _imeRect = [window convertRectToScreen:rect];
+
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        NSRect frame = window.frame;
+        NSRect contentRect = window.contentLayoutRect;
+        if (window.styleMask & NSWindowStyleMaskFullSizeContentView) // No title bar windows should be considered.
+            contentRect = frame;
+
+        NSRect firstScreenFrame = NSScreen.screens[0].frame;
+        _imeRect = NSMakeRect(_posX, _posY, 0, 0);
+        _imeRect.origin.y = firstScreenFrame.size.height - _imeRect.size.height - _imeRect.origin.y; // Opposite of ConvertNSRect()
+    }
+    else
+    {
+        NSRect contentRect = [window contentRectForFrameRect:window.frame];
+        NSRect rect = NSMakeRect(_posX, contentRect.size.height - _posY, 0, 0);
+        _imeRect = [window convertRectToScreen:rect];
+    }
 }
 
 - (void)viewDidMoveToWindow
@@ -242,6 +270,7 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
 - (void)onApplicationBecomeActive:(NSNotification*)aNotification;
 - (void)onApplicationBecomeInactive:(NSNotification*)aNotification;
+- (void)displaysDidChange:(NSNotification*)aNotification;
 
 @end
 
@@ -259,6 +288,11 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
     io.AddFocusEvent(false);
 }
 
+- (void)displaysDidChange:(NSNotification*)aNotification
+{
+    ImGui_ImplOSX_UpdateMonitors();
+}
+
 @end
 
 // Functions
@@ -413,11 +447,15 @@ bool ImGui_ImplOSX_Init(NSView* view)
     io.BackendPlatformName = "imgui_impl_osx";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     //io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;      // We can create multi-viewports on the Platform side (optional)
+    //io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
 
     bd->Observer = [ImGuiObserver new];
     bd->Window = view.window ?: NSApp.orderedWindows.firstObject;
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (__bridge_retained void*)bd->Window;
+    ImGui_ImplOSX_UpdateMonitors();
+    ImGui_ImplOSX_InitMultiViewportSupport();
 
     // Load cursors. Some of them are undocumented.
     bd->MouseCursorHidden = false;
@@ -429,6 +467,7 @@ bool ImGui_ImplOSX_Init(NSView* view)
     bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = [NSCursor respondsToSelector:@selector(_windowResizeNorthEastSouthWestCursor)] ? [NSCursor _windowResizeNorthEastSouthWestCursor] : [NSCursor closedHandCursor];
     bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = [NSCursor respondsToSelector:@selector(_windowResizeNorthWestSouthEastCursor)] ? [NSCursor _windowResizeNorthWestSouthEastCursor] : [NSCursor closedHandCursor];
     bd->MouseCursors[ImGuiMouseCursor_Hand] = [NSCursor pointingHandCursor];
+    bd->MouseCursors[ImGuiMouseCursor_Wait] = bd->MouseCursors[ImGuiMouseCursor_Progress] = [NSCursor respondsToSelector:@selector(busyButClickableCursor)] ? [NSCursor busyButClickableCursor] : [NSCursor arrowCursor];
     bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = [NSCursor operationNotAllowedCursor];
 
     // Note that imgui.cpp also include default OSX clipboard handlers which can be enabled
@@ -476,7 +515,7 @@ bool ImGui_ImplOSX_Init(NSView* view)
     [view addSubview:bd->KeyEventResponder];
     ImGui_ImplOSX_AddTrackingArea(view);
 
-    platform_io.Platform_SetImeDataFn = [](ImGuiContext*, ImGuiViewport* viewport, ImGuiPlatformImeData* data) -> void
+    platform_io.Platform_SetImeDataFn = [](ImGuiContext*, ImGuiViewport*, ImGuiPlatformImeData* data) -> void
     {
         ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
         if (data->WantVisible)
@@ -508,12 +547,12 @@ void ImGui_ImplOSX_Shutdown()
         bd->Monitor = nullptr;
     }
 
+    ImGui_ImplOSX_ShutdownMultiViewportSupport();
     ImGui_ImplOSX_DestroyBackendData();
-
     ImGuiIO& io = ImGui::GetIO();
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports);
 }
 
 static void ImGui_ImplOSX_UpdateMouseCursor()
@@ -536,7 +575,7 @@ static void ImGui_ImplOSX_UpdateMouseCursor()
     else
     {
         NSCursor* desired = bd->MouseCursors[imgui_cursor] ?: bd->MouseCursors[ImGuiMouseCursor_Arrow];
-        // -[NSCursor set] generates measureable overhead if called unconditionally.
+        // -[NSCursor set] generates measurable overhead if called unconditionally.
         if (desired != NSCursor.currentCursor)
         {
             [desired set];
@@ -552,8 +591,6 @@ static void ImGui_ImplOSX_UpdateMouseCursor()
 static void ImGui_ImplOSX_UpdateGamepads()
 {
     ImGuiIO& io = ImGui::GetIO();
-    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0) // FIXME: Technically feeding gamepad shouldn't depend on this now that they are regular inputs.
-        return;
 
 #if APPLE_HAS_CONTROLLER
     GCController* controller = GCController.current;
@@ -624,9 +661,9 @@ void ImGui_ImplOSX_NewFrame(NSView* view)
     // Setup display size
     if (view)
     {
-        const float dpi = (float)[view.window backingScaleFactor];
+        const float fb_scale = (float)[view.window backingScaleFactor];
         io.DisplaySize = ImVec2((float)view.bounds.size.width, (float)view.bounds.size.height);
-        io.DisplayFramebufferScale = ImVec2(dpi, dpi);
+        io.DisplayFramebufferScale = ImVec2(fb_scale, fb_scale);
     }
 
     // Setup time step
@@ -664,8 +701,11 @@ static ImGuiMouseSource GetMouseSource(NSEvent* event)
 
 static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view)
 {
-    ImGuiIO& io = ImGui::GetIO();
+    // Only process events from the window containing ImGui view
+    if (!ImGui::FindViewportByPlatformHandle((__bridge void*)event.window))
+        return false;
 
+    ImGuiIO& io = ImGui::GetIO();
     if (event.type == NSEventTypeLeftMouseDown || event.type == NSEventTypeRightMouseDown || event.type == NSEventTypeOtherMouseDown)
     {
         int button = (int)[event buttonNumber];
@@ -690,14 +730,23 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view)
 
     if (event.type == NSEventTypeMouseMoved || event.type == NSEventTypeLeftMouseDragged || event.type == NSEventTypeRightMouseDragged || event.type == NSEventTypeOtherMouseDragged)
     {
-        NSPoint mousePoint = event.locationInWindow;
-        if (event.window == nil)
-            mousePoint = [[view window] convertPointFromScreen:mousePoint];
-        mousePoint = [view convertPoint:mousePoint fromView:nil];
-        if ([view isFlipped])
-            mousePoint = NSMakePoint(mousePoint.x, mousePoint.y);
+        NSPoint mousePoint;
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            mousePoint = NSEvent.mouseLocation;
+            mousePoint.y = CGDisplayPixelsHigh(kCGDirectMainDisplay) - mousePoint.y; // Normalize y coordinate to top-left of main display.
+        }
         else
-            mousePoint = NSMakePoint(mousePoint.x, view.bounds.size.height - mousePoint.y);
+        {
+            mousePoint = event.locationInWindow;
+            if (event.window == nil)
+                mousePoint = [[view window] convertPointFromScreen:mousePoint];
+            mousePoint = [view convertPoint:mousePoint fromView:nil]; // Convert to local coordinates of view
+            if ([view isFlipped])
+                mousePoint = NSMakePoint(mousePoint.x, mousePoint.y);
+            else
+                mousePoint = NSMakePoint(mousePoint.x, view.bounds.size.height - mousePoint.y);
+        }
         io.AddMouseSourceEvent(GetMouseSource(event));
         io.AddMousePosEvent((float)mousePoint.x, (float)mousePoint.y);
         return io.WantCaptureMouse;
@@ -789,8 +838,6 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view)
                 default:
                     return io.WantCaptureKeyboard;
             }
-
-            NSEventModifierFlags modifier_flags = [event modifierFlags];
             io.AddKeyEvent(key, (modifier_flags & mask) != 0);
             io.SetKeyEventNativeData(key, key_code, -1); // To support legacy indexing (<1.87 user code)
         }
@@ -825,6 +872,300 @@ static void ImGui_ImplOSX_AddTrackingArea(NSView* _Nonnull view)
     }];
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the back-end to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+struct ImGui_ImplOSX_ViewportData
+{
+    NSWindow*        Window;
+    bool             WindowOwned;
+
+    ImGui_ImplOSX_ViewportData()  { WindowOwned = false; }
+    ~ImGui_ImplOSX_ViewportData() { IM_ASSERT(Window == nil); }
+};
+
+@interface ImGui_ImplOSX_Window: NSWindow
+@end
+
+@implementation ImGui_ImplOSX_Window
+
+- (BOOL)canBecomeKeyWindow
+{
+    return YES;
+}
+
+@end
+
+static void ConvertNSRect(NSRect* r)
+{
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    IM_ASSERT(firstScreenFrame.origin.x == 0 && firstScreenFrame.origin.y == 0);
+    r->origin.y = firstScreenFrame.size.height - r->origin.y - r->size.height;
+}
+
+static void ImGui_ImplOSX_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    ImGui_ImplOSX_ViewportData* vd = IM_NEW(ImGui_ImplOSX_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    NSScreen* screen = bd->Window.screen;
+    NSRect rect = NSMakeRect(viewport->Pos.x, viewport->Pos.y, viewport->Size.x, viewport->Size.y);
+    ConvertNSRect(&rect);
+
+    NSWindowStyleMask styleMask = 0;
+    if (viewport->Flags & ImGuiViewportFlags_NoDecoration)
+        styleMask |= NSWindowStyleMaskBorderless;
+    else
+        styleMask |= NSWindowStyleMaskTitled | NSWindowStyleMaskResizable | NSWindowStyleMaskClosable | NSWindowStyleMaskMiniaturizable;
+
+    NSWindow* window = [[ImGui_ImplOSX_Window alloc] initWithContentRect:rect
+                                                               styleMask:styleMask
+                                                                 backing:NSBackingStoreBuffered
+                                                                   defer:YES
+                                                                  screen:screen];
+    if (viewport->Flags & ImGuiViewportFlags_TopMost)
+        [window setLevel:NSFloatingWindowLevel];
+
+    window.title = @"Untitled";
+    window.opaque = YES;
+
+    KeyEventResponder* view = [[KeyEventResponder alloc] initWithFrame:rect];
+    if (floor(NSAppKitVersionNumber) > NSAppKitVersionNumber10_6 && ceil(NSAppKitVersionNumber) < NSAppKitVersionNumber10_15)
+        [view setWantsBestResolutionOpenGLSurface:YES];
+
+    window.contentView = view;
+
+    vd->Window = window;
+    vd->WindowOwned = true;
+    viewport->PlatformRequestResize = false;
+    viewport->PlatformHandle = viewport->PlatformHandleRaw = (__bridge_retained void*)window;
+}
+
+static void ImGui_ImplOSX_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData)
+    {
+        NSWindow* window = vd->Window;
+        if (window != nil && vd->WindowOwned)
+        {
+            window.contentView = nil;
+            window.contentViewController = nil;
+            [window orderOut:nil];
+        }
+        vd->Window = nil;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = viewport->PlatformHandleRaw = nullptr;
+}
+
+static void ImGui_ImplOSX_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        [vd->Window orderFront:nil];
+    else
+        [vd->Window makeKeyAndOrderFront:nil];
+
+    [vd->Window setIsVisible:YES];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSRect frame = window.frame;
+    NSRect contentRect = window.contentLayoutRect;
+    if (window.styleMask & NSWindowStyleMaskFullSizeContentView) // No title bar windows should be considered.
+        contentRect = frame;
+
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    return ImVec2(frame.origin.x, firstScreenFrame.size.height - frame.origin.y - contentRect.size.height);
+}
+
+static void ImGui_ImplOSX_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSSize size = window.frame.size;
+
+    NSRect r = NSMakeRect(pos.x, pos.y, size.width, size.height);
+    ConvertNSRect(&r);
+    [window setFrameOrigin:r.origin];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSSize size = window.contentLayoutRect.size;
+    return ImVec2(size.width, size.height);
+}
+
+static void ImGui_ImplOSX_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    NSWindow* window = vd->Window;
+    NSRect rect = window.frame;
+    rect.origin.y -= (size.y - rect.size.height);
+    rect.size.width = size.x;
+    rect.size.height = size.y;
+    [window setFrame:rect display:YES];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    NSWindow* window = vd->Window;
+    const float fb_scale = (float)[window backingScaleFactor];
+    return ImVec2(fb_scale, fb_scale);
+}
+
+static void ImGui_ImplOSX_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+    [vd->Window makeKeyAndOrderFront:bd->Window];
+}
+
+static bool ImGui_ImplOSX_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.isKeyWindow;
+}
+
+static bool ImGui_ImplOSX_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.isMiniaturized;
+}
+
+static void ImGui_ImplOSX_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    vd->Window.title = [NSString stringWithUTF8String:title];
+}
+
+static void ImGui_ImplOSX_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+    IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
+
+    vd->Window.alphaValue = alpha;
+}
+
+static float ImGui_ImplOSX_GetWindowDpiScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Window != 0);
+
+    return vd->Window.backingScaleFactor;
+}
+
+static void ImGui_ImplOSX_UpdateMonitors()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+
+    NSRect firstScreenFrame = NSScreen.screens[0].frame;
+    IM_ASSERT(firstScreenFrame.origin.x == 0 && firstScreenFrame.origin.y == 0);
+
+    for (NSScreen* screen in NSScreen.screens)
+    {
+        NSRect frame = screen.frame;
+        NSRect visibleFrame = screen.visibleFrame;
+        ConvertNSRect(&frame);
+        ConvertNSRect(&visibleFrame);
+
+        ImGuiPlatformMonitor imgui_monitor;
+        imgui_monitor.MainPos = ImVec2(frame.origin.x, frame.origin.y);
+        imgui_monitor.MainSize = ImVec2(frame.size.width, frame.size.height);
+        imgui_monitor.WorkPos = ImVec2(visibleFrame.origin.x, visibleFrame.origin.y);
+        imgui_monitor.WorkSize = ImVec2(visibleFrame.size.width, visibleFrame.size.height);
+        imgui_monitor.DpiScale = screen.backingScaleFactor;
+        imgui_monitor.PlatformHandle = (__bridge_retained void*)screen;
+
+        platform_io.Monitors.push_back(imgui_monitor);
+    }
+}
+
+static void ImGui_ImplOSX_InitMultiViewportSupport()
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplOSX_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplOSX_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplOSX_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplOSX_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplOSX_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplOSX_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplOSX_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplOSX_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplOSX_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplOSX_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplOSX_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplOSX_SetWindowTitle;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplOSX_SetWindowAlpha;
+    platform_io.Platform_GetWindowDpiScale = ImGui_ImplOSX_GetWindowDpiScale; // FIXME-DPI
+
+    // Register main window handle (which is owned by the main application, not by us)
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplOSX_ViewportData* vd = IM_NEW(ImGui_ImplOSX_ViewportData)();
+    vd->Window = bd->Window;
+    vd->WindowOwned = false;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (__bridge void*)bd->Window;
+
+    [NSNotificationCenter.defaultCenter addObserver:bd->Observer
+                                           selector:@selector(displaysDidChange:)
+                                               name:NSApplicationDidChangeScreenParametersNotification
+                                             object:nil];
+}
+
+static void ImGui_ImplOSX_ShutdownMultiViewportSupport()
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    [NSNotificationCenter.defaultCenter removeObserver:bd->Observer
+                                                  name:NSApplicationDidChangeScreenParametersNotification
+                                                object:nil];
+    bd->Observer = nullptr;
+    bd->Window = nullptr;
+    if (bd->Monitor != nullptr)
+    {
+        [NSEvent removeMonitor:bd->Monitor];
+        bd->Monitor = nullptr;
+    }
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplOSX_ViewportData* vd = (ImGui_ImplOSX_ViewportData*)main_viewport->PlatformUserData;
+    IM_DELETE(vd);
+    main_viewport->PlatformUserData = nullptr;
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdl2.cpp

@@ -7,9 +7,13 @@
 //  [X] Platform: Clipboard support.
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [ ] Platform: Multi-viewport: ParentViewportID not honored, and so io.ConfigViewportsNoDefaultParent has no effect (minor).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -21,9 +25,19 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-09-15: Content Scales are always reported as 1.0 on Wayland. (#8921)
+//  2025-07-08: Made ImGui_ImplSDL2_GetContentScaleForWindow(), ImGui_ImplSDL2_GetContentScaleForDisplay() helpers return 1.0f on Emscripten and Android platforms, matching macOS logic. (#8742, #8733)
+//  2025-06-11: Added ImGui_ImplSDL2_GetContentScaleForWindow(SDL_Window* window) and ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index) helper to facilitate making DPI-aware apps.
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-04-09: [Docking] Revert update monitors and work areas information every frame. Only do it on Windows. (#8415, #8558)
+//  2025-04-09: Don't attempt to call SDL_CaptureMouse() on drivers where we don't call SDL_GetGlobalMouseState(). (#8561)
+//  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
 //  2025-02-26: Only start SDL_CaptureMouse() when mouse is being dragged, to mitigate issues with e.g.Linux debuggers not claiming capture back. (#6410, #3650)
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
+//  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL2_SetGamepadMode(ImGui_ImplSDL2_GamepadMode_Manual) accept an empty array.
@@ -64,7 +78,7 @@
 //  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModsEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-08-17: Calling io.AddFocusEvent() on SDL_WINDOWEVENT_FOCUS_GAINED/SDL_WINDOWEVENT_FOCUS_LOST.
 //  2021-07-29: Inputs: MousePos is correctly reported when the host platform window is hovered but not focused (using SDL_GetMouseFocus() + SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, requires SDL 2.0.5+)
-//  2021-06-29: *BREAKING CHANGE* Removed 'SDL_Window* window' parameter to ImGui_ImplSDL2_NewFrame() which was unnecessary.
+//  2021-06:29: *BREAKING CHANGE* Removed 'SDL_Window* window' parameter to ImGui_ImplSDL2_NewFrame() which was unnecessary.
 //  2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
 //  2021-03-22: Rework global mouse pos availability check listing supported platforms explicitly, effectively fixing mouse access on Raspberry Pi. (#2837, #3950)
 //  2020-05-25: Misc: Report a zero display-size when window is minimized, to be consistent with other backends.
@@ -101,38 +115,53 @@
 // Clang warnings with -Weverything
 #if defined(__clang__)
 #pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wold-style-cast"                 // warning: use of old-style cast
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #endif
 
 // SDL
+// (the multi-viewports feature requires SDL features supported from SDL 2.0.4+. SDL 2.0.5+ is highly recommended)
 #include <SDL.h>
 #include <SDL_syswm.h>
+#include <stdio.h>              // for snprintf()
 #ifdef __APPLE__
 #include <TargetConditionals.h>
 #endif
 #ifdef __EMSCRIPTEN__
 #include <emscripten/em_js.h>
 #endif
+#undef Status // X11 headers are leaking this.
 
 #if SDL_VERSION_ATLEAST(2,0,4) && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !(defined(__APPLE__) && TARGET_OS_IOS) && !defined(__amigaos4__)
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    1
 #else
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
+#define SDL_HAS_WINDOW_ALPHA                SDL_VERSION_ATLEAST(2,0,5)
+#define SDL_HAS_ALWAYS_ON_TOP               SDL_VERSION_ATLEAST(2,0,5)
+#define SDL_HAS_USABLE_DISPLAY_BOUNDS       SDL_VERSION_ATLEAST(2,0,5)
+#define SDL_HAS_PER_MONITOR_DPI             SDL_VERSION_ATLEAST(2,0,4)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
+#define SDL_HAS_DISPLAY_EVENT               SDL_VERSION_ATLEAST(2,0,9)
 #define SDL_HAS_OPEN_URL                    SDL_VERSION_ATLEAST(2,0,14)
+#define SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT SDL_VERSION_ATLEAST(2,0,18)
 #if SDL_HAS_VULKAN
 #include <SDL_vulkan.h>
+#else
+static const Uint32 SDL_WINDOW_VULKAN = 0x10000000;
 #endif
 
 // SDL Data
 struct ImGui_ImplSDL2_Data
 {
     SDL_Window*             Window;
-    Uint32                  WindowID;
+    Uint32                  WindowID;       // Stored in ImGuiViewport::PlatformHandle. Use SDL_GetWindowFromID() to get SDL_Window* from Uint32 WindowID.
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
+    char                    BackendPlatformName[48];
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // Mouse handling
     Uint32                  MouseWindowID;
@@ -141,6 +170,8 @@ struct ImGui_ImplSDL2_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MouseLastLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    bool                    MouseCanUseCapture;
+    bool                    MouseCanReportHoveredViewport;  // This is hard to use/unreliable on SDL so we'll set ImGuiBackendFlags_HasMouseHoveredViewport dynamically based on state.
 
     // Gamepad handling
     ImVector<SDL_GameController*> Gamepads;
@@ -159,6 +190,11 @@ static ImGui_ImplSDL2_Data* ImGui_ImplSDL2_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDL2_Data*)ImGui::GetIO().BackendPlatformUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplSDL2_UpdateMonitors();
+static void ImGui_ImplSDL2_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL2_ShutdownMultiViewportSupport();
+
 // Functions
 static const char* ImGui_ImplSDL2_GetClipboardText(ImGuiContext*)
 {
@@ -175,13 +211,13 @@ static void ImGui_ImplSDL2_SetClipboardText(ImGuiContext*, const char* text)
 }
 
 // Note: native IME will only display if user calls SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1") _before_ SDL_CreateWindow().
-static void ImGui_ImplSDL2_PlatformSetImeData(ImGuiContext*, ImGuiViewport*, ImGuiPlatformImeData* data)
+static void ImGui_ImplSDL2_PlatformSetImeData(ImGuiContext*, ImGuiViewport* viewport, ImGuiPlatformImeData* data)
 {
     if (data->WantVisible)
     {
         SDL_Rect r;
-        r.x = (int)data->InputPos.x;
-        r.y = (int)data->InputPos.y;
+        r.x = (int)(data->InputPos.x - viewport->Pos.x);
+        r.y = (int)(data->InputPos.y - viewport->Pos.y + data->InputLineHeight);
         r.w = 1;
         r.h = (int)data->InputLineHeight;
         SDL_SetTextInputRect(&r);
@@ -347,15 +383,13 @@ static void ImGui_ImplSDL2_UpdateKeyModifiers(SDL_Keymod sdl_key_mods)
 
 static ImGuiViewport* ImGui_ImplSDL2_GetViewportForWindowID(Uint32 window_id)
 {
-    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
-    return (window_id == bd->WindowID) ? ImGui::GetMainViewport() : nullptr;
+    return ImGui::FindViewportByPlatformHandle((void*)(intptr_t)window_id);
 }
 
 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
-// If you have multiple SDL events and some of them are not meant to be used by dear imgui, you may need to filter events based on their windowID field.
 bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
@@ -369,6 +403,13 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             if (ImGui_ImplSDL2_GetViewportForWindowID(event->motion.windowID) == nullptr)
                 return false;
             ImVec2 mouse_pos((float)event->motion.x, (float)event->motion.y);
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                int window_x, window_y;
+                SDL_GetWindowPosition(SDL_GetWindowFromID(event->motion.windowID), &window_x, &window_y);
+                mouse_pos.x += window_x;
+                mouse_pos.y += window_y;
+            }
             io.AddMouseSourceEvent(event->motion.which == SDL_TOUCH_MOUSEID ? ImGuiMouseSource_TouchScreen : ImGuiMouseSource_Mouse);
             io.AddMousePosEvent(mouse_pos.x, mouse_pos.y);
             return true;
@@ -420,20 +461,32 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
         case SDL_KEYDOWN:
         case SDL_KEYUP:
         {
-            if (ImGui_ImplSDL2_GetViewportForWindowID(event->key.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL2_GetViewportForWindowID(event->key.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("SDL_KEY%s : key=0x%08X ('%s'), scancode=%d ('%s'), mod=%X, windowID=%d, viewport=%08X\n",
+            //    (event->type == SDL_KEYDOWN) ? "DOWN" : "UP  ", event->key.keysym.sym, SDL_GetKeyName(event->key.keysym.sym), event->key.keysym.scancode, SDL_GetScancodeName(event->key.keysym.scancode), event->key.keysym.mod, event->key.windowID, viewport ? viewport->ID : 0);
             ImGui_ImplSDL2_UpdateKeyModifiers((SDL_Keymod)event->key.keysym.mod);
-            //IMGUI_DEBUG_LOG("SDL_KEY_%s : key=%d ('%s'), scancode=%d ('%s'), mod=%X\n",
-            //    (event->type == SDL_KEYDOWN) ? "DOWN" : "UP  ", event->key.keysym.sym, SDL_GetKeyName(event->key.keysym.sym), event->key.keysym.scancode, SDL_GetScancodeName(event->key.keysym.scancode), event->key.keysym.mod);
             ImGuiKey key = ImGui_ImplSDL2_KeyEventToImGuiKey(event->key.keysym.sym, event->key.keysym.scancode);
             io.AddKeyEvent(key, (event->type == SDL_KEYDOWN));
-            io.SetKeyEventNativeData(key, event->key.keysym.sym, event->key.keysym.scancode, event->key.keysym.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
+            io.SetKeyEventNativeData(key, (int)event->key.keysym.sym, (int)event->key.keysym.scancode, (int)event->key.keysym.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
             return true;
         }
+#if SDL_HAS_DISPLAY_EVENT
+        case SDL_DISPLAYEVENT:
+        {
+            // 2.0.26 has SDL_DISPLAYEVENT_CONNECTED/SDL_DISPLAYEVENT_DISCONNECTED/SDL_DISPLAYEVENT_ORIENTATION,
+            // so change of DPI/Scaling are not reflected in this event. (SDL3 has it)
+            bd->WantUpdateMonitors = true;
+            return true;
+        }
+#endif
         case SDL_WINDOWEVENT:
         {
-            if (ImGui_ImplSDL2_GetViewportForWindowID(event->window.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL2_GetViewportForWindowID(event->window.windowID);
+            if (viewport == NULL)
                 return false;
+
             // - When capturing mouse, SDL will send a bunch of conflicting LEAVE/ENTER event on every mouse move, but the final ENTER tends to be right.
             // - However we won't get a correct LEAVE event for a captured window.
             // - In some cases, when detaching a window from main viewport SDL may send SDL_WINDOWEVENT_ENTER one frame too late,
@@ -447,10 +500,18 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             }
             if (window_event == SDL_WINDOWEVENT_LEAVE)
                 bd->MouseLastLeaveFrame = ImGui::GetFrameCount() + 1;
+            //if (window_event == SDL_WINDOWEVENT_FOCUS_GAINED) { IMGUI_DEBUG_LOG("SDL_WINDOWEVENT_FOCUS_GAINED: windowId %d, viewport: %08X\n", event->window.windowID, viewport ? viewport->ID : 0); }
+            //if (window_event == SDL_WINDOWEVENT_FOCUS_LOST) { IMGUI_DEBUG_LOG("SDL_WINDOWEVENT_FOCUS_LOST: windowId %d, viewport: %08X\n", event->window.windowID, viewport ? viewport->ID : 0); }
             if (window_event == SDL_WINDOWEVENT_FOCUS_GAINED)
                 io.AddFocusEvent(true);
-            else if (event->window.event == SDL_WINDOWEVENT_FOCUS_LOST)
+            if (window_event == SDL_WINDOWEVENT_FOCUS_LOST)
                 io.AddFocusEvent(false);
+            if (window_event == SDL_WINDOWEVENT_CLOSE)
+                viewport->PlatformRequestClose = true;
+            if (window_event == SDL_WINDOWEVENT_MOVED)
+                viewport->PlatformRequestMove = true;
+            if (window_event == SDL_WINDOWEVENT_RESIZED)
+                viewport->PlatformRequestResize = true;
             return true;
         }
         case SDL_CONTROLLERDEVICEADDED:
@@ -459,6 +520,8 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             bd->WantUpdateGamepadsList = true;
             return true;
         }
+        default:
+            break;
     }
     return false;
 }
@@ -472,29 +535,49 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     ImGuiIO& io = ImGui::GetIO();
     IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
+    //SDL_SetHint(SDL_HINT_EVENT_LOGGING, "2");
 
-    // Check and store if we are on a SDL backend that supports global mouse position
-    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
-    bool mouse_can_use_global_state = false;
-#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
-    const char* sdl_backend = SDL_GetCurrentVideoDriver();
-    const char* global_mouse_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
-    for (int n = 0; n < IM_ARRAYSIZE(global_mouse_whitelist); n++)
-        if (strncmp(sdl_backend, global_mouse_whitelist[n], strlen(global_mouse_whitelist[n])) == 0)
-            mouse_can_use_global_state = true;
-#endif
+    // Obtain compiled and runtime versions
+    SDL_version ver_compiled;
+    SDL_version ver_runtime;
+    SDL_VERSION(&ver_compiled);
+    SDL_GetVersion(&ver_runtime);
 
     // Setup backend capabilities flags
     ImGui_ImplSDL2_Data* bd = IM_NEW(ImGui_ImplSDL2_Data)();
+    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl2 (%u.%u.%u, %u.%u.%u)",
+        ver_compiled.major, ver_compiled.minor, ver_compiled.patch, ver_runtime.major, ver_runtime.minor, ver_runtime.patch);
     io.BackendPlatformUserData = (void*)bd;
-    io.BackendPlatformName = "imgui_impl_sdl2";
-    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;       // We can honor GetMouseCursor() values (optional)
-    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;        // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendPlatformName = bd->BackendPlatformName;
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    // (ImGuiBackendFlags_PlatformHasViewports may be set just below)
 
     bd->Window = window;
     bd->WindowID = SDL_GetWindowID(window);
     bd->Renderer = renderer;
-    bd->MouseCanUseGlobalState = mouse_can_use_global_state;
+
+    // SDL on Linux/OSX doesn't report events for unfocused windows (see https://github.com/ocornut/imgui/issues/4960)
+    // We will use 'MouseCanReportHoveredViewport' to set 'ImGuiBackendFlags_HasMouseHoveredViewport' dynamically each frame.
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
+
+    // Check and store if we are on a SDL backend that supports SDL_GetGlobalMouseState() and SDL_CaptureMouse()
+    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
+    bd->MouseCanUseGlobalState = false;
+    bd->MouseCanUseCapture = false;
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    const char* sdl_backend = SDL_GetCurrentVideoDriver();
+    const char* capture_and_global_state_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
+    for (const char* item : capture_and_global_state_whitelist)
+        if (strncmp(sdl_backend, item, strlen(item)) == 0)
+            bd->MouseCanUseGlobalState = bd->MouseCanUseCapture = true;
+#endif
+    if (bd->MouseCanUseGlobalState)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
@@ -507,6 +590,9 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     platform_io.Platform_OpenInShellFn = [](ImGuiContext*, const char* url) { return SDL_OpenURL(url) == 0; };
 #endif
 
+    // Update monitor a first time during init
+    ImGui_ImplSDL2_UpdateMonitors();
+
     // Gamepad handling
     bd->GamepadMode = ImGui_ImplSDL2_GamepadMode_AutoFirst;
     bd->WantUpdateGamepadsList = true;
@@ -561,7 +647,11 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
 #endif
 
-    (void)sdl_gl_context; // Unused in 'master' branch.
+    // We need SDL_CaptureMouse(), SDL_GetGlobalMouseState() from SDL 2.0.4+ to support multiple viewports.
+    // We left the call to ImGui_ImplSDL2_InitMultiViewportSupport() outside of #ifdef to avoid unused-function warnings.
+    if (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports)
+        ImGui_ImplSDL2_InitMultiViewportSupport(window, sdl_gl_context);
+
     return true;
 }
 
@@ -575,7 +665,11 @@ bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
 #if !SDL_HAS_VULKAN
     IM_ASSERT(0 && "Unsupported");
 #endif
-    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
+    if (!ImGui_ImplSDL2_Init(window, nullptr, nullptr))
+        return false;
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    bd->UseVulkan = true;
+    return true;
 }
 
 bool ImGui_ImplSDL2_InitForD3D(SDL_Window* window)
@@ -609,6 +703,8 @@ void ImGui_ImplSDL2_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplSDL2_ShutdownMultiViewportSupport();
+
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -617,10 +713,11 @@ void ImGui_ImplSDL2_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     IM_DELETE(bd);
 }
 
+// This code is incredibly messy because some of the functions we need for full viewport support are not available in SDL < 2.0.4.
 static void ImGui_ImplSDL2_UpdateMouseData()
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
@@ -629,35 +726,68 @@ static void ImGui_ImplSDL2_UpdateMouseData()
     // We forward mouse input when hovered or captured (via SDL_MOUSEMOTION) or when focused (below)
 #if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
     // - SDL_CaptureMouse() let the OS know e.g. that our drags can extend outside of parent boundaries (we want updated position) and shouldn't trigger other operations outside.
-    // - Debuggers under Linux tends to leave captured mouse on break, which may be very inconvenient, so to migitate the issue we wait until mouse has moved to begin capture.
-    bool want_capture = false;
-    for (int button_n = 0; button_n < ImGuiMouseButton_COUNT && !want_capture; button_n++)
-        if (ImGui::IsMouseDragging(button_n, 1.0f))
-            want_capture = true;
-    SDL_CaptureMouse(want_capture ? SDL_TRUE : SDL_FALSE);
+    // - Debuggers under Linux tends to leave captured mouse on break, which may be very inconvenient, so to mitigate the issue we wait until mouse has moved to begin capture.
+    if (bd->MouseCanUseCapture)
+    {
+        bool want_capture = false;
+        for (int button_n = 0; button_n < ImGuiMouseButton_COUNT && !want_capture; button_n++)
+            if (ImGui::IsMouseDragging(button_n, 1.0f))
+                want_capture = true;
+        SDL_CaptureMouse(want_capture ? SDL_TRUE : SDL_FALSE);
+    }
 
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
-    const bool is_app_focused = (bd->Window == focused_window);
+    const bool is_app_focused = (focused_window && (bd->Window == focused_window || ImGui_ImplSDL2_GetViewportForWindowID(SDL_GetWindowID(focused_window)) != NULL));
 #else
+    SDL_Window* focused_window = bd->Window;
     const bool is_app_focused = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0; // SDL 2.0.3 and non-windowed systems: single-viewport only
 #endif
+
     if (is_app_focused)
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
         if (io.WantSetMousePos)
-            SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
+        {
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                SDL_WarpMouseGlobal((int)io.MousePos.x, (int)io.MousePos.y);
+            else
+#endif
+                SDL_WarpMouseInWindow(bd->Window, (int)io.MousePos.x, (int)io.MousePos.y);
+        }
 
         // (Optional) Fallback to provide mouse position when focused (SDL_MOUSEMOTION already provides this when hovered or captured)
         const bool is_relative_mouse_mode = SDL_GetRelativeMouseMode() != 0;
         if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
             // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
-            int window_x, window_y, mouse_x_global, mouse_y_global;
-            SDL_GetGlobalMouseState(&mouse_x_global, &mouse_y_global);
-            SDL_GetWindowPosition(bd->Window, &window_x, &window_y);
-            io.AddMousePosEvent((float)(mouse_x_global - window_x), (float)(mouse_y_global - window_y));
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+            int mouse_x, mouse_y, window_x, window_y;
+            SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+            {
+                SDL_GetWindowPosition(focused_window, &window_x, &window_y);
+                mouse_x -= window_x;
+                mouse_y -= window_y;
+            }
+            io.AddMousePosEvent((float)mouse_x, (float)mouse_y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [!] SDL backend does NOT correctly ignore viewports with the _NoInputs flag.
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] SDL backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+    {
+        ImGuiID mouse_viewport_id = 0;
+        if (ImGuiViewport* mouse_viewport = ImGui_ImplSDL2_GetViewportForWindowID(bd->MouseWindowID))
+            mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL2_UpdateMouseCursor()
@@ -686,6 +816,30 @@ static void ImGui_ImplSDL2_UpdateMouseCursor()
     }
 }
 
+// - On Windows the process needs to be marked DPI-aware!! SDL2 doesn't do it by default. You can call ::SetProcessDPIAware() or call ImGui_ImplWin32_EnableDpiAwareness() from Win32 backend.
+// - Apple platforms use FramebufferScale so we always return 1.0f.
+// - Some accessibility applications are declaring virtual monitors with a DPI of 0.0f, see #7902. We preserve this value for caller to handle.
+float ImGui_ImplSDL2_GetContentScaleForWindow(SDL_Window* window)
+{
+    return ImGui_ImplSDL2_GetContentScaleForDisplay(SDL_GetWindowDisplayIndex(window));
+}
+
+float ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index)
+{
+    const char* sdl_driver = SDL_GetCurrentVideoDriver();
+    if (sdl_driver && strcmp(sdl_driver, "wayland") == 0)
+        return 1.0f;
+#if SDL_HAS_PER_MONITOR_DPI
+#if !defined(__APPLE__) && !defined(__EMSCRIPTEN__) && !defined(__ANDROID__)
+    float dpi = 0.0f;
+    if (SDL_GetDisplayDPI(display_index, &dpi, nullptr, nullptr) == 0)
+        return dpi / 96.0f;
+#endif
+#endif
+    IM_UNUSED(display_index);
+    return 1.0f;
+}
+
 static void ImGui_ImplSDL2_CloseGamepads()
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
@@ -755,9 +909,6 @@ static void ImGui_ImplSDL2_UpdateGamepads()
         bd->WantUpdateGamepadsList = false;
     }
 
-    // FIXME: Technically feeding gamepad shouldn't depend on this now that they are regular inputs.
-    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0)
-        return;
     io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
     if (bd->Gamepads.Size == 0)
         return;
@@ -791,29 +942,74 @@ static void ImGui_ImplSDL2_UpdateGamepads()
     ImGui_ImplSDL2_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown,  SDL_CONTROLLER_AXIS_RIGHTY, +thumb_dead_zone, +32767);
 }
 
+// FIXME: Note that doesn't update with DPI/Scaling change only as SDL2 doesn't have an event for it (SDL3 has).
+static void ImGui_ImplSDL2_UpdateMonitors()
+{
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+    bd->WantUpdateMonitors = false;
+    int display_count = SDL_GetNumVideoDisplays();
+    for (int n = 0; n < display_count; n++)
+    {
+        // Warning: the validity of monitor DPI information on Windows depends on the application DPI awareness settings, which generally needs to be set in the manifest or at runtime.
+        ImGuiPlatformMonitor monitor;
+        SDL_Rect r;
+        SDL_GetDisplayBounds(n, &r);
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+#if SDL_HAS_USABLE_DISPLAY_BOUNDS
+        if (SDL_GetDisplayUsableBounds(n, &r) == 0 && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
+#endif
+        float dpi_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(n);
+        if (dpi_scale <= 0.0f)
+            continue; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+        monitor.DpiScale = dpi_scale;
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        platform_io.Monitors.push_back(monitor);
+    }
+}
+
+static void ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(SDL_Window* window, SDL_Renderer* renderer, ImVec2* out_size, ImVec2* out_framebuffer_scale)
+{
+    int w, h;
+    int display_w, display_h;
+    SDL_GetWindowSize(window, &w, &h);
+    if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
+        w = h = 0;
+    if (renderer != nullptr)
+        SDL_GetRendererOutputSize(renderer, &display_w, &display_h);
+#if SDL_HAS_VULKAN
+    else if (SDL_GetWindowFlags(window) & SDL_WINDOW_VULKAN)
+        SDL_Vulkan_GetDrawableSize(window, &display_w, &display_h);
+#endif
+    else
+        SDL_GL_GetDrawableSize(window, &display_w, &display_h);
+    if (out_size != nullptr)
+        *out_size = ImVec2((float)w, (float)h);
+    if (out_framebuffer_scale != nullptr)
+        *out_framebuffer_scale = (w > 0 && h > 0) ? ImVec2((float)display_w / w, (float)display_h / h) : ImVec2(1.0f, 1.0f);
+}
+
 void ImGui_ImplSDL2_NewFrame()
 {
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDL2_Init()?");
     ImGuiIO& io = ImGui::GetIO();
 
-    // Setup display size (every frame to accommodate for window resizing)
-    int w, h;
-    int display_w, display_h;
-    SDL_GetWindowSize(bd->Window, &w, &h);
-    if (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_MINIMIZED)
-        w = h = 0;
-    if (bd->Renderer != nullptr)
-        SDL_GetRendererOutputSize(bd->Renderer, &display_w, &display_h);
-#if SDL_HAS_VULKAN
-    else if (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_VULKAN)
-        SDL_Vulkan_GetDrawableSize(bd->Window, &display_w, &display_h);
+    // Setup main viewport size (every frame to accommodate for window resizing)
+    ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(bd->Window, bd->Renderer, &io.DisplaySize, &io.DisplayFramebufferScale);
+
+    // Update monitors
+#ifdef WIN32
+    bd->WantUpdateMonitors = true; // Keep polling under Windows to handle changes of work area when resizing task-bar (#8415)
 #endif
-    else
-        SDL_GL_GetDrawableSize(bd->Window, &display_w, &display_h);
-    io.DisplaySize = ImVec2((float)w, (float)h);
-    if (w > 0 && h > 0)
-        io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplSDL2_UpdateMonitors();
 
     // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
     // (Accept SDL_GetPerformanceCounter() not returning a monotonically increasing value. Happens in VMs and Emscripten, see #6189, #6114, #3644)
@@ -831,6 +1027,13 @@ void ImGui_ImplSDL2_NewFrame()
         io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
     }
 
+    // Our io.AddMouseViewportEvent() calls will only be valid when not capturing.
+    // Technically speaking testing for 'bd->MouseButtonsDown == 0' would be more rigorous, but testing for payload reduces noise and potential side-effects.
+    if (bd->MouseCanReportHoveredViewport && ImGui::GetDragDropPayload() == nullptr)
+        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport;
+    else
+        io.BackendFlags &= ~ImGuiBackendFlags_HasMouseHoveredViewport;
+
     ImGui_ImplSDL2_UpdateMouseData();
     ImGui_ImplSDL2_UpdateMouseCursor();
 
@@ -838,6 +1041,266 @@ void ImGui_ImplSDL2_NewFrame()
     ImGui_ImplSDL2_UpdateGamepads();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL2_ViewportData
+{
+    SDL_Window*     Window;
+    Uint32          WindowID;       // Stored in ImGuiViewport::PlatformHandle. Use SDL_GetWindowFromID() to get SDL_Window* from Uint32 WindowID.
+    bool            WindowOwned;
+    SDL_GLContext   GLContext;
+
+    ImGui_ImplSDL2_ViewportData()   { Window = nullptr; WindowID = 0; WindowOwned = false; GLContext = nullptr; }
+    ~ImGui_ImplSDL2_ViewportData()  { IM_ASSERT(Window == nullptr && GLContext == nullptr); }
+};
+
+static void ImGui_ImplSDL2_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    ImGui_ImplSDL2_ViewportData* vd = IM_NEW(ImGui_ImplSDL2_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL2_ViewportData* main_viewport_data = (ImGui_ImplSDL2_ViewportData*)main_viewport->PlatformUserData;
+
+    // Share GL resources with main context
+    bool use_opengl = (main_viewport_data->GLContext != nullptr);
+    SDL_GLContext backup_context = nullptr;
+    if (use_opengl)
+    {
+        backup_context = SDL_GL_GetCurrentContext();
+        SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
+        SDL_GL_MakeCurrent(main_viewport_data->Window, main_viewport_data->GLContext);
+    }
+
+    Uint32 sdl_flags = 0;
+    sdl_flags |= use_opengl ? SDL_WINDOW_OPENGL : (bd->UseVulkan ? SDL_WINDOW_VULKAN : 0);
+    sdl_flags |= SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_ALLOW_HIGHDPI;
+    sdl_flags |= SDL_WINDOW_HIDDEN;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? SDL_WINDOW_BORDERLESS : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? 0 : SDL_WINDOW_RESIZABLE;
+#if !defined(_WIN32)
+    // See SDL hack in ImGui_ImplSDL2_ShowWindow().
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_SKIP_TASKBAR : 0;
+#endif
+#if SDL_HAS_ALWAYS_ON_TOP
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
+#endif
+    vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Pos.x, (int)viewport->Pos.y, (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+    vd->WindowOwned = true;
+    if (use_opengl)
+    {
+        vd->GLContext = SDL_GL_CreateContext(vd->Window);
+        SDL_GL_SetSwapInterval(0);
+    }
+    if (use_opengl && backup_context)
+        SDL_GL_MakeCurrent(vd->Window, backup_context);
+
+    viewport->PlatformHandle = (void*)(intptr_t)SDL_GetWindowID(vd->Window);
+    viewport->PlatformHandleRaw = nullptr;
+    SDL_SysWMinfo info;
+    SDL_VERSION(&info.version);
+    if (SDL_GetWindowWMInfo(vd->Window, &info))
+    {
+#if defined(SDL_VIDEO_DRIVER_WINDOWS)
+        viewport->PlatformHandleRaw = info.info.win.window;
+#elif defined(__APPLE__) && defined(SDL_VIDEO_DRIVER_COCOA)
+        viewport->PlatformHandleRaw = (void*)info.info.cocoa.window;
+#endif
+    }
+}
+
+static void ImGui_ImplSDL2_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->GLContext && vd->WindowOwned)
+            SDL_GL_DeleteContext(vd->GLContext);
+        if (vd->Window && vd->WindowOwned)
+            SDL_DestroyWindow(vd->Window);
+        vd->GLContext = nullptr;
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplSDL2_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+#if defined(_WIN32) && !(defined(WINAPI_FAMILY) && ((defined(WINAPI_FAMILY_APP) && WINAPI_FAMILY == WINAPI_FAMILY_APP) || (defined(WINAPI_FAMILY_GAMES) && WINAPI_FAMILY == WINAPI_FAMILY_GAMES)))
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+
+    // SDL hack: Hide icon from task bar
+    // Note: SDL 2.0.6+ has a SDL_WINDOW_SKIP_TASKBAR flag which is supported under Windows but the way it create the window breaks our seamless transition.
+    if (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon)
+    {
+        LONG ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);
+        ex_style &= ~WS_EX_APPWINDOW;
+        ex_style |= WS_EX_TOOLWINDOW;
+        ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
+    }
+#endif
+
+#if SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT
+    SDL_SetHint(SDL_HINT_WINDOW_NO_ACTIVATION_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "1" : "0");
+#elif defined(_WIN32)
+    // SDL hack: SDL always activate/focus windows :/
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+    {
+        ::ShowWindow(hwnd, SW_SHOWNA);
+        return;
+    }
+#endif
+    SDL_ShowWindow(vd->Window);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    SDL_GetWindowPosition(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplSDL2_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowPosition(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    SDL_GetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplSDL2_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static ImVec2 ImGui_ImplSDL2_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    // FIXME: SDL_Renderer does not support multi-viewport.
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    ImVec2 framebuffer_scale;
+    ImGui_ImplSDL2_GetWindowSizeAndFramebufferScale(vd->Window, nullptr, nullptr, &framebuffer_scale);
+    return framebuffer_scale;
+}
+
+static void ImGui_ImplSDL2_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowTitle(vd->Window, title);
+}
+
+#if SDL_HAS_WINDOW_ALPHA
+static void ImGui_ImplSDL2_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowOpacity(vd->Window, alpha);
+}
+#endif
+
+static void ImGui_ImplSDL2_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    SDL_RaiseWindow(vd->Window);
+}
+
+static bool ImGui_ImplSDL2_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0;
+}
+
+static bool ImGui_ImplSDL2_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_MINIMIZED) != 0;
+}
+
+static void ImGui_ImplSDL2_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+}
+
+static void ImGui_ImplSDL2_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+    {
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+        SDL_GL_SwapWindow(vd->Window);
+    }
+}
+
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+// SDL is graceful enough to _not_ need <vulkan/vulkan.h> so we can safely include this.
+#if SDL_HAS_VULKAN
+#include <SDL_vulkan.h>
+static int ImGui_ImplSDL2_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplSDL2_ViewportData* vd = (ImGui_ImplSDL2_ViewportData*)viewport->PlatformUserData;
+    (void)vk_allocator;
+    SDL_bool ret = SDL_Vulkan_CreateSurface(vd->Window, (VkInstance)vk_instance, (VkSurfaceKHR*)out_vk_surface);
+    return ret ? 0 : 1; // ret ? VK_SUCCESS : VK_NOT_READY
+}
+#endif // SDL_HAS_VULKAN
+
+static void ImGui_ImplSDL2_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context)
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplSDL2_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplSDL2_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplSDL2_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplSDL2_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplSDL2_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplSDL2_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplSDL2_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplSDL2_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplSDL2_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplSDL2_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplSDL2_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplSDL2_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplSDL2_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplSDL2_SwapBuffers;
+#if SDL_HAS_WINDOW_ALPHA
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplSDL2_SetWindowAlpha;
+#endif
+#if SDL_HAS_VULKAN
+    platform_io.Platform_CreateVkSurface = ImGui_ImplSDL2_CreateVkSurface;
+#endif
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL2_ViewportData* vd = IM_NEW(ImGui_ImplSDL2_ViewportData)();
+    vd->Window = window;
+    vd->WindowID = SDL_GetWindowID(window);
+    vd->WindowOwned = false;
+    vd->GLContext = sdl_gl_context;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)(intptr_t)vd->WindowID;
+}
+
+static void ImGui_ImplSDL2_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl2.h

@@ -6,9 +6,13 @@
 //  [X] Platform: Clipboard support.
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Basic IME support. App needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [ ] Platform: Multi-viewport: ParentViewportID not honored, and so io.ConfigViewportsNoDefaultParent has no effect (minor).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -38,6 +42,10 @@ IMGUI_IMPL_API void     ImGui_ImplSDL2_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDL2_NewFrame();
 IMGUI_IMPL_API bool     ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event);
 
+// DPI-related helpers (optional)
+IMGUI_IMPL_API float    ImGui_ImplSDL2_GetContentScaleForWindow(SDL_Window* window);
+IMGUI_IMPL_API float    ImGui_ImplSDL2_GetContentScaleForDisplay(int display_index);
+
 // Gamepad selection automatically starts in AutoFirst mode, picking first available SDL_Gamepad. You may override this.
 // When using manual mode, caller is responsible for opening/closing gamepad.
 enum ImGui_ImplSDL2_GamepadMode { ImGui_ImplSDL2_GamepadMode_AutoFirst, ImGui_ImplSDL2_GamepadMode_AutoAll, ImGui_ImplSDL2_GamepadMode_Manual };

backends/imgui_impl_sdl3.cpp

@@ -6,9 +6,12 @@
 //  [X] Platform: Clipboard support.
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-//  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [x] Platform: IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -20,13 +23,26 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-09-15: Use SDL_GetWindowDisplayScale() on Mac to output DisplayFrameBufferScale. The function is more reliable during resolution changes e.g. going fullscreen. (#8703, #4414)
+//  2025-06-27: IME: avoid calling SDL_StartTextInput() again if already active. (#8727)
+//  2025-05-15: [Docking] Add Platform_GetWindowFramebufferScale() handler, to allow varying Retina display density on multiple monitors.
+//  2025-05-06: [Docking] macOS: fixed secondary viewports not appearing on other monitors before of parenting.
+//  2025-04-09: [Docking] Revert update monitors and work areas information every frame. Only do it on Windows. (#8415, #8558)
+//  2025-04-22: IME: honor ImGuiPlatformImeData->WantTextInput as an alternative way to call SDL_StartTextInput(), without IME being necessarily visible.
+//  2025-04-09: Don't attempt to call SDL_CaptureMouse() on drivers where we don't call SDL_GetGlobalMouseState(). (#8561)
+//  2025-03-30: Update for SDL3 api changes: Revert SDL_GetClipboardText() memory ownership change. (#8530, #7801)
+//  2025-03-21: Fill gamepad inputs and set ImGuiBackendFlags_HasGamepad regardless of ImGuiConfigFlags_NavEnableGamepad being set.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
 //  2025-02-26: Only start SDL_CaptureMouse() when mouse is being dragged, to mitigate issues with e.g.Linux debuggers not claiming capture back. (#6410, #3650)
+//  2025-02-25: [Docking] Revert to use SDL_GetDisplayBounds() for WorkPos/WorkRect if SDL_GetDisplayUsableBounds() failed.
 //  2025-02-24: Avoid calling SDL_GetGlobalMouseState() when mouse is in relative mode.
+//  2025-02-21: [Docking] Update monitors and work areas information every frame, as the later may change regardless of monitor changes. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
 //  2025-02-10: Using SDL_OpenURL() in platform_io.Platform_OpenInShellFn handler.
 //  2025-01-20: Made ImGui_ImplSDL3_SetGamepadMode(ImGui_ImplSDL3_GamepadMode_Manual) accept an empty array.
 //  2024-10-24: Emscripten: SDL_EVENT_MOUSE_WHEEL event doesn't require dividing by 100.0f on Emscripten.
+//  2024-09-11: (Docking) Added support for viewport->ParentViewportId field to support parenting at OS level. (#7973)
 //  2024-09-03: Update for SDL3 api changes: SDL_GetGamepads() memory ownership revert. (#7918, #7898, #7807)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
 //               - io.GetClipboardTextFn    -> platform_io.Platform_GetClipboardTextFn
@@ -60,11 +76,13 @@
 // Clang warnings with -Weverything
 #if defined(__clang__)
 #pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wold-style-cast"                 // warning: use of old-style cast
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #endif
 
 // SDL
 #include <SDL3/SDL.h>
+#include <stdio.h>              // for snprintf()
 #if defined(__APPLE__)
 #include <TargetConditionals.h>
 #endif
@@ -97,6 +115,9 @@ struct ImGui_ImplSDL3_Data
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
+    char                    BackendPlatformName[48];
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // IME handling
     SDL_Window*             ImeWindow;
@@ -108,11 +129,13 @@ struct ImGui_ImplSDL3_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MousePendingLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    bool                    MouseCanUseCapture;
+    bool                    MouseCanReportHoveredViewport;  // This is hard to use/unreliable on SDL so we'll set ImGuiBackendFlags_HasMouseHoveredViewport dynamically based on state.
 
     // Gamepad handling
-    ImVector<SDL_Gamepad*>      Gamepads;
+    ImVector<SDL_Gamepad*>  Gamepads;
     ImGui_ImplSDL3_GamepadMode  GamepadMode;
-    bool                        WantUpdateGamepadsList;
+    bool                    WantUpdateGamepadsList;
 
     ImGui_ImplSDL3_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
@@ -126,14 +149,18 @@ static ImGui_ImplSDL3_Data* ImGui_ImplSDL3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDL3_Data*)ImGui::GetIO().BackendPlatformUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplSDL3_UpdateMonitors();
+static void ImGui_ImplSDL3_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL3_ShutdownMultiViewportSupport();
+
 // Functions
 static const char* ImGui_ImplSDL3_GetClipboardText(ImGuiContext*)
 {
     ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
-    const char* sdl_clipboard_text = SDL_GetClipboardText();
-    bd->ClipboardTextData = sdl_clipboard_text ? SDL_strdup(sdl_clipboard_text) : nullptr;
+    bd->ClipboardTextData = SDL_GetClipboardText();
     return bd->ClipboardTextData;
 }
 
@@ -147,7 +174,7 @@ static void ImGui_ImplSDL3_PlatformSetImeData(ImGuiContext*, ImGuiViewport* view
     ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
     SDL_WindowID window_id = (SDL_WindowID)(intptr_t)viewport->PlatformHandle;
     SDL_Window* window = SDL_GetWindowFromID(window_id);
-    if ((data->WantVisible == false || bd->ImeWindow != window) && bd->ImeWindow != nullptr)
+    if ((!(data->WantVisible || data->WantTextInput) || bd->ImeWindow != window) && bd->ImeWindow != nullptr)
     {
         SDL_StopTextInput(bd->ImeWindow);
         bd->ImeWindow = nullptr;
@@ -155,14 +182,15 @@ static void ImGui_ImplSDL3_PlatformSetImeData(ImGuiContext*, ImGuiViewport* view
     if (data->WantVisible)
     {
         SDL_Rect r;
-        r.x = (int)data->InputPos.x;
-        r.y = (int)data->InputPos.y;
+        r.x = (int)(data->InputPos.x - viewport->Pos.x);
+        r.y = (int)(data->InputPos.y - viewport->Pos.y + data->InputLineHeight);
         r.w = 1;
         r.h = (int)data->InputLineHeight;
         SDL_SetTextInputArea(window, &r, 0);
-        SDL_StartTextInput(window);
         bd->ImeWindow = window;
     }
+    if (!SDL_TextInputActive(window) && (data->WantVisible || data->WantTextInput))
+        SDL_StartTextInput(window);
 }
 
 // Not static to allow third-party code to use that if they want to (but undocumented)
@@ -327,18 +355,15 @@ static void ImGui_ImplSDL3_UpdateKeyModifiers(SDL_Keymod sdl_key_mods)
     io.AddKeyEvent(ImGuiMod_Super, (sdl_key_mods & SDL_KMOD_GUI) != 0);
 }
 
-
 static ImGuiViewport* ImGui_ImplSDL3_GetViewportForWindowID(SDL_WindowID window_id)
 {
-    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
-    return (window_id == bd->WindowID) ? ImGui::GetMainViewport() : nullptr;
+    return ImGui::FindViewportByPlatformHandle((void*)(intptr_t)window_id);
 }
 
 // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
-// If you have multiple SDL events and some of them are not meant to be used by dear imgui, you may need to filter events based on their windowID field.
 bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
 {
     ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
@@ -352,6 +377,13 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
             if (ImGui_ImplSDL3_GetViewportForWindowID(event->motion.windowID) == nullptr)
                 return false;
             ImVec2 mouse_pos((float)event->motion.x, (float)event->motion.y);
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                int window_x, window_y;
+                SDL_GetWindowPosition(SDL_GetWindowFromID(event->motion.windowID), &window_x, &window_y);
+                mouse_pos.x += window_x;
+                mouse_pos.y += window_y;
+            }
             io.AddMouseSourceEvent(event->motion.which == SDL_TOUCH_MOUSEID ? ImGuiMouseSource_TouchScreen : ImGuiMouseSource_Mouse);
             io.AddMousePosEvent(mouse_pos.x, mouse_pos.y);
             return true;
@@ -395,14 +427,24 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
         case SDL_EVENT_KEY_DOWN:
         case SDL_EVENT_KEY_UP:
         {
-            if (ImGui_ImplSDL3_GetViewportForWindowID(event->key.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->key.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("SDL_EVENT_KEY_%s : key=0x%08X ('%s'), scancode=%d ('%s'), mod=%X, windowID=%d, viewport=%08X\n",
+            //    (event->type == SDL_EVENT_KEY_DOWN) ? "DOWN" : "UP  ", event->key.key, SDL_GetKeyName(event->key.key), event->key.scancode, SDL_GetScancodeName(event->key.scancode), event->key.mod, event->key.windowID, viewport ? viewport->ID : 0);
             ImGui_ImplSDL3_UpdateKeyModifiers((SDL_Keymod)event->key.mod);
-            //IMGUI_DEBUG_LOG("SDL_EVENT_KEY_%s : key=%d ('%s'), scancode=%d ('%s'), mod=%X\n",
-            //    (event->type == SDL_EVENT_KEY_DOWN) ? "DOWN" : "UP  ", event->key.key, SDL_GetKeyName(event->key.key), event->key.scancode, SDL_GetScancodeName(event->key.scancode), event->key.mod);
             ImGuiKey key = ImGui_ImplSDL3_KeyEventToImGuiKey(event->key.key, event->key.scancode);
             io.AddKeyEvent(key, (event->type == SDL_EVENT_KEY_DOWN));
-            io.SetKeyEventNativeData(key, event->key.key, event->key.scancode, event->key.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
+            io.SetKeyEventNativeData(key, (int)event->key.key, (int)event->key.scancode, (int)event->key.scancode); // To support legacy indexing (<1.87 user code). Legacy backend uses SDLK_*** as indices to IsKeyXXX() functions.
+            return true;
+        }
+        case SDL_EVENT_DISPLAY_ORIENTATION:
+        case SDL_EVENT_DISPLAY_ADDED:
+        case SDL_EVENT_DISPLAY_REMOVED:
+        case SDL_EVENT_DISPLAY_MOVED:
+        case SDL_EVENT_DISPLAY_CONTENT_SCALE_CHANGED:
+        {
+            bd->WantUpdateMonitors = true;
             return true;
         }
         case SDL_EVENT_WINDOW_MOUSE_ENTER:
@@ -427,17 +469,36 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
         case SDL_EVENT_WINDOW_FOCUS_GAINED:
         case SDL_EVENT_WINDOW_FOCUS_LOST:
         {
-            if (ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID) == nullptr)
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID);
+            if (viewport == nullptr)
                 return false;
+            //IMGUI_DEBUG_LOG("%s: windowId %d, viewport: %08X\n", (event->type == SDL_EVENT_WINDOW_FOCUS_GAINED) ? "SDL_EVENT_WINDOW_FOCUS_GAINED" : "SDL_WINDOWEVENT_FOCUS_LOST", event->window.windowID, viewport ? viewport->ID : 0);
             io.AddFocusEvent(event->type == SDL_EVENT_WINDOW_FOCUS_GAINED);
             return true;
         }
+        case SDL_EVENT_WINDOW_CLOSE_REQUESTED:
+        case SDL_EVENT_WINDOW_MOVED:
+        case SDL_EVENT_WINDOW_RESIZED:
+        {
+            ImGuiViewport* viewport = ImGui_ImplSDL3_GetViewportForWindowID(event->window.windowID);
+            if (viewport == NULL)
+                return false;
+            if (event->type == SDL_EVENT_WINDOW_CLOSE_REQUESTED)
+                viewport->PlatformRequestClose = true;
+            if (event->type == SDL_EVENT_WINDOW_MOVED)
+                viewport->PlatformRequestMove = true;
+            if (event->type == SDL_EVENT_WINDOW_RESIZED)
+                viewport->PlatformRequestResize = true;
+            return true;
+        }
         case SDL_EVENT_GAMEPAD_ADDED:
         case SDL_EVENT_GAMEPAD_REMOVED:
         {
             bd->WantUpdateGamepadsList = true;
             return true;
         }
+        default:
+            break;
     }
     return false;
 }
@@ -448,7 +509,7 @@ static void ImGui_ImplSDL3_SetupPlatformHandles(ImGuiViewport* viewport, SDL_Win
     viewport->PlatformHandleRaw = nullptr;
 #if defined(_WIN32) && !defined(__WINRT__)
     viewport->PlatformHandleRaw = (HWND)SDL_GetPointerProperty(SDL_GetWindowProperties(window), SDL_PROP_WINDOW_WIN32_HWND_POINTER, nullptr);
-#elif defined(__APPLE__) && defined(SDL_VIDEO_DRIVER_COCOA)
+#elif defined(__APPLE__)
     viewport->PlatformHandleRaw = SDL_GetPointerProperty(SDL_GetWindowProperties(window), SDL_PROP_WINDOW_COCOA_WINDOW_POINTER, nullptr);
 #endif
 }
@@ -459,29 +520,45 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
     IM_UNUSED(sdl_gl_context); // Unused in this branch
+    //SDL_SetHint(SDL_HINT_EVENT_LOGGING, "2");
 
-    // Check and store if we are on a SDL backend that supports global mouse position
-    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
-    bool mouse_can_use_global_state = false;
-#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
-    const char* sdl_backend = SDL_GetCurrentVideoDriver();
-    const char* global_mouse_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
-    for (int n = 0; n < IM_ARRAYSIZE(global_mouse_whitelist); n++)
-        if (strncmp(sdl_backend, global_mouse_whitelist[n], strlen(global_mouse_whitelist[n])) == 0)
-            mouse_can_use_global_state = true;
-#endif
+    const int ver_linked = SDL_GetVersion();
 
     // Setup backend capabilities flags
     ImGui_ImplSDL3_Data* bd = IM_NEW(ImGui_ImplSDL3_Data)();
+    snprintf(bd->BackendPlatformName, sizeof(bd->BackendPlatformName), "imgui_impl_sdl3 (%d.%d.%d; %d.%d.%d)",
+        SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_MICRO_VERSION, SDL_VERSIONNUM_MAJOR(ver_linked), SDL_VERSIONNUM_MINOR(ver_linked), SDL_VERSIONNUM_MICRO(ver_linked));
     io.BackendPlatformUserData = (void*)bd;
-    io.BackendPlatformName = "imgui_impl_sdl3";
+    io.BackendPlatformName = bd->BackendPlatformName;
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    // (ImGuiBackendFlags_PlatformHasViewports may be set just below)
 
     bd->Window = window;
     bd->WindowID = SDL_GetWindowID(window);
     bd->Renderer = renderer;
-    bd->MouseCanUseGlobalState = mouse_can_use_global_state;
+
+    // SDL on Linux/OSX doesn't report events for unfocused windows (see https://github.com/ocornut/imgui/issues/4960)
+    // We will use 'MouseCanReportHoveredViewport' to set 'ImGuiBackendFlags_HasMouseHoveredViewport' dynamically each frame.
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
+
+    // Check and store if we are on a SDL backend that supports SDL_GetGlobalMouseState() and SDL_CaptureMouse()
+    // ("wayland" and "rpi" don't support it, but we chose to use a white-list instead of a black-list)
+    bd->MouseCanUseGlobalState = false;
+    bd->MouseCanUseCapture = false;
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+    const char* sdl_backend = SDL_GetCurrentVideoDriver();
+    const char* capture_and_global_state_whitelist[] = { "windows", "cocoa", "x11", "DIVE", "VMAN" };
+    for (const char* item : capture_and_global_state_whitelist)
+        if (strncmp(sdl_backend, item, strlen(item)) == 0)
+            bd->MouseCanUseGlobalState = bd->MouseCanUseCapture = true;
+#endif
+    if (bd->MouseCanUseGlobalState)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
 
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_SetClipboardTextFn = ImGui_ImplSDL3_SetClipboardText;
@@ -489,6 +566,9 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     platform_io.Platform_SetImeDataFn = ImGui_ImplSDL3_PlatformSetImeData;
     platform_io.Platform_OpenInShellFn = [](ImGuiContext*, const char* url) { return SDL_OpenURL(url) == 0; };
 
+    // Update monitor a first time during init
+    ImGui_ImplSDL3_UpdateMonitors();
+
     // Gamepad handling
     bd->GamepadMode = ImGui_ImplSDL3_GamepadMode_AutoFirst;
     bd->WantUpdateGamepadsList = true;
@@ -515,28 +595,36 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     // Without this, when clicking to gain focus, our widgets wouldn't activate even though they showed as hovered.
     // (This is unfortunately a global SDL setting, so enabling it might have a side-effect on your application.
     // It is unlikely to make a difference, but if your app absolutely needs to ignore the initial on-focus click:
-    // you can ignore SDL_EVENT_MOUSE_BUTTON_DOWN events coming right after a SDL_WINDOWEVENT_FOCUS_GAINED)
-#ifdef SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH
+    // you can ignore SDL_EVENT_MOUSE_BUTTON_DOWN events coming right after a SDL_EVENT_WINDOW_FOCUS_GAINED)
     SDL_SetHint(SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, "1");
-#endif
 
     // From 2.0.22: Disable auto-capture, this is preventing drag and drop across multiple windows (see #5710)
-#ifdef SDL_HINT_MOUSE_AUTO_CAPTURE
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
-#endif
+
+    // SDL 3.x : see https://github.com/libsdl-org/SDL/issues/6659
+    SDL_SetHint("SDL_BORDERLESS_WINDOWED_STYLE", "0");
+
+    // We need SDL_CaptureMouse(), SDL_GetGlobalMouseState() from SDL 2.0.4+ to support multiple viewports.
+    // We left the call to ImGui_ImplSDL3_InitPlatformInterface() outside of #ifdef to avoid unused-function warnings.
+    if (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports)
+        ImGui_ImplSDL3_InitMultiViewportSupport(window, sdl_gl_context);
 
     return true;
 }
 
+// Should technically be a SDL_GLContext but due to typedef it is sane to keep it void* in public interface.
 bool ImGui_ImplSDL3_InitForOpenGL(SDL_Window* window, void* sdl_gl_context)
 {
-    IM_UNUSED(sdl_gl_context); // Viewport branch will need this.
     return ImGui_ImplSDL3_Init(window, nullptr, sdl_gl_context);
 }
 
 bool ImGui_ImplSDL3_InitForVulkan(SDL_Window* window)
 {
-    return ImGui_ImplSDL3_Init(window, nullptr, nullptr);
+    if (!ImGui_ImplSDL3_Init(window, nullptr, nullptr))
+        return false;
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    bd->UseVulkan = true;
+    return true;
 }
 
 bool ImGui_ImplSDL3_InitForD3D(SDL_Window* window)
@@ -575,6 +663,8 @@ void ImGui_ImplSDL3_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplSDL3_ShutdownMultiViewportSupport();
+
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -583,10 +673,11 @@ void ImGui_ImplSDL3_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     IM_DELETE(bd);
 }
 
+// This code is incredibly messy because some of the functions we need for full viewport support are not available in SDL < 2.0.4.
 static void ImGui_ImplSDL3_UpdateMouseData()
 {
     ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
@@ -595,15 +686,18 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     // We forward mouse input when hovered or captured (via SDL_EVENT_MOUSE_MOTION) or when focused (below)
 #if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
     // - SDL_CaptureMouse() let the OS know e.g. that our drags can extend outside of parent boundaries (we want updated position) and shouldn't trigger other operations outside.
-    // - Debuggers under Linux tends to leave captured mouse on break, which may be very inconvenient, so to migitate the issue we wait until mouse has moved to begin capture.
-    bool want_capture = false;
-    for (int button_n = 0; button_n < ImGuiMouseButton_COUNT && !want_capture; button_n++)
-        if (ImGui::IsMouseDragging(button_n, 1.0f))
-            want_capture = true;
-    SDL_CaptureMouse(want_capture);
+    // - Debuggers under Linux tends to leave captured mouse on break, which may be very inconvenient, so to mitigate the issue we wait until mouse has moved to begin capture.
+    if (bd->MouseCanUseCapture)
+    {
+        bool want_capture = false;
+        for (int button_n = 0; button_n < ImGuiMouseButton_COUNT && !want_capture; button_n++)
+            if (ImGui::IsMouseDragging(button_n, 1.0f))
+                want_capture = true;
+        SDL_CaptureMouse(want_capture);
+    }
 
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
-    const bool is_app_focused = (bd->Window == focused_window);
+    const bool is_app_focused = (focused_window && (bd->Window == focused_window || ImGui_ImplSDL3_GetViewportForWindowID(SDL_GetWindowID(focused_window)) != NULL));
 #else
     SDL_Window* focused_window = bd->Window;
     const bool is_app_focused = (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0; // SDL 2.0.3 and non-windowed systems: single-viewport only
@@ -612,20 +706,48 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
         if (io.WantSetMousePos)
-            SDL_WarpMouseInWindow(bd->Window, io.MousePos.x, io.MousePos.y);
+        {
+#if SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                SDL_WarpMouseGlobal(io.MousePos.x, io.MousePos.y);
+            else
+#endif
+                SDL_WarpMouseInWindow(bd->Window, io.MousePos.x, io.MousePos.y);
+        }
 
         // (Optional) Fallback to provide mouse position when focused (SDL_EVENT_MOUSE_MOTION already provides this when hovered or captured)
         const bool is_relative_mouse_mode = SDL_GetWindowRelativeMouseMode(bd->Window);
         if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0 && !is_relative_mouse_mode)
         {
             // Single-viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
-            float mouse_x_global, mouse_y_global;
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+            float mouse_x, mouse_y;
             int window_x, window_y;
-            SDL_GetGlobalMouseState(&mouse_x_global, &mouse_y_global);
-            SDL_GetWindowPosition(focused_window, &window_x, &window_y);
-            io.AddMousePosEvent(mouse_x_global - window_x, mouse_y_global - window_y);
+            SDL_GetGlobalMouseState(&mouse_x, &mouse_y);
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+            {
+                SDL_GetWindowPosition(focused_window, &window_x, &window_y);
+                mouse_x -= window_x;
+                mouse_y -= window_y;
+            }
+            io.AddMousePosEvent((float)mouse_x, (float)mouse_y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [!] SDL backend does NOT correctly ignore viewports with the _NoInputs flag.
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] SDL backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+    {
+        ImGuiID mouse_viewport_id = 0;
+        if (ImGuiViewport* mouse_viewport = ImGui_ImplSDL3_GetViewportForWindowID(bd->MouseWindowID))
+            mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL3_UpdateMouseCursor()
@@ -724,9 +846,6 @@ static void ImGui_ImplSDL3_UpdateGamepads()
         SDL_free(sdl_gamepads);
     }
 
-    // FIXME: Technically feeding gamepad shouldn't depend on this now that they are regular inputs.
-    if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0)
-        return;
     io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
     if (bd->Gamepads.Size == 0)
         return;
@@ -760,24 +879,78 @@ static void ImGui_ImplSDL3_UpdateGamepads()
     ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown,  SDL_GAMEPAD_AXIS_RIGHTY, +thumb_dead_zone, +32767);
 }
 
+static void ImGui_ImplSDL3_UpdateMonitors()
+{
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
+    bd->WantUpdateMonitors = false;
+
+    int display_count;
+    SDL_DisplayID* displays = SDL_GetDisplays(&display_count);
+    for (int n = 0; n < display_count; n++)
+    {
+        // Warning: the validity of monitor DPI information on Windows depends on the application DPI awareness settings, which generally needs to be set in the manifest or at runtime.
+        SDL_DisplayID display_id = displays[n];
+        ImGuiPlatformMonitor monitor;
+        SDL_Rect r;
+        SDL_GetDisplayBounds(display_id, &r);
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        if (SDL_GetDisplayUsableBounds(display_id, &r) && r.w > 0 && r.h > 0)
+        {
+            monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+            monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        }
+        monitor.DpiScale = SDL_GetDisplayContentScale(display_id); // See https://wiki.libsdl.org/SDL3/README-highdpi for details.
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        if (monitor.DpiScale <= 0.0f)
+            continue; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+        platform_io.Monitors.push_back(monitor);
+    }
+    SDL_free(displays);
+}
+
+static void ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(SDL_Window* window, ImVec2* out_size, ImVec2* out_framebuffer_scale)
+{
+    int w, h;
+    SDL_GetWindowSize(window, &w, &h);
+    if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
+        w = h = 0;
+
+#if defined(__APPLE__)
+    float fb_scale_x = SDL_GetWindowDisplayScale(window); // Seems more reliable during resolution change (#8703)
+    float fb_scale_y = fb_scale_x;
+#else
+    int display_w, display_h;
+    SDL_GetWindowSizeInPixels(window, &display_w, &display_h);
+    float fb_scale_x = (w > 0) ? (float)display_w / w : 1.0f;
+    float fb_scale_y = (h > 0) ? (float)display_h / h : 1.0f;
+#endif
+
+    if (out_size != nullptr)
+        *out_size = ImVec2((float)w, (float)h);
+    if (out_framebuffer_scale != nullptr)
+        *out_framebuffer_scale = ImVec2(fb_scale_x, fb_scale_y);
+}
+
 void ImGui_ImplSDL3_NewFrame()
 {
     ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDL3_Init()?");
     ImGuiIO& io = ImGui::GetIO();
 
-    // Setup display size (every frame to accommodate for window resizing)
-    int w, h;
-    int display_w, display_h;
-    SDL_GetWindowSize(bd->Window, &w, &h);
-    if (SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_MINIMIZED)
-        w = h = 0;
-    SDL_GetWindowSizeInPixels(bd->Window, &display_w, &display_h);
-    io.DisplaySize = ImVec2((float)w, (float)h);
-    if (w > 0 && h > 0)
-        io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
+    // Setup main viewport size (every frame to accommodate for window resizing)
+    ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(bd->Window, &io.DisplaySize, &io.DisplayFramebufferScale);
 
-    // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
+    // Update monitors
+#ifdef WIN32
+    bd->WantUpdateMonitors = true; // Keep polling under Windows to handle changes of work area when resizing task-bar (#8415)
+#endif
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplSDL3_UpdateMonitors();
+
+    // Setup time step (we could also use SDL_GetTicksNS() available since SDL3)
     // (Accept SDL_GetPerformanceCounter() not returning a monotonically increasing value. Happens in VMs and Emscripten, see #6189, #6114, #3644)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
     Uint64 current_time = SDL_GetPerformanceCounter();
@@ -793,6 +966,13 @@ void ImGui_ImplSDL3_NewFrame()
         io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
     }
 
+    // Our io.AddMouseViewportEvent() calls will only be valid when not capturing.
+    // Technically speaking testing for 'bd->MouseButtonsDown == 0' would be more rigorous, but testing for payload reduces noise and potential side-effects.
+    if (bd->MouseCanReportHoveredViewport && ImGui::GetDragDropPayload() == nullptr)
+        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport;
+    else
+        io.BackendFlags &= ~ImGuiBackendFlags_HasMouseHoveredViewport;
+
     ImGui_ImplSDL3_UpdateMouseData();
     ImGui_ImplSDL3_UpdateMouseCursor();
 
@@ -800,6 +980,273 @@ void ImGui_ImplSDL3_NewFrame()
     ImGui_ImplSDL3_UpdateGamepads();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL3_ViewportData
+{
+    SDL_Window*     Window;
+    SDL_Window*     ParentWindow;
+    Uint32          WindowID;       // Stored in ImGuiViewport::PlatformHandle. Use SDL_GetWindowFromID() to get SDL_Window* from Uint32 WindowID.
+    bool            WindowOwned;
+    SDL_GLContext   GLContext;
+
+    ImGui_ImplSDL3_ViewportData()   { Window = ParentWindow = nullptr; WindowID = 0; WindowOwned = false; GLContext = nullptr; }
+    ~ImGui_ImplSDL3_ViewportData()  { IM_ASSERT(Window == nullptr && GLContext == nullptr); }
+};
+
+static SDL_Window* ImGui_ImplSDL3_GetSDLWindowFromViewportID(ImGuiID viewport_id)
+{
+    if (viewport_id != 0)
+        if (ImGuiViewport* viewport = ImGui::FindViewportByID(viewport_id))
+        {
+            SDL_WindowID window_id = (SDL_WindowID)(intptr_t)viewport->PlatformHandle;
+            return SDL_GetWindowFromID(window_id);
+        }
+    return nullptr;
+}
+
+static void ImGui_ImplSDL3_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
+    ImGui_ImplSDL3_ViewportData* vd = IM_NEW(ImGui_ImplSDL3_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    vd->ParentWindow = ImGui_ImplSDL3_GetSDLWindowFromViewportID(viewport->ParentViewportId);
+
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL3_ViewportData* main_viewport_data = (ImGui_ImplSDL3_ViewportData*)main_viewport->PlatformUserData;
+
+    // Share GL resources with main context
+    bool use_opengl = (main_viewport_data->GLContext != nullptr);
+    SDL_GLContext backup_context = nullptr;
+    if (use_opengl)
+    {
+        backup_context = SDL_GL_GetCurrentContext();
+        SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
+        SDL_GL_MakeCurrent(main_viewport_data->Window, main_viewport_data->GLContext);
+    }
+
+    SDL_WindowFlags sdl_flags = 0;
+    sdl_flags |= SDL_WINDOW_HIDDEN;
+    sdl_flags |= use_opengl ? SDL_WINDOW_OPENGL : (bd->UseVulkan ? SDL_WINDOW_VULKAN : 0);
+    sdl_flags |= SDL_GetWindowFlags(bd->Window) & SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? SDL_WINDOW_BORDERLESS : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? 0 : SDL_WINDOW_RESIZABLE;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_UTILITY : 0;
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
+    vd->Window = SDL_CreateWindow("No Title Yet", (int)viewport->Size.x, (int)viewport->Size.y, sdl_flags);
+#ifndef __APPLE__ // On Mac, SDL3 Parenting appears to prevent viewport from appearing in another monitor
+    SDL_SetWindowParent(vd->Window, vd->ParentWindow);
+#endif
+    SDL_SetWindowPosition(vd->Window, (int)viewport->Pos.x, (int)viewport->Pos.y);
+    vd->WindowOwned = true;
+    if (use_opengl)
+    {
+        vd->GLContext = SDL_GL_CreateContext(vd->Window);
+        SDL_GL_SetSwapInterval(0);
+    }
+    if (use_opengl && backup_context)
+        SDL_GL_MakeCurrent(vd->Window, backup_context);
+
+    ImGui_ImplSDL3_SetupPlatformHandles(viewport, vd->Window);
+}
+
+static void ImGui_ImplSDL3_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->GLContext && vd->WindowOwned)
+            SDL_GL_DestroyContext(vd->GLContext);
+        if (vd->Window && vd->WindowOwned)
+            SDL_DestroyWindow(vd->Window);
+        vd->GLContext = nullptr;
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplSDL3_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+#if defined(_WIN32) && !(defined(WINAPI_FAMILY) && ((defined(WINAPI_FAMILY_APP) && WINAPI_FAMILY == WINAPI_FAMILY_APP) || (defined(WINAPI_FAMILY_GAMES) && WINAPI_FAMILY == WINAPI_FAMILY_GAMES)))
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+
+    // SDL hack: Show icon in task bar (#7989)
+    // Note: SDL_WINDOW_UTILITY can be used to control task bar visibility, but on Windows, it does not affect child windows.
+    if (!(viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon))
+    {
+        LONG ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);
+        ex_style |= WS_EX_APPWINDOW;
+        ex_style &= ~WS_EX_TOOLWINDOW;
+        ::ShowWindow(hwnd, SW_HIDE);
+        ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
+    }
+#endif
+
+#ifdef __APPLE__
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, "1"); // Otherwise new window appear under
+#else
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "0" : "1");
+#endif
+    SDL_ShowWindow(vd->Window);
+}
+
+static void ImGui_ImplSDL3_UpdateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    IM_UNUSED(vd);
+
+#ifndef __APPLE__ // On Mac, SDL3 Parenting appears to prevent viewport from appearing in another monitor
+    // Update SDL3 parent if it changed _after_ creation.
+    // This is for advanced apps that are manipulating ParentViewportID manually.
+    SDL_Window* new_parent = ImGui_ImplSDL3_GetSDLWindowFromViewportID(viewport->ParentViewportId);
+    if (new_parent != vd->ParentWindow)
+    {
+        vd->ParentWindow = new_parent;
+        SDL_SetWindowParent(vd->Window, vd->ParentWindow);
+    }
+#endif
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    SDL_GetWindowPosition(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplSDL3_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowPosition(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    SDL_GetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplSDL3_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static ImVec2 ImGui_ImplSDL3_GetWindowFramebufferScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    ImVec2 framebuffer_scale;
+    ImGui_ImplSDL3_GetWindowSizeAndFramebufferScale(vd->Window, nullptr, &framebuffer_scale);
+    return framebuffer_scale;
+}
+
+static void ImGui_ImplSDL3_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowTitle(vd->Window, title);
+}
+
+static void ImGui_ImplSDL3_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_SetWindowOpacity(vd->Window, alpha);
+}
+
+static void ImGui_ImplSDL3_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    SDL_RaiseWindow(vd->Window);
+}
+
+static bool ImGui_ImplSDL3_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_INPUT_FOCUS) != 0;
+}
+
+static bool ImGui_ImplSDL3_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    return (SDL_GetWindowFlags(vd->Window) & SDL_WINDOW_MINIMIZED) != 0;
+}
+
+static void ImGui_ImplSDL3_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+}
+
+static void ImGui_ImplSDL3_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    if (vd->GLContext)
+    {
+        SDL_GL_MakeCurrent(vd->Window, vd->GLContext);
+        SDL_GL_SwapWindow(vd->Window);
+    }
+}
+
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+// SDL is graceful enough to _not_ need <vulkan/vulkan.h> so we can safely include this.
+#include <SDL3/SDL_vulkan.h>
+static int ImGui_ImplSDL3_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+    (void)vk_allocator;
+    bool ret = SDL_Vulkan_CreateSurface(vd->Window, (VkInstance)vk_instance, (const VkAllocationCallbacks*)vk_allocator, (VkSurfaceKHR*)out_vk_surface);
+    return ret ? 0 : 1; // ret ? VK_SUCCESS : VK_NOT_READY
+}
+
+static void ImGui_ImplSDL3_InitMultiViewportSupport(SDL_Window* window, void* sdl_gl_context)
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplSDL3_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplSDL3_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplSDL3_ShowWindow;
+    platform_io.Platform_UpdateWindow = ImGui_ImplSDL3_UpdateWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplSDL3_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplSDL3_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplSDL3_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplSDL3_GetWindowSize;
+    platform_io.Platform_GetWindowFramebufferScale = ImGui_ImplSDL3_GetWindowFramebufferScale;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplSDL3_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplSDL3_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplSDL3_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplSDL3_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplSDL3_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplSDL3_SwapBuffers;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplSDL3_SetWindowAlpha;
+    platform_io.Platform_CreateVkSurface = ImGui_ImplSDL3_CreateVkSurface;
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplSDL3_ViewportData* vd = IM_NEW(ImGui_ImplSDL3_ViewportData)();
+    vd->Window = window;
+    vd->WindowID = SDL_GetWindowID(window);
+    vd->WindowOwned = false;
+    vd->GLContext = (SDL_GLContext)sdl_gl_context;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)(intptr_t)vd->WindowID;
+}
+
+static void ImGui_ImplSDL3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl3.h

@@ -6,9 +6,12 @@
 //  [X] Platform: Clipboard support.
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-//  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [x] Platform: IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_sdlgpu3.cpp

@@ -2,8 +2,10 @@
 // This needs to be used along with the SDL3 Platform Backend
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use simply cast a reference to your SDL_GPUTextureSamplerBinding to ImTextureID.
-//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: User texture binding. Use 'SDL_GPUTexture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef! **IMPORTANT** Before 2025/08/08, ImTextureID was a reference to a SDL_GPUTextureSamplerBinding struct.
+//  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_sdlgpu3.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -17,10 +19,19 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // Important note to the reader who wish to integrate imgui_impl_sdlgpu3.cpp/.h in their own engine/app.
-// - Unlike other backends, the user must call the function Imgui_ImplSDLGPU3_PrepareDrawData() BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU3_RenderDrawData.
+// - Unlike other backends, the user must call the function ImGui_ImplSDLGPU3_PrepareDrawData() BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU3_RenderDrawData.
 //   Calling the function is MANDATORY, otherwise the ImGui will not upload neither the vertex nor the index buffer for the GPU. See imgui_impl_sdlgpu3.cpp for more info.
 
 // CHANGELOG
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-08-20: Added ImGui_ImplSDLGPU3_InitInfo::SwapchainComposition and ImGui_ImplSDLGPU3_InitInfo::PresentMode to configure how secondary viewports are created.
+//  2025-08-08: *BREAKING* Changed ImTextureID type from SDL_GPUTextureSamplerBinding* to SDL_GPUTexture*, which is more natural and easier for user to manage. If you need to change the current sampler, you can access the ImGui_ImplSDLGPU3_RenderState struct. (#8866, #8163, #7998, #7988)
+//  2025-08-08: Expose SamplerDefault and SamplerCurrent in ImGui_ImplSDLGPU3_RenderState. Allow callback to change sampler.
+//  2025-06-25: Mapping transfer buffer for texture update use cycle=true. Fixes artifacts e.g. on Metal backend.
+//  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLGPU3_CreateFontsTexture() and ImGui_ImplSDLGPU3_DestroyFontsTexture().
+//  2025-04-28: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
+//  2025-03-30: Made ImGui_ImplSDLGPU3_PrepareDrawData() reuse GPU Transfer Buffers which were unusually slow to recreate every frame. Much faster now.
+//  2025-03-21: Fixed typo in function name Imgui_ImplSDLGPU3_PrepareDrawData() -> ImGui_ImplSDLGPU3_PrepareDrawData().
 //  2025-01-16: Renamed ImGui_ImplSDLGPU3_InitInfo::GpuDevice to Device.
 //  2025-01-09: SDL_GPU: Added the SDL_GPU3 backend.
 
@@ -34,10 +45,12 @@
 // Reusable buffers used for rendering 1 current in-flight frame, for ImGui_ImplSDLGPU3_RenderDrawData()
 struct ImGui_ImplSDLGPU3_FrameData
 {
-    SDL_GPUBuffer*      VertexBuffer     = nullptr;
-    SDL_GPUBuffer*      IndexBuffer      = nullptr;
-    uint32_t            VertexBufferSize = 0;
-    uint32_t            IndexBufferSize  = 0;
+    SDL_GPUBuffer*          VertexBuffer            = nullptr;
+    SDL_GPUTransferBuffer*  VertexTransferBuffer    = nullptr;
+    uint32_t                VertexBufferSize        = 0;
+    SDL_GPUBuffer*          IndexBuffer             = nullptr;
+    SDL_GPUTransferBuffer*  IndexTransferBuffer     = nullptr;
+    uint32_t                IndexBufferSize         = 0;
 };
 
 struct ImGui_ImplSDLGPU3_Data
@@ -45,14 +58,12 @@ struct ImGui_ImplSDLGPU3_Data
     ImGui_ImplSDLGPU3_InitInfo   InitInfo;
 
     // Graphics pipeline & shaders
-    SDL_GPUShader*               VertexShader   = nullptr;
-    SDL_GPUShader*               FragmentShader = nullptr;
-    SDL_GPUGraphicsPipeline*     Pipeline       = nullptr;
-
-    // Font data
-    SDL_GPUSampler*              FontSampler = nullptr;
-    SDL_GPUTexture*              FontTexture = nullptr;
-    SDL_GPUTextureSamplerBinding FontBinding = { nullptr, nullptr };
+    SDL_GPUShader*               VertexShader           = nullptr;
+    SDL_GPUShader*               FragmentShader         = nullptr;
+    SDL_GPUGraphicsPipeline*     Pipeline               = nullptr;
+    SDL_GPUSampler*              TexSamplerLinear       = nullptr;
+    SDL_GPUTransferBuffer*       TexTransferBuffer      = nullptr;
+    uint32_t                     TexTransferBufferSize  = 0;
 
     // Frame data for main window
     ImGui_ImplSDLGPU3_FrameData  MainWindowFrameData;
@@ -73,12 +84,13 @@ static ImGui_ImplSDLGPU3_Data* ImGui_ImplSDLGPU3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplSDLGPU3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
-static void ImGui_ImplSDLGPU3_SetupRenderState(ImDrawData* draw_data, SDL_GPUGraphicsPipeline* pipeline, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass * render_pass, ImGui_ImplSDLGPU3_FrameData* fd, uint32_t fb_width, uint32_t fb_height)
+static void ImGui_ImplSDLGPU3_SetupRenderState(ImDrawData* draw_data, ImGui_ImplSDLGPU3_RenderState* render_state, SDL_GPUGraphicsPipeline* pipeline, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, ImGui_ImplSDLGPU3_FrameData* fd, uint32_t fb_width, uint32_t fb_height)
 {
-    //ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
+    ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
+    render_state->SamplerCurrent = bd->TexSamplerLinear;
 
     // Bind graphics pipeline
-    SDL_BindGPUGraphicsPipeline(render_pass,pipeline);
+    SDL_BindGPUGraphicsPipeline(render_pass, pipeline);
 
     // Bind Vertex And Index Buffers
     if (draw_data->TotalVtxCount > 0)
@@ -113,14 +125,15 @@ static void ImGui_ImplSDLGPU3_SetupRenderState(ImDrawData* draw_data, SDL_GPUGra
     SDL_PushGPUVertexUniformData(command_buffer, 0, &ubo, sizeof(UBO));
 }
 
-static void CreateOrResizeBuffer(SDL_GPUBuffer** buffer, uint32_t* old_size, uint32_t new_size, SDL_GPUBufferUsageFlags usage)
+static void CreateOrResizeBuffers(SDL_GPUBuffer** buffer, SDL_GPUTransferBuffer** transferbuffer, uint32_t* old_size, uint32_t new_size, SDL_GPUBufferUsageFlags usage)
 {
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
 
-    // Even though this is fairly rarely called.
+    // FIXME-OPT: Not optimal, but this is fairly rarely called.
     SDL_WaitForGPUIdle(v->Device);
     SDL_ReleaseGPUBuffer(v->Device, *buffer);
+    SDL_ReleaseGPUTransferBuffer(v->Device, *transferbuffer);
 
     SDL_GPUBufferCreateInfo buffer_info = {};
     buffer_info.usage = usage;
@@ -129,12 +142,18 @@ static void CreateOrResizeBuffer(SDL_GPUBuffer** buffer, uint32_t* old_size, uin
     *buffer = SDL_CreateGPUBuffer(v->Device, &buffer_info);
     *old_size = new_size;
     IM_ASSERT(*buffer != nullptr && "Failed to create GPU Buffer, call SDL_GetError() for more information");
+
+    SDL_GPUTransferBufferCreateInfo transferbuffer_info = {};
+    transferbuffer_info.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
+    transferbuffer_info.size = new_size;
+    *transferbuffer = SDL_CreateGPUTransferBuffer(v->Device, &transferbuffer_info);
+    IM_ASSERT(*transferbuffer != nullptr && "Failed to create GPU Transfer Buffer, call SDL_GetError() for more information");
 }
 
 // SDL_GPU doesn't allow copy passes to occur while a render or compute pass is bound!
 // The only way to allow a user to supply their own RenderPass (to render to a texture instead of the window for example),
 // is to split the upload part of ImGui_ImplSDLGPU3_RenderDrawData() to another function that needs to be called by the user before rendering.
-void Imgui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer)
+void ImGui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer)
 {
     // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
     int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
@@ -142,6 +161,13 @@ void Imgui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
     if (fb_width <= 0 || fb_height <= 0 || draw_data->TotalVtxCount <= 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplSDLGPU3_UpdateTexture(tex);
+
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
     ImGui_ImplSDLGPU3_FrameData* fd = &bd->MainWindowFrameData;
@@ -149,42 +175,28 @@ void Imgui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
     uint32_t vertex_size = draw_data->TotalVtxCount * sizeof(ImDrawVert);
     uint32_t index_size  = draw_data->TotalIdxCount * sizeof(ImDrawIdx);
     if (fd->VertexBuffer == nullptr || fd->VertexBufferSize < vertex_size)
-        CreateOrResizeBuffer(&fd->VertexBuffer, &fd->VertexBufferSize, vertex_size, SDL_GPU_BUFFERUSAGE_VERTEX);
+        CreateOrResizeBuffers(&fd->VertexBuffer, &fd->VertexTransferBuffer, &fd->VertexBufferSize, vertex_size, SDL_GPU_BUFFERUSAGE_VERTEX);
     if (fd->IndexBuffer == nullptr || fd->IndexBufferSize < index_size)
-        CreateOrResizeBuffer(&fd->IndexBuffer, &fd->IndexBufferSize, index_size, SDL_GPU_BUFFERUSAGE_INDEX);
+        CreateOrResizeBuffers(&fd->IndexBuffer, &fd->IndexTransferBuffer, &fd->IndexBufferSize, index_size, SDL_GPU_BUFFERUSAGE_INDEX);
 
-    // FIXME: It feels like more code could be shared there.
-    SDL_GPUTransferBufferCreateInfo vertex_transferbuffer_info = {};
-    vertex_transferbuffer_info.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
-    vertex_transferbuffer_info.size = vertex_size;
-    SDL_GPUTransferBufferCreateInfo index_transferbuffer_info = {};
-    index_transferbuffer_info.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
-    index_transferbuffer_info.size = index_size;
-
-    SDL_GPUTransferBuffer* vertex_transferbuffer = SDL_CreateGPUTransferBuffer(v->Device, &vertex_transferbuffer_info);
-    IM_ASSERT(vertex_transferbuffer != nullptr && "Failed to create the vertex transfer buffer, call SDL_GetError() for more information");
-    SDL_GPUTransferBuffer* index_transferbuffer = SDL_CreateGPUTransferBuffer(v->Device, &index_transferbuffer_info);
-    IM_ASSERT(index_transferbuffer != nullptr && "Failed to create the index transfer buffer, call SDL_GetError() for more information");
-
-    ImDrawVert* vtx_dst = (ImDrawVert*)SDL_MapGPUTransferBuffer(v->Device, vertex_transferbuffer, true);
-    ImDrawIdx*  idx_dst = (ImDrawIdx*)SDL_MapGPUTransferBuffer(v->Device, index_transferbuffer, true);
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    ImDrawVert* vtx_dst = (ImDrawVert*)SDL_MapGPUTransferBuffer(v->Device, fd->VertexTransferBuffer, true);
+    ImDrawIdx* idx_dst = (ImDrawIdx*)SDL_MapGPUTransferBuffer(v->Device, fd->IndexTransferBuffer, true);
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
         idx_dst += draw_list->IdxBuffer.Size;
     }
-    SDL_UnmapGPUTransferBuffer(v->Device, vertex_transferbuffer);
-    SDL_UnmapGPUTransferBuffer(v->Device, index_transferbuffer);
+    SDL_UnmapGPUTransferBuffer(v->Device, fd->VertexTransferBuffer);
+    SDL_UnmapGPUTransferBuffer(v->Device, fd->IndexTransferBuffer);
 
     SDL_GPUTransferBufferLocation vertex_buffer_location = {};
     vertex_buffer_location.offset = 0;
-    vertex_buffer_location.transfer_buffer = vertex_transferbuffer;
+    vertex_buffer_location.transfer_buffer = fd->VertexTransferBuffer;
     SDL_GPUTransferBufferLocation index_buffer_location = {};
     index_buffer_location.offset = 0;
-    index_buffer_location.transfer_buffer = index_transferbuffer;
+    index_buffer_location.transfer_buffer = fd->IndexTransferBuffer;
 
     SDL_GPUBufferRegion vertex_buffer_region = {};
     vertex_buffer_region.buffer = fd->VertexBuffer;
@@ -200,8 +212,6 @@ void Imgui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuff
     SDL_UploadToGPUBuffer(copy_pass, &vertex_buffer_location, &vertex_buffer_region, true);
     SDL_UploadToGPUBuffer(copy_pass, &index_buffer_location, &index_buffer_region, true);
     SDL_EndGPUCopyPass(copy_pass);
-    SDL_ReleaseGPUTransferBuffer(v->Device, index_transferbuffer);
-    SDL_ReleaseGPUTransferBuffer(v->Device, vertex_transferbuffer);
 }
 
 void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, SDL_GPUGraphicsPipeline* pipeline)
@@ -218,25 +228,36 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
     if (pipeline == nullptr)
         pipeline = bd->Pipeline;
 
-    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
-
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
     ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are often (2,2)
 
+    // Setup render state structure (for callbacks and custom texture bindings)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    ImGui_ImplSDLGPU3_RenderState render_state;
+    render_state.Device = bd->InitInfo.Device;
+    render_state.SamplerDefault = render_state.SamplerCurrent = bd->TexSamplerLinear;
+    platform_io.Renderer_RenderState = &render_state;
+
+    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, &render_state, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
+
     // Render command lists
     // (Because we merged all buffers into a single one, we maintain our own offset into them)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback != nullptr)
             {
-                pcmd->UserCallback(draw_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplSDLGPU3_SetupRenderState(draw_data, &render_state, pipeline, command_buffer, render_pass, fd, fb_width, fb_height);
+                else
+                    pcmd->UserCallback(draw_list, pcmd);
             }
             else
             {
@@ -261,9 +282,14 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
                 SDL_SetGPUScissor(render_pass,&scissor_rect);
 
                 // Bind DescriptorSet with font or user texture
-                SDL_BindGPUFragmentSamplers(render_pass, 0, (SDL_GPUTextureSamplerBinding*)pcmd->GetTexID(), 1);
+                SDL_GPUTextureSamplerBinding texture_sampler_binding;
+                texture_sampler_binding.texture = (SDL_GPUTexture*)(intptr_t)pcmd->GetTexID();
+                texture_sampler_binding.sampler = render_state.SamplerCurrent;
+                SDL_BindGPUFragmentSamplers(render_pass, 0, &texture_sampler_binding, 1);
 
                 // Draw
+                // **IF YOU GET A CRASH HERE** In 1.92.2 on 2025/08/08 we have changed ImTextureID to store 'SDL_GPUTexture*' instead of storing 'SDL_GPUTextureSamplerBinding'.
+                // Any code loading custom texture using this backend needs to be updated.
                 SDL_DrawGPUIndexedPrimitives(render_pass, pcmd->ElemCount, 1, pcmd->IdxOffset + global_idx_offset, pcmd->VtxOffset + global_vtx_offset, 0);
             }
         }
@@ -279,94 +305,111 @@ void ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffe
     SDL_SetGPUScissor(render_pass, &scissor_rect);
 }
 
-void ImGui_ImplSDLGPU3_CreateFontsTexture()
+static void ImGui_ImplSDLGPU3_DestroyTexture(ImTextureData* tex)
+{
+    ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
+    SDL_GPUTexture* raw_tex = (SDL_GPUTexture*)(intptr_t)tex->GetTexID();
+    if (raw_tex != nullptr)
+        SDL_ReleaseGPUTexture(bd->InitInfo.Device, raw_tex);
+
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+}
+
+void ImGui_ImplSDLGPU3_UpdateTexture(ImTextureData* tex)
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
 
-    // Destroy existing texture (if any)
-    if (bd->FontTexture)
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
-        SDL_WaitForGPUIdle(v->Device);
-        ImGui_ImplSDLGPU3_DestroyFontsTexture();
-    }
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
 
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
-    uint32_t upload_size = width * height * 4 * sizeof(char);
-
-    // Create the Image:
-    {
+        // Create texture
         SDL_GPUTextureCreateInfo texture_info = {};
-        texture_info.type   = SDL_GPU_TEXTURETYPE_2D;
+        texture_info.type = SDL_GPU_TEXTURETYPE_2D;
         texture_info.format = SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;
         texture_info.usage = SDL_GPU_TEXTUREUSAGE_SAMPLER;
-        texture_info.width  = width;
-        texture_info.height = height;
+        texture_info.width = tex->Width;
+        texture_info.height = tex->Height;
         texture_info.layer_count_or_depth = 1;
         texture_info.num_levels = 1;
         texture_info.sample_count = SDL_GPU_SAMPLECOUNT_1;
 
-        bd->FontTexture = SDL_CreateGPUTexture(v->Device, &texture_info);
-        IM_ASSERT(bd->FontTexture && "Failed to create font texture, call SDL_GetError() for more info");
+        SDL_GPUTexture* raw_tex = SDL_CreateGPUTexture(v->Device, &texture_info);
+        IM_ASSERT(raw_tex != nullptr && "Failed to create texture, call SDL_GetError() for more info");
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)raw_tex);
     }
 
-    // Assign the texture to the TextureSamplerBinding
-    bd->FontBinding.texture = bd->FontTexture;
-
-    // Create all the upload structures and upload:
+    if (tex->Status == ImTextureStatus_WantCreate || tex->Status == ImTextureStatus_WantUpdates)
     {
-        SDL_GPUTransferBufferCreateInfo transferbuffer_info = {};
-        transferbuffer_info.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
-        transferbuffer_info.size = upload_size;
+        SDL_GPUTexture* raw_tex = (SDL_GPUTexture*)(intptr_t)tex->GetTexID();
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
 
-        SDL_GPUTransferBuffer* transferbuffer = SDL_CreateGPUTransferBuffer(v->Device, &transferbuffer_info);
-        IM_ASSERT(transferbuffer != nullptr && "Failed to create font transfer buffer, call SDL_GetError() for more information");
+        // Update full texture or selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->UpdateRect but you can use tex->Updates[] to upload individual regions.
+        // We could use the smaller rect on _WantCreate but using the full rect allows us to clear the texture.
+        const int upload_x = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.x;
+        const int upload_y = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.y;
+        const int upload_w = (tex->Status == ImTextureStatus_WantCreate) ? tex->Width : tex->UpdateRect.w;
+        const int upload_h = (tex->Status == ImTextureStatus_WantCreate) ? tex->Height : tex->UpdateRect.h;
+        uint32_t upload_pitch = upload_w * tex->BytesPerPixel;
+        uint32_t upload_size = upload_w * upload_h * tex->BytesPerPixel;
 
-        void* texture_ptr = SDL_MapGPUTransferBuffer(v->Device, transferbuffer, false);
-        memcpy(texture_ptr, pixels, upload_size);
-        SDL_UnmapGPUTransferBuffer(v->Device, transferbuffer);
+        // Create transfer buffer
+        if (bd->TexTransferBufferSize < upload_size)
+        {
+            SDL_ReleaseGPUTransferBuffer(v->Device, bd->TexTransferBuffer);
+            SDL_GPUTransferBufferCreateInfo transferbuffer_info = {};
+            transferbuffer_info.usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD;
+            transferbuffer_info.size = upload_size + 1024;
+            bd->TexTransferBufferSize = upload_size + 1024;
+            bd->TexTransferBuffer = SDL_CreateGPUTransferBuffer(v->Device, &transferbuffer_info);
+            IM_ASSERT(bd->TexTransferBuffer != nullptr && "Failed to create transfer buffer, call SDL_GetError() for more information");
+        }
+
+        // Copy to transfer buffer
+        {
+            void* texture_ptr = SDL_MapGPUTransferBuffer(v->Device, bd->TexTransferBuffer, true);
+            for (int y = 0; y < upload_h; y++)
+                memcpy((void*)((uintptr_t)texture_ptr + y * upload_pitch), tex->GetPixelsAt(upload_x, upload_y + y), upload_pitch);
+            SDL_UnmapGPUTransferBuffer(v->Device, bd->TexTransferBuffer);
+        }
 
         SDL_GPUTextureTransferInfo transfer_info = {};
         transfer_info.offset = 0;
-        transfer_info.transfer_buffer = transferbuffer;
+        transfer_info.transfer_buffer = bd->TexTransferBuffer;
 
         SDL_GPUTextureRegion texture_region = {};
-        texture_region.texture = bd->FontTexture;
-        texture_region.w = width;
-        texture_region.h = height;
+        texture_region.texture = raw_tex;
+        texture_region.x = (Uint32)upload_x;
+        texture_region.y = (Uint32)upload_y;
+        texture_region.w = (Uint32)upload_w;
+        texture_region.h = (Uint32)upload_h;
         texture_region.d = 1;
 
-        SDL_GPUCommandBuffer* cmd = SDL_AcquireGPUCommandBuffer(v->Device);
-        SDL_GPUCopyPass* copy_pass = SDL_BeginGPUCopyPass(cmd);
-        SDL_UploadToGPUTexture(copy_pass, &transfer_info, &texture_region, false);
-        SDL_EndGPUCopyPass(copy_pass);
-        SDL_SubmitGPUCommandBuffer(cmd);
-        SDL_ReleaseGPUTransferBuffer(v->Device, transferbuffer);
-    }
+        // Upload
+        {
+            SDL_GPUCommandBuffer* cmd = SDL_AcquireGPUCommandBuffer(v->Device);
+            SDL_GPUCopyPass* copy_pass = SDL_BeginGPUCopyPass(cmd);
+            SDL_UploadToGPUTexture(copy_pass, &transfer_info, &texture_region, false);
+            SDL_EndGPUCopyPass(copy_pass);
+            SDL_SubmitGPUCommandBuffer(cmd);
+        }
 
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)&bd->FontBinding);
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+        ImGui_ImplSDLGPU3_DestroyTexture(tex);
 }
 
-// You probably never need to call this, as it is called by ImGui_ImplSDLGPU3_CreateFontsTexture() and ImGui_ImplSDLGPU3_Shutdown().
-void ImGui_ImplSDLGPU3_DestroyFontsTexture()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
-    ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
-    if (bd->FontTexture)
-    {
-        SDL_ReleaseGPUTexture(v->Device, bd->FontTexture);
-        bd->FontBinding.texture = nullptr;
-        bd->FontTexture = nullptr;
-    }
-    io.Fonts->SetTexID(0);
-}
-
-static void Imgui_ImplSDLGPU3_CreateShaders()
+static void ImGui_ImplSDLGPU3_CreateShaders()
 {
     // Create the shader modules
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
@@ -431,7 +474,7 @@ static void ImGui_ImplSDLGPU3_CreateGraphicsPipeline()
 {
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
-    Imgui_ImplSDLGPU3_CreateShaders();
+    ImGui_ImplSDLGPU3_CreateShaders();
 
     SDL_GPUVertexBufferDescription vertex_buffer_desc[1];
     vertex_buffer_desc[0].slot = 0;
@@ -515,7 +558,9 @@ void ImGui_ImplSDLGPU3_CreateDeviceObjects()
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
 
-    if (!bd->FontSampler)
+    ImGui_ImplSDLGPU3_DestroyDeviceObjects();
+
+    if (bd->TexSamplerLinear == nullptr)
     {
         // Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling.
         SDL_GPUSamplerCreateInfo sampler_info = {};
@@ -532,13 +577,11 @@ void ImGui_ImplSDLGPU3_CreateDeviceObjects()
         sampler_info.max_anisotropy = 1.0f;
         sampler_info.enable_compare = false;
 
-        bd->FontSampler = SDL_CreateGPUSampler(v->Device, &sampler_info);
-        bd->FontBinding.sampler = bd->FontSampler;
-        IM_ASSERT(bd->FontSampler != nullptr && "Failed to create font sampler, call SDL_GetError() for more information");
+        bd->TexSamplerLinear = SDL_CreateGPUSampler(v->Device, &sampler_info);
+        IM_ASSERT(bd->TexSamplerLinear != nullptr && "Failed to create sampler, call SDL_GetError() for more information");
     }
 
     ImGui_ImplSDLGPU3_CreateGraphicsPipeline();
-    ImGui_ImplSDLGPU3_CreateFontsTexture();
 }
 
 void ImGui_ImplSDLGPU3_DestroyFrameData()
@@ -546,12 +589,14 @@ void ImGui_ImplSDLGPU3_DestroyFrameData()
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
 
-    SDL_ReleaseGPUBuffer(v->Device, bd->MainWindowFrameData.VertexBuffer);
-    SDL_ReleaseGPUBuffer(v->Device, bd->MainWindowFrameData.IndexBuffer);
-    bd->MainWindowFrameData.VertexBuffer = nullptr;
-    bd->MainWindowFrameData.IndexBuffer = nullptr;
-    bd->MainWindowFrameData.VertexBufferSize = 0;
-    bd->MainWindowFrameData.IndexBufferSize = 0;
+    ImGui_ImplSDLGPU3_FrameData* fd = &bd->MainWindowFrameData;
+    SDL_ReleaseGPUBuffer(v->Device, fd->VertexBuffer);
+    SDL_ReleaseGPUBuffer(v->Device, fd->IndexBuffer);
+    SDL_ReleaseGPUTransferBuffer(v->Device, fd->VertexTransferBuffer);
+    SDL_ReleaseGPUTransferBuffer(v->Device, fd->IndexTransferBuffer);
+    fd->VertexBuffer = fd->IndexBuffer = nullptr;
+    fd->VertexTransferBuffer = fd->IndexTransferBuffer = nullptr;
+    fd->VertexBufferSize = fd->IndexBufferSize = 0;
 }
 
 void ImGui_ImplSDLGPU3_DestroyDeviceObjects()
@@ -560,14 +605,21 @@ void ImGui_ImplSDLGPU3_DestroyDeviceObjects()
     ImGui_ImplSDLGPU3_InitInfo* v = &bd->InitInfo;
 
     ImGui_ImplSDLGPU3_DestroyFrameData();
-    ImGui_ImplSDLGPU3_DestroyFontsTexture();
 
-    if (bd->VertexShader)   { SDL_ReleaseGPUShader(v->Device, bd->VertexShader); bd->VertexShader = nullptr;}
-    if (bd->FragmentShader) { SDL_ReleaseGPUShader(v->Device, bd->FragmentShader); bd->FragmentShader = nullptr;}
-    if (bd->FontSampler)    { SDL_ReleaseGPUSampler(v->Device, bd->FontSampler); bd->FontSampler = nullptr;}
-    if (bd->Pipeline)       { SDL_ReleaseGPUGraphicsPipeline(v->Device, bd->Pipeline); bd->Pipeline = nullptr;}
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplSDLGPU3_DestroyTexture(tex);
+    if (bd->TexTransferBuffer)  { SDL_ReleaseGPUTransferBuffer(v->Device, bd->TexTransferBuffer); bd->TexTransferBuffer = nullptr; }
+    if (bd->VertexShader)       { SDL_ReleaseGPUShader(v->Device, bd->VertexShader); bd->VertexShader = nullptr; }
+    if (bd->FragmentShader)     { SDL_ReleaseGPUShader(v->Device, bd->FragmentShader); bd->FragmentShader = nullptr; }
+    if (bd->TexSamplerLinear)   { SDL_ReleaseGPUSampler(v->Device, bd->TexSamplerLinear); bd->TexSamplerLinear = nullptr; }
+    if (bd->Pipeline)           { SDL_ReleaseGPUGraphicsPipeline(v->Device, bd->Pipeline); bd->Pipeline = nullptr; }
 }
 
+static void ImGui_ImplSDLGPU3_InitMultiViewportSupport();
+static void ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport();
+
 bool ImGui_ImplSDLGPU3_Init(ImGui_ImplSDLGPU3_InitInfo* info)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -579,13 +631,15 @@ bool ImGui_ImplSDLGPU3_Init(ImGui_ImplSDLGPU3_InitInfo* info)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_sdlgpu3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     IM_ASSERT(info->Device != nullptr);
     IM_ASSERT(info->ColorTargetFormat != SDL_GPU_TEXTUREFORMAT_INVALID);
 
     bd->InitInfo = *info;
 
-    ImGui_ImplSDLGPU3_CreateDeviceObjects();
+    ImGui_ImplSDLGPU3_InitMultiViewportSupport();
 
     return true;
 }
@@ -596,10 +650,11 @@ void ImGui_ImplSDLGPU3_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport();
     ImGui_ImplSDLGPU3_DestroyDeviceObjects();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -608,8 +663,80 @@ void ImGui_ImplSDLGPU3_NewFrame()
     ImGui_ImplSDLGPU3_Data* bd = ImGui_ImplSDLGPU3_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDLGPU3_Init()?");
 
-    if (!bd->FontTexture)
-        ImGui_ImplSDLGPU3_CreateFontsTexture();
+    if (!bd->TexSamplerLinear)
+        ImGui_ImplSDLGPU3_CreateDeviceObjects();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+static void ImGui_ImplSDLGPU3_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+    SDL_ClaimWindowForGPUDevice(data->InitInfo.Device, window);
+    SDL_SetGPUSwapchainParameters(data->InitInfo.Device, window, data->InitInfo.SwapchainComposition, data->InitInfo.PresentMode);
+    viewport->RendererUserData = (void*)1;
+}
+
+static void ImGui_ImplSDLGPU3_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+
+    ImDrawData* draw_data = viewport->DrawData;
+
+    SDL_GPUCommandBuffer* command_buffer = SDL_AcquireGPUCommandBuffer(data->InitInfo.Device);
+
+    SDL_GPUTexture* swapchain_texture;
+    SDL_AcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, nullptr, nullptr);
+
+    if (swapchain_texture != nullptr)
+    {
+        ImGui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer); // FIXME-OPT: Not optimal, may this be done earlier?
+        SDL_GPUColorTargetInfo target_info = {};
+        target_info.texture = swapchain_texture;
+        target_info.clear_color = SDL_FColor{ 0.0f,0.0f,0.0f,1.0f };
+        target_info.load_op = SDL_GPU_LOADOP_CLEAR;
+        target_info.store_op = SDL_GPU_STOREOP_STORE;
+        target_info.mip_level = 0;
+        target_info.layer_or_depth_plane = 0;
+        target_info.cycle = false;
+        SDL_GPURenderPass* render_pass = SDL_BeginGPURenderPass(command_buffer, &target_info, 1, nullptr);
+        ImGui_ImplSDLGPU3_RenderDrawData(draw_data, command_buffer, render_pass);
+        SDL_EndGPURenderPass(render_pass);
+    }
+
+    SDL_SubmitGPUCommandBuffer(command_buffer);
+}
+
+static void ImGui_ImplSDLGPU3_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDLGPU3_Data* data = ImGui_ImplSDLGPU3_GetBackendData();
+    if (viewport->RendererUserData)
+    {
+        SDL_Window* window = SDL_GetWindowFromID((SDL_WindowID)(intptr_t)viewport->PlatformHandle);
+        SDL_ReleaseWindowFromGPUDevice(data->InitInfo.Device, window);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplSDLGPU3_InitMultiViewportSupport()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplSDLGPU3_RenderWindow;
+    platform_io.Renderer_CreateWindow = ImGui_ImplSDLGPU3_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplSDLGPU3_DestroyWindow;
+}
+
+static void ImGui_ImplSDLGPU3_ShutdownMultiViewportSupport()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+//-----------------------------------------------------------------------------
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdlgpu3.h

@@ -2,8 +2,10 @@
 // This needs to be used along with the SDL3 Platform Backend
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use simply cast a reference to your SDL_GPUTextureSamplerBinding to ImTextureID.
-//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: User texture binding. Use 'SDL_GPUTexture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef! **IMPORTANT** Before 2025/08/08, ImTextureID was a reference to a SDL_GPUTextureSamplerBinding struct.
+//  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // The aim of imgui_impl_sdlgpu3.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -17,7 +19,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // Important note to the reader who wish to integrate imgui_impl_sdlgpu3.cpp/.h in their own engine/app.
-// - Unline other backends, the user must call the function Imgui_ImplSDLGPU_PrepareDrawData BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU_RenderDrawData.
+// - Unlike other backends, the user must call the function ImGui_ImplSDLGPU_PrepareDrawData BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU_RenderDrawData.
 //   Calling the function is MANDATORY, otherwise the ImGui will not upload neither the vertex nor the index buffer for the GPU. See imgui_impl_sdlgpu3.cpp for more info.
 
 #pragma once
@@ -26,24 +28,38 @@
 #include <SDL3/SDL_gpu.h>
 
 // Initialization data, for ImGui_ImplSDLGPU_Init()
-// - Remember to set ColorTargetFormat to the correct format. If you're rendering to the swapchain, call SDL_GetGPUSwapchainTextureFormat to query the right value
+// - Remember to set ColorTargetFormat to the correct format. If you're rendering to the swapchain, call SDL_GetGPUSwapchainTextureFormat() to query the right value
 struct ImGui_ImplSDLGPU3_InitInfo
 {
-    SDL_GPUDevice*       Device             = nullptr;
-    SDL_GPUTextureFormat ColorTargetFormat  = SDL_GPU_TEXTUREFORMAT_INVALID;
-    SDL_GPUSampleCount   MSAASamples        = SDL_GPU_SAMPLECOUNT_1;
+    SDL_GPUDevice*              Device                  = nullptr;
+    SDL_GPUTextureFormat        ColorTargetFormat       = SDL_GPU_TEXTUREFORMAT_INVALID;
+    SDL_GPUSampleCount          MSAASamples             = SDL_GPU_SAMPLECOUNT_1;
+    SDL_GPUSwapchainComposition SwapchainComposition    = SDL_GPU_SWAPCHAINCOMPOSITION_SDR;     // Only used in multi-viewports mode.
+    SDL_GPUPresentMode          PresentMode             = SDL_GPU_PRESENTMODE_VSYNC;            // Only used in multi-viewports mode.
 };
 
 // Follow "Getting Started" link and check examples/ folder to learn about using backends!
 IMGUI_IMPL_API bool     ImGui_ImplSDLGPU3_Init(ImGui_ImplSDLGPU3_InitInfo* info);
 IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_NewFrame();
-IMGUI_IMPL_API void     Imgui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer);
+IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_PrepareDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer);
 IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_RenderDrawData(ImDrawData* draw_data, SDL_GPUCommandBuffer* command_buffer, SDL_GPURenderPass* render_pass, SDL_GPUGraphicsPipeline* pipeline = nullptr);
 
+// Use if you want to reset your rendering device without losing Dear ImGui state.
 IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_DestroyDeviceObjects();
-IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_CreateFontsTexture();
-IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_DestroyFontsTexture();
+
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplSDLGPU3_UpdateTexture(ImTextureData* tex);
+
+// [BETA] Selected render state data shared with callbacks.
+// This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplSDLGPU3_RenderDrawData() call.
+// (Please open an issue if you feel you need access to more data)
+struct ImGui_ImplSDLGPU3_RenderState
+{
+    SDL_GPUDevice*      Device;
+    SDL_GPUSampler*     SamplerDefault;     // Default sampler (bilinear filtering)
+    SDL_GPUSampler*     SamplerCurrent;     // Current sampler (may be changed by callback)
+};
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdlrenderer2.cpp

@@ -10,9 +10,12 @@
 // and it might be difficult to step out of those boundaries.
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -23,6 +26,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+//  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer2_CreateFontsTexture() and ImGui_ImplSDLRenderer2_DestroyFontsTexture().
 //  2025-01-18: Use endian-dependent RGBA32 texture format, to match SDL_Color.
 //  2024-10-09: Expose selected render state in ImGui_ImplSDLRenderer2_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
 //  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
@@ -42,6 +46,8 @@
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wsign-conversion"    // warning: implicit conversion changes signedness
+#elif defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wfloat-equal"                      // warning: comparing floating-point with '==' or '!=' is unsafe
 #endif
 
 // SDL
@@ -54,7 +60,7 @@
 struct ImGui_ImplSDLRenderer2_Data
 {
     SDL_Renderer*   Renderer;       // Main viewport's renderer
-    SDL_Texture*    FontTexture;
+
     ImGui_ImplSDLRenderer2_Data()   { memset((void*)this, 0, sizeof(*this)); }
 };
 
@@ -78,6 +84,7 @@ bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_sdlrenderer2";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
 
     bd->Renderer = renderer;
 
@@ -94,7 +101,7 @@ void ImGui_ImplSDLRenderer2_Shutdown()
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
     IM_DELETE(bd);
 }
 
@@ -110,9 +117,7 @@ void ImGui_ImplSDLRenderer2_NewFrame()
 {
     ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDLRenderer2_Init()?");
-
-    if (!bd->FontTexture)
-        ImGui_ImplSDLRenderer2_CreateDeviceObjects();
+    IM_UNUSED(bd);
 }
 
 void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
@@ -133,6 +138,13 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     if (fb_width == 0 || fb_height == 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplSDLRenderer2_UpdateTexture(tex);
+
     // Backup SDL_Renderer state that will be modified to restore it afterwards
     struct BackupSDLRendererState
     {
@@ -159,9 +171,8 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
 
@@ -218,55 +229,67 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     SDL_RenderSetClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
-// Called by Init/NewFrame/Shutdown
-bool ImGui_ImplSDLRenderer2_CreateFontsTexture()
+void ImGui_ImplSDLRenderer2_UpdateTexture(ImTextureData* tex)
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
 
-    // Build texture atlas
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
-
-    // Upload texture to graphics system
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, width, height);
-    if (bd->FontTexture == nullptr)
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
-        SDL_Log("error creating texture");
-        return false;
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // Create texture
+        // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+        SDL_Texture* sdl_texture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, tex->Width, tex->Height);
+        IM_ASSERT(sdl_texture != nullptr && "Backend failed to create texture!");
+        SDL_UpdateTexture(sdl_texture, nullptr, tex->GetPixels(), tex->GetPitch());
+        SDL_SetTextureBlendMode(sdl_texture, SDL_BLENDMODE_BLEND);
+        SDL_SetTextureScaleMode(sdl_texture, SDL_ScaleModeLinear);
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)sdl_texture);
+        tex->SetStatus(ImTextureStatus_OK);
     }
-    SDL_UpdateTexture(bd->FontTexture, nullptr, pixels, 4 * width);
-    SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
-    SDL_SetTextureScaleMode(bd->FontTexture, SDL_ScaleModeLinear);
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer2_DestroyFontsTexture()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
-    if (bd->FontTexture)
+    else if (tex->Status == ImTextureStatus_WantUpdates)
     {
-        io.Fonts->SetTexID(0);
-        SDL_DestroyTexture(bd->FontTexture);
-        bd->FontTexture = nullptr;
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        SDL_Texture* sdl_texture = (SDL_Texture*)(intptr_t)tex->TexID;
+        for (ImTextureRect& r : tex->Updates)
+        {
+            SDL_Rect sdl_r = { r.x, r.y, r.w, r.h };
+            SDL_UpdateTexture(sdl_texture, &sdl_r, tex->GetPixelsAt(r.x, r.y), tex->GetPitch());
+        }
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        SDL_Texture* sdl_texture = (SDL_Texture*)(intptr_t)tex->TexID;
+        if (sdl_texture == nullptr)
+            return;
+        SDL_DestroyTexture(sdl_texture);
+
+        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
     }
 }
 
-bool ImGui_ImplSDLRenderer2_CreateDeviceObjects()
+void ImGui_ImplSDLRenderer2_CreateDeviceObjects()
 {
-    return ImGui_ImplSDLRenderer2_CreateFontsTexture();
 }
 
 void ImGui_ImplSDLRenderer2_DestroyDeviceObjects()
 {
-    ImGui_ImplSDLRenderer2_DestroyFontsTexture();
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+        {
+            tex->SetStatus(ImTextureStatus_WantDestroy);
+            ImGui_ImplSDLRenderer2_UpdateTexture(tex);
+        }
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_sdlrenderer2.h

@@ -10,9 +10,12 @@
 // and it might be difficult to step out of those boundaries.
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -35,11 +38,12 @@ IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
 
 // Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_CreateFontsTexture();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_DestroyFontsTexture();
-IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplSDLRenderer2_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_sdlrenderer3.cpp

@@ -10,9 +10,12 @@
 // and it might be difficult to step out of those boundaries.
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -23,6 +26,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+//  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer3_CreateFontsTexture() and ImGui_ImplSDLRenderer3_DestroyFontsTexture().
 //  2025-01-18: Use endian-dependent RGBA32 texture format, to match SDL_Color.
 //  2024-10-09: Expose selected render state in ImGui_ImplSDLRenderer3_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
 //  2024-07-01: Update for SDL3 api changes: SDL_RenderGeometryRaw() uint32 version was removed (SDL#9009).
@@ -39,6 +43,8 @@
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wsign-conversion"    // warning: implicit conversion changes signedness
+#elif defined(__GNUC__)
+#pragma GCC diagnostic ignored "-Wfloat-equal"          // warning: comparing floating-point with '==' or '!=' is unsafe
 #endif
 
 // SDL
@@ -51,7 +57,6 @@
 struct ImGui_ImplSDLRenderer3_Data
 {
     SDL_Renderer*           Renderer;       // Main viewport's renderer
-    SDL_Texture*            FontTexture;
     ImVector<SDL_FColor>    ColorBuffer;
 
     ImGui_ImplSDLRenderer3_Data()   { memset((void*)this, 0, sizeof(*this)); }
@@ -77,6 +82,7 @@ bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_sdlrenderer3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
 
     bd->Renderer = renderer;
 
@@ -93,7 +99,7 @@ void ImGui_ImplSDLRenderer3_Shutdown()
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
     IM_DELETE(bd);
 }
 
@@ -109,9 +115,7 @@ void ImGui_ImplSDLRenderer3_NewFrame()
 {
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDLRenderer3_Init()?");
-
-    if (!bd->FontTexture)
-        ImGui_ImplSDLRenderer3_CreateDeviceObjects();
+    IM_UNUSED(bd);
 }
 
 // https://github.com/libsdl-org/SDL/issues/9009
@@ -152,6 +156,13 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     if (fb_width == 0 || fb_height == 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplSDLRenderer3_UpdateTexture(tex);
+
     // Backup SDL_Renderer state that will be modified to restore it afterwards
     struct BackupSDLRendererState
     {
@@ -180,9 +191,8 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data;
         const ImDrawIdx* idx_buffer = draw_list->IdxBuffer.Data;
 
@@ -235,55 +245,67 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     SDL_SetRenderClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
-// Called by Init/NewFrame/Shutdown
-bool ImGui_ImplSDLRenderer3_CreateFontsTexture()
+void ImGui_ImplSDLRenderer3_UpdateTexture(ImTextureData* tex)
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
 
-    // Build texture atlas
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bit (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
-
-    // Upload texture to graphics system
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    bd->FontTexture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, width, height);
-    if (bd->FontTexture == nullptr)
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
-        SDL_Log("error creating texture");
-        return false;
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // Create texture
+        // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+        SDL_Texture* sdl_texture = SDL_CreateTexture(bd->Renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STATIC, tex->Width, tex->Height);
+        IM_ASSERT(sdl_texture != nullptr && "Backend failed to create texture!");
+        SDL_UpdateTexture(sdl_texture, nullptr, tex->GetPixels(), tex->GetPitch());
+        SDL_SetTextureBlendMode(sdl_texture, SDL_BLENDMODE_BLEND);
+        SDL_SetTextureScaleMode(sdl_texture, SDL_SCALEMODE_LINEAR);
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)sdl_texture);
+        tex->SetStatus(ImTextureStatus_OK);
     }
-    SDL_UpdateTexture(bd->FontTexture, nullptr, pixels, 4 * width);
-    SDL_SetTextureBlendMode(bd->FontTexture, SDL_BLENDMODE_BLEND);
-    SDL_SetTextureScaleMode(bd->FontTexture, SDL_SCALEMODE_LINEAR);
-
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)(intptr_t)bd->FontTexture);
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer3_DestroyFontsTexture()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
-    if (bd->FontTexture)
+    else if (tex->Status == ImTextureStatus_WantUpdates)
     {
-        io.Fonts->SetTexID(0);
-        SDL_DestroyTexture(bd->FontTexture);
-        bd->FontTexture = nullptr;
+        // Update selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->Updates[] but you can use tex->UpdateRect to upload a single region.
+        SDL_Texture* sdl_texture = (SDL_Texture*)(intptr_t)tex->TexID;
+        for (ImTextureRect& r : tex->Updates)
+        {
+            SDL_Rect sdl_r = { r.x, r.y, r.w, r.h };
+            SDL_UpdateTexture(sdl_texture, &sdl_r, tex->GetPixelsAt(r.x, r.y), tex->GetPitch());
+        }
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    else if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        SDL_Texture* sdl_texture = (SDL_Texture*)(intptr_t)tex->TexID;
+        if (sdl_texture == nullptr)
+            return;
+        SDL_DestroyTexture(sdl_texture);
+
+        // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
     }
 }
 
-bool ImGui_ImplSDLRenderer3_CreateDeviceObjects()
+void ImGui_ImplSDLRenderer3_CreateDeviceObjects()
 {
-    return ImGui_ImplSDLRenderer3_CreateFontsTexture();
 }
 
 void ImGui_ImplSDLRenderer3_DestroyDeviceObjects()
 {
-    ImGui_ImplSDLRenderer3_DestroyFontsTexture();
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+        {
+            tex->SetStatus(ImTextureStatus_WantDestroy);
+            ImGui_ImplSDLRenderer3_UpdateTexture(tex);
+        }
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_sdlrenderer3.h

@@ -10,9 +10,12 @@
 // and it might be difficult to step out of those boundaries.
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'SDL_Texture*' as texture identifier. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows).
 
 // You can copy and use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -35,11 +38,12 @@ IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
 
 // Called by Init/NewFrame/Shutdown
-IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_CreateFontsTexture();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_DestroyFontsTexture();
-IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_CreateDeviceObjects();
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_DestroyDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplSDLRenderer3_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_vulkan.h

@@ -2,9 +2,11 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [!] Renderer: User texture binding. Use 'VkDescriptorSet' as ImTextureID. Call ImGui_ImplVulkan_AddTexture() to register one. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
+//  [!] Renderer: User texture binding. Use 'VkDescriptorSet' as texture identifier. Call ImGui_ImplVulkan_AddTexture() to register one. Read the FAQ about ImTextureID/ImTextureRef + https://github.com/ocornut/imgui/pull/914 for discussions.
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
+//  [X] Renderer: Texture updates support for dynamic font atlas (ImGuiBackendFlags_RendererHasTextures).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 
 // The aim of imgui_impl_vulkan.h/.cpp is to be usable in your engine without any modification.
 // IF YOU FEEL YOU NEED TO MAKE ANY CHANGE TO THIS CODE, please share them and your feedback at https://github.com/ocornut/imgui/
@@ -61,9 +63,8 @@
 #define IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
 #endif
 
-// Current version of the backend use 1 descriptor for the font atlas + as many as additional calls done to ImGui_ImplVulkan_AddTexture().
-// It is expected that as early as Q1 2025 the backend will use a few more descriptors. Use this value + number of desired calls to ImGui_ImplVulkan_AddTexture().
-#define IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE   (1)     // Minimum per atlas
+// Backend uses a small number of descriptors per font atlas + as many as additional calls done to ImGui_ImplVulkan_AddTexture().
+#define IMGUI_IMPL_VULKAN_MINIMUM_IMAGE_SAMPLER_POOL_SIZE   (8)     // Minimum per atlas
 
 // Initialization data, for ImGui_ImplVulkan_Init()
 // [Please zero-clear before use!]
@@ -82,29 +83,27 @@ struct ImGui_ImplVulkan_InitInfo
     uint32_t                        QueueFamily;
     VkQueue                         Queue;
     VkDescriptorPool                DescriptorPool;             // See requirements in note above; ignored if using DescriptorPoolSize > 0
-    VkRenderPass                    RenderPass;                 // Ignored if using dynamic rendering
+    uint32_t                        DescriptorPoolSize;         // Optional: set to create internal descriptor pool automatically instead of using DescriptorPool.
     uint32_t                        MinImageCount;              // >= 2
     uint32_t                        ImageCount;                 // >= MinImageCount
+    VkPipelineCache                 PipelineCache;              // Optional
+
+    // Pipeline
+    VkRenderPass                    RenderPass;                 // Ignored if using dynamic rendering
+    uint32_t                        Subpass;
     VkSampleCountFlagBits           MSAASamples;                // 0 defaults to VK_SAMPLE_COUNT_1_BIT
 
-    // (Optional)
-    VkPipelineCache                 PipelineCache;
-    uint32_t                        Subpass;
-
-    // (Optional) Set to create internal descriptor pool instead of using DescriptorPool
-    uint32_t                        DescriptorPoolSize;
-
     // (Optional) Dynamic Rendering
-    // Need to explicitly enable VK_KHR_dynamic_rendering extension to use this, even for Vulkan 1.3.
+    // Need to explicitly enable VK_KHR_dynamic_rendering extension to use this, even for Vulkan 1.3 + setup PipelineRenderingCreateInfo.
     bool                            UseDynamicRendering;
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
-    VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo;
+    VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo;   // Optional, valid if .sType == VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO_KHR
 #endif
 
     // (Optional) Allocation, Debugging
     const VkAllocationCallbacks*    Allocator;
     void                            (*CheckVkResultFn)(VkResult err);
-    VkDeviceSize                    MinAllocationSize;          // Minimum allocation size. Set to 1024*1024 to satisfy zealous best practices validation layer and waste a little memory.
+    VkDeviceSize                    MinAllocationSize;              // Minimum allocation size. Set to 1024*1024 to satisfy zealous best practices validation layer and waste a little memory.
 };
 
 // Follow "Getting Started" link and check examples/ folder to learn about using backends!
@@ -112,10 +111,25 @@ IMGUI_IMPL_API bool             ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo*
 IMGUI_IMPL_API void             ImGui_ImplVulkan_Shutdown();
 IMGUI_IMPL_API void             ImGui_ImplVulkan_NewFrame();
 IMGUI_IMPL_API void             ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer command_buffer, VkPipeline pipeline = VK_NULL_HANDLE);
-IMGUI_IMPL_API bool             ImGui_ImplVulkan_CreateFontsTexture();
-IMGUI_IMPL_API void             ImGui_ImplVulkan_DestroyFontsTexture();
 IMGUI_IMPL_API void             ImGui_ImplVulkan_SetMinImageCount(uint32_t min_image_count); // To override MinImageCount after initialization (e.g. if swap chain is recreated)
 
+// (Advanced) Use e.g. if you need to recreate pipeline without reinitializing the backend (see #8110, #8111)
+// The main window pipeline will be created by ImGui_ImplVulkan_Init() if possible (== RenderPass xor (UseDynamicRendering && PipelineRenderingCreateInfo->sType == VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO_KHR))
+// Else, the pipeline can be created, or re-created, using ImGui_ImplVulkan_CreateMainPipeline() before rendering.
+struct ImGui_ImplVulkan_MainPipelineCreateInfo
+{
+    VkRenderPass                RenderPass = VK_NULL_HANDLE;
+    uint32_t                    Subpass = 0;
+    VkSampleCountFlagBits       MSAASamples = {};
+#ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
+    VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo;   // Optional, valid if .sType == VK_STRUCTURE_TYPE_PIPELINE_RENDERING_CREATE_INFO_KHR
+#endif
+};
+IMGUI_IMPL_API void             ImGui_ImplVulkan_CreateMainPipeline(const ImGui_ImplVulkan_MainPipelineCreateInfo& info); // (render_pass xor (p_dynamic_rendering && p_dynamic_rendering is correct (sType and pNext)))
+
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void             ImGui_ImplVulkan_UpdateTexture(ImTextureData* tex);
+
 // Register a texture (VkDescriptorSet == ImTextureID)
 // FIXME: This is experimental in the sense that we are unsure how to best design/tackle this problem
 // Please post to https://github.com/ocornut/imgui/pull/914 if you have suggestions.
@@ -150,20 +164,20 @@ struct ImGui_ImplVulkan_RenderState
 //
 // Your engine/app will likely _already_ have code to setup all that stuff (swap chain,
 // render pass, frame buffers, etc.). You may read this code if you are curious, but
-// it is recommended you use you own custom tailored code to do equivalent work.
+// it is recommended you use your own custom tailored code to do equivalent work.
 //
 // We don't provide a strong guarantee that we won't change those functions API.
 //
 // The ImGui_ImplVulkanH_XXX functions should NOT interact with any of the state used
-// by the regular ImGui_ImplVulkan_XXX functions).
+// by the regular ImGui_ImplVulkan_XXX functions.
 //-------------------------------------------------------------------------
 
 struct ImGui_ImplVulkanH_Frame;
 struct ImGui_ImplVulkanH_Window;
 
 // Helpers
-IMGUI_IMPL_API void                 ImGui_ImplVulkanH_CreateOrResizeWindow(VkInstance instance, VkPhysicalDevice physical_device, VkDevice device, ImGui_ImplVulkanH_Window* wnd, uint32_t queue_family, const VkAllocationCallbacks* allocator, int w, int h, uint32_t min_image_count);
-IMGUI_IMPL_API void                 ImGui_ImplVulkanH_DestroyWindow(VkInstance instance, VkDevice device, ImGui_ImplVulkanH_Window* wnd, const VkAllocationCallbacks* allocator);
+IMGUI_IMPL_API void                 ImGui_ImplVulkanH_CreateOrResizeWindow(VkInstance instance, VkPhysicalDevice physical_device, VkDevice device, ImGui_ImplVulkanH_Window* wd, uint32_t queue_family, const VkAllocationCallbacks* allocator, int w, int h, uint32_t min_image_count);
+IMGUI_IMPL_API void                 ImGui_ImplVulkanH_DestroyWindow(VkInstance instance, VkDevice device, ImGui_ImplVulkanH_Window* wd, const VkAllocationCallbacks* allocator);
 IMGUI_IMPL_API VkSurfaceFormatKHR   ImGui_ImplVulkanH_SelectSurfaceFormat(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkFormat* request_formats, int request_formats_count, VkColorSpaceKHR request_color_space);
 IMGUI_IMPL_API VkPresentModeKHR     ImGui_ImplVulkanH_SelectPresentMode(VkPhysicalDevice physical_device, VkSurfaceKHR surface, const VkPresentModeKHR* request_modes, int request_modes_count);
 IMGUI_IMPL_API VkPhysicalDevice     ImGui_ImplVulkanH_SelectPhysicalDevice(VkInstance instance);
@@ -200,7 +214,6 @@ struct ImGui_ImplVulkanH_Window
     VkSurfaceFormatKHR  SurfaceFormat;
     VkPresentModeKHR    PresentMode;
     VkRenderPass        RenderPass;
-    VkPipeline          Pipeline;               // The window pipeline may uses a different VkRenderPass than the one passed in ImGui_ImplVulkan_InitInfo
     bool                UseDynamicRendering;
     bool                ClearEnable;
     VkClearValue        ClearValue;

backends/imgui_impl_wgpu.cpp

@@ -3,9 +3,12 @@
 // (Please note that WebGPU is currently experimental, will not run on non-beta browsers, and may break.)
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Texture updates support for dynamic font system (ImGuiBackendFlags_RendererHasTextures).
+// Missing features or Issues:
+//  [ ] Renderer: Multi-viewport support (multiple windows), useful for desktop.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -17,6 +20,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-06-12: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. (#8465)
 //  2025-02-26: Recreate image bind groups during render. (#8426, #8046, #7765, #8027) + Update for latest webgpu-native changes.
 //  2024-10-14: Update Dawn support for change of string usages. (#8082, #8083)
 //  2024-10-07: Expose selected render state in ImGui_ImplWGPU_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
@@ -71,11 +75,15 @@ extern ImGuiID ImHashData(const void* data_p, size_t data_size, ImU32 seed);
 #define MEMALIGN(_SIZE,_ALIGN)        (((_SIZE) + ((_ALIGN) - 1)) & ~((_ALIGN) - 1))    // Memory align (copied from IM_ALIGN() macro).
 
 // WebGPU data
+struct ImGui_ImplWGPU_Texture
+{
+    WGPUTexture         Texture = nullptr;
+    WGPUTextureView     TextureView = nullptr;
+};
+
 struct RenderResources
 {
-    WGPUTexture         FontTexture = nullptr;          // Font texture
-    WGPUTextureView     FontTextureView = nullptr;      // Texture view for font texture
-    WGPUSampler         Sampler = nullptr;              // Sampler for the font texture
+    WGPUSampler         Sampler = nullptr;              // Sampler for textures
     WGPUBuffer          Uniforms = nullptr;             // Shader uniforms
     WGPUBindGroup       CommonBindGroup = nullptr;      // Resources bind-group to bind the common resources to pipeline
     ImGuiStorage        ImageBindGroups;                // Resources bind-group to bind the font/image resources to pipeline (this is a key->value map)
@@ -232,23 +240,8 @@ static void SafeRelease(WGPUShaderModule& res)
         wgpuShaderModuleRelease(res);
     res = nullptr;
 }
-static void SafeRelease(WGPUTextureView& res)
-{
-    if (res)
-        wgpuTextureViewRelease(res);
-    res = nullptr;
-}
-static void SafeRelease(WGPUTexture& res)
-{
-    if (res)
-        wgpuTextureRelease(res);
-    res = nullptr;
-}
-
 static void SafeRelease(RenderResources& res)
 {
-    SafeRelease(res.FontTexture);
-    SafeRelease(res.FontTextureView);
     SafeRelease(res.Sampler);
     SafeRelease(res.Uniforms);
     SafeRelease(res.CommonBindGroup);
@@ -376,9 +369,16 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     // Avoid rendering when minimized
     int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
     int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdListsCount == 0)
+    if (fb_width <= 0 || fb_height <= 0 || draw_data->CmdLists.Size == 0)
         return;
 
+    // Catch up with texture updates. Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // (This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates).
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplWGPU_UpdateTexture(tex);
+
     // FIXME: Assuming that this only gets called once per frame!
     // If not, we can't just re-allocate the IB or VB, we'll have to do a proper allocator.
     ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
@@ -444,9 +444,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     // Upload vertex/index data into a single contiguous GPU buffer
     ImDrawVert* vtx_dst = (ImDrawVert*)fr->VertexBufferHost;
     ImDrawIdx* idx_dst = (ImDrawIdx*)fr->IndexBufferHost;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         memcpy(vtx_dst, draw_list->VtxBuffer.Data, draw_list->VtxBuffer.Size * sizeof(ImDrawVert));
         memcpy(idx_dst, draw_list->IdxBuffer.Data, draw_list->IdxBuffer.Size * sizeof(ImDrawIdx));
         vtx_dst += draw_list->VtxBuffer.Size;
@@ -473,9 +472,8 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     int global_idx_offset = 0;
     ImVec2 clip_scale = draw_data->FramebufferScale;
     ImVec2 clip_off = draw_data->DisplayPos;
-    for (int n = 0; n < draw_data->CmdListsCount; n++)
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
     {
-        const ImDrawList* draw_list = draw_data->CmdLists[n];
         for (int cmd_i = 0; cmd_i < draw_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &draw_list->CmdBuffer[cmd_i];
@@ -534,33 +532,52 @@ void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURenderPassEncoder
     platform_io.Renderer_RenderState = nullptr;
 }
 
-static void ImGui_ImplWGPU_CreateFontsTexture()
+static void ImGui_ImplWGPU_DestroyTexture(ImTextureData* tex)
 {
-    // Build texture atlas
-    ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
-    ImGuiIO& io = ImGui::GetIO();
-    unsigned char* pixels;
-    int width, height, size_pp;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &size_pp);
+    ImGui_ImplWGPU_Texture* backend_tex = (ImGui_ImplWGPU_Texture*)tex->BackendUserData;
+    if (backend_tex == nullptr)
+        return;
 
-    // Upload texture to graphics system
+    IM_ASSERT(backend_tex->TextureView == (WGPUTextureView)(intptr_t)tex->TexID);
+    wgpuTextureViewRelease(backend_tex->TextureView);
+    wgpuTextureRelease(backend_tex->Texture);
+    IM_DELETE(backend_tex);
+
+    // Clear identifiers and mark as destroyed (in order to allow e.g. calling InvalidateDeviceObjects while running)
+    tex->SetTexID(ImTextureID_Invalid);
+    tex->SetStatus(ImTextureStatus_Destroyed);
+    tex->BackendUserData = nullptr;
+}
+
+void ImGui_ImplWGPU_UpdateTexture(ImTextureData* tex)
+{
+    ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
+    if (tex->Status == ImTextureStatus_WantCreate)
     {
+        // Create and upload new texture to graphics system
+        //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+        ImGui_ImplWGPU_Texture* backend_tex = IM_NEW(ImGui_ImplWGPU_Texture)();
+
+        // Create texture
         WGPUTextureDescriptor tex_desc = {};
 #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
-        tex_desc.label = { "Dear ImGui Font Texture", WGPU_STRLEN };
+        tex_desc.label = { "Dear ImGui Texture", WGPU_STRLEN };
 #else
-        tex_desc.label = "Dear ImGui Font Texture";
+        tex_desc.label = "Dear ImGui Texture";
 #endif
         tex_desc.dimension = WGPUTextureDimension_2D;
-        tex_desc.size.width = width;
-        tex_desc.size.height = height;
+        tex_desc.size.width = tex->Width;
+        tex_desc.size.height = tex->Height;
         tex_desc.size.depthOrArrayLayers = 1;
         tex_desc.sampleCount = 1;
         tex_desc.format = WGPUTextureFormat_RGBA8Unorm;
         tex_desc.mipLevelCount = 1;
         tex_desc.usage = WGPUTextureUsage_CopyDst | WGPUTextureUsage_TextureBinding;
-        bd->renderResources.FontTexture = wgpuDeviceCreateTexture(bd->wgpuDevice, &tex_desc);
+        backend_tex->Texture = wgpuDeviceCreateTexture(bd->wgpuDevice, &tex_desc);
 
+        // Create texture view
         WGPUTextureViewDescriptor tex_view_desc = {};
         tex_view_desc.format = WGPUTextureFormat_RGBA8Unorm;
         tex_view_desc.dimension = WGPUTextureViewDimension_2D;
@@ -569,19 +586,35 @@ static void ImGui_ImplWGPU_CreateFontsTexture()
         tex_view_desc.baseArrayLayer = 0;
         tex_view_desc.arrayLayerCount = 1;
         tex_view_desc.aspect = WGPUTextureAspect_All;
-        bd->renderResources.FontTextureView = wgpuTextureCreateView(bd->renderResources.FontTexture, &tex_view_desc);
+        backend_tex->TextureView = wgpuTextureCreateView(backend_tex->Texture, &tex_view_desc);
+
+        // Store identifiers
+        tex->SetTexID((ImTextureID)(intptr_t)backend_tex->TextureView);
+        tex->BackendUserData = backend_tex;
+        // We don't set tex->Status to ImTextureStatus_OK to let the code fallthrough below.
     }
 
-    // Upload texture data
+    if (tex->Status == ImTextureStatus_WantCreate || tex->Status == ImTextureStatus_WantUpdates)
     {
+        ImGui_ImplWGPU_Texture* backend_tex = (ImGui_ImplWGPU_Texture*)tex->BackendUserData;
+        IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
+
+        // We could use the smaller rect on _WantCreate but using the full rect allows us to clear the texture.
+        const int upload_x = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.x;
+        const int upload_y = (tex->Status == ImTextureStatus_WantCreate) ? 0 : tex->UpdateRect.y;
+        const int upload_w = (tex->Status == ImTextureStatus_WantCreate) ? tex->Width : tex->UpdateRect.w;
+        const int upload_h = (tex->Status == ImTextureStatus_WantCreate) ? tex->Height : tex->UpdateRect.h;
+
+        // Update full texture or selected blocks. We only ever write to textures regions which have never been used before!
+        // This backend choose to use tex->UpdateRect but you can use tex->Updates[] to upload individual regions.
 #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
         WGPUTexelCopyTextureInfo dst_view = {};
 #else
         WGPUImageCopyTexture dst_view = {};
 #endif
-        dst_view.texture = bd->renderResources.FontTexture;
+        dst_view.texture = backend_tex->Texture;
         dst_view.mipLevel = 0;
-        dst_view.origin = { 0, 0, 0 };
+        dst_view.origin = { (uint32_t)upload_x, (uint32_t)upload_y, 0 };
         dst_view.aspect = WGPUTextureAspect_All;
 #if defined(IMGUI_IMPL_WEBGPU_BACKEND_DAWN) || defined(IMGUI_IMPL_WEBGPU_BACKEND_WGPU)
         WGPUTexelCopyBufferLayout layout = {};
@@ -589,29 +622,14 @@ static void ImGui_ImplWGPU_CreateFontsTexture()
         WGPUTextureDataLayout layout = {};
 #endif
         layout.offset = 0;
-        layout.bytesPerRow = width * size_pp;
-        layout.rowsPerImage = height;
-        WGPUExtent3D size = { (uint32_t)width, (uint32_t)height, 1 };
-        wgpuQueueWriteTexture(bd->defaultQueue, &dst_view, pixels, (uint32_t)(width * size_pp * height), &layout, &size);
+        layout.bytesPerRow = tex->Width * tex->BytesPerPixel;
+        layout.rowsPerImage = upload_h;
+        WGPUExtent3D write_size = { (uint32_t)upload_w, (uint32_t)upload_h, 1 };
+        wgpuQueueWriteTexture(bd->defaultQueue, &dst_view, tex->GetPixelsAt(upload_x, upload_y), (uint32_t)(tex->Width * upload_h * tex->BytesPerPixel), &layout, &write_size);
+        tex->SetStatus(ImTextureStatus_OK);
     }
-
-    // Create the associated sampler
-    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
-    {
-        WGPUSamplerDescriptor sampler_desc = {};
-        sampler_desc.minFilter = WGPUFilterMode_Linear;
-        sampler_desc.magFilter = WGPUFilterMode_Linear;
-        sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
-        sampler_desc.addressModeU = WGPUAddressMode_ClampToEdge;
-        sampler_desc.addressModeV = WGPUAddressMode_ClampToEdge;
-        sampler_desc.addressModeW = WGPUAddressMode_ClampToEdge;
-        sampler_desc.maxAnisotropy = 1;
-        bd->renderResources.Sampler = wgpuDeviceCreateSampler(bd->wgpuDevice, &sampler_desc);
-    }
-
-    // Store our identifier
-    static_assert(sizeof(ImTextureID) >= sizeof(bd->renderResources.FontTexture), "Can't pack descriptor handle into TexID, 32-bit not supported yet.");
-    io.Fonts->SetTexID((ImTextureID)bd->renderResources.FontTextureView);
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+        ImGui_ImplWGPU_DestroyTexture(tex);
 }
 
 static void ImGui_ImplWGPU_CreateUniformBuffer()
@@ -755,16 +773,26 @@ bool ImGui_ImplWGPU_CreateDeviceObjects()
 
     bd->pipelineState = wgpuDeviceCreateRenderPipeline(bd->wgpuDevice, &graphics_pipeline_desc);
 
-    ImGui_ImplWGPU_CreateFontsTexture();
     ImGui_ImplWGPU_CreateUniformBuffer();
 
+    // Create sampler
+    // (Bilinear sampling is required by default. Set 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines' or 'style.AntiAliasedLinesUseTex = false' to allow point/nearest sampling)
+    WGPUSamplerDescriptor sampler_desc = {};
+    sampler_desc.minFilter = WGPUFilterMode_Linear;
+    sampler_desc.magFilter = WGPUFilterMode_Linear;
+    sampler_desc.mipmapFilter = WGPUMipmapFilterMode_Linear;
+    sampler_desc.addressModeU = WGPUAddressMode_ClampToEdge;
+    sampler_desc.addressModeV = WGPUAddressMode_ClampToEdge;
+    sampler_desc.addressModeW = WGPUAddressMode_ClampToEdge;
+    sampler_desc.maxAnisotropy = 1;
+    bd->renderResources.Sampler = wgpuDeviceCreateSampler(bd->wgpuDevice, &sampler_desc);
+
     // Create resource bind group
     WGPUBindGroupEntry common_bg_entries[] =
     {
         { nullptr, 0, bd->renderResources.Uniforms, 0, MEMALIGN(sizeof(Uniforms), 16), 0, 0 },
         { nullptr, 1, 0, 0, 0, bd->renderResources.Sampler, 0 },
     };
-
     WGPUBindGroupDescriptor common_bg_descriptor = {};
     common_bg_descriptor.layout = bg_layouts[0];
     common_bg_descriptor.entryCount = sizeof(common_bg_entries) / sizeof(WGPUBindGroupEntry);
@@ -789,8 +817,10 @@ void ImGui_ImplWGPU_InvalidateDeviceObjects()
     SafeRelease(bd->pipelineState);
     SafeRelease(bd->renderResources);
 
-    ImGuiIO& io = ImGui::GetIO();
-    io.Fonts->SetTexID(0); // We copied g_pFontTextureView to io.Fonts->TexID so let's clear that as well.
+    // Destroy all textures
+    for (ImTextureData* tex : ImGui::GetPlatformIO().Textures)
+        if (tex->RefCount == 1)
+            ImGui_ImplWGPU_DestroyTexture(tex);
 
     for (unsigned int i = 0; i < bd->numFramesInFlight; i++)
         SafeRelease(bd->pFrameResources[i]);
@@ -815,6 +845,7 @@ bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
     io.BackendRendererName = "imgui_impl_webgpu";
 #endif
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
 
     bd->initInfo = *init_info;
     bd->wgpuDevice = init_info->Device;
@@ -824,8 +855,6 @@ bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
     bd->numFramesInFlight = init_info->NumFramesInFlight;
     bd->frameIndex = UINT_MAX;
 
-    bd->renderResources.FontTexture = nullptr;
-    bd->renderResources.FontTextureView = nullptr;
     bd->renderResources.Sampler = nullptr;
     bd->renderResources.Uniforms = nullptr;
     bd->renderResources.CommonBindGroup = nullptr;
@@ -864,7 +893,7 @@ void ImGui_ImplWGPU_Shutdown()
 
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
     IM_DELETE(bd);
 }
 
@@ -872,7 +901,8 @@ void ImGui_ImplWGPU_NewFrame()
 {
     ImGui_ImplWGPU_Data* bd = ImGui_ImplWGPU_GetBackendData();
     if (!bd->pipelineState)
-        ImGui_ImplWGPU_CreateDeviceObjects();
+        if (!ImGui_ImplWGPU_CreateDeviceObjects())
+            IM_ASSERT(0 && "ImGui_ImplWGPU_CreateDeviceObjects() failed!");
 }
 
 //-----------------------------------------------------------------------------

backends/imgui_impl_wgpu.h

@@ -10,9 +10,12 @@
 //#define IMGUI_IMPL_WEBGPU_BACKEND_WGPU
 
 // Implemented features:
-//  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID/ImTextureRef!
 //  [X] Renderer: Large meshes support (64k+ vertices) even with 16-bit indices (ImGuiBackendFlags_RendererHasVtxOffset).
 //  [X] Renderer: Expose selected render state for draw callbacks to use. Access in '(ImGui_ImplXXXX_RenderState*)GetPlatformIO().Renderer_RenderState'.
+//  [X] Renderer: Texture updates support for dynamic font system (ImGuiBackendFlags_RendererHasTextures).
+// Missing features or Issues:
+//  [ ] Renderer: Multi-viewport support (multiple windows), useful for desktop.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -55,6 +58,9 @@ IMGUI_IMPL_API void ImGui_ImplWGPU_RenderDrawData(ImDrawData* draw_data, WGPURen
 IMGUI_IMPL_API bool ImGui_ImplWGPU_CreateDeviceObjects();
 IMGUI_IMPL_API void ImGui_ImplWGPU_InvalidateDeviceObjects();
 
+// (Advanced) Use e.g. if you need to precisely control the timing of texture updates (e.g. for staged rendering), by setting ImDrawData::Textures = NULL to handle this manually.
+IMGUI_IMPL_API void ImGui_ImplWGPU_UpdateTexture(ImTextureData* tex);
+
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplWGPU_RenderDrawData() call.
 // (Please open an issue if you feel you need access to more data)

backends/imgui_impl_win32.cpp

@@ -5,8 +5,9 @@
 //  [X] Platform: Clipboard support (for Win32 this is actually part of core dear imgui)
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen/Pen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy VK_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -21,8 +22,16 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-06-02: [Docking] WM_DPICHANGED also apply io.ConfigDpiScaleViewports for main viewport instead of letting it be done by application code.
+//  2025-04-30: Inputs: Fixed an issue where externally losing mouse capture (due to e.g. focus loss) would fail to claim it again the next subsequent click. (#8594)
+//  2025-03-26: [Docking] Viewports: fixed an issue when closing a window from the OS close button (with io.ConfigViewportsNoDecoration = false) while user code was discarding the 'bool* p_open = false' output from Begin(). Because we allowed the Win32 window to close early, Windows destroyed it and our imgui window became not visible even though user code was still submitting it.
 //  2025-03-10: When dealing with OEM keys, use scancodes instead of translated keycodes to choose ImGuiKey values. (#7136, #7201, #7206, #7306, #7670, #7672, #8468)
+//  2025-02-21: [Docking] WM_SETTINGCHANGE's SPI_SETWORKAREA message also triggers a refresh of monitor list. (#8415)
 //  2025-02-18: Added ImGuiMouseCursor_Wait and ImGuiMouseCursor_Progress mouse cursor support.
+//  2024-11-21: [Docking] Fixed a crash when multiple processes are running with multi-viewports, caused by misusage of GetProp(). (#8162, #8069)
+//  2024-10-28: [Docking] Rely on property stored inside HWND to retrieve context/viewport, should facilitate attempt to use this for parallel contexts. (#8069)
+//  2024-09-16: [Docking] Inputs: fixed an issue where a viewport destroyed while clicking would hog mouse tracking and temporary lead to incorrect update of HoveredWindow. (#7971)
 //  2024-07-08: Inputs: Fixed ImGuiMod_Super being mapped to VK_APPS instead of VK_LWIN||VK_RWIN. (#7768)
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F24 function keys, app back/forward keys.
 //  2023-09-25: Inputs: Synthesize key-down event on key-up for VK_SNAPSHOT / ImGuiKey_PrintScreen as Windows doesn't emit it (same behavior as GLFW/SDL).
@@ -105,6 +114,11 @@ typedef DWORD(WINAPI* PFN_XInputGetState)(DWORD, XINPUT_STATE*);
 #pragma GCC diagnostic ignored "-Wcast-function-type"       // warning: cast between incompatible function types (for loader)
 #endif
 
+// Forward Declarations
+static void ImGui_ImplWin32_InitMultiViewportSupport(bool platform_has_own_dc);
+static void ImGui_ImplWin32_ShutdownMultiViewportSupport();
+static void ImGui_ImplWin32_UpdateMonitors();
+
 struct ImGui_ImplWin32_Data
 {
     HWND                        hWnd;
@@ -115,6 +129,7 @@ struct ImGui_ImplWin32_Data
     INT64                       TicksPerSecond;
     ImGuiMouseCursor            LastMouseCursor;
     UINT32                      KeyboardCodePage;
+    bool                        WantUpdateMonitors;
 
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     bool                        HasGamepad;
@@ -169,6 +184,8 @@ static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
     io.BackendPlatformName = "imgui_impl_win32";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
+    io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
 
     bd->hWnd = (HWND)hwnd;
     bd->TicksPerSecond = perf_frequency;
@@ -176,10 +193,17 @@ static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
     bd->LastMouseCursor = ImGuiMouseCursor_COUNT;
     ImGui_ImplWin32_UpdateKeyboardCodePage(io);
 
-    // Set platform dependent data in viewport
+    // Update monitor a first time during init
+    ImGui_ImplWin32_UpdateMonitors();
+
+    // Our mouse update function expect PlatformHandle to be filled for the main viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
     main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (void*)bd->hWnd;
-    IM_UNUSED(platform_has_own_dc); // Used in 'docking' branch
+
+    // Be aware that GetPropA()/SetPropA() may be accessed from other processes.
+    // So as we store a pointer in IMGUI_CONTEXT we need to make sure we only call GetPropA() on windows owned by our process.
+    ::SetPropA(bd->hWnd, "IMGUI_CONTEXT", ImGui::GetCurrentContext());
+    ImGui_ImplWin32_InitMultiViewportSupport(platform_has_own_dc);
 
     // Dynamically load XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
@@ -222,6 +246,9 @@ void    ImGui_ImplWin32_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ::SetPropA(bd->hWnd, "IMGUI_CONTEXT", nullptr);
+    ImGui_ImplWin32_ShutdownMultiViewportSupport();
+
     // Unload XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     if (bd->XInputDLL)
@@ -230,7 +257,7 @@ void    ImGui_ImplWin32_Shutdown()
 
     io.BackendPlatformName = nullptr;
     io.BackendPlatformUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad);
+    io.BackendFlags &= ~(ImGuiBackendFlags_HasMouseCursors | ImGuiBackendFlags_HasSetMousePos | ImGuiBackendFlags_HasGamepad | ImGuiBackendFlags_PlatformHasViewports | ImGuiBackendFlags_HasMouseHoveredViewport);
     IM_DELETE(bd);
 }
 
@@ -302,32 +329,69 @@ static void ImGui_ImplWin32_UpdateKeyModifiers(ImGuiIO& io)
     io.AddKeyEvent(ImGuiMod_Super, IsVkDown(VK_LWIN) || IsVkDown(VK_RWIN));
 }
 
-static void ImGui_ImplWin32_UpdateMouseData(ImGuiIO& io)
+static ImGuiViewport* ImGui_ImplWin32_FindViewportByPlatformHandle(ImGuiPlatformIO& platform_io, HWND hwnd)
+{
+    // We cannot use ImGui::FindViewportByPlatformHandle() because it doesn't take a context.
+    // When called from ImGui_ImplWin32_WndProcHandler_PlatformWindow() we don't assume that context is bound.
+    //return ImGui::FindViewportByPlatformHandle((void*)hwnd);
+    for (ImGuiViewport* viewport : platform_io.Viewports)
+        if (viewport->PlatformHandle == hwnd)
+            return viewport;
+    return nullptr;
+}
+
+// This code supports multi-viewports (multiple OS Windows mapped into different Dear ImGui viewports)
+// Because of that, it is a little more complicated than your typical single-viewport binding code!
+static void ImGui_ImplWin32_UpdateMouseData(ImGuiIO& io, ImGuiPlatformIO& platform_io)
 {
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData(io);
     IM_ASSERT(bd->hWnd != 0);
 
+    POINT mouse_screen_pos;
+    bool has_mouse_screen_pos = ::GetCursorPos(&mouse_screen_pos) != 0;
+
     HWND focused_window = ::GetForegroundWindow();
-    const bool is_app_focused = (focused_window == bd->hWnd);
+    const bool is_app_focused = (focused_window && (focused_window == bd->hWnd || ::IsChild(focused_window, bd->hWnd) || ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, focused_window)));
     if (is_app_focused)
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when io.ConfigNavMoveSetMousePos is enabled by user)
+        // When multi-viewports are enabled, all Dear ImGui positions are same as OS positions.
         if (io.WantSetMousePos)
         {
             POINT pos = { (int)io.MousePos.x, (int)io.MousePos.y };
-            if (::ClientToScreen(bd->hWnd, &pos))
-                ::SetCursorPos(pos.x, pos.y);
+            if ((io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) == 0)
+                ::ClientToScreen(focused_window, &pos);
+            ::SetCursorPos(pos.x, pos.y);
         }
 
         // (Optional) Fallback to provide mouse position when focused (WM_MOUSEMOVE already provides this when hovered or captured)
         // This also fills a short gap when clicking non-client area: WM_NCMOUSELEAVE -> modal OS move -> gap -> WM_NCMOUSEMOVE
-        if (!io.WantSetMousePos && bd->MouseTrackedArea == 0)
+        if (!io.WantSetMousePos && bd->MouseTrackedArea == 0 && has_mouse_screen_pos)
         {
-            POINT pos;
-            if (::GetCursorPos(&pos) && ::ScreenToClient(bd->hWnd, &pos))
-                io.AddMousePosEvent((float)pos.x, (float)pos.y);
+            // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+            // (This is the position you can get with ::GetCursorPos() + ::ScreenToClient() or WM_MOUSEMOVE.)
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+            // (This is the position you can get with ::GetCursorPos() or WM_MOUSEMOVE + ::ClientToScreen(). In theory adding viewport->Pos to a client position would also be the same.)
+            POINT mouse_pos = mouse_screen_pos;
+            if (!(io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable))
+                ::ScreenToClient(bd->hWnd, &mouse_pos);
+            io.AddMousePosEvent((float)mouse_pos.x, (float)mouse_pos.y);
         }
     }
+
+    // (Optional) When using multiple viewports: call io.AddMouseViewportEvent() with the viewport the OS mouse cursor is hovering.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the backend, Dear imGui will ignore this field and infer the information using its flawed heuristic.
+    // - [X] Win32 backend correctly ignore viewports with the _NoInputs flag (here using ::WindowFromPoint with WM_NCHITTEST + HTTRANSPARENT in WndProc does that)
+    //       Some backend are not able to handle that correctly. If a backend report an hovered viewport that has the _NoInputs flag (e.g. when dragging a window
+    //       for docking, the viewport has the _NoInputs flag in order to allow us to find the viewport under), then Dear ImGui is forced to ignore the value reported
+    //       by the backend, and use its flawed heuristic to guess the viewport behind.
+    // - [X] Win32 backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+    ImGuiID mouse_viewport_id = 0;
+    if (has_mouse_screen_pos)
+        if (HWND hovered_hwnd = ::WindowFromPoint(mouse_screen_pos))
+            if (ImGuiViewport* viewport = ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, hovered_hwnd))
+                mouse_viewport_id = viewport->ID;
+    io.AddMouseViewportEvent(mouse_viewport_id);
 }
 
 // Gamepad navigation mapping
@@ -335,8 +399,6 @@ static void ImGui_ImplWin32_UpdateGamepads(ImGuiIO& io)
 {
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData(io);
-    //if ((io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) == 0) // FIXME: Technically feeding gamepad shouldn't depend on this now that they are regular inputs.
-    //    return;
 
     // Calling XInputGetState() every frame on disconnected gamepads is unfortunately too slow.
     // Instead we refresh gamepad availability by calling XInputGetCapabilities() _only_ after receiving WM_DEVICECHANGE.
@@ -388,16 +450,50 @@ static void ImGui_ImplWin32_UpdateGamepads(ImGuiIO& io)
 #endif
 }
 
+static BOOL CALLBACK ImGui_ImplWin32_UpdateMonitors_EnumFunc(HMONITOR monitor, HDC, LPRECT, LPARAM)
+{
+    MONITORINFO info = {};
+    info.cbSize = sizeof(MONITORINFO);
+    if (!::GetMonitorInfo(monitor, &info))
+        return TRUE;
+    ImGuiPlatformMonitor imgui_monitor;
+    imgui_monitor.MainPos = ImVec2((float)info.rcMonitor.left, (float)info.rcMonitor.top);
+    imgui_monitor.MainSize = ImVec2((float)(info.rcMonitor.right - info.rcMonitor.left), (float)(info.rcMonitor.bottom - info.rcMonitor.top));
+    imgui_monitor.WorkPos = ImVec2((float)info.rcWork.left, (float)info.rcWork.top);
+    imgui_monitor.WorkSize = ImVec2((float)(info.rcWork.right - info.rcWork.left), (float)(info.rcWork.bottom - info.rcWork.top));
+    imgui_monitor.DpiScale = ImGui_ImplWin32_GetDpiScaleForMonitor(monitor);
+    imgui_monitor.PlatformHandle = (void*)monitor;
+    if (imgui_monitor.DpiScale <= 0.0f)
+        return TRUE; // Some accessibility applications are declaring virtual monitors with a DPI of 0, see #7902.
+    ImGuiPlatformIO& io = ImGui::GetPlatformIO();
+    if (info.dwFlags & MONITORINFOF_PRIMARY)
+        io.Monitors.push_front(imgui_monitor);
+    else
+        io.Monitors.push_back(imgui_monitor);
+    return TRUE;
+}
+
+static void ImGui_ImplWin32_UpdateMonitors()
+{
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    ImGui::GetPlatformIO().Monitors.resize(0);
+    ::EnumDisplayMonitors(nullptr, nullptr, ImGui_ImplWin32_UpdateMonitors_EnumFunc, 0);
+    bd->WantUpdateMonitors = false;
+}
+
 void    ImGui_ImplWin32_NewFrame()
 {
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
     IM_ASSERT(bd != nullptr && "Context or backend not initialized? Did you call ImGui_ImplWin32_Init()?");
     ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
     // Setup display size (every frame to accommodate for window resizing)
     RECT rect = { 0, 0, 0, 0 };
     ::GetClientRect(bd->hWnd, &rect);
     io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplWin32_UpdateMonitors();
 
     // Setup time step
     INT64 current_time = 0;
@@ -406,7 +502,7 @@ void    ImGui_ImplWin32_NewFrame()
     bd->Time = current_time;
 
     // Update OS mouse position
-    ImGui_ImplWin32_UpdateMouseData(io);
+    ImGui_ImplWin32_UpdateMouseData(io, platform_io);
 
     // Process workarounds for known Windows key handling issues
     ImGui_ImplWin32_ProcessKeyEventsWorkarounds(io);
@@ -572,6 +668,7 @@ ImGuiKey ImGui_ImplWin32_KeyEventToImGuiKey(WPARAM wParam, LPARAM lParam)
     case 51: return ImGuiKey_Comma;
     case 52: return ImGuiKey_Period;
     case 53: return ImGuiKey_Slash;
+    default: break;
     }
 
     return ImGuiKey_None;
@@ -610,6 +707,10 @@ static ImGuiMouseSource ImGui_ImplWin32_GetMouseSourceFromMessageExtraInfo()
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);                // Use ImGui::GetCurrentContext()
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, ImGuiIO& io); // Doesn't use ImGui::GetCurrentContext()
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED 0x02E0 // From Windows SDK 8.1+ headers
+#endif
+
 IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     // Most backends don't have silent checks like this one, but we need it because WndProc are called early in CreateWindow().
@@ -644,8 +745,11 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hwnd, UINT msg, WPA
             bd->MouseTrackedArea = area;
         }
         POINT mouse_pos = { (LONG)GET_X_LPARAM(lParam), (LONG)GET_Y_LPARAM(lParam) };
-        if (msg == WM_NCMOUSEMOVE && ::ScreenToClient(hwnd, &mouse_pos) == FALSE) // WM_NCMOUSEMOVE are provided in absolute coordinates.
-            return 0;
+        bool want_absolute_pos = (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) != 0;
+        if (msg == WM_MOUSEMOVE && want_absolute_pos)    // WM_MOUSEMOVE are client-relative coordinates.
+            ::ClientToScreen(hwnd, &mouse_pos);
+        if (msg == WM_NCMOUSEMOVE && !want_absolute_pos) // WM_NCMOUSEMOVE are absolute coordinates.
+            ::ScreenToClient(hwnd, &mouse_pos);
         io.AddMouseSourceEvent(mouse_source);
         io.AddMousePosEvent((float)mouse_pos.x, (float)mouse_pos.y);
         return 0;
@@ -684,7 +788,10 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hwnd, UINT msg, WPA
         if (msg == WM_RBUTTONDOWN || msg == WM_RBUTTONDBLCLK) { button = 1; }
         if (msg == WM_MBUTTONDOWN || msg == WM_MBUTTONDBLCLK) { button = 2; }
         if (msg == WM_XBUTTONDOWN || msg == WM_XBUTTONDBLCLK) { button = (GET_XBUTTON_WPARAM(wParam) == XBUTTON1) ? 3 : 4; }
-        if (bd->MouseButtonsDown == 0 && ::GetCapture() == nullptr)
+        HWND hwnd_with_capture = ::GetCapture();
+        if (bd->MouseButtonsDown != 0 && hwnd_with_capture != hwnd) // Did we externally lost capture?
+            bd->MouseButtonsDown = 0;
+        if (bd->MouseButtonsDown == 0 && hwnd_with_capture == nullptr)
             ::SetCapture(hwnd); // Allow us to read mouse coordinates when dragging mouse outside of our window bounds.
         bd->MouseButtonsDown |= 1 << button;
         io.AddMouseSourceEvent(mouse_source);
@@ -791,6 +898,20 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandlerEx(HWND hwnd, UINT msg, WPA
             bd->WantUpdateHasGamepad = true;
 #endif
         return 0;
+    case WM_DISPLAYCHANGE:
+        bd->WantUpdateMonitors = true;
+        return 0;
+    case WM_SETTINGCHANGE:
+        if (wParam == SPI_SETWORKAREA)
+            bd->WantUpdateMonitors = true;
+        return 0;
+    case WM_DPICHANGED:
+    {
+        const RECT* suggested_rect = (RECT*)lParam;
+        if (io.ConfigDpiScaleViewports)
+            ::SetWindowPos(hwnd, nullptr, suggested_rect->left, suggested_rect->top, suggested_rect->right - suggested_rect->left, suggested_rect->bottom - suggested_rect->top, SWP_NOZORDER | SWP_NOACTIVATE);
+        return 0;
+    }
     }
     return 0;
 }
@@ -855,6 +976,10 @@ typedef DPI_AWARENESS_CONTEXT(WINAPI* PFN_SetThreadDpiAwarenessContext)(DPI_AWAR
 // Helper function to enable DPI awareness without setting up a manifest
 void ImGui_ImplWin32_EnableDpiAwareness()
 {
+    // Make sure monitors will be updated with latest correct scaling
+    if (ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData())
+        bd->WantUpdateMonitors = true;
+
     if (_IsWindows10OrGreater())
     {
         static HINSTANCE user32_dll = ::LoadLibraryA("user32.dll"); // Reference counted per-process
@@ -954,6 +1079,386 @@ void ImGui_ImplWin32_EnableAlphaCompositing(void* hwnd)
     }
 }
 
+//---------------------------------------------------------------------------------------------------------
+// MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
+// This is an _advanced_ and _optional_ feature, allowing the backend to create and handle multiple viewports simultaneously.
+// If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
+//--------------------------------------------------------------------------------------------------------
+
+// Helper structure we store in the void* PlatformUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplWin32_ViewportData
+{
+    HWND    Hwnd;               // Stored in ImGuiViewport::PlatformHandle + PlatformHandleRaw
+    HWND    HwndParent;
+    bool    HwndOwned;
+    DWORD   DwStyle;
+    DWORD   DwExStyle;
+
+    ImGui_ImplWin32_ViewportData() { Hwnd = HwndParent = nullptr; HwndOwned = false;  DwStyle = DwExStyle = 0; }
+    ~ImGui_ImplWin32_ViewportData() { IM_ASSERT(Hwnd == nullptr); }
+};
+
+static void ImGui_ImplWin32_GetWin32StyleFromViewportFlags(ImGuiViewportFlags flags, DWORD* out_style, DWORD* out_ex_style)
+{
+    if (flags & ImGuiViewportFlags_NoDecoration)
+        *out_style = WS_POPUP;
+    else
+        *out_style = WS_OVERLAPPEDWINDOW;
+
+    if (flags & ImGuiViewportFlags_NoTaskBarIcon)
+        *out_ex_style = WS_EX_TOOLWINDOW;
+    else
+        *out_ex_style = WS_EX_APPWINDOW;
+
+    if (flags & ImGuiViewportFlags_TopMost)
+        *out_ex_style |= WS_EX_TOPMOST;
+}
+
+static HWND ImGui_ImplWin32_GetHwndFromViewportID(ImGuiID viewport_id)
+{
+    if (viewport_id != 0)
+        if (ImGuiViewport* viewport = ImGui::FindViewportByID(viewport_id))
+            return (HWND)viewport->PlatformHandle;
+    return nullptr;
+}
+
+static void ImGui_ImplWin32_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = IM_NEW(ImGui_ImplWin32_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    // Select style and parent window
+    ImGui_ImplWin32_GetWin32StyleFromViewportFlags(viewport->Flags, &vd->DwStyle, &vd->DwExStyle);
+    vd->HwndParent = ImGui_ImplWin32_GetHwndFromViewportID(viewport->ParentViewportId);
+
+    // Create window
+    RECT rect = { (LONG)viewport->Pos.x, (LONG)viewport->Pos.y, (LONG)(viewport->Pos.x + viewport->Size.x), (LONG)(viewport->Pos.y + viewport->Size.y) };
+    ::AdjustWindowRectEx(&rect, vd->DwStyle, FALSE, vd->DwExStyle);
+    vd->Hwnd = ::CreateWindowExW(
+        vd->DwExStyle, L"ImGui Platform", L"Untitled", vd->DwStyle,       // Style, class name, window name
+        rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,    // Window area
+        vd->HwndParent, nullptr, ::GetModuleHandle(nullptr), nullptr);          // Owner window, Menu, Instance, Param
+    vd->HwndOwned = true;
+    viewport->PlatformRequestResize = false;
+    viewport->PlatformHandle = viewport->PlatformHandleRaw = vd->Hwnd;
+
+    // Secondary viewports store their imgui context
+    ::SetPropA(vd->Hwnd, "IMGUI_CONTEXT", ImGui::GetCurrentContext());
+}
+
+static void ImGui_ImplWin32_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    if (ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData)
+    {
+        if (::GetCapture() == vd->Hwnd)
+        {
+            // Transfer capture so if we started dragging from a window that later disappears, we'll still receive the MOUSEUP event.
+            ::ReleaseCapture();
+            ::SetCapture(bd->hWnd);
+        }
+        if (vd->Hwnd && vd->HwndOwned)
+            ::DestroyWindow(vd->Hwnd);
+        vd->Hwnd = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplWin32_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+
+    // ShowParent() also brings parent to front, which is not always desirable,
+    // so we temporarily disable parenting. (#7354)
+    if (vd->HwndParent != NULL)
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)nullptr);
+
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        ::ShowWindow(vd->Hwnd, SW_SHOWNA);
+    else
+        ::ShowWindow(vd->Hwnd, SW_SHOW);
+
+    // Restore
+    if (vd->HwndParent != NULL)
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)vd->HwndParent);
+}
+
+static void ImGui_ImplWin32_UpdateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+
+    // Update Win32 parent if it changed _after_ creation
+    // Unlike style settings derived from configuration flags, this is more likely to change for advanced apps that are manipulating ParentViewportID manually.
+    HWND new_parent = ImGui_ImplWin32_GetHwndFromViewportID(viewport->ParentViewportId);
+    if (new_parent != vd->HwndParent)
+    {
+        // Win32 windows can either have a "Parent" (for WS_CHILD window) or an "Owner" (which among other thing keeps window above its owner).
+        // Our Dear Imgui-side concept of parenting only mostly care about what Win32 call "Owner".
+        // The parent parameter of CreateWindowEx() sets up Parent OR Owner depending on WS_CHILD flag. In our case an Owner as we never use WS_CHILD.
+        // Calling ::SetParent() here would be incorrect: it will create a full child relation, alter coordinate system and clipping.
+        // Calling ::SetWindowLongPtr() with GWLP_HWNDPARENT seems correct although poorly documented.
+        // https://devblogs.microsoft.com/oldnewthing/20100315-00/?p=14613
+        vd->HwndParent = new_parent;
+        ::SetWindowLongPtr(vd->Hwnd, GWLP_HWNDPARENT, (LONG_PTR)vd->HwndParent);
+    }
+
+    // (Optional) Update Win32 style if it changed _after_ creation.
+    // Generally they won't change unless configuration flags are changed, but advanced uses (such as manually rewriting viewport flags) make this useful.
+    DWORD new_style;
+    DWORD new_ex_style;
+    ImGui_ImplWin32_GetWin32StyleFromViewportFlags(viewport->Flags, &new_style, &new_ex_style);
+
+    // Only reapply the flags that have been changed from our point of view (as other flags are being modified by Windows)
+    if (vd->DwStyle != new_style || vd->DwExStyle != new_ex_style)
+    {
+        // (Optional) Update TopMost state if it changed _after_ creation
+        bool top_most_changed = (vd->DwExStyle & WS_EX_TOPMOST) != (new_ex_style & WS_EX_TOPMOST);
+        HWND insert_after = top_most_changed ? ((viewport->Flags & ImGuiViewportFlags_TopMost) ? HWND_TOPMOST : HWND_NOTOPMOST) : 0;
+        UINT swp_flag = top_most_changed ? 0 : SWP_NOZORDER;
+
+        // Apply flags and position (since it is affected by flags)
+        vd->DwStyle = new_style;
+        vd->DwExStyle = new_ex_style;
+        ::SetWindowLong(vd->Hwnd, GWL_STYLE, vd->DwStyle);
+        ::SetWindowLong(vd->Hwnd, GWL_EXSTYLE, vd->DwExStyle);
+        RECT rect = { (LONG)viewport->Pos.x, (LONG)viewport->Pos.y, (LONG)(viewport->Pos.x + viewport->Size.x), (LONG)(viewport->Pos.y + viewport->Size.y) };
+        ::AdjustWindowRectEx(&rect, vd->DwStyle, FALSE, vd->DwExStyle); // Client to Screen
+        ::SetWindowPos(vd->Hwnd, insert_after, rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top, swp_flag | SWP_NOACTIVATE | SWP_FRAMECHANGED);
+        ::ShowWindow(vd->Hwnd, SW_SHOWNA); // This is necessary when we alter the style
+        viewport->PlatformRequestMove = viewport->PlatformRequestResize = true;
+    }
+}
+
+static ImVec2 ImGui_ImplWin32_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    POINT pos = { 0, 0 };
+    ::ClientToScreen(vd->Hwnd, &pos);
+    return ImVec2((float)pos.x, (float)pos.y);
+}
+
+static void ImGui_ImplWin32_UpdateWin32StyleFromWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    vd->DwStyle = ::GetWindowLongW(vd->Hwnd, GWL_STYLE);
+    vd->DwExStyle = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE);
+}
+
+static void ImGui_ImplWin32_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect = { (LONG)pos.x, (LONG)pos.y, (LONG)pos.x, (LONG)pos.y };
+    if (viewport->Flags & ImGuiViewportFlags_OwnedByApp)
+        ImGui_ImplWin32_UpdateWin32StyleFromWindow(viewport); // Not our window, poll style before using
+    ::AdjustWindowRectEx(&rect, vd->DwStyle, FALSE, vd->DwExStyle);
+    ::SetWindowPos(vd->Hwnd, nullptr, rect.left, rect.top, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_NOACTIVATE);
+}
+
+static ImVec2 ImGui_ImplWin32_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect;
+    ::GetClientRect(vd->Hwnd, &rect);
+    return ImVec2(float(rect.right - rect.left), float(rect.bottom - rect.top));
+}
+
+static void ImGui_ImplWin32_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    RECT rect = { 0, 0, (LONG)size.x, (LONG)size.y };
+    if (viewport->Flags & ImGuiViewportFlags_OwnedByApp)
+        ImGui_ImplWin32_UpdateWin32StyleFromWindow(viewport); // Not our window, poll style before using
+    ::AdjustWindowRectEx(&rect, vd->DwStyle, FALSE, vd->DwExStyle); // Client to Screen
+    ::SetWindowPos(vd->Hwnd, nullptr, 0, 0, rect.right - rect.left, rect.bottom - rect.top, SWP_NOZORDER | SWP_NOMOVE | SWP_NOACTIVATE);
+}
+
+static void ImGui_ImplWin32_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    ::BringWindowToTop(vd->Hwnd);
+    ::SetForegroundWindow(vd->Hwnd);
+    ::SetFocus(vd->Hwnd);
+}
+
+static bool ImGui_ImplWin32_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ::GetForegroundWindow() == vd->Hwnd;
+}
+
+static bool ImGui_ImplWin32_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ::IsIconic(vd->Hwnd) != 0;
+}
+
+static void ImGui_ImplWin32_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    // ::SetWindowTextA() doesn't properly handle UTF-8 so we explicitely convert our string.
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    int n = ::MultiByteToWideChar(CP_UTF8, 0, title, -1, nullptr, 0);
+    ImVector<wchar_t> title_w;
+    title_w.resize(n);
+    ::MultiByteToWideChar(CP_UTF8, 0, title, -1, title_w.Data, n);
+
+    // Calling SetWindowTextW() in a project where UNICODE is not set doesn't work but there's a trick
+    // which is to pass it directly to the DefWindowProcW() handler.
+    // See: https://stackoverflow.com/questions/9410681/setwindowtextw-in-an-ansi-project
+    //::SetWindowTextW(vd->Hwnd, title_w.Data);
+    ::DefWindowProcW(vd->Hwnd, WM_SETTEXT, 0, (LPARAM)title_w.Data);
+}
+
+static void ImGui_ImplWin32_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
+    if (alpha < 1.0f)
+    {
+        DWORD ex_style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) | WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, ex_style);
+        ::SetLayeredWindowAttributes(vd->Hwnd, 0, (BYTE)(255 * alpha), LWA_ALPHA);
+    }
+    else
+    {
+        DWORD ex_style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) & ~WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, ex_style);
+    }
+}
+
+static float ImGui_ImplWin32_GetWindowDpiScale(ImGuiViewport* viewport)
+{
+    ImGui_ImplWin32_ViewportData* vd = (ImGui_ImplWin32_ViewportData*)viewport->PlatformUserData;
+    IM_ASSERT(vd->Hwnd != 0);
+    return ImGui_ImplWin32_GetDpiScaleForHwnd(vd->Hwnd);
+}
+
+// FIXME-DPI: Testing DPI related ideas
+static void ImGui_ImplWin32_OnChangedViewport(ImGuiViewport* viewport)
+{
+    (void)viewport;
+#if 0
+    ImGuiStyle default_style;
+    //default_style.WindowPadding = ImVec2(0, 0);
+    //default_style.WindowBorderSize = 0.0f;
+    //default_style.ItemSpacing.y = 3.0f;
+    //default_style.FramePadding = ImVec2(0, 0);
+    default_style.ScaleAllSizes(viewport->DpiScale);
+    ImGuiStyle& style = ImGui::GetStyle();
+    style = default_style;
+#endif
+}
+
+namespace ImGui { extern ImGuiIO& GetIO(ImGuiContext*); extern ImGuiPlatformIO& GetPlatformIO(ImGuiContext*); }
+
+static LRESULT CALLBACK ImGui_ImplWin32_WndProcHandler_PlatformWindow(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    // Allow secondary viewport WndProc to be called regardless of current context
+    ImGuiContext* ctx = (ImGuiContext*)::GetPropA(hWnd, "IMGUI_CONTEXT");
+    if (ctx == NULL)
+        return DefWindowProc(hWnd, msg, wParam, lParam); // unlike ImGui_ImplWin32_WndProcHandler() we are called directly by Windows, we can't just return 0.
+
+    ImGuiIO& io = ImGui::GetIO(ctx);
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO(ctx);
+    LRESULT result = 0;
+    if (ImGui_ImplWin32_WndProcHandlerEx(hWnd, msg, wParam, lParam, io))
+        result = 1;
+    else if (ImGuiViewport* viewport = ImGui_ImplWin32_FindViewportByPlatformHandle(platform_io, hWnd))
+    {
+        switch (msg)
+        {
+        case WM_CLOSE:
+            viewport->PlatformRequestClose = true;
+            return 0; // 0 = Operating system will ignore the message and not destroy the window. We close ourselves.
+        case WM_MOVE:
+            viewport->PlatformRequestMove = true;
+            break;
+        case WM_SIZE:
+            viewport->PlatformRequestResize = true;
+            break;
+        case WM_MOUSEACTIVATE:
+            if (viewport->Flags & ImGuiViewportFlags_NoFocusOnClick)
+                result = MA_NOACTIVATE;
+            break;
+        case WM_NCHITTEST:
+            // Let mouse pass-through the window. This will allow the backend to call io.AddMouseViewportEvent() correctly. (which is optional).
+            // The ImGuiViewportFlags_NoInputs flag is set while dragging a viewport, as want to detect the window behind the one we are dragging.
+            // If you cannot easily access those viewport flags from your windowing/event code: you may manually synchronize its state e.g. in
+            // your main loop after calling UpdatePlatformWindows(). Iterate all viewports/platform windows and pass the flag to your windowing system.
+            if (viewport->Flags & ImGuiViewportFlags_NoInputs)
+                result = HTTRANSPARENT;
+            break;
+        }
+    }
+    if (result == 0)
+        result = DefWindowProc(hWnd, msg, wParam, lParam);
+    return result;
+}
+
+static void ImGui_ImplWin32_InitMultiViewportSupport(bool platform_has_own_dc)
+{
+    WNDCLASSEXW wcex;
+    wcex.cbSize = sizeof(WNDCLASSEXW);
+    wcex.style = CS_HREDRAW | CS_VREDRAW | (platform_has_own_dc ? CS_OWNDC : 0);
+    wcex.lpfnWndProc = ImGui_ImplWin32_WndProcHandler_PlatformWindow;
+    wcex.cbClsExtra = 0;
+    wcex.cbWndExtra = 0;
+    wcex.hInstance = ::GetModuleHandle(nullptr);
+    wcex.hIcon = nullptr;
+    wcex.hCursor = nullptr;
+    wcex.hbrBackground = (HBRUSH)(COLOR_BACKGROUND + 1);
+    wcex.lpszMenuName = nullptr;
+    wcex.lpszClassName = L"ImGui Platform";
+    wcex.hIconSm = nullptr;
+    ::RegisterClassExW(&wcex);
+
+    ImGui_ImplWin32_UpdateMonitors();
+
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplWin32_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplWin32_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplWin32_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplWin32_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplWin32_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplWin32_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplWin32_GetWindowSize;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplWin32_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplWin32_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplWin32_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplWin32_SetWindowTitle;
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplWin32_SetWindowAlpha;
+    platform_io.Platform_UpdateWindow = ImGui_ImplWin32_UpdateWindow;
+    platform_io.Platform_GetWindowDpiScale = ImGui_ImplWin32_GetWindowDpiScale; // FIXME-DPI
+    platform_io.Platform_OnChangedViewport = ImGui_ImplWin32_OnChangedViewport; // FIXME-DPI
+
+    // Register main window handle (which is owned by the main application, not by us)
+    // This is mostly for simplicity and consistency, so that our code (e.g. mouse handling etc.) can use same logic for main and secondary viewports.
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    ImGui_ImplWin32_ViewportData* vd = IM_NEW(ImGui_ImplWin32_ViewportData)();
+    vd->Hwnd = bd->hWnd;
+    vd->HwndOwned = false;
+    main_viewport->PlatformUserData = vd;
+}
+
+static void ImGui_ImplWin32_ShutdownMultiViewportSupport()
+{
+    ::UnregisterClassW(L"ImGui Platform", ::GetModuleHandle(nullptr));
+    ImGui::DestroyPlatformWindows();
+}
+
 //---------------------------------------------------------------------------------------------------------
 
 #if defined(__GNUC__)

backends/imgui_impl_win32.h

@@ -5,8 +5,9 @@
 //  [X] Platform: Clipboard support (for Win32 this is actually part of core dear imgui)
 //  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen/Pen.
 //  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy VK_* values are obsolete since 1.87 and not supported since 1.91.5]
-//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Gamepad support.
 //  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

docs/BACKENDS.md

@@ -1,18 +1,33 @@
 _(You may browse this at https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md or view this file with any Markdown viewer)_
 
-## Dear ImGui: Backends
+# Dear ImGui: Backends
 
-### Integrating backends
+## Index
+
+- [Introduction](#introduction)
+   - [Getting Started](#getting-started)
+   - [What are Backends?](#what-are-backends)
+- [Using standard Backends](#using-standard-backends)
+- [Using third-party Backends](#using-third-party-backends)
+- [Writing your own Backend](#writing-your-own-backend)
+  - [Using a custom engine?](#using-a-custom-engine)
+  - [Platform: Implementing your Platform Backend](#platform-implementing-your-platform-backend)
+  - [Rendering: Implementing your RenderDrawData function](#rendering-implementing-your-renderdrawdata-function)
+  - [Rendering: Adding support for `ImGuiBackendFlags_RendererHasTextures` (1.92+)](#rendering-adding-support-for-imguibackendflags_rendererhastextures-192)
+
+## Introduction
+
+### Getting Started
 
 💡 The **[Getting Started](https://github.com/ocornut/imgui/wiki/Getting-Started) wiki guide** has examples of how to integrate Dear ImGui into an existing application.
 <BR> The [EXAMPLES.MD](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md) documentation may also be worth a read.
 
-### What are backends?
+### What are Backends?
 
 Dear ImGui is highly portable and only requires a few things to run and render, typically:
 
  - Required: providing mouse/keyboard inputs (fed into the `ImGuiIO` structure).
- - Required: uploading the font atlas texture into graphics memory.
+ - Required: creating, updating and destroying textures.
  - Required: rendering indexed textured triangles with a clipping rectangle.
 
  Extra features are opt-in, our backends try to support as many as possible:
@@ -34,13 +49,13 @@ and the backends which we are describing here (backends/ folder).
 - You should be able to write backends for pretty much any platform and any 3D graphics API.
   e.g. you can get creative and use software rendering or render remotely on a different machine.
 
-### Standard backends
+## Using standard Backends
 
 **The [backends/](https://github.com/ocornut/imgui/blob/master/backends) folder contains backends for popular platforms/graphics API, which you can use in
 your application or engine to easily integrate Dear ImGui.** Each backend is typically self-contained in a pair of files: imgui_impl_XXXX.cpp + imgui_impl_XXXX.h.
 
 - The 'Platform' backends are in charge of: mouse/keyboard/gamepad inputs, cursor shape, timing, and windowing.<BR>
-  e.g. Windows ([imgui_impl_win32.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_win32.cpp)), GLFW ([imgui_impl_glfw.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_glfw.cpp)), SDL2 ([imgui_impl_sdl2.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_sdl2.cpp)), etc.
+  e.g. Windows ([imgui_impl_win32.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_win32.cpp)), SDL3 ([imgui_impl_sdl3.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_sdl3.cpp)), GLFW ([imgui_impl_glfw.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_glfw.cpp)), etc.
 
 - The 'Renderer' backends are in charge of: creating atlas texture, and rendering imgui draw data.<BR>
   e.g. DirectX11 ([imgui_impl_dx11.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_dx11.cpp)), OpenGL/WebGL ([imgui_impl_opengl3.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_opengl3.cpp)), Vulkan ([imgui_impl_vulkan.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_vulkan.cpp)), etc.
@@ -53,44 +68,41 @@ For example, the [example_win32_directx11](https://github.com/ocornut/imgui/tree
 
 **Once Dear ImGui is setup and running, run and refer to `ImGui::ShowDemoWindow()` in imgui_demo.cpp for usage of the end-user API.**
 
-### List of backends
+### List of standard Backends
 
 In the [backends/](https://github.com/ocornut/imgui/blob/master/backends) folder:
 
 List of Platforms Backends:
 
-    imgui_impl_android.cpp    ; Android native app API
-    imgui_impl_glfw.cpp       ; GLFW (Windows, macOS, Linux, etc.) http://www.glfw.org/
-    imgui_impl_osx.mm         ; macOS native API (not as feature complete as glfw/sdl backends)
-    imgui_impl_sdl2.cpp       ; SDL2 (Windows, macOS, Linux, iOS, Android) https://www.libsdl.org
-    imgui_impl_sdl3.cpp       ; SDL3 (Windows, macOS, Linux, iOS, Android) https://www.libsdl.org (*EXPERIMENTAL UNTIL SDL3 IS RELEASED*)
-    imgui_impl_win32.cpp      ; Win32 native API (Windows)
-    imgui_impl_glut.cpp       ; GLUT/FreeGLUT (this is prehistoric software and absolutely not recommended today!)
+    imgui_impl_android.cpp      ; Android native app API
+    imgui_impl_glfw.cpp         ; GLFW (Windows, macOS, Linux, etc.) http://www.glfw.org/
+    imgui_impl_osx.mm           ; macOS native API (not as feature complete as glfw/sdl backends)
+    imgui_impl_sdl2.cpp         ; SDL2 (Windows, macOS, Linux, iOS, Android) https://www.libsdl.org
+    imgui_impl_sdl3.cpp         ; SDL3 (Windows, macOS, Linux, iOS, Android) https://www.libsdl.org
+    imgui_impl_win32.cpp        ; Win32 native API (Windows)
+    imgui_impl_glut.cpp         ; GLUT/FreeGLUT (this is prehistoric software and absolutely not recommended today!)
 
 List of Renderer Backends:
 
-    imgui_impl_dx9.cpp        ; DirectX9
-    imgui_impl_dx10.cpp       ; DirectX10
-    imgui_impl_dx11.cpp       ; DirectX11
-    imgui_impl_dx12.cpp       ; DirectX12
-    imgui_impl_metal.mm       ; Metal (with ObjC)
-    imgui_impl_opengl2.cpp    ; OpenGL 2 (legacy, fixed pipeline <- don't use with modern OpenGL context)
-    imgui_impl_opengl3.cpp    ; OpenGL 3/4, OpenGL ES 2, OpenGL ES 3 (modern programmable pipeline)
+    imgui_impl_dx9.cpp          ; DirectX9
+    imgui_impl_dx10.cpp         ; DirectX10
+    imgui_impl_dx11.cpp         ; DirectX11
+    imgui_impl_dx12.cpp         ; DirectX12
+    imgui_impl_metal.mm         ; Metal (ObjC or C++)
+    imgui_impl_opengl2.cpp      ; OpenGL 2 (legacy fixed pipeline. Don't use with modern OpenGL code!)
+    imgui_impl_opengl3.cpp      ; OpenGL 3/4, OpenGL ES 2/3, WebGL
+    imgui_impl_sdlgpu3.cpp      ; SDL_GPU (portable 3D graphics API of SDL3)
     imgui_impl_sdlrenderer2.cpp ; SDL_Renderer (optional component of SDL2 available from SDL 2.0.18+)
-    imgui_impl_sdlrenderer3.cpp ; SDL_Renderer (optional component of SDL3 available from SDL 3.0.0+)
-    imgui_impl_vulkan.cpp     ; Vulkan
-    imgui_impl_wgpu.cpp       ; WebGPU (web and desktop)
+    imgui_impl_sdlrenderer3.cpp ; SDL_Renderer (optional component of SDL3. Prefer using SDL_GPU!).
+    imgui_impl_vulkan.cpp       ; Vulkan
+    imgui_impl_wgpu.cpp         ; WebGPU (web + desktop)
 
 List of high-level Frameworks Backends (combining Platform + Renderer):
 
     imgui_impl_allegro5.cpp
 
 Emscripten is also supported!
-The SDL+GL, GLFW+GL and GLFW+WebGPU examples are all ready to build and run with Emscripten.
-
-### Backends for third-party frameworks, graphics API or other languages
-
-See https://github.com/ocornut/imgui/wiki/Bindings for the full list (e.g. Adventure Game Studio, Cinder, Cocos2d-x, Game Maker Studio2, Godot, LÖVE+LUA, Magnum, Monogame, Ogre, openFrameworks, OpenSceneGraph, SFML, Sokol, Unity, Unreal Engine and many others).
+The SDL2+GL, SDL3+GL, GLFW+GL and GLFW+WebGPU examples are all ready to build and run with Emscripten.
 
 ### Recommended Backends
 
@@ -98,18 +110,32 @@ If you are not sure which backend to use, the recommended platform/frameworks fo
 
 |Library |Website |Backend |Note |
 |--------|--------|--------|-----|
-| GLFW | https://github.com/glfw/glfw | imgui_impl_glfw.cpp | |
+| SDL3 | https://www.libsdl.org | imgui_impl_sdl3.cpp | Recommended |
 | SDL2 | https://www.libsdl.org | imgui_impl_sdl2.cpp | |
+| GLFW | https://github.com/glfw/glfw | imgui_impl_glfw.cpp | |
 | Sokol | https://github.com/floooh/sokol | [util/sokol_imgui.h](https://github.com/floooh/sokol/blob/master/util/sokol_imgui.h) | Lower-level than GLFW/SDL |
 
+If your application runs on Windows or if you are using multi-viewport, the win32 backend handles some details a little better than other backends.
+
+## Using third-party Backends
+
+See https://github.com/ocornut/imgui/wiki/Bindings for the full list (e.g. Adventure Game Studio, Cinder, Cocos2d-x, Game Maker Studio2, Godot, LÖVE+LUA, Magnum, Monogame, Ogre, openFrameworks, OpenSceneGraph, SFML, Sokol, Unity, Unreal Engine and many others).
+
+## Writing your own Backend
 
 ### Using a custom engine?
 
 You will likely be tempted to start by rewrite your own backend using your own custom/high-level facilities...<BR>
 Think twice!
 
-If you are new to Dear ImGui, first try using the existing backends as-is.
+TL;DR;
+- Writing your own Renderer Backend is easy.
+- Writing your own Platform Backend is harder and you are more likely to introduce bugs.
+- **It is unlikely you will add value to your project by creating your own backend.**
+
+**Consider using the existing backends as-is**.
 You will save lots of time integrating the library.
+Standard backends are battle-tested and handle subtleties that you are likely to implement incorrectly.
 You can LATER decide to rewrite yourself a custom backend if you really need to.
 In most situations, custom backends have fewer features and more bugs than the standard backends we provide.
 If you want portability, you can use multiple backends and choose between them either at compile time
@@ -131,16 +157,221 @@ Suggestion: try using a non-portable backend first (e.g. win32 + underlying grap
 your desktop builds working first. This will get you running faster and get your acquainted with
 how Dear ImGui works and is setup. You can then rewrite a custom backend using your own engine API...
 
-Generally:
-It is unlikely you will add value to your project by creating your own backend.
-
 Also:
 The [multi-viewports feature](https://github.com/ocornut/imgui/wiki/Multi-Viewports) of the 'docking' branch allows
 Dear ImGui windows to be seamlessly detached from the main application window. This is achieved using an
 extra layer to the Platform and Renderer backends, which allows Dear ImGui to communicate platform-specific
 requests such as: "create an additional OS window", "create a render context", "get the OS position of this
-window" etc. See 'ImGuiPlatformIO' for details.
+window", but some things are more difficult "find OS window under mouse position BUT with some windows marked as passthrough". See 'ImGuiPlatformIO' for details.
 Supporting the multi-viewports feature correctly using 100% of your own abstractions is more difficult
 than supporting single-viewport.
 If you decide to use unmodified imgui_impl_XXXX.cpp files, you can automatically benefit from
 improvements and fixes related to viewports and platform windows without extra work on your side.
+
+### Platform: Implementing your Platform Backend
+
+The Platform backends in impl_impl_XXX.cpp files contain many implementations.
+
+**In your `ImGui_ImplXXX_Init()` function:**
+- You can allocate your backend data and use `io.BackendPlatformUserData` to store/retrieve it later.
+- Set `io.BackendPlatformName` to a name `"imgui_impl_xxxx"` which will be available in e.g. About box.
+- Set `io.BackendPlatformUserData` to your backend data.
+- Set `io.BackendFlags` with supported optional features:
+  - `ImGuiBackendFlags_HasGamepad`: supports gamepad and currently has one connected.
+  - `ImGuiBackendFlags_HasMouseCursors`: supports honoring GetMouseCursor() value to change the OS cursor shape.
+  - `ImGuiBackendFlags_HasSetMousePos`: supports io.WantSetMousePos requests to reposition the OS mouse position (only used if io.ConfigNavMoveSetMousePos is set).
+  - `ImGuiBackendFlags_PlatformHasViewports` supports multiple viewports. (multi-viewports only)
+  - `ImGuiBackendFlags_HasMouseHoveredViewport` supports calling io.AddMouseViewportEvent() with the viewport under the mouse. IF POSSIBLE, ignore viewports with the ImGuiViewportFlags_NoInputs flag. If this cannot be done, Dear ImGui needs to use a flawed heuristic to find the viewport under mouse position, as it doesn't know about foreign windows. (multi-viewports only)
+
+**In your `ImGui_ImplXXX_NewFrame()` function:**
+- Set `io.DeltaTime` to the time elapsed (in seconds) since last frame.
+- Set `io.DisplaySize` to your window size.
+- Set `io.DisplayFrameBufferSize` to your window pixel density (macOS/iOS only).
+- Update mouse cursor shape is supported.
+
+**In your `ImGui_ImplXXX_NewFrame()` function or event handlers:**
+- **Mouse Support**
+  - Use `io.AddMousePosEvent()`, `io.AddMouseButtonEvent()`, `io.AddMouseWheelEvent()` to pass mouse events.
+  - Use `io.AddMouseSourceEvent()` if you are able to distinguish Mouse from TouchScreen from Pen inputs. TouchScreen and Pen inputs requires different logic for some Dear ImGui features.
+  - Use `io.AddMouseViewportEvent()` to specify which viewport/OS window is being hovered by the mouse. Read instructions carefully as this is not as simple as it seems! (multi-viewports only)
+- **Keyboard Support**
+  - Use `io.AddKeyEvent()` to pass key events.
+  - Use `io.AddInputCharacter()` to pass text/character events.
+- **Gamepad Support**
+  - Use `io.AddKeyEvent()` and `io.AddKeyAnalogEvent()` to pass gamepad events, using `ImGuiKey_GamepadXXX` values.
+- **Miscellaneous**
+  - Clipboard Support: setup `Platform_GetClipboardTextFn()`, `Platform_SetClipboardTextFn()` handlers in `ImGuiPlatformIO`.
+  - Open in Shell support: setup `Platform_OpenInShellFn()` handler in `ImGuiPlatformIO`.
+  - IME Support: setup `Platform_SetImeDataFn()` handler in `ImGuiPlatformIO`.
+  - Use `io.AddFocusEvent()` to notify when application window gets focused/unfocused.
+- **Multi-viewport Support**
+  - Update monitor list if supported.
+  - Setup all required handlers in `ImGuiPlatformIO` to create/destroy/move/resize/title/focus/etc. windows.
+
+### Rendering: Implementing your RenderDrawData function
+
+Note: set `ImGuiBackendFlags_RendererHasVtxOffset` to signify your backend can handle rendering with a vertex offset (`ImDrawCmd::VtxOffset` field).
+Otherwise, rendering will be limited to 64K vertices per window, which may be limiting for advanced plot.
+As an alternative, you may also use `#define ImDrawIdx unsigned int` in your `imconfig.h` file to support 32-bit indices.
+
+```cpp
+void MyImGuiBackend_RenderDrawData(ImDrawData* draw_data)
+{
+    // TODO: Update textures.
+    // - Most of the times, the list will have 1 element with an OK status, aka nothing to do.
+    // - This almost always points to ImGui::GetPlatformIO().Textures[] but is part of ImDrawData to allow overriding or disabling texture updates.
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                MyImGuiBackend_UpdateTexture(tex);
+
+    // TODO: Setup render state:
+    // - Alpha-blending enabled
+    // - No backface culling
+    // - No depth testing, no depth writing
+    // - Scissor enabled
+    MyEngineSetupenderState();
+
+    // TODO: Setup texture sampling state
+    // - Sample with bilinear filtering (NOT point/nearest filtering).
+    // - Use 'io.Fonts->Flags |= ImFontAtlasFlags_NoBakedLines;' to allow point/nearest filtering.
+
+    // TODO: Setup viewport covering draw_data->DisplayPos to draw_data->DisplayPos + draw_data->DisplaySize
+
+    // TODO: Setup orthographic projection matrix cover draw_data->DisplayPos to draw_data->DisplayPos + draw_data->DisplaySize
+
+    // TODO: Setup shader: vertex { float2 pos, float2 uv, u32 color }, fragment shader sample color from 1 texture, multiply by vertex color.
+
+    // Render command lists
+    ImVec2 clip_off = draw_data->DisplayPos;
+    ImVec2 clip_scale = draw_data->FramebufferScale;
+    for (const ImDrawList* draw_list : draw_data->CmdLists)
+    {
+        const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;  // vertex buffer generated by Dear ImGui
+        const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;   // index buffer generated by Dear ImGui
+        for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
+        {
+            const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
+            if (pcmd->UserCallback)
+            {
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    MyEngineSetupenderState();
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
+            }
+            else
+            {
+                // Project scissor/clipping rectangles into framebuffer space
+                // - Clipping coordinates are provided in imgui coordinates space:
+                //   - For a given viewport, draw_data->DisplayPos == viewport->Pos and draw_data->DisplaySize == viewport->Size
+                //   - In a single viewport application, draw_data->DisplayPos == (0,0) and draw_data->DisplaySize == io.DisplaySize, but always use GetMainViewport()->Pos/Size instead of hardcoding those values.
+                //   - In the interest of supporting multi-viewport applications (see 'docking' branch on github),
+                //     always subtract draw_data->DisplayPos from clipping bounds to convert them to your viewport space.
+                // - Note that pcmd->ClipRect contains Min+Max bounds. Some graphics API may use Min+Max, other may use Min+Size (size being Max-Min)
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
+                if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
+                    continue;
+
+                // We are using scissoring to clip some objects. All low-level graphics API should support it.
+                // - If your engine doesn't support scissoring yet, you may ignore this at first. You will get some small glitches
+                //   (some elements visible outside their bounds) but you can fix that once everything else works!
+                MyEngineSetScissor(clip_min.x, clip_min.y, clip_max.x, clip_max.y);
+
+                // The texture for the draw call is specified by pcmd->GetTexID().
+                // The vast majority of draw calls will use the Dear ImGui texture atlas, which value you have set yourself during initialization.
+                MyEngineBindTexture((MyTexture*)pcmd->GetTexID());
+
+                // Render 'pcmd->ElemCount/3' indexed triangles.
+                // By default the indices ImDrawIdx are 16-bit, you can change them to 32-bit in imconfig.h if your engine doesn't support 16-bit indices.
+                MyEngineDrawIndexedTriangles(pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer + pcmd->IdxOffset, vtx_buffer, pcmd->VtxOffset);
+            }
+        }
+    }
+}
+```
+
+### Rendering: Adding support for `ImGuiBackendFlags_RendererHasTextures` (1.92+)
+
+Version [1.92.0](https://github.com/ocornut/imgui/releases/tag/v1.92.0) (June 2025), added texture support in Rendering Backends, which is the backbone for supporting dynamic font scaling among other things.
+
+**In order to move forward and take advantage of all new features, support for `ImGuiBackendFlags_RendererHasTextures` will likely be REQUIRED for all backends before June 2026.**
+
+`ImFontAtlas` functions such as `Build()`, `GetTexDataAsRGBA32()`, `GetTexDataAsAlpha8()`, `SetTexID()`, `IsBuilt()` were obsoleted in favor if iterating a `Textures[]` array and updating their state when requested by Dear ImGui.
+
+**TD;DR: List of commits which added support for `ImGuiBackendFlags_RendererHasTextures` in standard backends:**
+
+- Allegro5: [ee8941e](https://github.com/ocornut/imgui/commit/ee8941e) (+35 lines)
+- DirectX9: [75efba7](https://github.com/ocornut/imgui/commit/75efba7) (+48 lines)
+- DirectX10: [2d2b1bc](https://github.com/ocornut/imgui/commit/2d2b1bc) (+40 lines)
+- DirectX11: [372fd27](https://github.com/ocornut/imgui/commit/372fd27) (+40 lines)
+- DirectX12: [eefe5d5](https://github.com/ocornut/imgui/commit/eefe5d5) (+87 lines)
+- Metal: [26c017d](https://github.com/ocornut/imgui/commit/26c017d) (+55 lines)
+- OpenGL Legacy: [0430c55](https://github.com/ocornut/imgui/commit/0430c55) (+25 lines)
+- OpenGL3/WebGL/ES: [dbb91a5](https://github.com/ocornut/imgui/commit/dbb91a5) (+47 lines)
+- SDL_Renderer2: [9fa65cd](https://github.com/ocornut/imgui/commit/9fa65cd) (+20 lines)
+- SDL_Renderer3: [e538883](https://github.com/ocornut/imgui/commit/e538883) (+19 lines)
+- SDL_GPU: [16fe666](https://github.com/ocornut/imgui/commit/16fe666) (+41 lines)
+- Vulkan: [abe294b](https://github.com/ocornut/imgui/commit/abe294b) (+33 lines)
+- WGPU: [571dae9](https://github.com/ocornut/imgui/commit/571dae9) (+30 lines)
+
+**Instructions:**
+
+- Set `ImGuiBackendFlags_RendererHasTextures` to signify your backend can handle the feature.
+- During rendering, e.g. in your RenderDrawData function, iterate `ImDrawData->Textures` array and process all textures.
+- During shutdown, iterate the `ImGui::GetPlatformIO().Textures` and destroy all textures.
+- (Both arrays are `ImVector<ImTextureData*>`. They are only in different location because: to allow advanced users to perform multi-threaded rendering, we store a pointer to the texture list in ImDrawData, with the aim that multi-threaded rendering users replace it with their own pointer.)
+
+Pseudo-code for processing a texture:
+```cpp
+if (draw_data->Textures != nullptr)
+    for (ImTextureData* tex : *draw_data->Textures)
+        if (tex->Status != ImTextureStatus_OK)
+            MyImGuiBackend_UpdateTexture(tex);
+```
+```cpp
+void MyImGuiBackend_UpdateTexture(ImTextureData* tex)
+{
+    if (tex->Status == ImTextureStatus_WantCreate)
+    {
+        // Create texture based on tex->Width, tex->Height.
+        // - Most backends only support tex->Format == ImTextureFormat_RGBA32.
+        // - Backends for particularly memory constrainted platforms may support tex->Format == ImTextureFormat_Alpha8.
+
+        // Upload all texture pixels
+        // - Read from our CPU-side copy of the texture and copy to your graphics API.
+        // - Use tex->Width, tex->Height, tex->GetPixels(), tex->GetPixelsAt(), tex->GetPitch() as needed.
+
+        // Store your data, and acknowledge creation.
+        tex->SetTexID(xxxx); // Specify backend-specific ImTextureID identifier which will be stored in ImDrawCmd.
+        tex->SetStatus(ImTextureStatus_OK);
+        tex->BackendUserData = xxxx; // Store more backend data if needed (most backend allocate a small texture to store data in there)
+    }
+    if (tex->Status == ImTextureStatus_WantUpdates)
+    {
+        // Upload a rectangle of pixels to the existing texture
+        // - We only ever write to textures regions which have never been used before!
+        // - Use tex->TexID or tex->BackendUserData to retrieve your stored data.
+        // - Use tex->UpdateRect.x/y, tex->UpdateRect.w/h to obtain the block position and size.
+        //   - Use tex->Updates[] to obtain individual sub-regions within tex->UpdateRect. Not recommended.
+        // - Read from our CPU-side copy of the texture and copy to your graphics API.
+        // - Use tex->Width, tex->Height, tex->GetPixels(), tex->GetPixelsAt(), tex->GetPitch() as needed.
+
+        // Acknowledge update
+        tex->SetStatus(ImTextureStatus_OK);
+    }
+    if (tex->Status == ImTextureStatus_WantDestroy && tex->UnusedFrames > 0)
+    {
+        // If you use staged rendering and have in-flight renders, changed tex->UnusedFrames > 0 check to higher count as needed e.g. > 2
+
+        // Destroy texture
+        // - Use tex->TexID or tex->BackendUserData to retrieve your stored data.
+        // - Destroy texture in your graphics API.
+
+        // Acknowledge destruction
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
+    }
+}
+```
+Refer to "List of commits which added support for `ImGuiBackendFlags_RendererHasTextures` in standard backends" above for concrete examples of this.

docs/EXAMPLES.md

@@ -3,7 +3,7 @@ _(You may browse this at https://github.com/ocornut/imgui/blob/master/docs/EXAMP
 ## Dear ImGui: Examples
 
 **The [examples/](https://github.com/ocornut/imgui/blob/master/examples) folder example applications (standalone, ready-to-build) for variety of
-platforms and graphics APIs.** They all use standard backends from the [backends/](https://github.com/ocornut/imgui/blob/master/backends) folder (see [BACKENDS.md](https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md)).
+platforms and graphics APIs.** They all use standard backends from the [backends/](https://github.com/ocornut/imgui/blob/master/backends) folder (see [docs/BACKENDS.md](https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md)).
 
 The purpose of Examples is to showcase integration with backends, let you try Dear ImGui, and guide you toward
 integrating Dear ImGui in your own application/game/engine.
@@ -58,7 +58,7 @@ Allegro 5 example. <BR>
 Android + OpenGL3 (ES) example. <BR>
 = main.cpp + imgui_impl_android.cpp + imgui_impl_opengl3.cpp
 
-[example_apple_metal/](https://github.com/ocornut/imgui/blob/master/examples/example_metal/) <BR>
+[example_apple_metal/](https://github.com/ocornut/imgui/tree/master/examples/example_apple_metal/) <BR>
 OSX & iOS + Metal example. <BR>
 = main.m + imgui_impl_osx.mm + imgui_impl_metal.mm <BR>
 It is based on the "cross-platform" game template provided with Xcode as of Xcode 9.
@@ -149,6 +149,10 @@ SDL2 (Win32, Mac, Linux, etc.) + Vulkan example. <BR>
 This is quite long and tedious, because: Vulkan. <BR>
 For this example, the main.cpp file exceptionally use helpers function from imgui_impl_vulkan.h/cpp.
 
+[example_sdl3_metal/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl3_metal/) <BR>
+SDL3 + Metal example (Mac). <BR>
+= main.cpp + imgui_impl_sdl3.cpp + imgui_impl_metal.mm <BR>
+
 [example_sdl3_opengl3/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl3_opengl3/) <BR>
 SDL3 (Win32, Mac, Linux, etc.) + OpenGL3+/ES2/ES3 example. <BR>
 = main.cpp + imgui_impl_sdl3.cpp + imgui_impl_opengl3.cpp <BR>

docs/FAQ.md

@@ -19,12 +19,13 @@ or view this file with any Markdown viewer.
 | **[How can I tell whether to dispatch mouse/keyboard to Dear ImGui or my application?](#q-how-can-i-tell-whether-to-dispatch-mousekeyboard-to-dear-imgui-or-my-application)** |
 | [How can I enable keyboard or gamepad controls?](#q-how-can-i-enable-keyboard-or-gamepad-controls) |
 | [How can I use this on a machine without mouse, keyboard or screen? (input share, remote display)](#q-how-can-i-use-this-on-a-machine-without-mouse-keyboard-or-screen-input-share-remote-display) |
+| [How can I create my own backend?](#q-how-can-i-create-my-own-backend)
 | [I integrated Dear ImGui in my engine and little squares are showing instead of text...](#q-i-integrated-dear-imgui-in-my-engine-and-little-squares-are-showing-instead-of-text) |
 | [I integrated Dear ImGui in my engine and some elements are clipping or disappearing when I move windows around...](#q-i-integrated-dear-imgui-in-my-engine-and-some-elements-are-clipping-or-disappearing-when-i-move-windows-around) |
 | [I integrated Dear ImGui in my engine and some elements are displaying outside their expected windows boundaries...](#q-i-integrated-dear-imgui-in-my-engine-and-some-elements-are-displaying-outside-their-expected-windows-boundaries) |
 | **Q&A: Usage** |
 | **[About the ID Stack system..<br>Why is my widget not reacting when I click on it?<br>Why is the wrong widget reacting when I click on one?<br>How can I have widgets with an empty label?<br>How can I have multiple widgets with the same label?<br>How can I have multiple windows with the same label?](#q-about-the-id-stack-system)** |
-| [How can I display an image? What is ImTextureID, how does it work?](#q-how-can-i-display-an-image-what-is-imtextureid-how-does-it-work)|
+| [How can I display an image?](#q-how-can-i-display-an-image)<br>[What are ImTextureID/ImTextureRef?](#q-what-are-imtextureidimtextureref)|
 | [How can I use maths operators with ImVec2?](#q-how-can-i-use-maths-operators-with-imvec2) |
 | [How can I use my own maths types instead of ImVec2/ImVec4?](#q-how-can-i-use-my-own-maths-types-instead-of-imvec2imvec4) |
 | [How can I interact with standard C++ types (such as std::string and std::vector)?](#q-how-can-i-interact-with-standard-c-types-such-as-stdstring-and-stdvector) |
@@ -92,8 +93,8 @@ Many projects are using this branch and it is kept in sync with master regularly
 ### Q: How to get started?
 
 Read [Getting Started](https://github.com/ocornut/imgui/wiki/Getting-Started). <BR>
-Read [EXAMPLES.md](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md). <BR>
-Read [BACKENDS.md](https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md). <BR>
+Read [docs/EXAMPLES.md](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md). <BR>
+Read [docs/BACKENDS.md](https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md). <BR>
 Read `PROGRAMMER GUIDE` section of [imgui.cpp](https://github.com/ocornut/imgui/blob/master/imgui.cpp). <BR>
 The [Wiki](https://github.com/ocornut/imgui/wiki) is a hub to many resources and links.
 
@@ -159,9 +160,18 @@ Console SDK also sometimes provide equivalent tooling or wrapper for Synergy-lik
 
 ---
 
+### Q: How can I create my own backend?
+- See [docs/BACKENDS.md](https://github.com/ocornut/imgui/blob/master/docs/BACKENDS.md).
+- See Documentation at the top of imgui.cpp.
+
+##### [Return to Index](#index)
+
+---
+
 ### Q: I integrated Dear ImGui in my engine and little squares are showing instead of text...
 Your renderer backend is not using the font texture correctly or it hasn't been uploaded to the GPU.
-- If this happens using the standard backends: A) have you modified the font atlas after `ImGui_ImplXXX_NewFrame()`? B) maybe the texture failed to upload, which **can if your texture atlas is too big**. Also see [docs/FONTS.md](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md).
+- If this happens using standard backends (before 1.92): A) have you modified the font atlas after `ImGui_ImplXXX_NewFrame()`? B) maybe the texture failed to upload, which **can if your texture atlas is too big**. Also see [docs/FONTS.md](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md).
+- If this happens using standard backends (after 1.92): please report.
 - If this happens with a custom backend: make sure you have uploaded the font texture to the GPU, that all shaders are rendering states are setup properly (e.g. texture is bound). Compare your code to existing backends and use a graphics debugger such as [RenderDoc](https://renderdoc.org) to debug your rendering states.
 
 ##### [Return to Index](#index)
@@ -375,23 +385,73 @@ node open/closed state differently. See what makes more sense in your situation!
 
 ---
 
-### Q: How can I display an image? What is ImTextureID, how does it work?
+### Q: How can I display an image?
+### Q: What are ImTextureID/ImTextureRef?
 
-Short explanation:
-- Refer to [Image Loading and Displaying Examples](https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples) on the [Wiki](https://github.com/ocornut/imgui/wiki).
+**Short explanation:**
 - You may use functions such as `ImGui::Image()`, `ImGui::ImageButton()` or lower-level `ImDrawList::AddImage()` to emit draw calls that will use your own textures.
+- To load and display your own textures, refer to [Image Loading and Displaying Examples](https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples) on the [Wiki](https://github.com/ocornut/imgui/wiki).
 - Actual textures are identified in a way that is up to the user/engine. Those identifiers are stored and passed as an opaque ImTextureID value.
 - By default ImTextureID can store up to 64-bits. You may `#define` it to a custom type/structure if you need.
 - Loading image files from the disk and turning them into a texture is not within the scope of Dear ImGui (for a good reason), but the examples linked above may be useful references.
 
+**Details:**
+
+1.92 introduced `ImTextureRef` in June 2025.
+- All drawing functions using `ImTextureID` were changed to use `ImTextureRef`.
+- You can trivially create a `ImTextureRef` from a `ImTextureID`.
+- **If you use Image functions with textures that you have loaded/created yourself, you will mostly likely only ever store/manipulate `ImTextureID` and then pass them as `ImTextureRef`.**
+- You only NEED to manipulate `ImTextureRef` when dealing with textures managed by the backend itself, aka mainly the atlas texture for now.
+- We intentionally do not provide an implicit `ImTextureRef` -> `ImTextureID` cast operator because it is technically lossy to convert ImTextureRef to ImTextureID before rendering.
+
+**ImTextureID = backend specific, low-level identifier for a texture uploaded in GPU/graphics system.**
+```cpp
+#ifndef ImTextureID
+typedef ImU64 ImTextureID;  // Default: store up to 64-bits (any pointer or integer). A majority of backends are ok with that.
+#endif
+```
+- When a Rendered Backend creates a texture, it store its native identifier into a ImTextureID value (e.g. Used by DX11 backend to a `ID3D11ShaderResourceView*`; Used by OpenGL backends to store `GLuint`; Used by SDLGPU backend to store a `SDL_GPUTextureSamplerBinding*`, etc.).
+- User may submit their own textures to e.g. `ImGui::Image()` function by passing this value.
+- During the rendering loop, the Renderer Backend retrieve the ImTextureID, which stored inside a ImTextureRef, which is stored inside ImDrawCmd.
+- Compile-time type configuration:
+  - To use something other than a 64-bit value: add '#define ImTextureID MyTextureType*' in your imconfig.h file.
+  - This can be whatever to you want it to be! read the FAQ entry about textures for details.
+  - You may decide to store a higher-level structure containing texture, sampler, shader etc. with various constructors if you like. You will need to implement ==/!= operators.
+
+**ImTextureRef = higher-level identifier for a texture.**
+```cpp
+// Store a ImTextureID _or_ a ImTextureData*.
+struct ImTextureRef
+{
+    ImTextureRef()                          { _TexData = NULL; _TexID = ImTextureID_Invalid; }
+    ImTextureRef(ImTextureID tex_id)        { _TexData = NULL; _TexID = tex_id; }
+    inline ImTextureID  GetTexID() const    { return _TexData ? _TexData->TexID : _TexID; }
+
+    // Members (either are set, never both!)
+    ImTextureData*      _TexData;           //      A texture, generally owned by a ImFontAtlas. Will convert to ImTextureID during render loop, after texture has been uploaded.
+    ImTextureID         _TexID;             // _OR_ Low-level backend texture identifier, if already uploaded or created by user/app. Generally provided to e.g. ImGui::Image() calls.
+};
+```
+- The identifier is valid even before the texture has been uploaded to the GPU/graphics system.
+- This is what gets passed to functions such as `ImGui::Image()`, `ImDrawList::AddImage()`.
+- This is what gets stored in draw commands (`ImDrawCmd`) to identify a texture during rendering.
+ - When a texture is created by user code (e.g. custom images), we directly store the low-level `ImTextureID`.
+   - Because of this, when displaying your own texture you are likely to ever only manage ImTextureID values on your side.
+ - When a texture is created by the backend, we store a `ImTextureData*` which becomes an indirection to extract the `ImTextureID` value during rendering, after texture upload has happened.
+ - To create a `ImTextureRef` from a `ImTextureData*` you can use `ImTextureData::GetTexRef()`.
+   We intentionally do not provide an `ImTextureRef` constructor for this: we don't expect this to be frequently useful to the end-user, and it would be erroneously called by many legacy code.
+ - There is no constructor to create a `ImTextureRef` from a `ImTextureData*` as we don't expect this to be useful to the end-user, and it would be erroneously called by many legacy code.
+ - If you want to bind the current atlas when using custom rectangles, you can use `io.Fonts->TexRef`.
+ - Binding generators for languages such as C (which don't have constructors), should provide a helper, e.g. `inline ImTextureRef ImTextureRefFromID(ImTextureID tex_id) { ImTextureRef tex_ref = { ._TexData = NULL, .TexID = tex_id }; return tex_ref; }`
+
 **Please read documentations or tutorials on your graphics API to understand how to display textures on the screen before moving onward.**
 
 Long explanation:
 - Dear ImGui's job is to create "meshes", defined in a renderer-agnostic format made of draw commands and vertices. At the end of the frame, those meshes (ImDrawList) will be displayed by your rendering function. They are made up of textured polygons and the code to render them is generally fairly short (a few dozen lines). In the examples/ folder, we provide functions for popular graphics APIs (OpenGL, DirectX, etc.).
 - Each rendering function decides on a data type to represent "textures". The concept of what is a "texture" is entirely tied to your underlying engine/graphics API.
- We carry the information to identify a "texture" in the ImTextureID type.
+We carry the information to identify a "texture" in the ImTextureID type, which itself tends to be stored inside a ImTextureRef.
 ImTextureID default to ImU64 aka 8 bytes worth of data: just enough to store one pointer or integer of your choice.
-Dear ImGui doesn't know or understand what you are storing in ImTextureID, it merely passes ImTextureID values until they reach your rendering function.
+Dear ImGui doesn't know or understand what you are storing in ImTextureID, it merely passes values until they reach your rendering function.
 - In the [examples/](https://github.com/ocornut/imgui/tree/master/examples) backends, for each graphics API we decided on a type that is likely to be a good representation for specifying an image from the end-user perspective. This is what the _examples_ rendering functions are using:
 ```cpp
 OpenGL:
@@ -539,30 +599,49 @@ ImGui::End();
 
 ### Q: How should I handle DPI in my application?
 
-The short answer is: obtain the desired DPI scale, load your fonts resized with that scale (always round down fonts size to the nearest integer), and scale your Style structure accordingly using `style.ScaleAllSizes()`.
+Since 1.92 (June 2025) fonts may be dynamically used at any size.
 
-Your application may want to detect DPI change and reload the fonts and reset style between frames.
+**Scaling fonts**
+
+To change font size:
+```cpp
+ImGui::PushFont(NULL, 42.0f);
+```
+To change font and font size:
+```cpp
+ImGui::PushFont(new_font, 42.0f);
+```
+To scale all fonts:
+```cpp
+style.FontScaleDpi = 2.0f;
+```
+In `docking` branch or with multi-viewports:
+```cpp
+io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+```
+
+**Scaling style** (paddings, spacings, thicknesses)
+
+This is still massively work in progress, expect turbulence.
+Style values are currently not easily scalable dynamically.
+For single viewport application you can call once:
+```cpp
+style.ScaleAllSizes(factor); // call once!
+```
+If you need to change the scaling factor, it is currently most practical to reset the style and call this again with a new value.
 
 Your UI code should avoid using hardcoded constants for size and positioning. Prefer to express values as multiple of reference values such as `ImGui::GetFontSize()` or `ImGui::GetFrameHeight()`. So e.g. instead of seeing a hardcoded height of 500 for a given item/window, you may want to use `30*ImGui::GetFontSize()` instead.
 
-Down the line Dear ImGui will provide a variety of standardized reference values to facilitate using this.
+Down the line Dear ImGui will provide a variety of standardized reference values to facilitate using this. This is expected to happen during subsequent 1.92.x releases.
 
-Applications in the `examples/` folder are not DPI aware partly because they are unable to load a custom font from the file-system (may change that in the future).
+Applications in the `examples/` folder are partly DPI aware but they are unable to load a custom font from the file-system, so they look ugly (may change that in the future).
 
-The reason DPI is not auto-magically solved in stock examples is that we don't yet have a satisfying solution for the "multi-dpi" problem (using the `docking` branch: when multiple viewport windows are over multiple monitors using different DPI scales). The current way to handle this on the application side is:
-- Create and maintain one font atlas per active DPI scale (e.g. by iterating `platform_io.Monitors[]` before `NewFrame()`).
-- Hook `platform_io.OnChangedViewport()` to detect when a `Begin()` call makes a Dear ImGui window change monitor (and therefore DPI).
-- In the hook: swap atlas, swap style with correctly sized one, and remap the current font from one atlas to the other (you may need to maintain a remapping table of your fonts at varying DPI scales).
+The reason DPI is not auto-magically solved in stock examples is that we don't yet have a satisfying solution for the "multi-dpi" problem (using the `docking` branch: when multiple viewport windows are over multiple monitors using different DPI scales) specifically for the `ImGuiStyle` structure. Fonts are however now perfectly scalable.
 
-This approach is relatively easy and functional but comes with two issues:
-- It's not possibly to reliably size or position a window ahead of `Begin()` without knowing on which monitor it'll land.
-- Style override may be lost during the `Begin()` call crossing monitor boundaries. You may need to do some custom scaling mumbo-jumbo if you want your `OnChangedViewport()` handler to preserve style overrides.
-
-Please note that if you are not using multi-viewports with multi-monitors using different DPI scales, you can ignore that and use the simpler technique recommended at the top.
-
-On Windows, in addition to scaling the font size (make sure to round to an integer) and using `style.ScaleAllSizes()`, you will need to inform Windows that your application is DPI aware. If this is not done, Windows will scale the application window and the UI text will be blurry. Potential solutions to indicate DPI awareness on Windows are:
-
-- For SDL2: the flag `SDL_WINDOW_ALLOW_HIGHDPI` needs to be passed to `SDL_CreateWindow()`.
+**On Windows, you need to inform Windows that your application is DPI aware!**
+If this is not done, Windows will scale the application window and the UI text will be blurry. Potential solutions to indicate DPI awareness on Windows are:
+- For SDL2: the flag `SDL_WINDOW_ALLOW_HIGHDPI` needs to be passed to `SDL_CreateWindow()` + call `::SetProcessDPIAware()`.
 - For SDL3: the flag `SDL_WINDOW_HIGH_PIXEL_DENSITY` needs to be passed to `SDL_CreateWindow()`.
 - For GLFW: this is done automatically.
 - For other Windows projects with other backends, or wrapper projects:
@@ -615,9 +694,12 @@ Use the font atlas to pack them into a single texture. Read [docs/FONTS.md](http
 ---
 
 ### Q: How can I display and input non-Latin characters such as Chinese, Japanese, Korean, Cyrillic?
-When loading a font, pass custom Unicode ranges to specify the glyphs to load.
 
+Since 1.92 (June 2025) and with an updated backend, it is not necessary to specify glyph ranges at all.
+
+Before 1.92, when loading a font, pass custom Unicode ranges to specify the glyphs to load.
 ```cpp
+// [BEFORE 1.92]
 // Add default Japanese ranges
 io.Fonts->AddFontFromFileTTF("myfontfile.ttf", size_in_pixels, nullptr, io.Fonts->GetGlyphRangesJapanese());
 
@@ -641,8 +723,8 @@ Text input: it is up to your application to pass the right character code by cal
 The applications in examples/ are doing that.
 Windows: you can use the WM_CHAR or WM_UNICHAR or WM_IME_CHAR message (depending if your app is built using Unicode or MultiByte mode).
 You may also use `MultiByteToWideChar()` or `ToUnicode()` to retrieve Unicode codepoints from MultiByte characters or keyboard state.
-Windows: if your language is relying on an Input Method Editor (IME), you can write your HWND to ImGui::GetMainViewport()->PlatformHandleRaw
-for the default implementation of GetPlatformIO().Platform_SetImeDataFn() to set your Microsoft IME position correctly.
+Windows: if your language is relying on an Input Method Editor (IME), you can write your HWND to `ImGui::GetMainViewport()->PlatformHandleRaw`
+for the default implementation of `GetPlatformIO().Platform_SetImeDataFn()` to set your Microsoft IME position correctly.
 
 ##### [Return to Index](#index)
 

docs/FONTS.md

@@ -2,7 +2,7 @@ _(You may browse this at https://github.com/ocornut/imgui/blob/master/docs/FONTS
 
 ## Dear ImGui: Using Fonts
 
-The code in imgui.cpp embeds a copy of 'ProggyClean.ttf' (by Tristan Grimmer),
+The code in imgui.cpp embeds a copy of [ProggyClean.ttf](http://proggyfonts.net) (by Tristan Grimmer),
 a 13 pixels high, pixel-perfect font used by default. We embed it in the source code so you can use Dear ImGui without any file system access. ProggyClean does not scale smoothly, therefore it is recommended that you load your own file when using Dear ImGui in an application aiming to look nice and wanting to support multiple resolutions.
 
 You may also load external .TTF/.OTF files.
@@ -12,11 +12,13 @@ In the [misc/fonts/](https://github.com/ocornut/imgui/tree/master/misc/fonts) fo
 
 ## Index
 - [Troubleshooting](#troubleshooting)
+- [New! Dynamic Fonts system in 1.92 (June 2025)](#new-dynamic-fonts-system-in-192-june-2025)
 - [How should I handle DPI in my application?](#how-should-i-handle-dpi-in-my-application)
 - [Fonts Loading Instructions](#fonts-loading-instructions)
 - [Loading Font Data from Memory](#loading-font-data-from-memory)
 - [Loading Font Data Embedded In Source Code](#loading-font-data-embedded-in-source-code)
 - [Using Icon Fonts](#using-icon-fonts)
+  - [Excluding Overlapping Ranges](#excluding-overlapping-ranges)
 - [Using FreeType Rasterizer (imgui_freetype)](#using-freetype-rasterizer-imgui_freetype)
 - [Using Colorful Glyphs/Emojis](#using-colorful-glyphsemojis)
 - [Using Custom Glyph Ranges](#using-custom-glyph-ranges)
@@ -35,7 +37,7 @@ In the [misc/fonts/](https://github.com/ocornut/imgui/tree/master/misc/fonts) fo
 
 ### (1) Invalid filename due to use of `\` or unexpected working directory.
 
-See [About Filenames](#about-filenames). AddFontXXX functions should assert if the filename is incorrect.
+See [About Filenames](#about-filenames). AddFontXXX() functions should assert if the filename is incorrect.
 
 ### (2) Invalid UTF-8 encoding of your non-ASCII strings.
 
@@ -43,14 +45,18 @@ See [About UTF-8 Encoding](#about-utf-8-encoding). Use the encoding viewer to co
 
 ### (3) Missing glyph ranges.
 
-You need to load a font with explicit glyph ranges if you want to use non-ASCII characters. See [Fonts Loading Instructions](#fonts-loading-instructions). Use [Debug Tools](#debug-tools) confirm loaded fonts and loaded glyph ranges.
+🆕 **Since 1.92, with an up to date backend: specifying glyph ranges is unnecessary.**
 
-This is a current constraint of Dear ImGui (which we will lift in the future): when loading a font you need to specify which characters glyphs to load.
+⏪ Before 1.92: you need to load a font with explicit glyph ranges if you want to use non-ASCII characters. See [Fonts Loading Instructions](#fonts-loading-instructions). Use [Debug Tools](#debug-tools) confirm loaded fonts and loaded glyph ranges.
+
+This was a previous  constraint of Dear ImGui (lifted in 1.92): when loading a font you need to specify which characters glyphs to load.
 All loaded fonts glyphs are rendered into a single texture atlas ahead of time. Calling either of `io.Fonts->GetTexDataAsAlpha8()`, `io.Fonts->GetTexDataAsRGBA32()` or `io.Fonts->Build()` will build the atlas. This is generally called by the Renderer backend, e.g. `ImGui_ImplDX11_NewFrame()` calls it. **If you use custom glyphs ranges, make sure the array is persistent** and available during the calls to `GetTexDataAsAlpha8()/GetTexDataAsRGBA32()/Build()`.
 
 ### (4) Font atlas texture fails to upload to GPU.
 
-This is often of byproduct of point 3. If you have large number of glyphs or multiple fonts, the texture may become too big for your graphics API. **The typical result of failing to upload a texture is if every glyph or everything appears as empty white rectangles.** Mind the fact that some graphics drivers have texture size limitation. If you are building a PC application, mind the fact that your users may use hardware with lower limitations than yours.
+🆕 **Since 1.92, with an up to date backend: atlas is built incrementally and dynamically resized, this is less likely to happen**
+
+:rewind: This is often of byproduct of point 3. If you have large number of glyphs or multiple fonts, the texture may become too big for your graphics API. **The typical result of failing to upload a texture is if every glyph or everything appears as empty white rectangles.** Mind the fact that some graphics drivers have texture size limitation. If you are building a PC application, mind the fact that your users may use hardware with lower limitations than yours.
 
 ![empty squares](https://github.com/user-attachments/assets/68b50fb5-8b9d-4c38-baec-6ac384f06d26)
 
@@ -60,9 +66,22 @@ Some solutions:
 - Reduce glyphs ranges by calculating them from source localization data.
   You can use the `ImFontGlyphRangesBuilder` for this purpose and rebuilding your atlas between frames when new characters are needed. This will be the biggest win!
 - Set `io.Fonts.Flags |= ImFontAtlasFlags_NoPowerOfTwoHeight;` to disable rounding the texture height to the next power of two.
-- Set `io.Fonts.TexDesiredWidth` to specify a texture width to reduce maximum texture height (see comment in `ImFontAtlas::Build()` function).
 
-Future versions of Dear ImGui should solve this problem.
+##### [Return to Index](#index)
+
+---------------------------------------
+
+## New! Dynamic Fonts system in 1.92 (June 2025)
+
+v1.92 introduces a newer, dynamic font system. It requires backend to support the `ImGuiBackendFlags_HasTextures` feature:
+- Users of icons, Asian and non-English languages do not need to pre-build all glyphs ahead of time. Saving on loading time, memory, and also reducing issues with missing glyphs. Specifying glyph ranges is not needed anymore.
+- `PushFont(NULL, new_size)` may be used anytime to change font size.
+- Packing custom rectangles is more convenient as pixels may be written to immediately.
+- Any update to fonts previously required backend specific calls to re-upload the texture, and said calls were not portable across backends. It is now possible to scale fonts etc. in a way that doesn't require you to make backend-specific calls.
+- It is possible to plug a custom loader/backend to any font source.
+
+See [#8465](https://github.com/ocornut/imgui/issues/8465) for more details.
+
 
 ##### [Return to Index](#index)
 
@@ -85,6 +104,13 @@ io.Fonts->AddFontDefault();
 ```
 
 **Load .TTF/.OTF file with:**
+
+🆕 **Since 1.92, with an up to date backend: passing a size is not necessary**
+```cpp
+ImGuiIO& io = ImGui::GetIO();
+io.Fonts->AddFontFromFileTTF("font.ttf");
+```
+:rewind: **Before 1.92, or without an up to date backend:**
 ```cpp
 ImGuiIO& io = ImGui::GetIO();
 io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels);
@@ -95,14 +121,14 @@ If you get an assert stating "Could not load font file!", your font filename is
 ```cpp
 // Init
 ImGuiIO& io = ImGui::GetIO();
-ImFont* font1 = io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels);
-ImFont* font2 = io.Fonts->AddFontFromFileTTF("anotherfont.otf", size_pixels);
+ImFont* font1 = io.Fonts->AddFontFromFileTTF("font.ttf",);
+ImFont* font2 = io.Fonts->AddFontFromFileTTF("anotherfont.otf");
 ```
 
 In your application loop, select which font to use:
 ```cpp
 ImGui::Text("Hello"); // use the default font (which is the first loaded font)
-ImGui::PushFont(font2);
+ImGui::PushFont(font2, 0.0f); // change font, keep current size
 ImGui::Text("Hello with another font");
 ImGui::PopFont();
 ```
@@ -110,11 +136,22 @@ ImGui::PopFont();
 **For advanced options create a ImFontConfig structure and pass it to the AddFont() function (it will be copied internally):**
 ```cpp
 ImFontConfig config;
-config.RasterizerDensity = 2.0f;
+config.OversampleH = 1.0f;
 ImFont* font = io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels, &config);
 ```
 
 **Combine multiple fonts into one:**
+
+🆕 **Since 1.92, with an up to date backend: specifying glyph ranges is unnecessary.**
+```cpp
+// Load a first font
+ImFont* font = io.Fonts->AddFontDefault();
+ImFontConfig config;
+config.MergeMode = true;
+io.Fonts->AddFontFromFileTTF("DroidSans.ttf", 0.0f, &config);           // Merge into first font to add e.g. Asian characters
+io.Fonts->AddFontFromFileTTF("fontawesome-webfont.ttf", 0.0f, &config); // Merge into first font to add Icons
+```
+:rewind: **Before 1.92, or without an up to date backend:**
 ```cpp
 // Load a first font
 ImFont* font = io.Fonts->AddFontDefault();
@@ -132,6 +169,7 @@ io.Fonts->Build();
 
 **Add a fourth parameter to bake specific font ranges only:**
 
+🆕 **Since 1.92, with an up to date backend: specifying glyph ranges is unnecessary. All the GetGlyphRangesXXX() functions are marked obsolete.**
 ```cpp
 // Basic Latin, Extended Latin
 io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels, nullptr, io.Fonts->GetGlyphRangesDefault());
@@ -146,10 +184,18 @@ See [Using Custom Glyph Ranges](#using-custom-glyph-ranges) section to create yo
 
 **Example loading and using a Japanese font:**
 
+🆕 **Since 1.92, with an up to date backend:**
+```cpp
+ImGuiIO& io = ImGui::GetIO();
+io.Fonts->AddFontFromFileTTF("NotoSansCJKjp-Medium.otf");
+```
+
+:rewind: **Before 1.92, or without an up to date backend:**
 ```cpp
 ImGuiIO& io = ImGui::GetIO();
 io.Fonts->AddFontFromFileTTF("NotoSansCJKjp-Medium.otf", 20.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
 ```
+
 ```cpp
 ImGui::Text(u8"こんにちは！テスト %d", 123);
 if (ImGui::Button(u8"ロード"))
@@ -216,12 +262,24 @@ To refer to the icon UTF-8 codepoints from your C++ code, you may use those head
 
 So you can use `ICON_FA_SEARCH` as a string that will render as a "Search" icon.
 
+🆕 **Since 1.92, with an up to date backend: specifying glyph ranges is unnecessary. You can omit this parameter.**
 Example Setup:
 ```cpp
 // Merge icons into default tool font
 #include "IconsFontAwesome.h"
 ImGuiIO& io = ImGui::GetIO();
 io.Fonts->AddFontDefault();
+ImFontConfig config;
+config.MergeMode = true;
+config.GlyphMinAdvanceX = 13.0f; // Use if you want to make the icon monospaced
+io.Fonts->AddFontFromFileTTF("fonts/fontawesome-webfont.ttf", 13.0f, &config);
+```
+:rewind: **Before 1.92:**
+```cpp
+// Merge icons into default tool font
+#include "IconsFontAwesome.h"
+ImGuiIO& io = ImGui::GetIO();
+io.Fonts->AddFontDefault();
 
 ImFontConfig config;
 config.MergeMode = true;
@@ -241,7 +299,8 @@ See Links below for other icons fonts and related tools.
 
 **Monospace Icons?**
 
-To make your icon look more monospace and facilitate alignment, you may want to set the ImFontConfig::GlyphMinAdvanceX value when loading an icon font.
+To make your icon look more monospace and facilitate alignment, you may want to set the `ImFontConfig::GlyphMinAdvanceX` value when loading an icon font.
+If you `GlyphMinAdvanceX` you need to pass a `font_size` to `AddFontXXX()` calls, as the MinAdvanceX value will be specified for the given size and scaled otherwise.
 
 **Screenshot**
 
@@ -252,11 +311,49 @@ Here's an application using icons ("Avoyd", https://www.avoyd.com):
 
 ---------------------------------------
 
+### Excluding Overlapping Ranges
+
+🆕 **Since 1.92, with an up to date backend: glyphs ranges are ignored**: when loading a glyph, input fonts in the merge list are queried in order. The first font which has the glyph loads it.
+<BR>‼️ **If you are merging several fonts, you may have undesirable overlapping ranges.** You can use `ImFontConfig::GlyphExcludeRanges[] `to specify ranges to ignore in a given Input.
+
+```cpp
+// Add Font Source 1 but ignore ICON_MIN_FA..ICON_MAX_FA range
+static ImWchar exclude_ranges[] = { ICON_MIN_FA, ICON_MAX_FA, 0 };
+ImFontConfig cfg1;
+cfg1.GlyphExcludeRanges = exclude_ranges;
+io.Fonts->AddFontFromFileTTF("segoeui.ttf", 0.0f, &cfg1);
+
+// Add Font Source 2, which expects to use the range above
+ImFontConfig cfg2;
+cfg2.MergeMode = true;
+io.Fonts->AddFontFromFileTTF("FontAwesome4.ttf", 0.0f, &cfg2);
+```
+Another (silly) example:
+```cpp
+// Remove 'A'-'Z' from first font
+static ImWchar exclude_ranges[] = { 'A', 'Z', 0 };
+ImFontConfig cfg1;
+cfg1.GlyphExcludeRanges = exclude_ranges;
+io.Fonts->AddFontFromFileTTF("segoeui.ttf", 0.0f, &cfg1);
+
+// Load another font to fill the gaps
+ImFontConfig cfg2;
+cfg2.MergeMode = true;
+io.Fonts->AddFontFromFileTTF("Roboto-Medium.ttf", 0.0f, &cfg2);
+```
+![image](https://github.com/user-attachments/assets/f3d751d3-1aee-4698-bd9b-f511902f56bb)
+
+You can use `Metrics/Debugger->Fonts->Font->Input Glyphs Overlap Detection Tool` to see list of glyphs available in multiple font sources. This can facilitate understanding which font input is providing which glyph.
+
+##### [Return to Index](#index)
+
+---------------------------------------
+
 ## Using FreeType Rasterizer (imgui_freetype)
 
-- Dear ImGui uses imstb\_truetype.h to rasterize fonts (with optional oversampling). This technique and its implementation are not ideal for fonts rendered at small sizes, which may appear a little blurry or hard to read.
-- There is an implementation of the ImFontAtlas builder using FreeType that you can use in the [misc/freetype/](https://github.com/ocornut/imgui/tree/master/misc/freetype) folder.
-- FreeType supports auto-hinting which tends to improve the readability of small fonts.
+- Dear ImGui uses [stb_truetype.h](https://github.com/nothings/stb/) to rasterize fonts (with optional oversampling). This technique and its implementation are not ideal for fonts rendered at small sizes, which may appear a little blurry or hard to read.
+- You can however use `imgui_freetype.cpp` from the [misc/freetype/](https://github.com/ocornut/imgui/tree/master/misc/freetype) folder. Compile with this file and add `#define IMGUI_ENABLE_FREETYPE` to your imconfig.h file or build system to automatically activate it.
+- FreeType supports auto-hinting which tends to improve the readability of small fonts. It makes a big difference especially at smaller resolutions.
 - Read documentation in the [misc/freetype/](https://github.com/ocornut/imgui/tree/master/misc/freetype) folder.
 - Correct sRGB space blending will have an important effect on your font rendering quality.
 
@@ -278,10 +375,9 @@ Here's an application using icons ("Avoyd", https://www.avoyd.com):
 io.Fonts->AddFontFromFileTTF("../../../imgui_dev/data/fonts/NotoSans-Regular.ttf", 16.0f);
 static ImWchar ranges[] = { 0x1, 0x1FFFF, 0 };
 static ImFontConfig cfg;
-cfg.OversampleH = cfg.OversampleV = 1;
 cfg.MergeMode = true;
-cfg.FontBuilderFlags |= ImGuiFreeTypeBuilderFlags_LoadColor;
-io.Fonts->AddFontFromFileTTF("C:\\Windows\\Fonts\\seguiemj.ttf", 16.0f, &cfg, ranges);
+cfg.FontLoaderFlags |= ImGuiFreeTypeLoaderFlags_LoadColor;
+io.Fonts->AddFontFromFileTTF("C:\\Windows\\Fonts\\seguiemj.ttf", 16.0f, &cfg);
 ```
 
 ##### [Return to Index](#index)
@@ -290,7 +386,9 @@ io.Fonts->AddFontFromFileTTF("C:\\Windows\\Fonts\\seguiemj.ttf", 16.0f, &cfg, ra
 
 ## Using Custom Glyph Ranges
 
-You can use the `ImFontGlyphRangesBuilder` helper to create glyph ranges based on text input. For example: for a game where your script is known, if you can feed your entire script to it and only build the characters the game needs.
+🆕 **Since 1.92, with an up to date backend: specifying glyph ranges is unnecessary. Therefore this is not really useful any more.**
+
+:rewind: You can use the `ImFontGlyphRangesBuilder` helper to create glyph ranges based on text input. For example: for a game where your script is known, if you can feed your entire script to it and only build the characters the game needs.
 ```cpp
 ImVector<ImWchar> ranges;
 ImFontGlyphRangesBuilder builder;
@@ -309,10 +407,19 @@ io.Fonts->Build();                                     // Build the atlas while
 
 ## Using Custom Colorful Icons
 
+🆕 **Since 1.92, with an up to date backend: this system has been revamped.**
+
+TL;DR; With the new system, it is recommended that you create a custom `ImFontLoader` and register your fonts with it.
+`AddCustomRectFontGlyph()` has been obsoleted because its API does not make much sense with resizable fonts.
+
+You can ask questions in [#8466](https://github.com/ocornut/imgui/issues/8466).
+
+:rewind: **Before 1.92:**
+
 As an alternative to rendering colorful glyphs using imgui_freetype with `ImGuiFreeTypeBuilderFlags_LoadColor`, you may allocate your own space in the texture atlas and write yourself into it. **(This is a BETA api, use if you are familiar with dear imgui and with your rendering backend)**
 
 - You can use the `ImFontAtlas::AddCustomRect()` and `ImFontAtlas::AddCustomRectFontGlyph()` api to register rectangles that will be packed into the font atlas texture. Register them before building the atlas, then call Build()`.
-- You can then use `ImFontAtlas::GetCustomRectByIndex(int)` to query the position/size of your rectangle within the texture, and blit/copy any graphics data of your choice into those rectangles.
+- You can then use `ImFontAtlas::GetCustomRect(int)` to query the position/size of your rectangle within the texture, and blit/copy any graphics data of your choice into those rectangles.
 - This API is beta because it is likely to change in order to support multi-dpi (multiple viewports on multiple monitors with varying DPI scale).
 
 #### Pseudo-code:
@@ -332,9 +439,7 @@ int tex_width, tex_height;
 io.Fonts->GetTexDataAsRGBA32(&tex_pixels, &tex_width, &tex_height);
 
 for (int rect_n = 0; rect_n < IM_ARRAYSIZE(rect_ids); rect_n++)
-{
-    int rect_id = rect_ids[rect_n];
-    if (const ImFontAtlasCustomRect* rect = io.Fonts->GetCustomRectByIndex(rect_id))
+    if (const ImTextureRect* rect = io.Fonts->GetCustomRect(rect_ids[rect_n]))
     {
         // Fill the custom rectangle with red pixels (in reality you would draw/copy your bitmap data here!)
         for (int y = 0; y < rect->Height; y++)
@@ -344,7 +449,6 @@ for (int rect_n = 0; rect_n < IM_ARRAYSIZE(rect_ids); rect_n++)
                 *p++ = IM_COL32(255, 0, 0, 255);
         }
     }
-}
 ```
 
 ##### [Return to Index](#index)
@@ -483,15 +587,18 @@ Some fonts files are available in the `misc/fonts/` folder:
 
 #### MONOSPACE FONTS
 
+<img width="1172" height="715" alt="image" src="https://github.com/user-attachments/assets/c9702534-4877-41c9-ae0d-252933c26ced" />
+
 Pixel Perfect:
 - Proggy Fonts, by Tristan Grimmer http://www.proggyfonts.net or http://upperboundsinteractive.com/fonts.php
 - Sweet16, Sweet16 Mono, by Martin Sedlak (Latin + Supplemental + Extended A) https://github.com/kmar/Sweet16Font (also include an .inl file to use directly in dear imgui.)
 
 Regular:
-- Google Noto Mono Fonts https://www.google.com/get/noto/
-- Typefaces for source code beautification https://github.com/chrissimpkins/codeface
-- Programmation fonts http://s9w.github.io/font_compare/
-- Inconsolata http://www.levien.com/type/myfonts/inconsolata.html
+- ProggyVector if you want the old school Dear ImGui font to scale: https://github.com/bluescan/proggyfonts
+- Google Noto Mono Fonts: https://www.google.com/get/noto/
+- Typefaces for source code beautification: https://github.com/chrissimpkins/codeface
+- Programmation fonts: http://s9w.github.io/font_compare/
+- Inconsolata: http://www.levien.com/type/myfonts/inconsolata.html
 - Adobe Source Code Pro: Monospaced font family for ui & coding environments https://github.com/adobe-fonts/source-code-pro
 - Monospace/Fixed Width Programmer's Fonts http://www.lowing.org/fonts/
 

docs/README.md

@@ -16,7 +16,7 @@ Businesses: support continued development and maintenance via invoiced sponsorin
 | [The Pitch](#the-pitch) - [Usage](#usage) - [How it works](#how-it-works) - [Releases & Changelogs](#releases--changelogs) - [Demo](#demo) - [Getting Started & Integration](#getting-started--integration) |
 :----------------------------------------------------------: |
 | [Gallery](#gallery) - [Support, FAQ](#support-frequently-asked-questions-faq) -  [How to help](#how-to-help) - **[Funding & Sponsors](https://github.com/ocornut/imgui/wiki/Funding)** - [Credits](#credits) - [License](#license) |
-| [Wiki](https://github.com/ocornut/imgui/wiki) - [Extensions](https://github.com/ocornut/imgui/wiki/Useful-Extensions) - [Languages bindings & frameworks backends](https://github.com/ocornut/imgui/wiki/Bindings) - [Software using Dear ImGui](https://github.com/ocornut/imgui/wiki/Software-using-dear-imgui) - [User quotes](https://github.com/ocornut/imgui/wiki/Quotes) |
+| [Wiki](https://github.com/ocornut/imgui/wiki) - [Extensions](https://github.com/ocornut/imgui/wiki/Useful-Extensions) - [Language bindings & framework backends](https://github.com/ocornut/imgui/wiki/Bindings) - [Software using Dear ImGui](https://github.com/ocornut/imgui/wiki/Software-using-dear-imgui) - [User quotes](https://github.com/ocornut/imgui/wiki/Quotes) |
 
 ### The Pitch
 
@@ -110,7 +110,7 @@ Reading the changelogs is a good way to keep up to date with the things Dear ImG
 Calling the `ImGui::ShowDemoWindow()` function will create a demo window showcasing a variety of features and examples. The code is always available for reference in `imgui_demo.cpp`. [Here's how the demo looks](https://raw.githubusercontent.com/wiki/ocornut/imgui/web/v167/v167-misc.png).
 
 You should be able to build the examples from sources. If you don't, let us know! If you want to have a quick look at some Dear ImGui features, you can download Windows binaries of the demo app here:
-- [imgui-demo-binaries-20241211.zip](https://www.dearimgui.com/binaries/imgui-demo-binaries-20241211.zip) (Windows, 1.91.6, built 2024/11/11, master) or [older binaries](https://www.dearimgui.com/binaries).
+- [imgui-demo-binaries-20250625.zip](https://www.dearimgui.com/binaries/imgui-demo-binaries-20250625.zip) (Windows, 1.92.0, built 2025/06/25, master) or [older binaries](https://www.dearimgui.com/binaries).
 
 The demo applications are not DPI aware so expect some blurriness on a 4K screen. For DPI awareness in your application, you can load/reload your font at a different scale and scale your style with `style.ScaleAllSizes()` (see [FAQ](https://www.dearimgui.com/faq)).
 
@@ -120,7 +120,7 @@ See the [Getting Started](https://github.com/ocornut/imgui/wiki/Getting-Started)
 
 On most platforms and when using C++, **you should be able to use a combination of the [imgui_impl_xxxx](https://github.com/ocornut/imgui/tree/master/backends) backends without modification** (e.g. `imgui_impl_win32.cpp` + `imgui_impl_dx11.cpp`). If your engine supports multiple platforms, consider using more imgui_impl_xxxx files instead of rewriting them: this will be less work for you, and you can get Dear ImGui running immediately. You can _later_ decide to rewrite a custom backend using your custom engine functions if you wish so.
 
-Integrating Dear ImGui within your custom engine is a matter of 1) wiring mouse/keyboard/gamepad inputs 2) uploading a texture to your GPU/render engine 3) providing a render function that can bind textures and render textured triangles, which is essentially what Backends are doing. The [examples/](https://github.com/ocornut/imgui/tree/master/examples) folder is populated with applications doing just that: setting up a window and using backends. If you follow the [Getting Started](https://github.com/ocornut/imgui/wiki/Getting-Started) guide it should in theory takes you less than an hour to integrate Dear ImGui.  **Make sure to spend time reading the [FAQ](https://www.dearimgui.com/faq), comments, and the examples applications!**
+Integrating Dear ImGui within your custom engine is a matter of 1) wiring mouse/keyboard/gamepad inputs 2) uploading a texture to your GPU/render engine 3) providing a render function that can bind textures and render textured triangles, which is essentially what Backends are doing. The [examples/](https://github.com/ocornut/imgui/tree/master/examples) folder is populated with applications doing just that: setting up a window and using backends. If you follow the [Getting Started](https://github.com/ocornut/imgui/wiki/Getting-Started) guide it should in theory take you less than an hour to integrate Dear ImGui.  **Make sure to spend time reading the [FAQ](https://www.dearimgui.com/faq), comments, and the examples applications!**
 
 Officially maintained backends/bindings (in repository):
 - Renderers: DirectX9, DirectX10, DirectX11, DirectX12, Metal, OpenGL/ES/ES2, SDL_GPU, SDL_Renderer2/3, Vulkan, WebGPU.
@@ -184,7 +184,7 @@ How to help
 - See [GitHub Forum/Issues](https://github.com/ocornut/imgui/issues).
 - You may help with development and submit pull requests! Please understand that by submitting a PR you are also submitting a request for the maintainer to review your code and then take over its maintenance forever. PR should be crafted both in the interest of the end-users and also to ease the maintainer into understanding and accepting it.
 - See [Help wanted](https://github.com/ocornut/imgui/wiki/Help-Wanted) on the [Wiki](https://github.com/ocornut/imgui/wiki/) for some more ideas.
-- Be a [Funding Supporter](https://github.com/ocornut/imgui/wiki/Funding)! Have your company financially support this project via invoiced sponsors/maintenance or by buying a license for [Dear ImGui Test Engine](https://github.com/ocornut/imgui_test_engine) (please reach out: omar AT dearimgui DOT com).
+- Be a [Funding Supporter](https://github.com/ocornut/imgui/wiki/Funding)! Have your company financially support this project via invoiced sponsors/maintenance or by buying a license for [Dear ImGui Test Engine](https://github.com/ocornut/imgui_test_engine) (please reach out: contact AT dearimgui DOT com).
 
 Sponsors
 --------
@@ -214,7 +214,7 @@ Omar: "I first discovered the IMGUI paradigm at [Q-Games](https://www.q-games.co
 Embeds [ProggyClean.ttf](https://www.proggyfonts.net) font by Tristan Grimmer (MIT license).
 <br>Embeds [stb_textedit.h, stb_truetype.h, stb_rect_pack.h](https://github.com/nothings/stb/) by Sean Barrett (public domain).
 
-Inspiration, feedback, and testing for early versions: Casey Muratori, Atman Binstock, Mikko Mononen, Emmanuel Briney, Stefan Kamoda, Anton Mikhailov, Matt Willis. Also thank you to everyone posting feedback, questions and patches on GitHub.
+Inspiration, feedback, and testing for early versions: Casey Muratori, Atman Binstock, Mikko Mononen, Emmanuel Briney, Stefan Kamoda, Anton Mikhailov, Matt Willis. Special thanks to Alex Evans, Patrick Doane, Marco Koegler for kindly helping. Also thank you to everyone posting feedback, questions and patches on GitHub.
 
 License
 -------

docs/TODO.txt

@@ -26,9 +26,6 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - window/size: manually triggered auto-fit (double-click on grip) shouldn't resize window down to viewport size?
  - window/size: how to allow to e.g. auto-size vertically to fit contents, but be horizontally resizable? Assuming SetNextWindowSize() is modified to treat -1.0f on each axis as "keep as-is" (would be good but might break erroneous code): Problem is UpdateWindowManualResize() and lots of code treat (window->AutoFitFramesX > 0 || window->AutoFitFramesY > 0) together.
  - window/opt: freeze window flag: if not focused/hovered, return false, render with previous ImDrawList. and/or reduce refresh rate. -> this may require enforcing that it is illegal to submit contents if Begin returns false.
- - window/child: background options for child windows, border option (disable rounding).
- - window/child: allow resizing of child windows (possibly given min/max for each axis?.)
- - window/child: allow SetNextWindowContentSize() to work on child windows.
  - window/clipping: some form of clipping when DisplaySize (or corresponding viewport) is zero.
  - window/tabbing: add a way to signify that a window or docked window requires attention (e.g. blinking title bar, trying to click behind a modal).
  - window/id_stack: add e.g. window->GetIDFromPath() with support for leading / and ../ (#1390, #331) -> model from test engine.
@@ -90,7 +87,6 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - input text multi-line: line numbers? status bar? (follow up on #200)
  - input text multi-line: behave better when user changes input buffer while editing is active (even though it is illegal behavior). namely, the change of buffer can create a scrollbar glitch (#725)
  - input text multi-line: better horizontal scrolling support (#383, #1224)
- - input text multi-line: single call to AddText() should be coarse clipped on InputTextEx() end.
  - input number: optional range min/max for Input*() functions
  - input number: holding [-]/[+] buttons could increase the step speed non-linearly (or user-controlled)
  - input number: use mouse wheel to step up/down
@@ -127,7 +123,35 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - separator: width, thickness, centering (#1643, #2657)
  - splitter: formalize the splitter idiom into an official api (we want to handle n-way split) (#319)
 
- - docking: merge docking branch (#2109)
+ - docking: B: ordering currently held in tab bar should be implicitly held by windows themselves (also see #2304)
+ - docking: B- tab bar: the order/focus restoring code could be part of TabBar and not DockNode? (#8)
+ - docking: B~ rework code to be able to lazily create tab bar instance in a single place. The _Unsorted tab flag could be replacing a trailing-counter in DockNode?
+ - docking: B~ fully track windows/settings reference in dock nodes. perhaps find a representation that allows facilitate use of dock builder functions.
+ - docking: B~ Unreal style document system (requires low-level controls of dockspace serialization fork/copy/delete). this is mostly working but the DockBuilderXXX api are not exposed/finished.
+ - docking: B: when docking outer, perform size locking on neighbors nodes the same way we do it with splitters, so other nodes are not resized.
+ - docking: B~ central node resizing behavior incorrect.
+ - docking: B: changing title font/style per-window is not supported as dock nodes are created in NewFrame.
+ - docking: B- dock node inside its own viewports creates 1 temporary viewport per window on startup before ditching them (doesn't affect the user nor request platform windows to be created, but unnecessary)
+ - docking: B- resize sibling locking behavior may be less desirable if we merged same-axis sibling in a same node level?
+ - docking: B- single visible node part of a hidden split hierarchy (OnlyNodeWithWindows != NULL) should show a normal title bar (not a tab bar)
+ - docking: B~ SetNextWindowDock() calls (with conditional) -> defer everything to DockContextUpdate (repro: Documents->[X]Windows->Dock 1 elsewhere->Click Redock All
+ - docking: B~ tidy up tab list popup buttons features (available with manual tab-bar, see ImGuiTabBarFlags_NoTabListPopupButton code, not used by docking nodes)
+ - docking: B- SetNextWindowDockId(0) with a second Begin() in the frame will asserts
+ - docking: B: resize grip drawn in host window typically appears under scrollbar.
+ - docking: B: resize grip auto-resize on multiple node hierarchy doesn't make much sense or should be improved?
+ - docking: B- SetNextWindowFocus() doesn't seem to apply if the window is hidden this frame, need repro (#4)
+ - docking: B- resizing a dock tree small currently has glitches (overlapping collapse and close button, etc.)
+ - docking: B- dpi: look at interaction with the hi-dpi and multi-dpi stuff.
+ - docking: B- tab bar: appearing on first frame with a dumb layout would do less harm that not appearing? (when behind dynamic branch) or store titles + render in EndTabBar()
+ - docking: B- tab bar: make selected tab always shows its full title?
+ - docking: B- hide close button on single tab bar?
+ - docking: B- nav: design interactions so nav controls can dock/undock
+ - docking: B- dockspace: flag to lock the dock tree and/or sizes (ImGuiDockNodeFlags_Locked?)
+ - docking: B- reintroduce collapsing a floating dock node. also collapsing a docked dock node!
+ - docking: B- allow dragging a non-floating dock node by clicking on the title-bar-looking section (not just the collapse/menu button)
+ - docking: B- option to remember undocked window size? (instead of keeping their docked size) (relate to #2104)
+ - docking: C- nav: CTRL+TAB highlighting tabs shows the mismatch between focus-stack and tab-order (not visible in VS because it doesn't highlight the tabs)
+ - docking: C- after a dock/undock, the Scrollbar Status update in Begin() should use an updated e.g. size_y_for_scrollbars to avoid a 1 frame scrollbar flicker.
 
  - tabs: "there is currently a problem because TabItem() will try to submit their own tooltip after 0.50 second, and this will have the effect of making your tooltip flicker once." -> tooltip priority work (WIP branch)
  - tabs: make EndTabBar fail if users doesn't respect BeginTabBar return value, for consistency/future-proofing.
@@ -244,22 +268,14 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
 
  - font: arbitrary line spacing. (#2945)
  - font: MergeMode: flags to select overwriting or not (this is now very easy with refactored ImFontAtlasBuildWithStbTruetype)
- - font: free the Alpha buffer if user only requested RGBA.
-!- font: better CalcTextSizeA() API, at least for simple use cases. current one is horrible (perhaps have simple vs extended versions).
+ - font: better CalcTextSizeA() API, at least for simple use cases. current one is horrible (perhaps have simple vs extended versions).
  - font: for the purpose of RenderTextEllipsis(), it might be useful that CalcTextSizeA() can ignore the trailing padding?
  - font: a CalcTextHeight() helper could run faster than CalcTextSize().y
  - font: enforce monospace through ImFontConfig (for icons?) + create dual ImFont output from same input, reusing rasterized data but with different glyphs/AdvanceX
- - font: finish CustomRectRegister() to allow mapping Unicode codepoint to custom texture data
- - font: remove ID from CustomRect registration, it seems unnecessary!
  - font: make it easier to submit own bitmap font (same texture, another texture?). (#2127, #2575)
- - font: PushFontSize API (#1018)
  - font: MemoryTTF taking ownership confusing/not obvious, maybe default should be opposite?
  - font: storing MinAdvanceX per font would allow us to skip calculating line width (under a threshold of character count) in loops looking for block width
- - font/demo: add tools to show glyphs used by a text blob, display U16 value, list missing glyphs.
  - font/demo: demonstrate use of ImFontGlyphRangesBuilder.
- - font/atlas: add a missing Glyphs.reserve()
- - font/atlas: incremental updates
- - font/atlas: dynamic font atlas to avoid baking huge ranges into bitmap and make scaling easier.
  - font/draw: vertical and/or rotated text renderer (#705) - vertical is easier clipping wise
  - font/draw: need to be able to specify wrap start position.
  - font/draw: better reserve policy for large horizontal block of text (shouldn't reserve for all clipped lines). also see #3349.
@@ -268,7 +284,6 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - font: optimization: for monospace font (like the default one) we can trim IndexXAdvance as long as trailing value is == FallbackXAdvance (need to make sure TAB is still correct), would save on cache line.
  - font: add support for kerning, probably optional. A) perhaps default to (32..128)^2 matrix ~ 9K entries = 36KB, then hash for non-ascii?. B) or sparse lookup into per-char list?
  - font: add a simpler CalcTextSizeA() api? current one ok but not welcome if user needs to call it directly (without going through ImGui::CalcTextSize)
- - font: fix AddRemapChar() to work before atlas  has been built.
  - font: (api breaking) remove "TTF" from symbol names. also because it now supports OTF.
  - font/opt: Considering storing standalone AdvanceX table as 16-bit fixed point integer?
  - font/opt: Glyph currently 40 bytes (2+9*4). Consider storing UV as 16-bits integer? (->32 bytes). X0/Y0/X1/Y1 as 16 fixed-point integers? Or X0/Y0 as float and X1/Y1 as fixed8_8?
@@ -299,6 +314,21 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - nav/windowing: Resizing window will currently fail with certain types of resizing constraints/callback applied
  - focus: preserve ActiveId/focus stack state, e.g. when opening a menu and close it, previously selected InputText() focus gets restored (#622)
 
+ - viewport: make it possible to have no main/hosting viewport (see #8268)
+ - viewport: We set ImGuiViewportFlags_NoFocusOnAppearing in a way that is required for GLFW/SDL binding, but could be handled better without
+   on a custom e.g. Win32 bindings. It prevents newly dragged-out viewports from taking the focus, which makes ALT+F4 more ambiguous.
+ - viewport: not focusing newly undocked viewport means clicking back on previous one doesn't bring OS window to front.
+ - viewport: with platform decoration enabled, platform may force constraint (e.g. minimum size)
+ - viewport: use getfocus/setfocus api to synchronize imgui<>platform focus better (e.g imgui-side ctrl-tab can focus os window, OS initial setup and alt-tab can focus imgui window etc.)
+ - viewport: store per-viewport/monitor DPI in .ini file so an application reload or main window changing DPI on reload can be properly patched for.
+ - viewport: implicit/fallback Debug window can hog a zombie viewport (harmless, noisy?) > could at least clear out the reference on a per session basis?
+ - viewport: need to clarify how to use GetMousePos() from a user point of view.
+ - viewport: could apply monitor boundaries to cliprect to coarse clip things out of monitor? (#8698)
+ - platform: glfw: no support for ImGuiBackendFlags_HasMouseHoveredViewport.
+ - platform: sdl: no support for ImGuiBackendFlags_HasMouseHoveredViewport. maybe we could use SDL_GetMouseFocus() / SDL_WINDOW_MOUSE_FOCUS if imgui could fallback on its heuristic when NoInputs is set
+ - platform: sdl: no refresh of monitor/display (SDL doesn't seem to have an event for it).
+ - platform: sdl: multi-viewport + minimized window seems to break mouse wheel events (at least under Win32).
+
  - inputs: support track pad style scrolling & slider edit.
  - inputs/io: backspace and arrows in the context of a text input could use system repeat rate.
  - inputs/io: clarify/standardize/expose repeat rate and repeat delays (#1808)

examples/example_allegro5/main.cpp

@@ -28,7 +28,7 @@ int main(int, char**)
     al_install_mouse();
     al_init_primitives_addon();
     al_set_new_display_flags(ALLEGRO_RESIZABLE);
-    ALLEGRO_DISPLAY* display = al_create_display(1280, 720);
+    ALLEGRO_DISPLAY* display = al_create_display(1280, 800);
     al_set_window_title(display, "Dear ImGui Allegro 5 example");
     ALLEGRO_EVENT_QUEUE* queue = al_create_event_queue();
     al_register_event_source(queue, al_get_display_event_source(display));
@@ -40,6 +40,7 @@ int main(int, char**)
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -52,16 +53,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     bool show_demo_window = true;

examples/example_android_opengl3/android/.gitignore

@@ -1,12 +1,14 @@
-.cxx
-.externalNativeBuild
 build/
 *.iml
-
-.idea
 .gradle
+.idea
+.DS_Store
+/captures
+.externalNativeBuild
+.cxx
 local.properties
 
 # Android Studio puts a Gradle wrapper here, that we don't want:
 gradle/
+!gradle/libs.versions.toml
 gradlew*

examples/example_android_opengl3/android/app/build.gradle

@@ -1,16 +1,16 @@
-apply plugin: 'com.android.application'
-apply plugin: 'kotlin-android'
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+}
 
 android {
-    compileSdkVersion 33
-    buildToolsVersion "33.0.2"
-    ndkVersion "25.2.9519653"
+    namespace 'imgui.example.android'
+    compileSdk 36
 
     defaultConfig {
         applicationId "imgui.example.android"
-        namespace "imgui.example.android"
-        minSdkVersion 24
-        targetSdkVersion 33
+        minSdk 24
+        targetSdk 36
         versionCode 1
         versionName "1.0"
     }
@@ -21,26 +21,17 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt')
         }
     }
-
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_11
         targetCompatibility JavaVersion.VERSION_11
     }
-
     kotlinOptions {
-        jvmTarget="11"
+        jvmTarget = '11'
     }
-
     externalNativeBuild {
         cmake {
-            path "../../CMakeLists.txt"
+            path file('../../CMakeLists.txt')
             version '3.22.1'
         }
     }
 }
-repositories {
-    mavenCentral()
-}
-dependencies {
-    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
-}

examples/example_android_opengl3/android/app/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
 
     <application
         android:label="ImGuiExample"

examples/example_android_opengl3/android/build.gradle

@@ -1,24 +1,5 @@
-buildscript {
-    ext.kotlin_version = '1.8.0'
-    repositories {
-        google()
-        mavenCentral()
-
-    }
-    dependencies {
-        classpath 'com.android.tools.build:gradle:7.4.1'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-
-    }
-}
-
-allprojects {
-    repositories {
-        google()
-        mavenCentral()
-    }
-}
-
-task clean(type: Delete) {
-    delete rootProject.buildDir
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.android) apply false
 }

examples/example_android_opengl3/android/gradle/libs.versions.toml

@@ -0,0 +1,8 @@
+[versions]
+agp = "8.12.0"
+kotlin = "2.0.21"
+
+[plugins]
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+

examples/example_android_opengl3/android/settings.gradle

@@ -1 +1,22 @@
+pluginManagement {
+    repositories {
+        google {
+            content {
+                includeGroupByRegex("com\\.android.*")
+                includeGroupByRegex("com\\.google.*")
+                includeGroupByRegex("androidx.*")
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
 include ':app'

examples/example_android_opengl3/main.cpp

@@ -154,8 +154,7 @@ void Init(struct android_app* app)
     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Android: The TTF files have to be placed into the assets/ directory (android/app/src/main/assets), we use our GetAssetData() helper to retrieve them.
 
@@ -181,7 +180,7 @@ void Init(struct android_app* app)
     //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 15.0f);
     //IM_ASSERT(font != nullptr);
     //font_data_size = GetAssetData("ArialUni.ttf", &font_data);
-    //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //font = io.Fonts->AddFontFromMemoryTTF(font_data, font_data_size, 18.0f);
     //IM_ASSERT(font != nullptr);
 
     // Arbitrary scale-up

examples/example_apple_metal/Makefile

@@ -0,0 +1,21 @@
+# Makefile for example_apple_metal, for macOS only (**not iOS**)
+CXX = clang++
+EXE = example_apple_metal
+IMGUI_DIR = ../../
+SOURCES = main.mm
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_osx.mm $(IMGUI_DIR)/backends/imgui_impl_metal.mm
+
+CXXFLAGS = -std=c++11 -ObjC++ -fobjc-arc -Wall -Wextra -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+FRAMEWORKS = -framework AppKit -framework Metal -framework MetalKit -framework QuartzCore -framework GameController
+
+all: $(EXE)
+
+$(EXE): $(SOURCES)
+	$(CXX) $(CXXFLAGS) $^ $(FRAMEWORKS) -o $@
+
+run: all
+	./$(EXE)
+
+clean:
+	rm -f $(EXE) *.o

examples/example_apple_metal/example_apple_metal.xcodeproj/project.pbxproj

@@ -3,11 +3,14 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 48;
+	objectVersion = 54;
 	objects = {
 
 /* Begin PBXBuildFile section */
+		050450AB2768052600AB6805 /* imgui_tables.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5079822D257677DB0038A28D /* imgui_tables.cpp */; };
+		050450AD276863B000AB6805 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 050450AC276863B000AB6805 /* QuartzCore.framework */; };
 		05318E0F274C397200A8DE2E /* GameController.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 05318E0E274C397200A8DE2E /* GameController.framework */; };
+		05A275442773BEA20084EF39 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 05A275432773BEA20084EF39 /* QuartzCore.framework */; };
 		07A82ED82139413D0078D120 /* imgui_widgets.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 07A82ED72139413C0078D120 /* imgui_widgets.cpp */; };
 		07A82ED92139418F0078D120 /* imgui_widgets.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 07A82ED72139413C0078D120 /* imgui_widgets.cpp */; };
 		5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5079822D257677DB0038A28D /* imgui_tables.cpp */; };
@@ -33,7 +36,11 @@
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		050450AC276863B000AB6805 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = System/Library/Frameworks/QuartzCore.framework; sourceTree = SDKROOT; };
 		05318E0E274C397200A8DE2E /* GameController.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = GameController.framework; path = System/Library/Frameworks/GameController.framework; sourceTree = SDKROOT; };
+		05A2754027728F5B0084EF39 /* imgui_impl_metal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_impl_metal.h; path = ../../backends/imgui_impl_metal.h; sourceTree = "<group>"; };
+		05A2754127728F5B0084EF39 /* imgui_impl_osx.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_impl_osx.h; path = ../../backends/imgui_impl_osx.h; sourceTree = "<group>"; };
+		05A275432773BEA20084EF39 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS15.2.sdk/System/Library/Frameworks/QuartzCore.framework; sourceTree = DEVELOPER_DIR; };
 		07A82ED62139413C0078D120 /* imgui_internal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = imgui_internal.h; path = ../../imgui_internal.h; sourceTree = "<group>"; };
 		07A82ED72139413C0078D120 /* imgui_widgets.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = imgui_widgets.cpp; path = ../../imgui_widgets.cpp; sourceTree = "<group>"; };
 		5079822D257677DB0038A28D /* imgui_tables.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = imgui_tables.cpp; path = ../../imgui_tables.cpp; sourceTree = "<group>"; };
@@ -66,6 +73,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				05A275442773BEA20084EF39 /* QuartzCore.framework in Frameworks */,
 				8309BD8F253CCAAA0045E2A1 /* UIKit.framework in Frameworks */,
 				83BBE9E720EB46BD00295997 /* MetalKit.framework in Frameworks */,
 				83BBE9E520EB46B900295997 /* Metal.framework in Frameworks */,
@@ -76,6 +84,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				050450AD276863B000AB6805 /* QuartzCore.framework in Frameworks */,
 				8309BDC6253CCCFE0045E2A1 /* AppKit.framework in Frameworks */,
 				83BBE9EC20EB471700295997 /* MetalKit.framework in Frameworks */,
 				05318E0F274C397200A8DE2E /* GameController.framework in Frameworks */,
@@ -136,6 +145,8 @@
 		83BBE9E320EB46B800295997 /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				050450AC276863B000AB6805 /* QuartzCore.framework */,
+				05A275432773BEA20084EF39 /* QuartzCore.framework */,
 				05318E0E274C397200A8DE2E /* GameController.framework */,
 				8309BDC5253CCCFE0045E2A1 /* AppKit.framework */,
 				8309BD8E253CCAAA0045E2A1 /* UIKit.framework */,
@@ -153,7 +164,9 @@
 			isa = PBXGroup;
 			children = (
 				5079822D257677DB0038A28D /* imgui_tables.cpp */,
+				05A2754027728F5B0084EF39 /* imgui_impl_metal.h */,
 				8309BDB5253CCC9D0045E2A1 /* imgui_impl_metal.mm */,
+				05A2754127728F5B0084EF39 /* imgui_impl_osx.h */,
 				8309BDB6253CCC9D0045E2A1 /* imgui_impl_osx.mm */,
 				83BBEA0420EB54E700295997 /* imconfig.h */,
 				83BBEA0320EB54E700295997 /* imgui.cpp */,
@@ -209,7 +222,8 @@
 		8307E7B620E9F9C700473790 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 1200;
+				BuildIndependentTargetsInParallel = YES;
+				LastUpgradeCheck = 1530;
 				ORGANIZATIONNAME = "Warren Moore";
 				TargetAttributes = {
 					8307E7C320E9F9C900473790 = {
@@ -284,7 +298,7 @@
 				83BBEA0A20EB54E700295997 /* imgui.cpp in Sources */,
 				83BBEA0820EB54E700295997 /* imgui_demo.cpp in Sources */,
 				83BBEA0620EB54E700295997 /* imgui_draw.cpp in Sources */,
-				5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */,
+				050450AB2768052600AB6805 /* imgui_tables.cpp in Sources */,
 				07A82ED92139418F0078D120 /* imgui_widgets.cpp in Sources */,
 				8309BDA8253CCC080045E2A1 /* main.mm in Sources */,
 			);
@@ -327,9 +341,11 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				DEAD_CODE_STRIPPING = YES;
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
@@ -383,9 +399,11 @@
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				DEAD_CODE_STRIPPING = YES;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -405,8 +423,11 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "$(SRCROOT)/iOS/Info-iOS.plist";
-				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
 				PRODUCT_BUNDLE_IDENTIFIER = "org.imgui.example.apple-metal-ios";
 				PRODUCT_NAME = example_apple_metal;
 				SDKROOT = iphoneos;
@@ -422,8 +443,11 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "$(SRCROOT)/iOS/Info-iOS.plist";
-				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
 				PRODUCT_BUNDLE_IDENTIFIER = "org.imgui.example.apple-metal-ios";
 				PRODUCT_NAME = example_apple_metal;
 				SDKROOT = iphoneos;
@@ -439,10 +463,14 @@
 				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
+				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "$(SRCROOT)/macOS/Info-macOS.plist";
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 10.12;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/../Frameworks",
+				);
+				MACOSX_DEPLOYMENT_TARGET = "$(RECOMMENDED_MACOSX_DEPLOYMENT_TARGET)";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.imgui.example.apple-metal-macos";
 				PRODUCT_NAME = example_apple_metal;
 				SDKROOT = macosx;
@@ -456,10 +484,14 @@
 				CODE_SIGN_IDENTITY = "-";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
+				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "$(SRCROOT)/macOS/Info-macOS.plist";
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 10.12;
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/../Frameworks",
+				);
+				MACOSX_DEPLOYMENT_TARGET = "$(RECOMMENDED_MACOSX_DEPLOYMENT_TARGET)";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.imgui.example.apple-metal-macos";
 				PRODUCT_NAME = example_apple_metal;
 				SDKROOT = macosx;

examples/example_apple_metal/main.mm

@@ -60,11 +60,21 @@
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Renderer backend
     ImGui_ImplMetal_Init(_device);
 
@@ -72,16 +82,16 @@
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     return self;
@@ -94,7 +104,7 @@
 
 -(void)loadView
 {
-    self.view = [[MTKView alloc] initWithFrame:CGRectMake(0, 0, 1200, 720)];
+    self.view = [[MTKView alloc] initWithFrame:CGRectMake(0, 0, 1200, 800)];
 }
 
 -(void)viewDidLoad
@@ -195,6 +205,13 @@
     // Present
     [commandBuffer presentDrawable:view.currentDrawable];
     [commandBuffer commit];
+
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
 }
 
 -(void)mtkView:(MTKView*)view drawableSizeWillChange:(CGSize)size
@@ -319,9 +336,20 @@
 
 #if TARGET_OS_OSX
 
-int main(int argc, const char * argv[])
+int main(int, const char**)
 {
-    return NSApplicationMain(argc, argv);
+    @autoreleasepool
+    {
+        [NSApplication sharedApplication];
+        [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
+
+        AppDelegate *appDelegate = [[AppDelegate alloc] init];   // creates window
+        [NSApp setDelegate:appDelegate];
+
+        [NSApp activateIgnoringOtherApps:YES];
+        [NSApp run];
+    }
+    return 0;
 }
 
 #else

examples/example_apple_opengl2/Makefile

@@ -0,0 +1,21 @@
+# Makefile for example_apple_metal, for macOS only (**not iOS**)
+CXX = clang++
+EXE = example_apple_opengl2
+IMGUI_DIR = ../../
+SOURCES = main.mm
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_osx.mm $(IMGUI_DIR)/backends/imgui_impl_opengl2.cpp
+
+CXXFLAGS = -std=c++11 -ObjC++ -fobjc-arc -Wall -Wextra -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+FRAMEWORKS = -framework Cocoa -framework OpenGL -framework GameController
+
+all: $(EXE)
+
+$(EXE): $(SOURCES)
+	$(CXX) $(CXXFLAGS) $(SOURCES) -o $(EXE) $(FRAMEWORKS)
+
+run: all
+	./$(EXE)
+
+clean:
+	rm -f $(EXE) *.o

examples/example_apple_opengl2/example_apple_opengl2.xcodeproj/project.pbxproj

@@ -289,7 +289,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CODE_SIGN_STYLE = Automatic;
-				MACOSX_DEPLOYMENT_TARGET = 10.12;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				USER_HEADER_SEARCH_PATHS = ../..;
 			};
@@ -299,7 +299,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				CODE_SIGN_STYLE = Automatic;
-				MACOSX_DEPLOYMENT_TARGET = 10.12;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				USER_HEADER_SEARCH_PATHS = ../..;
 			};

examples/example_apple_opengl2/main.mm

@@ -6,6 +6,8 @@
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp
 
+// FIXME: Multi-viewports is not yet functional in this example. May need backend rework/coordination.
+
 #import <Cocoa/Cocoa.h>
 #import <OpenGL/gl.h>
 #import <OpenGL/glu.h>
@@ -47,11 +49,21 @@
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplOSX_Init(self);
     ImGui_ImplOpenGL2_Init();
@@ -60,16 +72,16 @@
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 }
 
@@ -136,6 +148,13 @@
 
     ImGui_ImplOpenGL2_RenderDrawData(draw_data);
 
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
+
     // Present
     [[self openGLContext] flushBuffer];
 
@@ -171,7 +190,7 @@
     if (_window != nil)
         return (_window);
 
-    NSRect viewRect = NSMakeRect(100.0, 100.0, 100.0 + 1280.0, 100 + 720.0);
+    NSRect viewRect = NSMakeRect(100.0, 100.0, 100.0 + 1280.0, 100 + 800.0);
 
     _window = [[NSWindow alloc] initWithContentRect:viewRect styleMask:NSWindowStyleMaskTitled|NSWindowStyleMaskMiniaturizable|NSWindowStyleMaskResizable|NSWindowStyleMaskClosable backing:NSBackingStoreBuffered defer:YES];
     [_window setTitle:@"Dear ImGui OSX+OpenGL2 Example"];

examples/example_glfw_metal/main.mm

@@ -27,44 +27,44 @@ static void glfw_error_callback(int error, const char* description)
 
 int main(int, char**)
 {
-    // Setup Dear ImGui context
-    IMGUI_CHECKVERSION();
-    ImGui::CreateContext();
-    ImGuiIO& io = ImGui::GetIO(); (void)io;
-    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
-    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
-
-    // Setup style
-    ImGui::StyleColorsDark();
-    //ImGui::StyleColorsLight();
-
-    // Load Fonts
-    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
-    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
-    // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
-    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
-    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
-    //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
-    //IM_ASSERT(font != nullptr);
-
-    // Setup window
     glfwSetErrorCallback(glfw_error_callback);
     if (!glfwInit())
         return 1;
 
     // Create window with graphics context
+    float main_scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfwGetPrimaryMonitor()); // Valid on GLFW 3.3+ only
     glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
-    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+Metal example", nullptr, nullptr);
+    GLFWwindow* window = glfwCreateWindow((int)(1280 * main_scale), (int)(800 * main_scale), "Dear ImGui GLFW+Metal example", nullptr, nullptr);
     if (window == nullptr)
         return 1;
 
+    // Setup Dear ImGui context
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+
+    // Setup Dear ImGui style
+    ImGui::StyleColorsDark();
+    //ImGui::StyleColorsLight();
+
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     id <MTLDevice> device = MTLCreateSystemDefaultDevice();
     id <MTLCommandQueue> commandQueue = [device newCommandQueue];
 
@@ -72,6 +72,22 @@ int main(int, char**)
     ImGui_ImplGlfw_InitForOpenGL(window, true);
     ImGui_ImplMetal_Init(device);
 
+    // Load Fonts
+    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
+    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
+    // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
+    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
+    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
+    //io.Fonts->AddFontDefault();
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
+    //IM_ASSERT(font != nullptr);
+
     NSWindow *nswin = glfwGetCocoaWindow(window);
     CAMetalLayer *layer = [CAMetalLayer layer];
     layer.device = device;
@@ -157,6 +173,13 @@ int main(int, char**)
             ImGui::Render();
             ImGui_ImplMetal_RenderDrawData(ImGui::GetDrawData(), commandBuffer, renderEncoder);
 
+            // Update and Render additional Platform Windows
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                ImGui::UpdatePlatformWindows();
+                ImGui::RenderPlatformWindowsDefault();
+            }
+
             [renderEncoder popDebugGroup];
             [renderEncoder endEncoding];
 

examples/example_glfw_opengl2/Makefile

@@ -21,6 +21,7 @@ SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui
 SOURCES += $(IMGUI_DIR)/backends/imgui_impl_glfw.cpp $(IMGUI_DIR)/backends/imgui_impl_opengl2.cpp
 OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
 UNAME_S := $(shell uname -s)
+LINUX_GL_LIBS = -lGL
 
 CXXFLAGS = -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
 CXXFLAGS += -g -Wall -Wformat
@@ -32,7 +33,7 @@ LIBS =
 
 ifeq ($(UNAME_S), Linux) #LINUX
 	ECHO_MESSAGE = "Linux"
-	LIBS += -lGL `pkg-config --static --libs glfw3`
+	LIBS += $(LINUX_GL_LIBS) -lX11 `pkg-config --static --libs glfw3`
 
 	CXXFLAGS += `pkg-config --cflags glfw3`
 	CFLAGS = $(CXXFLAGS)

examples/example_glfw_opengl2/main.cpp

@@ -40,7 +40,8 @@ int main(int, char**)
         return 1;
 
     // Create window with graphics context
-    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL2 example", nullptr, nullptr);
+    float main_scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfwGetPrimaryMonitor()); // Valid on GLFW 3.3+ only
+    GLFWwindow* window = glfwCreateWindow((int)(1280 * main_scale), (int)(800 * main_scale), "Dear ImGui GLFW+OpenGL2 example", nullptr, nullptr);
     if (window == nullptr)
         return 1;
     glfwMakeContextCurrent(window);
@@ -52,11 +53,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
     ImGui_ImplOpenGL2_Init();
@@ -65,16 +84,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -155,6 +174,17 @@ int main(int, char**)
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
         //glUseProgram(last_program);
 
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call glfwMakeContextCurrent(window) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+
         glfwMakeContextCurrent(window);
         glfwSwapBuffers(window);
     }

examples/example_glfw_opengl3/Makefile

@@ -41,7 +41,7 @@ LIBS =
 
 ifeq ($(UNAME_S), Linux) #LINUX
 	ECHO_MESSAGE = "Linux"
-	LIBS += $(LINUX_GL_LIBS) `pkg-config --static --libs glfw3`
+	LIBS += $(LINUX_GL_LIBS) -lX11 `pkg-config --static --libs glfw3`
 
 	CXXFLAGS += `pkg-config --cflags glfw3`
 	CFLAGS = $(CXXFLAGS)

examples/example_glfw_opengl3/Makefile.emscripten

@@ -32,8 +32,9 @@ EMS =
 ##---------------------------------------------------------------------
 
 # ("EMS" options gets added to both CPPFLAGS and LDFLAGS, whereas some options are for linker only)
-EMS += -s DISABLE_EXCEPTION_CATCHING=1
-LDFLAGS += -s USE_GLFW=3 -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s NO_EXIT_RUNTIME=0 -s ASSERTIONS=1
+# Note: For glfw, we use emscripten-glfw port (contrib.glfw3) instead of ('-s USE_GLFW=3' in LDFLAGS) to get a better support for High DPI displays.
+EMS += -s DISABLE_EXCEPTION_CATCHING=1 --use-port=contrib.glfw3
+LDFLAGS += -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s NO_EXIT_RUNTIME=0 -s ASSERTIONS=1
 
 # Build as single file (binary text encoded in .html file)
 #LDFLAGS += -sSINGLE_FILE

examples/example_glfw_opengl3/main.cpp

@@ -71,7 +71,8 @@ int main(int, char**)
 #endif
 
     // Create window with graphics context
-    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL3 example", nullptr, nullptr);
+    float main_scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfwGetPrimaryMonitor()); // Valid on GLFW 3.3+ only
+    GLFWwindow* window = glfwCreateWindow((int)(1280 * main_scale), (int)(800 * main_scale), "Dear ImGui GLFW+OpenGL3 example", nullptr, nullptr);
     if (window == nullptr)
         return 1;
     glfwMakeContextCurrent(window);
@@ -83,11 +84,31 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+#if GLFW_VERSION_MAJOR >= 3 && GLFW_VERSION_MINOR >= 3
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+#endif
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
 #ifdef __EMSCRIPTEN__
@@ -99,17 +120,17 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -190,6 +211,17 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call glfwMakeContextCurrent(window) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+
         glfwSwapBuffers(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_glfw_vulkan/CMakeLists.txt

@@ -36,6 +36,7 @@ find_package(Vulkan REQUIRED)
   #NAMES vulkan vulkan-1)
 #set(LIBRARIES "glfw;${VULKAN_LIBRARY}")
 set(LIBRARIES "glfw;Vulkan::Vulkan")
+# FIXME: Linux needs linking with "X11" as well?
 
 # Use vulkan headers from glfw:
 include_directories(${GLFW_DIR}/deps)

examples/example_glfw_vulkan/Makefile

@@ -0,0 +1,83 @@
+#
+# Cross Platform Makefile
+# Compatible with MSYS2/MINGW, Ubuntu 14.04.1 and Mac OS X
+#
+# You will need GLFW (http://www.glfw.org):
+# Linux:
+#   apt-get install libglfw-dev
+# Mac OS X:
+#   brew install glfw
+# MSYS2:
+#   pacman -S --noconfirm --needed mingw-w64-x86_64-toolchain mingw-w64-x86_64-glfw
+#
+
+#CXX = g++
+#CXX = clang++
+
+EXE = example_glfw_vulkan
+IMGUI_DIR = ../..
+SOURCES = main.cpp
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_glfw.cpp $(IMGUI_DIR)/backends/imgui_impl_vulkan.cpp
+OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
+UNAME_S := $(shell uname -s)
+LINUX_GL_LIBS = -lGL
+
+CXXFLAGS = -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+CXXFLAGS += -g -Wall -Wformat
+LIBS =
+
+##---------------------------------------------------------------------
+## BUILD FLAGS PER PLATFORM
+##---------------------------------------------------------------------
+
+ifeq ($(UNAME_S), Linux) #LINUX
+	ECHO_MESSAGE = "Linux"
+	LIBS += $(LINUX_GL_LIBS) -lX11 `pkg-config --static --libs glfw3 vulkan`
+
+	CXXFLAGS += `pkg-config --cflags glfw3 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(UNAME_S), Darwin) #APPLE
+	ECHO_MESSAGE = "Mac OS X"
+	LIBS += -framework Cocoa -framework IOKit -framework CoreVideo
+	LIBS += `pkg-config --libs glfw3 vulkan`
+	LIBS += -L/usr/local/lib -L/opt/local/lib -L/opt/homebrew/lib
+	#LIBS += -lglfw3
+
+	LIBS += `pkg-config --cflags glfw3 vulkan`
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include -I/opt/homebrew/include
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(OS), Windows_NT)
+	ECHO_MESSAGE = "MinGW"
+	LIBS += -lgdi32 -limm32
+	LIBS += `pkg-config --libs glfw3 vulkan`
+
+	CXXFLAGS += `pkg-config --cflags glfw3 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+##---------------------------------------------------------------------
+## BUILD RULES
+##---------------------------------------------------------------------
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete for $(ECHO_MESSAGE)
+
+$(EXE): $(OBJS)
+	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
+
+clean:
+	rm -f $(EXE) $(OBJS)

examples/example_glfw_vulkan/main.cpp

@@ -38,6 +38,7 @@
 //#define APP_USE_UNLIMITED_FRAME_RATE
 #ifdef _DEBUG
 #define APP_USE_VULKAN_DEBUG_REPORT
+static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 #endif
 
 // Data
@@ -47,7 +48,6 @@ static VkPhysicalDevice         g_PhysicalDevice = VK_NULL_HANDLE;
 static VkDevice                 g_Device = VK_NULL_HANDLE;
 static uint32_t                 g_QueueFamily = (uint32_t)-1;
 static VkQueue                  g_Queue = VK_NULL_HANDLE;
-static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 static VkPipelineCache          g_PipelineCache = VK_NULL_HANDLE;
 static VkDescriptorPool         g_DescriptorPool = VK_NULL_HANDLE;
 
@@ -357,7 +357,8 @@ int main(int, char**)
 
     // Create window with Vulkan context
     glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
-    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+Vulkan example", nullptr, nullptr);
+    float main_scale = ImGui_ImplGlfw_GetContentScaleForMonitor(glfwGetPrimaryMonitor()); // Valid on GLFW 3.3+ only
+    GLFWwindow* window = glfwCreateWindow((int)(1280 * main_scale), (int)(800 * main_scale), "Dear ImGui GLFW+Vulkan example", nullptr, nullptr);
     if (!glfwVulkanSupported())
     {
         printf("GLFW: Vulkan Not Supported\n");
@@ -388,11 +389,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForVulkan(window, true);
     ImGui_ImplVulkan_InitInfo init_info = {};
@@ -417,16 +436,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -504,17 +523,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_glfw_wgpu/Makefile.emscripten

@@ -32,8 +32,9 @@ EMS =
 ##---------------------------------------------------------------------
 
 # ("EMS" options gets added to both CPPFLAGS and LDFLAGS, whereas some options are for linker only)
-EMS += -s DISABLE_EXCEPTION_CATCHING=1
-LDFLAGS += -s USE_GLFW=3 -s USE_WEBGPU=1
+# Note: For glfw, we use emscripten-glfw port (contrib.glfw3) instead of (-s USE_GLFW=3) to get a better support for High DPI displays.
+EMS += -s DISABLE_EXCEPTION_CATCHING=1 --use-port=contrib.glfw3
+LDFLAGS += -s USE_WEBGPU=1
 LDFLAGS += -s WASM=1 -s ALLOW_MEMORY_GROWTH=1 -s NO_EXIT_RUNTIME=0 -s ASSERTIONS=1
 
 # Build as single file (binary text encoded in .html file)

examples/example_glfw_wgpu/main.cpp

@@ -37,7 +37,7 @@ static WGPUSurface       wgpu_surface = nullptr;
 static WGPUTextureFormat wgpu_preferred_fmt = WGPUTextureFormat_RGBA8Unorm;
 static WGPUSwapChain     wgpu_swap_chain = nullptr;
 static int               wgpu_swap_chain_width = 1280;
-static int               wgpu_swap_chain_height = 720;
+static int               wgpu_swap_chain_height = 800;
 
 // Forward declarations
 static bool InitWGPU(GLFWwindow* window);
@@ -93,6 +93,7 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -114,19 +115,19 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Emscripten allows preloading a file or folder to be accessible at runtime. See Makefile for details.
     //io.Fonts->AddFontDefault();
+    //style.FontSizeBase = 20.0f;
 #ifndef IMGUI_DISABLE_FILE_FUNCTIONS
-    //io.Fonts->AddFontFromFileTTF("fonts/segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("fonts/Cousine-Regular.ttf", 15.0f);
-    //io.Fonts->AddFontFromFileTTF("fonts/ProggyTiny.ttf", 10.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("fonts/ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("fonts/segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("fonts/Cousine-Regular.ttf");
+    //io.Fonts->AddFontFromFileTTF("fonts/ProggyTiny.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("fonts/ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 #endif
 

examples/example_glut_opengl2/main.cpp

@@ -48,7 +48,7 @@ int main(int argc, char** argv)
     glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_GLUTMAINLOOP_RETURNS);
 #endif
     glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_MULTISAMPLE);
-    glutInitWindowSize(1280, 720);
+    glutInitWindowSize(1280, 800);
     glutCreateWindow("Dear ImGui GLUT+OpenGL2 Example");
 
     // Setup GLUT display function
@@ -61,6 +61,7 @@ int main(int argc, char** argv)
     ImGui::CreateContext();
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
@@ -78,21 +79,20 @@ int main(int argc, char** argv)
     // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
     ImGui_ImplGLUT_InstallFuncs();
 
-
     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Main loop

examples/example_null/main.cpp

@@ -11,9 +11,10 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO();
 
     // Build atlas
-    unsigned char* tex_pixels = nullptr;
-    int tex_w, tex_h;
-    io.Fonts->GetTexDataAsRGBA32(&tex_pixels, &tex_w, &tex_h);
+    //unsigned char* tex_pixels = nullptr;
+    //int tex_w, tex_h;
+    //io.Fonts->GetTexDataAsRGBA32(&tex_pixels, &tex_w, &tex_h);
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;
 
     for (int n = 0; n < 20; n++)
     {

examples/example_sdl2_directx11/main.cpp

@@ -33,6 +33,9 @@ int main(int, char**)
     // Setup SDL
     // (Some versions of SDL before <2.0.10 appears to have performance/stalling issues on a minority of Windows systems,
     // depending on whether SDL_INIT_GAMECONTROLLER is enabled or disabled.. updating to the latest version of SDL is recommended!)
+#ifdef _WIN32
+    ::SetProcessDPIAware();
+#endif
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());
@@ -45,8 +48,9 @@ int main(int, char**)
 #endif
 
     // Setup window
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+DirectX11 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+DirectX11 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -71,11 +75,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForD3D(window);
     ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
@@ -84,16 +106,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -181,6 +203,13 @@ int main(int, char**)
         g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         g_pSwapChain->Present(1, 0); // Present with vsync
         //g_pSwapChain->Present(0, 0); // Present without vsync
     }

examples/example_sdl2_metal/main.mm

@@ -24,25 +24,35 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;    // Enable Multi-Viewport / Platform Windows
 
     // Setup style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Setup SDL
@@ -60,7 +70,7 @@ int main(int, char**)
     // Enable native IME.
     SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
 
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL+Metal example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL+Metal example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 800, SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     if (window == nullptr)
     {
         printf("Error creating window: %s\n", SDL_GetError());
@@ -168,6 +178,13 @@ int main(int, char**)
             ImGui::Render();
             ImGui_ImplMetal_RenderDrawData(ImGui::GetDrawData(), commandBuffer, renderEncoder);
 
+            // Update and Render additional Platform Windows
+            if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+            {
+                ImGui::UpdatePlatformWindows();
+                ImGui::RenderPlatformWindowsDefault();
+            }
+
             [renderEncoder popDebugGroup];
             [renderEncoder endEncoding];
 

examples/example_sdl2_opengl2/main.cpp

@@ -17,11 +17,17 @@
 #include <stdio.h>
 #include <SDL.h>
 #include <SDL_opengl.h>
+#ifdef _WIN32
+#include <windows.h>        // SetProcessDPIAware()
+#endif
 
 // Main code
 int main(int, char**)
 {
     // Setup SDL
+#ifdef _WIN32
+    ::SetProcessDPIAware();
+#endif
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());
@@ -39,8 +45,9 @@ int main(int, char**)
     SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
     SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -57,11 +64,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL2_Init();
@@ -70,16 +95,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -160,6 +185,19 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 

examples/example_sdl2_opengl3/main.cpp

@@ -17,6 +17,9 @@
 #else
 #include <SDL_opengl.h>
 #endif
+#ifdef _WIN32
+#include <windows.h>        // SetProcessDPIAware()
+#endif
 
 // This example can also compile and run with Emscripten! See 'Makefile.emscripten' for details.
 #ifdef __EMSCRIPTEN__
@@ -27,6 +30,9 @@
 int main(int, char**)
 {
     // Setup SDL
+#ifdef _WIN32
+    ::SetProcessDPIAware();
+#endif
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());
@@ -73,8 +79,9 @@ int main(int, char**)
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
     SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+OpenGL3 example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -97,11 +104,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL3_Init(glsl_version);
@@ -110,17 +135,17 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -207,6 +232,19 @@ int main(int, char**)
         glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_sdl2_sdlrenderer2/main.cpp

@@ -15,6 +15,9 @@
 #include "imgui_impl_sdlrenderer2.h"
 #include <stdio.h>
 #include <SDL.h>
+#ifdef _WIN32
+#include <windows.h>        // SetProcessDPIAware()
+#endif
 
 #if !SDL_VERSION_ATLEAST(2,0,17)
 #error This backend requires SDL 2.0.17+ because of SDL_RenderGeometry() function
@@ -24,6 +27,9 @@
 int main(int, char**)
 {
     // Setup SDL
+#ifdef _WIN32
+    ::SetProcessDPIAware();
+#endif
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());
@@ -36,8 +42,9 @@ int main(int, char**)
 #endif
 
     // Create window with SDL_Renderer graphics context
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+SDL_Renderer example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+SDL_Renderer example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -59,11 +66,19 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForSDLRenderer(window, renderer);
     ImGui_ImplSDLRenderer2_Init(renderer);
@@ -72,16 +87,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state

examples/example_sdl2_vulkan/Makefile

@@ -0,0 +1,80 @@
+#
+# Cross Platform Makefile
+# Compatible with MSYS2/MINGW, Ubuntu 14.04.1 and Mac OS X
+#
+# You will need SDL2 (http://www.libsdl.org):
+# Linux:
+#   apt-get install libsdl2-dev
+# Mac OS X:
+#   brew install sdl2
+# MSYS2:
+#   pacman -S mingw-w64-i686-SDL2
+#
+
+#CXX = g++
+#CXX = clang++
+
+EXE = example_sdl2_vulkan
+IMGUI_DIR = ../..
+SOURCES = main.cpp
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl2.cpp $(IMGUI_DIR)/backends/imgui_impl_vulkan.cpp
+OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
+UNAME_S := $(shell uname -s)
+
+CXXFLAGS = -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+CXXFLAGS += -g -Wall -Wformat
+LIBS =
+
+##---------------------------------------------------------------------
+## BUILD FLAGS PER PLATFORM
+##---------------------------------------------------------------------
+
+ifeq ($(UNAME_S), Linux) #LINUX
+	ECHO_MESSAGE = "Linux"
+	LIBS += -lGL -ldl 
+	LIBS += `pkg-config --libs sdl2 vulkan`
+	CXXFLAGS += `pkg-config --cflags sdl2 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(UNAME_S), Darwin) #APPLE
+	ECHO_MESSAGE = "Mac OS X"
+	LIBS += -framework Cocoa -framework IOKit -framework CoreVideo
+	LIBS += `pkg-config --libs sdl2 vulkan`
+	LIBS += -L/usr/local/lib -L/opt/local/lib
+
+	CXXFLAGS += `pkg-config --cflags sdl2 vulkan`
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(OS), Windows_NT)
+	ECHO_MESSAGE = "MinGW"
+	LIBS += -lgdi32 -lopengl32 -limm32 `pkg-config --static --libs sdl2 vulkan`
+
+	CXXFLAGS += `pkg-config --cflags sdl2 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+##---------------------------------------------------------------------
+## BUILD RULES
+##---------------------------------------------------------------------
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete for $(ECHO_MESSAGE)
+
+$(EXE): $(OBJS)
+	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
+
+clean:
+	rm -f $(EXE) $(OBJS)

examples/example_sdl2_vulkan/main.cpp

@@ -20,6 +20,9 @@
 #include <stdlib.h>         // abort
 #include <SDL.h>
 #include <SDL_vulkan.h>
+#ifdef _WIN32
+#include <windows.h>        // SetProcessDPIAware()
+#endif
 
 // Volk headers
 #ifdef IMGUI_IMPL_VULKAN_USE_VOLK
@@ -30,6 +33,7 @@
 //#define APP_USE_UNLIMITED_FRAME_RATE
 #ifdef _DEBUG
 #define APP_USE_VULKAN_DEBUG_REPORT
+static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 #endif
 
 // Data
@@ -39,7 +43,6 @@ static VkPhysicalDevice         g_PhysicalDevice = VK_NULL_HANDLE;
 static VkDevice                 g_Device = VK_NULL_HANDLE;
 static uint32_t                 g_QueueFamily = (uint32_t)-1;
 static VkQueue                  g_Queue = VK_NULL_HANDLE;
-static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 static VkPipelineCache          g_PipelineCache = VK_NULL_HANDLE;
 static VkDescriptorPool         g_DescriptorPool = VK_NULL_HANDLE;
 
@@ -340,6 +343,9 @@ static void FramePresent(ImGui_ImplVulkanH_Window* wd)
 int main(int, char**)
 {
     // Setup SDL
+#ifdef _WIN32
+    ::SetProcessDPIAware();
+#endif
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());
@@ -352,8 +358,9 @@ int main(int, char**)
 #endif
 
     // Create window with Vulkan graphics context
+    float main_scale = ImGui_ImplSDL2_GetContentScaleForDisplay(0);
     SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+Vulkan example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL2+Vulkan example", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -388,11 +395,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoTaskBarIcons;
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoMerge;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForVulkan(window);
     ImGui_ImplVulkan_InitInfo init_info = {};
@@ -417,16 +442,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -513,17 +538,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_sdl3_metal/Makefile

@@ -0,0 +1,48 @@
+#
+# You will need SDL3 (http://www.libsdl.org):
+#   brew install sdl3
+#
+
+#CXX = g++
+#CXX = clang++
+
+EXE = example_sdl3_metal
+IMGUI_DIR = ../..
+SOURCES = main.mm
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl3.cpp $(IMGUI_DIR)/backends/imgui_impl_metal.mm
+OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
+
+LIBS = -framework Metal -framework MetalKit -framework Cocoa -framework IOKit -framework CoreVideo -framework QuartzCore
+LIBS += `pkg-config --libs sdl3`
+LIBS += -L/usr/local/lib -L/opt/local/lib
+
+CXXFLAGS += `pkg-config --cflags sdl3`
+CXXFLAGS += -I/usr/local/include -I/opt/local/include
+CXXFLAGS += -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+CXXFLAGS += -Wall -Wformat
+CFLAGS = $(CXXFLAGS)
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:%.mm
+	$(CXX) $(CXXFLAGS) -ObjC++ -fobjc-weak -fobjc-arc -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.mm
+	$(CXX) $(CXXFLAGS) -ObjC++ -fobjc-weak -fobjc-arc -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete
+
+$(EXE): $(OBJS)
+	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
+
+clean:
+	rm -f $(EXE) $(OBJS)

examples/example_sdl3_metal/main.mm

@@ -0,0 +1,208 @@
+// Dear ImGui: standalone example application for SDL3 + Metal
+// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
+
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
+
+#include "imgui.h"
+#include "imgui_impl_sdl3.h"
+#include "imgui_impl_metal.h"
+#include <stdio.h>          // printf, fprintf
+#include <SDL3/SDL.h>
+
+#import <Metal/Metal.h>
+#import <QuartzCore/QuartzCore.h>
+
+// Main code
+int main(int, char**)
+{
+    // Setup SDL
+    // [If using SDL_MAIN_USE_CALLBACKS: all code below until the main loop starts would likely be your SDL_AppInit() function]
+    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMEPAD))
+    {
+        printf("Error: SDL_Init(): %s\n", SDL_GetError());
+        return -1;
+    }
+
+    // Create SDL window graphics context
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
+    SDL_WindowFlags window_flags = SDL_WINDOW_METAL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+Metal example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
+    if (window == nullptr)
+    {
+        printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
+        return -1;
+    }
+    SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
+    SDL_ShowWindow(window);
+
+    // Create Metal device _before_ creating the view/layer
+    id<MTLDevice> metalDevice = MTLCreateSystemDefaultDevice(); 
+    if (!metalDevice)
+    {
+        printf("Error: failed to create Metal device.\n");
+        SDL_DestroyWindow(window);
+        SDL_Quit();
+        return -1;
+    }
+    SDL_MetalView view = SDL_Metal_CreateView(window);
+    CAMetalLayer* layer = (__bridge CAMetalLayer*)SDL_Metal_GetLayer(view);
+    layer.device = metalDevice;
+    layer.pixelFormat = MTLPixelFormatBGRA8Unorm;
+
+    id<MTLCommandQueue> commandQueue = [layer.device newCommandQueue];
+    MTLRenderPassDescriptor* renderPassDescriptor = [MTLRenderPassDescriptor new];
+
+    // Setup Dear ImGui context
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO(); (void)io;
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+
+    // Setup Dear ImGui style
+    ImGui::StyleColorsDark();
+    //ImGui::StyleColorsLight();
+
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+
+    // Setup Platform/Renderer backends
+    ImGui_ImplMetal_Init(layer.device);
+    ImGui_ImplSDL3_InitForMetal(window);
+
+    // Load Fonts
+    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
+    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
+    // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
+    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
+    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
+    //io.Fonts->AddFontDefault();
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
+    //IM_ASSERT(font != nullptr);
+
+    // Our state
+    bool show_demo_window = true;
+    bool show_another_window = false;
+    float clear_color[4] = { 0.45f, 0.55f, 0.60f, 1.00f };
+
+    // Main loop
+    bool done = false;
+    while (!done)
+    {
+        @autoreleasepool
+        {
+            // Poll and handle events (inputs, window resize, etc.)
+            // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
+            // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data.
+            // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data.
+            // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
+            // [If using SDL_MAIN_USE_CALLBACKS: call ImGui_ImplSDL3_ProcessEvent() from your SDL_AppEvent() function]
+            SDL_Event event;
+            while (SDL_PollEvent(&event))
+            {
+                ImGui_ImplSDL3_ProcessEvent(&event);
+                if (event.type == SDL_EVENT_QUIT)
+                    done = true;
+                if (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED && event.window.windowID == SDL_GetWindowID(window))
+                    done = true;
+            }
+
+            // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppIterate() function]
+            if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
+            {
+                SDL_Delay(10);
+                continue;
+            }
+
+            int width, height;
+            SDL_GetWindowSizeInPixels(window, &width, &height);
+        
+            layer.drawableSize = CGSizeMake(width, height);
+            id<CAMetalDrawable> drawable = [layer nextDrawable];
+
+            id<MTLCommandBuffer> commandBuffer = [commandQueue commandBuffer];
+            renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(clear_color[0] * clear_color[3], clear_color[1] * clear_color[3], clear_color[2] * clear_color[3], clear_color[3]);
+            renderPassDescriptor.colorAttachments[0].texture = drawable.texture;
+            renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
+            renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;
+            id <MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
+            [renderEncoder pushDebugGroup:@"ImGui demo"];
+
+            // Start the Dear ImGui frame
+            ImGui_ImplMetal_NewFrame(renderPassDescriptor);
+            ImGui_ImplSDL3_NewFrame();
+            ImGui::NewFrame();
+
+            // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
+            if (show_demo_window)
+                ImGui::ShowDemoWindow(&show_demo_window);
+
+            // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
+            {
+                static float f = 0.0f;
+                static int counter = 0;
+
+                ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
+
+                ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
+                ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
+                ImGui::Checkbox("Another Window", &show_another_window);
+
+                ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
+                ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
+
+                if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
+                    counter++;
+                ImGui::SameLine();
+                ImGui::Text("counter = %d", counter);
+
+                ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+                ImGui::End();
+            }
+
+            // 3. Show another simple window.
+            if (show_another_window)
+            {
+                ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
+                ImGui::Text("Hello from another window!");
+                if (ImGui::Button("Close Me"))
+                    show_another_window = false;
+                ImGui::End();
+            }
+
+            // Rendering
+            ImGui::Render();
+            ImDrawData* draw_data = ImGui::GetDrawData();
+            ImGui_ImplMetal_RenderDrawData(draw_data, commandBuffer, renderEncoder);
+
+            [renderEncoder popDebugGroup];
+            [renderEncoder endEncoding];
+
+            [commandBuffer presentDrawable:drawable];
+            [commandBuffer commit];
+        }
+    }
+
+    // Cleanup
+    // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppQuit() function]
+    ImGui_ImplMetal_Shutdown();
+    ImGui_ImplSDL3_Shutdown();
+    ImGui::DestroyContext();
+
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+
+    return 0;
+}

examples/example_sdl3_opengl3/Makefile

@@ -45,10 +45,11 @@ endif
 
 ifeq ($(UNAME_S), Darwin) #APPLE
 	ECHO_MESSAGE = "Mac OS X"
-	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo `sdl3-config --libs`
+	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo
+	LIBS += `pkg-config --libs sdl3`
 	LIBS += -L/usr/local/lib -L/opt/local/lib
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `pkg-config --cflags sdl3`
 	CXXFLAGS += -I/usr/local/include -I/opt/local/include
 	CFLAGS = $(CXXFLAGS)
 endif

examples/example_sdl3_opengl3/main.cpp

@@ -68,14 +68,14 @@ int main(int, char**)
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
     SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
-    Uint32 window_flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN;
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+OpenGL3 example", 1280, 720, window_flags);
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
+    SDL_WindowFlags window_flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+OpenGL3 example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
         return -1;
     }
-    SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
     SDL_GLContext gl_context = SDL_GL_CreateContext(window);
     if (gl_context == nullptr)
     {
@@ -85,6 +85,7 @@ int main(int, char**)
 
     SDL_GL_MakeCurrent(window, gl_context);
     SDL_GL_SetSwapInterval(1); // Enable vsync
+    SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
     SDL_ShowWindow(window);
 
     // Setup Dear ImGui context
@@ -93,11 +94,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL3_Init(glsl_version);
@@ -106,17 +125,17 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -206,6 +225,19 @@ int main(int, char**)
         glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        // Update and Render additional Platform Windows
+        // (Platform functions may change the current OpenGL context, so we save/restore it to make it easier to paste this code elsewhere.
+        //  For this specific demo app we could also call SDL_GL_MakeCurrent(window, gl_context) directly)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            SDL_Window* backup_current_window = SDL_GL_GetCurrentWindow();
+            SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+        }
+
         SDL_GL_SwapWindow(window);
     }
 #ifdef __EMSCRIPTEN__

examples/example_sdl3_sdlgpu3/main.cpp

@@ -1,4 +1,5 @@
 // Dear ImGui: standalone example application for SDL3 + SDL_GPU
+// (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
 
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq
@@ -7,7 +8,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // Important note to the reader who wish to integrate imgui_impl_sdlgpu3.cpp/.h in their own engine/app.
-// - Unlike other backends, the user must call the function Imgui_ImplSDLGPU_PrepareDrawData() BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU_RenderDrawData.
+// - Unlike other backends, the user must call the function ImGui_ImplSDLGPU_PrepareDrawData() BEFORE issuing a SDL_GPURenderPass containing ImGui_ImplSDLGPU_RenderDrawData.
 //   Calling the function is MANDATORY, otherwise the ImGui will not upload neither the vertex nor the index buffer for the GPU. See imgui_impl_sdlgpu3.cpp for more info.
 
 #include "imgui.h"
@@ -34,12 +35,16 @@ int main(int, char**)
     }
 
     // Create SDL window graphics context
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_GPU example", 1280, 720, SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIGH_PIXEL_DENSITY);
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
+    SDL_WindowFlags window_flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_GPU example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
         return -1;
     }
+    SDL_SetWindowPosition(window, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
+    SDL_ShowWindow(window);
 
     // Create GPU Device
     SDL_GPUDevice* gpu_device = SDL_CreateGPUDevice(SDL_GPU_SHADERFORMAT_SPIRV | SDL_GPU_SHADERFORMAT_DXIL | SDL_GPU_SHADERFORMAT_METALLIB,true,nullptr);
@@ -55,7 +60,7 @@ int main(int, char**)
         printf("Error: SDL_ClaimWindowForGPUDevice(): %s\n", SDL_GetError());
         return -1;
     }
-    SDL_SetGPUSwapchainParameters(gpu_device, window, SDL_GPU_SWAPCHAINCOMPOSITION_SDR, SDL_GPU_PRESENTMODE_MAILBOX);
+    SDL_SetGPUSwapchainParameters(gpu_device, window, SDL_GPU_SWAPCHAINCOMPOSITION_SDR, SDL_GPU_PRESENTMODE_VSYNC);
 
     // Setup Dear ImGui context
     IMGUI_CHECKVERSION();
@@ -63,33 +68,51 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForSDLGPU(window);
     ImGui_ImplSDLGPU3_InitInfo init_info = {};
     init_info.Device = gpu_device;
     init_info.ColorTargetFormat = SDL_GetGPUSwapchainTextureFormat(gpu_device, window);
-    init_info.MSAASamples = SDL_GPU_SAMPLECOUNT_1;
+    init_info.MSAASamples = SDL_GPU_SAMPLECOUNT_1;                      // Only used in multi-viewports mode.
+    init_info.SwapchainComposition = SDL_GPU_SWAPCHAINCOMPOSITION_SDR;  // Only used in multi-viewports mode.
+    init_info.PresentMode = SDL_GPU_PRESENTMODE_VSYNC;
     ImGui_ImplSDLGPU3_Init(&init_info);
 
     // Load Fonts
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -145,7 +168,7 @@ int main(int, char**)
             ImGui::Checkbox("Another Window", &show_another_window);
 
             ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
-            ImGui::ColorEdit4("clear color", (float*)&clear_color); // Edit 3 floats representing a color
+            ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
 
             if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
                 counter++;
@@ -174,12 +197,12 @@ int main(int, char**)
         SDL_GPUCommandBuffer* command_buffer = SDL_AcquireGPUCommandBuffer(gpu_device); // Acquire a GPU command buffer
 
         SDL_GPUTexture* swapchain_texture;
-        SDL_AcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, nullptr, nullptr); // Acquire a swapchain texture
+        SDL_WaitAndAcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, nullptr, nullptr); // Acquire a swapchain texture
 
         if (swapchain_texture != nullptr && !is_minimized)
         {
-            // This is mandatory: call Imgui_ImplSDLGPU3_PrepareDrawData() to upload the vertex/index buffer!
-            Imgui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer);
+            // This is mandatory: call ImGui_ImplSDLGPU3_PrepareDrawData() to upload the vertex/index buffer!
+            ImGui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer);
 
             // Setup and start a render pass
             SDL_GPUColorTargetInfo target_info = {};
@@ -198,6 +221,13 @@ int main(int, char**)
             SDL_EndGPURenderPass(render_pass);
         }
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Submit the command buffer
         SDL_SubmitGPUCommandBuffer(command_buffer);
     }

examples/example_sdl3_sdlrenderer3/Makefile

@@ -26,7 +26,7 @@ LIBS =
 
 ifeq ($(UNAME_S), Linux) #LINUX
 	ECHO_MESSAGE = "Linux"
-	LIBS += -ldl `pkg-config sdl3  --libs`
+	LIBS += -ldl `pkg-config sdl3 --libs`
 
 	CXXFLAGS += `pkg-config sdl3 --cflags`
 	CFLAGS = $(CXXFLAGS)
@@ -34,10 +34,11 @@ endif
 
 ifeq ($(UNAME_S), Darwin) #APPLE
 	ECHO_MESSAGE = "Mac OS X"
-	LIBS += -framework Cocoa -framework IOKit -framework CoreVideo `sdl3-config --libs`
+	LIBS += -framework Cocoa -framework IOKit -framework CoreVideo
+	LIBS += `pkg-config --libs sdl3`
 	LIBS += -L/usr/local/lib -L/opt/local/lib
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `pkg-config --cflags sdl3`
 	CXXFLAGS += -I/usr/local/include -I/opt/local/include
 	CFLAGS = $(CXXFLAGS)
 endif

examples/example_sdl3_sdlrenderer3/main.cpp

@@ -32,8 +32,9 @@ int main(int, char**)
     }
 
     // Create window with SDL_Renderer graphics context
-    Uint32 window_flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN;
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_Renderer example", 1280, 720, window_flags);
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
+    SDL_WindowFlags window_flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_Renderer example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -55,11 +56,19 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    //io.ConfigDpiScaleFonts = true;        // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    //io.ConfigDpiScaleViewports = true;    // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForSDLRenderer(window, renderer);
     ImGui_ImplSDLRenderer3_Init(renderer);
@@ -68,17 +77,17 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
     // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details.
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -164,7 +173,7 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        //SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
+        SDL_SetRenderScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
         SDL_SetRenderDrawColorFloat(renderer, clear_color.x, clear_color.y, clear_color.z, clear_color.w);
         SDL_RenderClear(renderer);
         ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData(), renderer);

examples/example_sdl3_vulkan/Makefile

@@ -0,0 +1,77 @@
+#
+# Cross Platform Makefile
+# Compatible with MSYS2/MINGW, Ubuntu 14.04.1 and Mac OS X
+#
+# You will need SDL3 (http://www.libsdl.org) which is still unreleased/unpackaged.
+# Mac OS X:
+#   brew install sdl3
+
+#CXX = g++
+#CXX = clang++
+
+EXE = example_sdl3_vulkan
+IMGUI_DIR = ../..
+SOURCES = main.cpp
+SOURCES += $(IMGUI_DIR)/imgui.cpp $(IMGUI_DIR)/imgui_demo.cpp $(IMGUI_DIR)/imgui_draw.cpp $(IMGUI_DIR)/imgui_tables.cpp $(IMGUI_DIR)/imgui_widgets.cpp
+SOURCES += $(IMGUI_DIR)/backends/imgui_impl_sdl3.cpp $(IMGUI_DIR)/backends/imgui_impl_vulkan.cpp
+OBJS = $(addsuffix .o, $(basename $(notdir $(SOURCES))))
+UNAME_S := $(shell uname -s)
+
+CXXFLAGS = -std=c++11 -I$(IMGUI_DIR) -I$(IMGUI_DIR)/backends
+CXXFLAGS += -g -Wall -Wformat
+LIBS =
+
+
+##---------------------------------------------------------------------
+## BUILD FLAGS PER PLATFORM
+##---------------------------------------------------------------------
+
+ifeq ($(UNAME_S), Linux) #LINUX
+	ECHO_MESSAGE = "Linux"
+	LIBS += -ldl
+	LIBS += `pkg-config --libs sdl3 vulkan`
+
+	CXXFLAGS += `pkg-config --cflags sdl3 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(UNAME_S), Darwin) #APPLE
+	ECHO_MESSAGE = "Mac OS X"
+	LIBS += -framework Cocoa -framework IOKit -framework CoreVideo 
+	LIBS += `pkg-config --libs sdl3 vulkan`
+	LIBS += -L/usr/local/lib -L/opt/local/lib
+
+	CXXFLAGS += `pkg-config --cflags sdl3 vulkan`
+	CXXFLAGS += -I/usr/local/include -I/opt/local/include
+	CFLAGS = $(CXXFLAGS)
+endif
+
+ifeq ($(OS), Windows_NT)
+	ECHO_MESSAGE = "MinGW"
+	LIBS += -lgdi32 -limm32 `pkg-config --static --libs sdl3 vulkan`
+
+	CXXFLAGS += `pkg-config --cflags sdl3 vulkan`
+	CFLAGS = $(CXXFLAGS)
+endif
+
+##---------------------------------------------------------------------
+## BUILD RULES
+##---------------------------------------------------------------------
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+%.o:$(IMGUI_DIR)/backends/%.cpp
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+all: $(EXE)
+	@echo Build complete for $(ECHO_MESSAGE)
+
+$(EXE): $(OBJS)
+	$(CXX) -o $@ $^ $(CXXFLAGS) $(LIBS)
+
+clean:
+	rm -f $(EXE) $(OBJS)

examples/example_sdl3_vulkan/main.cpp

@@ -35,6 +35,7 @@
 //#define APP_USE_UNLIMITED_FRAME_RATE
 #ifdef _DEBUG
 #define APP_USE_VULKAN_DEBUG_REPORT
+static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 #endif
 
 // Data
@@ -44,7 +45,6 @@ static VkPhysicalDevice         g_PhysicalDevice = VK_NULL_HANDLE;
 static VkDevice                 g_Device = VK_NULL_HANDLE;
 static uint32_t                 g_QueueFamily = (uint32_t)-1;
 static VkQueue                  g_Queue = VK_NULL_HANDLE;
-static VkDebugReportCallbackEXT g_DebugReport = VK_NULL_HANDLE;
 static VkPipelineCache          g_PipelineCache = VK_NULL_HANDLE;
 static VkDescriptorPool         g_DescriptorPool = VK_NULL_HANDLE;
 
@@ -353,8 +353,9 @@ int main(int, char**)
     }
 
     // Create window with Vulkan graphics context
-    SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIGH_PIXEL_DENSITY | SDL_WINDOW_HIDDEN);
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+Vulkan example", 1280, 720, window_flags);
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
+    SDL_WindowFlags window_flags = SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+Vulkan example", (int)(1280 * main_scale), (int)(800 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -393,11 +394,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoTaskBarIcons;
+    //io.ConfigFlags |= ImGuiConfigFlags_ViewportsNoMerge;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForVulkan(window);
     ImGui_ImplVulkan_InitInfo init_info = {};
@@ -422,16 +441,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -521,17 +540,25 @@ int main(int, char**)
 
         // Rendering
         ImGui::Render();
-        ImDrawData* draw_data = ImGui::GetDrawData();
-        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);
-        if (!is_minimized)
+        ImDrawData* main_draw_data = ImGui::GetDrawData();
+        const bool main_is_minimized = (main_draw_data->DisplaySize.x <= 0.0f || main_draw_data->DisplaySize.y <= 0.0f);
+        wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
+        wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
+        wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
+        wd->ClearValue.color.float32[3] = clear_color.w;
+        if (!main_is_minimized)
+            FrameRender(wd, main_draw_data);
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
         {
-            wd->ClearValue.color.float32[0] = clear_color.x * clear_color.w;
-            wd->ClearValue.color.float32[1] = clear_color.y * clear_color.w;
-            wd->ClearValue.color.float32[2] = clear_color.z * clear_color.w;
-            wd->ClearValue.color.float32[3] = clear_color.w;
-            FrameRender(wd, draw_data);
-            FramePresent(wd);
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
         }
+
+        // Present Main Platform Window
+        if (!main_is_minimized)
+            FramePresent(wd);
     }
 
     // Cleanup

examples/example_win32_directx10/main.cpp

@@ -30,11 +30,14 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 // Main code
 int main(int, char**)
 {
+    // Make process DPI aware and obtain main monitor scale
+    ImGui_ImplWin32_EnableDpiAwareness();
+    float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(::MonitorFromPoint(POINT{ 0, 0 }, MONITOR_DEFAULTTOPRIMARY));
+
     // Create application window
-    //ImGui_ImplWin32_EnableDpiAwareness();
     WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, L"ImGui Example", nullptr };
     ::RegisterClassExW(&wc);
-    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX10 Example", WS_OVERLAPPEDWINDOW, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
+    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX10 Example", WS_OVERLAPPEDWINDOW, 100, 100, (int)(1280 * main_scale), (int)(800 * main_scale), nullptr, nullptr, wc.hInstance, nullptr);
 
     // Initialize Direct3D
     if (!CreateDeviceD3D(hwnd))
@@ -54,11 +57,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplWin32_Init(hwnd);
     ImGui_ImplDX10_Init(g_pd3dDevice);
@@ -67,16 +88,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -167,6 +188,13 @@ int main(int, char**)
         g_pd3dDevice->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX10_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Present
         HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
         //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
@@ -186,7 +214,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain

examples/example_win32_directx11/main.cpp

@@ -30,11 +30,14 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 // Main code
 int main(int, char**)
 {
+    // Make process DPI aware and obtain main monitor scale
+    ImGui_ImplWin32_EnableDpiAwareness();
+    float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(::MonitorFromPoint(POINT{ 0, 0 }, MONITOR_DEFAULTTOPRIMARY));
+
     // Create application window
-    //ImGui_ImplWin32_EnableDpiAwareness();
     WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, L"ImGui Example", nullptr };
     ::RegisterClassExW(&wc);
-    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX11 Example", WS_OVERLAPPEDWINDOW, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
+    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX11 Example", WS_OVERLAPPEDWINDOW, 100, 100, (int)(1280 * main_scale), (int)(800 * main_scale), nullptr, nullptr, wc.hInstance, nullptr);
 
     // Initialize Direct3D
     if (!CreateDeviceD3D(hwnd))
@@ -54,11 +57,32 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
+    //io.ConfigViewportsNoDefaultParent = true;
+    //io.ConfigDockingAlwaysTabBar = true;
+    //io.ConfigDockingTransparentPayload = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplWin32_Init(hwnd);
     ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
@@ -67,16 +91,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -167,6 +191,13 @@ int main(int, char**)
         g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Present
         HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
         //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
@@ -186,7 +217,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain

examples/example_win32_directx12/main.cpp

@@ -109,11 +109,14 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 // Main code
 int main(int, char**)
 {
+    // Make process DPI aware and obtain main monitor scale
+    ImGui_ImplWin32_EnableDpiAwareness();
+    float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(::MonitorFromPoint(POINT{ 0, 0 }, MONITOR_DEFAULTTOPRIMARY));
+
     // Create application window
-    //ImGui_ImplWin32_EnableDpiAwareness();
     WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, L"ImGui Example", nullptr };
     ::RegisterClassExW(&wc);
-    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX12 Example", WS_OVERLAPPEDWINDOW, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
+    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX12 Example", WS_OVERLAPPEDWINDOW, 100, 100, (int)(1280 * main_scale), (int)(800 * main_scale), nullptr, nullptr, wc.hInstance, nullptr);
 
     // Initialize Direct3D
     if (!CreateDeviceD3D(hwnd))
@@ -133,11 +136,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplWin32_Init(hwnd);
 
@@ -161,16 +182,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -196,7 +217,7 @@ int main(int, char**)
             break;
 
         // Handle window screen locked
-        if (g_SwapChainOccluded && g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED)
+        if ((g_SwapChainOccluded && g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED) || ::IsIconic(hwnd))
         {
             ::Sleep(10);
             continue;
@@ -275,6 +296,13 @@ int main(int, char**)
 
         g_pd3dCommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&g_pd3dCommandList);
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         // Present
         HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
         //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
@@ -301,7 +329,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain

examples/example_win32_directx9/main.cpp

@@ -28,11 +28,14 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 // Main code
 int main(int, char**)
 {
+    // Make process DPI aware and obtain main monitor scale
+    ImGui_ImplWin32_EnableDpiAwareness();
+    float main_scale = ImGui_ImplWin32_GetDpiScaleForMonitor(::MonitorFromPoint(POINT{ 0, 0 }, MONITOR_DEFAULTTOPRIMARY));
+
     // Create application window
-    //ImGui_ImplWin32_EnableDpiAwareness();
     WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, L"ImGui Example", nullptr };
     ::RegisterClassExW(&wc);
-    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX9 Example", WS_OVERLAPPEDWINDOW, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
+    HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX9 Example", WS_OVERLAPPEDWINDOW, 100, 100, (int)(1280 * main_scale), (int)(800 * main_scale), nullptr, nullptr, wc.hInstance, nullptr);
 
     // Initialize Direct3D
     if (!CreateDeviceD3D(hwnd))
@@ -52,11 +55,29 @@ int main(int, char**)
     ImGuiIO& io = ImGui::GetIO(); (void)io;
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;       // Enable Multi-Viewport / Platform Windows
+    //io.ConfigViewportsNoAutoMerge = true;
+    //io.ConfigViewportsNoTaskBarIcon = true;
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+    io.ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
+    io.ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.
+
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplWin32_Init(hwnd);
     ImGui_ImplDX9_Init(g_pd3dDevice);
@@ -65,16 +86,16 @@ int main(int, char**)
     // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
     // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
     // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
-    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
     // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
-    // - Read 'docs/FONTS.md' for more instructions and details.
+    // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author!
     // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
+    //style.FontSizeBase = 20.0f;
     //io.Fonts->AddFontDefault();
-    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
-    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
-    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
+    //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf");
+    //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf");
+    //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf");
     //IM_ASSERT(font != nullptr);
 
     // Our state
@@ -177,6 +198,14 @@ int main(int, char**)
             ImGui_ImplDX9_RenderDrawData(ImGui::GetDrawData());
             g_pd3dDevice->EndScene();
         }
+
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+        }
+
         HRESULT result = g_pd3dDevice->Present(nullptr, nullptr, nullptr, nullptr);
         if (result == D3DERR_DEVICELOST)
             g_DeviceLost = true;
@@ -195,7 +224,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     if ((g_pD3D = Direct3DCreate9(D3D_SDK_VERSION)) == nullptr)