Merge branch 'master' into docking

# Conflicts:
#	imgui.cpp

.github/FUNDING.yml

@@ -1 +1 @@
-custom: ['https://github.com/ocornut/imgui/wiki/Funding']
+custom: ['https://github.com/ocornut/imgui/wiki/Sponsors']

.github/workflows/build.yml

@@ -489,12 +489,12 @@ jobs:
         popd
         make -C examples/example_sdl2_opengl3 -f Makefile.emscripten
 
-    - name: Build example_glfw_wgpu
+    - name: Build example_emscripten_wgpu
       run: |
         pushd emsdk-master
         source ./emsdk_env.sh
         popd
-        make -C examples/example_glfw_wgpu -f Makefile.emscripten
+        make -C examples/example_emscripten_wgpu -f Makefile.emscripten
 
   Android:
     runs-on: ubuntu-22.04

.gitignore

@@ -40,9 +40,8 @@ examples/*.o.tmp
 examples/*.out.js
 examples/*.out.wasm
 examples/example_glfw_opengl3/web/*
-examples/example_glfw_wgpu/web/*
-examples/example_glfw_wgpu/external/*
 examples/example_sdl2_opengl3/web/*
+examples/example_emscripten_wgpu/web/*
 
 ## JetBrains IDE artifacts
 .idea

backends/imgui_impl_allegro5.cpp

@@ -6,7 +6,8 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Clipboard support (from Allegro 5.1.12)
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Issues:
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows)..
 //  [ ] Renderer: The renderer is suboptimal as we need to convert vertices manually.
 //  [ ] Platform: Missing gamepad support.
 
@@ -423,7 +424,6 @@ static ImGuiKey ImGui_ImplAllegro5_KeyCodeToImGuiKey(int key_code)
 bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
 
     // Setup backend capabilities flags
@@ -491,9 +491,8 @@ static void ImGui_ImplAllegro5_UpdateKeyModifiers()
 // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
 bool ImGui_ImplAllegro5_ProcessEvent(ALLEGRO_EVENT* ev)
 {
-    ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplAllegro5_Init()?");
     ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
 
     switch (ev->type)
     {
@@ -588,7 +587,7 @@ static void ImGui_ImplAllegro5_UpdateMouseCursor()
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplAllegro5_Init()?");
 
     if (!bd->Texture)
         ImGui_ImplAllegro5_CreateDeviceObjects();

backends/imgui_impl_allegro5.h

@@ -6,7 +6,8 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Clipboard support (from Allegro 5.1.12)
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Issues:
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows)..
 //  [ ] Renderer: The renderer is suboptimal as we need to unindex our buffers and convert vertices manually.
 //  [ ] Platform: Missing gamepad support.
 

backends/imgui_impl_android.cpp

@@ -8,6 +8,7 @@
 //  [ ] Platform: Clipboard support.
 //  [ ] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [ ] Platform: Mouse cursor shape and visibility. 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)
@@ -263,8 +264,6 @@ int32_t ImGui_ImplAndroid_HandleInputEvent(const AInputEvent* input_event)
 
 bool ImGui_ImplAndroid_Init(ANativeWindow* window)
 {
-    IMGUI_CHECKVERSION();
-
     g_Window = window;
     g_Time = 0.0;
 

backends/imgui_impl_android.h

@@ -8,6 +8,7 @@
 //  [ ] Platform: Clipboard support.
 //  [ ] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [ ] Platform: Mouse cursor shape and visibility. 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

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  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).
 //  2021-05-19: DirectX10: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
@@ -79,6 +81,10 @@ static ImGui_ImplDX10_Data* ImGui_ImplDX10_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX10_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX10_InitPlatformInterface();
+static void ImGui_ImplDX10_ShutdownPlatformInterface();
+
 // Functions
 static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device* ctx)
 {
@@ -534,7 +540,6 @@ void    ImGui_ImplDX10_InvalidateDeviceObjects()
 bool    ImGui_ImplDX10_Init(ID3D10Device* device)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -542,6 +547,7 @@ 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_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -558,6 +564,8 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
     if (pDXGIAdapter) pDXGIAdapter->Release();
     bd->pd3dDevice->AddRef();
 
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX10_InitPlatformInterface();
     return true;
 }
 
@@ -567,24 +575,148 @@ void ImGui_ImplDX10_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX10_ShutdownPlatformInterface();
     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_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 void ImGui_ImplDX10_NewFrame()
 {
     ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX10_Init()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplDX10_Init()?");
 
     if (!bd->pFontSampler)
         ImGui_ImplDX10_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_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_Window*).
+    // 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_InitPlatformInterface()
+{
+    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_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx10.h

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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.

backends/imgui_impl_dx11.cpp

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  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).
 //  2021-05-19: DirectX11: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
@@ -80,6 +82,10 @@ static ImGui_ImplDX11_Data* ImGui_ImplDX11_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX11_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX11_InitPlatformInterface();
+static void ImGui_ImplDX11_ShutdownPlatformInterface();
+
 // Functions
 static void ImGui_ImplDX11_SetupRenderState(ImDrawData* draw_data, ID3D11DeviceContext* ctx)
 {
@@ -546,7 +552,6 @@ void    ImGui_ImplDX11_InvalidateDeviceObjects()
 bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_context)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -554,6 +559,7 @@ 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_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     // Get factory from device
     IDXGIDevice* pDXGIDevice = nullptr;
@@ -573,6 +579,9 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
     bd->pd3dDevice->AddRef();
     bd->pd3dDeviceContext->AddRef();
 
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX11_InitPlatformInterface();
+
     return true;
 }
 
@@ -582,25 +591,149 @@ void ImGui_ImplDX11_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX11_ShutdownPlatformInterface();
     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_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplDX11_Init()?");
 
     if (!bd->pFontSampler)
         ImGui_ImplDX11_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_ImplDX11_ViewportData
+{
+    IDXGISwapChain*                 SwapChain;
+    ID3D11RenderTargetView*         RTView;
+
+    ImGui_ImplDX11_ViewportData()   { SwapChain = nullptr; RTView = nullptr; }
+    ~ImGui_ImplDX11_ViewportData()  { IM_ASSERT(SwapChain == nullptr && RTView == nullptr); }
+};
+
+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_Window*).
+    // 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)
+    {
+        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_InitPlatformInterface()
+{
+    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;
+}
+
+static void ImGui_ImplDX11_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx11.h

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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.

backends/imgui_impl_dx12.cpp

@@ -4,6 +4,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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.
 
 // Important: to compile on 32-bit systems, this backend requires code to be compiled with '#define ImTextureID ImU64'.
 // This is because we need ImTextureID to carry a 64-bit value and by default ImTextureID is defined as void*.
@@ -23,6 +25,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  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).
 //  2021-05-19: DirectX12: Replaced direct access to ImDrawCmd::TextureId with a call to ImDrawCmd::GetTexID(). (will become a requirement)
@@ -54,7 +57,6 @@
 #endif
 
 // DirectX data
-struct ImGui_ImplDX12_RenderBuffers;
 struct ImGui_ImplDX12_Data
 {
     ID3D12Device*               pd3dDevice;
@@ -67,10 +69,7 @@ struct ImGui_ImplDX12_Data
     ID3D12DescriptorHeap*       pd3dSrvDescHeap;
     UINT                        numFramesInFlight;
 
-    ImGui_ImplDX12_RenderBuffers* pFrameResources;
-    UINT                        frameIndex;
-
-    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
@@ -89,11 +88,88 @@ 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* ctx, ImGui_ImplDX12_RenderBuffers* fr)
 {
@@ -167,11 +243,10 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
         return;
 
-    // FIXME: I'm 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_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)
@@ -678,6 +753,13 @@ bool    ImGui_ImplDX12_CreateDeviceObjects()
     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();
@@ -689,20 +771,12 @@ void    ImGui_ImplDX12_InvalidateDeviceObjects()
     SafeRelease(bd->pPipelineState);
     SafeRelease(bd->pFontTextureResource);
     io.Fonts->SetTexID(0); // We copied bd->pFontTextureView 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);
-    }
 }
 
 bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FORMAT rtv_format, ID3D12DescriptorHeap* cbv_srv_heap,
                          D3D12_CPU_DESCRIPTOR_HANDLE font_srv_cpu_desc_handle, D3D12_GPU_DESCRIPTOR_HANDLE font_srv_gpu_desc_handle)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -710,25 +784,21 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
     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_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX12_InitPlatformInterface();
 
     bd->pd3dDevice = device;
     bd->RTVFormat = rtv_format;
     bd->hFontSrvCpuDescHandle = font_srv_cpu_desc_handle;
     bd->hFontSrvGpuDescHandle = font_srv_gpu_desc_handle;
-    bd->pFrameResources = new ImGui_ImplDX12_RenderBuffers[num_frames_in_flight];
     bd->numFramesInFlight = num_frames_in_flight;
     bd->pd3dSrvDescHeap = cbv_srv_heap;
-    bd->frameIndex = UINT_MAX;
 
-    // Create buffers with a default size (they will later be grown as needed)
-    for (int i = 0; i < num_frames_in_flight; i++)
-    {
-        ImGui_ImplDX12_RenderBuffers* fr = &bd->pFrameResources[i];
-        fr->IndexBuffer = nullptr;
-        fr->VertexBuffer = nullptr;
-        fr->IndexBufferSize = 10000;
-        fr->VertexBufferSize = 5000;
-    }
+    // 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);
 
     return true;
 }
@@ -739,24 +809,276 @@ 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_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 void ImGui_ImplDX12_NewFrame()
 {
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplDX12_Init()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplDX12_Init()?");
 
     if (!bd->pPipelineState)
         ImGui_ImplDX12_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_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_Window*).
+    // 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, (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();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx12.h

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // Important: to compile on 32-bit systems, this backend requires code to be compiled with '#define ImTextureID ImU64'.
 // See imgui_impl_dx12.cpp file for details.

backends/imgui_impl_dx9.cpp

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  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.
 //  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).
@@ -76,6 +78,12 @@ static ImGui_ImplDX9_Data* ImGui_ImplDX9_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplDX9_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplDX9_InitPlatformInterface();
+static void ImGui_ImplDX9_ShutdownPlatformInterface();
+static void ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
+static void ImGui_ImplDX9_InvalidateDeviceObjectsForPlatformWindows();
+
 // Functions
 static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
 {
@@ -272,6 +280,11 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
         global_vtx_offset += cmd_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
     bd->pd3dDevice->SetTransform(D3DTS_WORLD, &last_world);
     bd->pd3dDevice->SetTransform(D3DTS_VIEW, &last_view);
@@ -285,7 +298,6 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
 bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -293,10 +305,14 @@ 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_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     bd->pd3dDevice = device;
     bd->pd3dDevice->AddRef();
 
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplDX9_InitPlatformInterface();
+
     return true;
 }
 
@@ -306,11 +322,12 @@ void ImGui_ImplDX9_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplDX9_ShutdownPlatformInterface();
     ImGui_ImplDX9_InvalidateDeviceObjects();
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
@@ -384,6 +401,7 @@ bool ImGui_ImplDX9_CreateDeviceObjects()
         return false;
     if (!ImGui_ImplDX9_CreateFontsTexture())
         return false;
+    ImGui_ImplDX9_CreateDeviceObjectsForPlatformWindows();
     return true;
 }
 
@@ -395,17 +413,160 @@ void ImGui_ImplDX9_InvalidateDeviceObjects()
     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_ASSERT(bd != nullptr && "Did you call ImGui_ImplDX9_Init()?");
 
     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_Window*).
+    // 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_InitPlatformInterface()
+{
+    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_ShutdownPlatformInterface()
+{
+    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]);
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_dx9.h

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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.

backends/imgui_impl_glfw.cpp

@@ -9,6 +9,9 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange' (note: the resizing cursors requires GLFW 3.4+).
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Issues:
+//  [ ] 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.
@@ -20,6 +23,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2023-12-19: Emscripten: Added ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback() to register canvas selector and auto-resize GLFW window.
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F24 function keys.
 //  2023-07-18: Inputs: Revert ignoring mouse data on GLFW_CURSOR_DISABLED as it can be used differently. User may set ImGuiConfigFLags_NoMouse if desired. (#5625, #6609)
@@ -28,6 +32,7 @@
 //  2023-03-16: Inputs: Fixed key modifiers handling on secondary viewports (docking branch). Broken on 2023/01/04. (#6248, #6034)
 //  2023-03-14: Emscripten: Avoid using glfwGetError() and glfwGetGamepadState() which are not correctly implemented in Emscripten emulation. (#6240)
 //  2023-02-03: Emscripten: Registering custom low-level mouse wheel handler to get more accurate scrolling impulses on Emscripten. (#4019, #6096)
+//  2023-01-18: Handle unsupported glfwGetVideoMode() call on e.g. Emscripten.
 //  2023-01-04: Inputs: Fixed mods state on Linux when using Alt-GR text input (e.g. German keyboard layout), could lead to broken text input. Revert a 2022/01/17 change were we resumed using mods provided by GLFW, turns out they were faulty.
 //  2022-11-22: Perform a dummy glfwGetError() read to cancel missing names with glfwGetKeyName(). (#5908)
 //  2022-10-18: Perform a dummy glfwGetError() read to cancel missing mouse cursors errors. Using GLFW_VERSION_COMBINED directly. (#5785)
@@ -85,15 +90,11 @@
 
 #ifdef _WIN32
 #undef APIENTRY
-#ifndef GLFW_EXPOSE_NATIVE_WIN32
 #define GLFW_EXPOSE_NATIVE_WIN32
-#endif
 #include <GLFW/glfw3native.h>   // for glfwGetWin32Window()
 #endif
 #ifdef __APPLE__
-#ifndef GLFW_EXPOSE_NATIVE_COCOA
 #define GLFW_EXPOSE_NATIVE_COCOA
-#endif
 #include <GLFW/glfw3native.h>   // for glfwGetCocoaWindow()
 #endif
 
@@ -104,11 +105,29 @@
 
 // We gather version tests as define in order to easily see which features are version-dependent.
 #define GLFW_VERSION_COMBINED           (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 + GLFW_VERSION_REVISION)
+#define GLFW_HAS_WINDOW_TOPMOST         (GLFW_VERSION_COMBINED >= 3200) // 3.2+ GLFW_FLOATING
+#define GLFW_HAS_WINDOW_HOVERED         (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_HOVERED
+#define GLFW_HAS_WINDOW_ALPHA           (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwSetWindowOpacity
+#define GLFW_HAS_PER_MONITOR_DPI        (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorContentScale
+#if defined(__EMSCRIPTEN__) || defined(__SWITCH__)                      // no Vulkan support in GLFW for Emscripten or homebrew Nintendo Switch
+#define GLFW_HAS_VULKAN                 (0)
+#else
+#define GLFW_HAS_VULKAN                 (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwCreateWindowSurface
+#endif
+#define GLFW_HAS_FOCUS_WINDOW           (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwFocusWindow
+#define GLFW_HAS_FOCUS_ON_SHOW          (GLFW_VERSION_COMBINED >= 3300) // 3.3+ GLFW_FOCUS_ON_SHOW
+#define GLFW_HAS_MONITOR_WORK_AREA      (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorWorkarea
+#define GLFW_HAS_OSX_WINDOW_POS_FIX     (GLFW_VERSION_COMBINED >= 3301) // 3.3.1+ Fixed: Resizing window repositions it on MacOS #1553
 #ifdef GLFW_RESIZE_NESW_CURSOR          // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
 #define GLFW_HAS_NEW_CURSORS            (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
 #else
 #define GLFW_HAS_NEW_CURSORS            (0)
 #endif
+#ifdef GLFW_MOUSE_PASSTHROUGH           // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2020-07-17 (passthrough)
+#define GLFW_HAS_MOUSE_PASSTHROUGH      (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_MOUSE_PASSTHROUGH
+#else
+#define GLFW_HAS_MOUSE_PASSTHROUGH      (0)
+#endif
 #define GLFW_HAS_GAMEPAD_API            (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetGamepadState() new api
 #define GLFW_HAS_GETKEYNAME             (GLFW_VERSION_COMBINED >= 3200) // 3.2+ glfwGetKeyName()
 #define GLFW_HAS_GETERROR               (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetError()
@@ -129,8 +148,10 @@ struct ImGui_ImplGlfw_Data
     GLFWwindow*             MouseWindow;
     GLFWcursor*             MouseCursors[ImGuiMouseCursor_COUNT];
     ImVec2                  LastValidMousePos;
+    GLFWwindow*             KeyOwnerWindows[GLFW_KEY_LAST];
     bool                    InstalledCallbacks;
     bool                    CallbacksChainForAllWindows;
+    bool                    WantUpdateMonitors;
 #ifdef __EMSCRIPTEN__
     const char*             CanvasSelector;
 #endif
@@ -145,7 +166,7 @@ struct ImGui_ImplGlfw_Data
     GLFWcharfun             PrevUserCallbackChar;
     GLFWmonitorfun          PrevUserCallbackMonitor;
 #ifdef _WIN32
-    WNDPROC                 GlfwWndProc;
+    WNDPROC                 PrevWndProc;
 #endif
 
     ImGui_ImplGlfw_Data()   { memset((void*)this, 0, sizeof(*this)); }
@@ -163,6 +184,11 @@ static ImGui_ImplGlfw_Data* ImGui_ImplGlfw_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplGlfw_Data*)ImGui::GetIO().BackendPlatformUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplGlfw_UpdateMonitors();
+static void ImGui_ImplGlfw_InitPlatformInterface();
+static void ImGui_ImplGlfw_ShutdownPlatformInterface();
+
 // Functions
 static const char* ImGui_ImplGlfw_GetClipboardText(void* user_data)
 {
@@ -388,6 +414,9 @@ void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, i
 
     ImGui_ImplGlfw_UpdateKeyModifiers(window);
 
+    if (keycode >= 0 && keycode < IM_ARRAYSIZE(bd->KeyOwnerWindows))
+        bd->KeyOwnerWindows[keycode] = (action == GLFW_PRESS) ? window : nullptr;
+
     keycode = ImGui_ImplGlfw_TranslateUntranslatedKey(keycode, scancode);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -413,6 +442,13 @@ void ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y)
         bd->PrevUserCallbackCursorPos(window, x, y);
 
     ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        int window_x, window_y;
+        glfwGetWindowPos(window, &window_x, &window_y);
+        x += window_x;
+        y += window_y;
+    }
     io.AddMousePosEvent((float)x, (float)y);
     bd->LastValidMousePos = ImVec2((float)x, (float)y);
 }
@@ -451,7 +487,8 @@ void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
 
 void ImGui_ImplGlfw_MonitorCallback(GLFWmonitor*, int)
 {
-	// Unused in 'master' branch but 'docking' branch will use this, so we declare it ahead of it so if you have to install callbacks you can install this one too.
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    bd->WantUpdateMonitors = true;
 }
 
 #ifdef __EMSCRIPTEN__
@@ -473,32 +510,7 @@ static EM_BOOL ImGui_ImplEmscripten_WheelCallback(int, const EmscriptenWheelEven
 #endif
 
 #ifdef _WIN32
-// GLFW doesn't allow to distinguish Mouse vs TouchScreen vs Pen.
-// Add support for Win32 (based on imgui_impl_win32), because we rely on _TouchScreen info to trickle inputs differently.
-static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
-{
-    LPARAM extra_info = ::GetMessageExtraInfo();
-    if ((extra_info & 0xFFFFFF80) == 0xFF515700)
-        return ImGuiMouseSource_Pen;
-    if ((extra_info & 0xFFFFFF80) == 0xFF515780)
-        return ImGuiMouseSource_TouchScreen;
-    return ImGuiMouseSource_Mouse;
-}
-static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
-{
-    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    switch (msg)
-    {
-    case WM_MOUSEMOVE: case WM_NCMOUSEMOVE:
-    case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK: case WM_LBUTTONUP:
-    case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK: case WM_RBUTTONUP:
-    case WM_MBUTTONDOWN: case WM_MBUTTONDBLCLK: case WM_MBUTTONUP:
-    case WM_XBUTTONDOWN: case WM_XBUTTONDBLCLK: case WM_XBUTTONUP:
-        ImGui::GetIO().AddMouseSourceEvent(GetMouseSourceFromMessageExtraInfo());
-        break;
-    }
-    return ::CallWindowProcW(bd->GlfwWndProc, hWnd, msg, wParam, lParam);
-}
+static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 #endif
 
 void ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window)
@@ -556,7 +568,6 @@ void ImGui_ImplGlfw_SetCallbacksChainForAllWindows(bool chain_for_all_windows)
 static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, GlfwClientApi client_api)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
     //printf("GLFW_VERSION: %d.%d.%d (%d)", GLFW_VERSION_MAJOR, GLFW_VERSION_MINOR, GLFW_VERSION_REVISION, GLFW_VERSION_COMBINED);
 
@@ -566,9 +577,16 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     io.BackendPlatformName = "imgui_impl_glfw";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
+#ifndef __EMSCRIPTEN__
+    io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
+#endif
+#if GLFW_HAS_MOUSE_PASSTHROUGH || GLFW_HAS_WINDOW_HOVERED
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can call io.AddMouseViewportEvent() with correct data (optional)
+#endif
 
     bd->Window = window;
     bd->Time = 0.0;
+    bd->WantUpdateMonitors = true;
 
     io.SetClipboardTextFn = ImGui_ImplGlfw_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplGlfw_GetClipboardText;
@@ -610,8 +628,13 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     emscripten_set_wheel_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, nullptr, false, ImGui_ImplEmscripten_WheelCallback);
 #endif
 
+    // Update monitors the first time (note: monitor callback are broken in GLFW 3.2 and earlier, see github.com/glfw/glfw/issues/784)
+    ImGui_ImplGlfw_UpdateMonitors();
+    glfwSetMonitorCallback(ImGui_ImplGlfw_MonitorCallback);
+
     // Set platform dependent data in viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->PlatformHandle = (void*)bd->Window;
 #ifdef _WIN32
     main_viewport->PlatformHandleRaw = glfwGetWin32Window(bd->Window);
 #elif defined(__APPLE__)
@@ -619,11 +642,13 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 #else
     IM_UNUSED(main_viewport);
 #endif
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplGlfw_InitPlatformInterface();
 
     // Windows: register a WndProc hook so we can intercept some messages.
 #ifdef _WIN32
-    bd->GlfwWndProc = (WNDPROC)::GetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC);
-    IM_ASSERT(bd->GlfwWndProc != nullptr);
+    bd->PrevWndProc = (WNDPROC)::GetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC);
+    IM_ASSERT(bd->PrevWndProc != nullptr);
     ::SetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplGlfw_WndProc);
 #endif
 
@@ -652,6 +677,8 @@ void ImGui_ImplGlfw_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplGlfw_ShutdownPlatformInterface();
+
     if (bd->InstalledCallbacks)
         ImGui_ImplGlfw_RestoreCallbacks(bd->Window);
 #ifdef __EMSCRIPTEN__
@@ -661,16 +688,16 @@ void ImGui_ImplGlfw_Shutdown()
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
         glfwDestroyCursor(bd->MouseCursors[cursor_n]);
 
-    // Windows: register a WndProc hook so we can intercept some messages.
+    // Windows: restore our WndProc hook
 #ifdef _WIN32
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
-    ::SetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC, (LONG_PTR)bd->GlfwWndProc);
-    bd->GlfwWndProc = nullptr;
+    ::SetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC, (LONG_PTR)bd->PrevWndProc);
+    bd->PrevWndProc = nullptr;
 #endif
 
     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);
 }
 
@@ -678,10 +705,15 @@ static void ImGui_ImplGlfw_UpdateMouseData()
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
     ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
 
-    // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
+    ImGuiID mouse_viewport_id = 0;
+    const ImVec2 mouse_pos_prev = io.MousePos;
+    for (int n = 0; n < platform_io.Viewports.Size; n++)
     {
-        GLFWwindow* window = bd->Window;
+        ImGuiViewport* viewport = platform_io.Viewports[n];
+        GLFWwindow* window = (GLFWwindow*)viewport->PlatformHandle;
+
 #ifdef __EMSCRIPTEN__
         const bool is_window_focused = true;
 #else
@@ -690,19 +722,54 @@ static void ImGui_ImplGlfw_UpdateMouseData()
         if (is_window_focused)
         {
             // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
+            // When multi-viewports are enabled, all Dear ImGui positions are same as OS positions.
             if (io.WantSetMousePos)
-                glfwSetCursorPos(window, (double)io.MousePos.x, (double)io.MousePos.y);
+                glfwSetCursorPos(window, (double)(mouse_pos_prev.x - viewport->Pos.x), (double)(mouse_pos_prev.y - viewport->Pos.y));
 
             // (Optional) Fallback to provide mouse position when focused (ImGui_ImplGlfw_CursorPosCallback already provides this when hovered or captured)
             if (bd->MouseWindow == nullptr)
             {
                 double mouse_x, mouse_y;
                 glfwGetCursorPos(window, &mouse_x, &mouse_y);
+                if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                {
+                    // 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)
+                    // 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 window_x, window_y;
+                    glfwGetWindowPos(window, &window_x, &window_y);
+                    mouse_x += window_x;
+                    mouse_y += window_y;
+                }
                 bd->LastValidMousePos = ImVec2((float)mouse_x, (float)mouse_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.
+        // - [X] GLFW >= 3.3 backend ON WINDOWS ONLY does correctly ignore viewports with the _NoInputs flag (since we implement hit via our WndProc hook)
+        //       On other platforms we rely on the library fallbacking to its own search when reporting a viewport with _NoInputs flag.
+        // - [!] GLFW <= 3.2 backend CANNOT correctly ignore viewports with the _NoInputs flag, and CANNOT reported Hovered Viewport because of mouse capture.
+        //       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] GLFW backend correctly reports this regardless of another viewport behind focused and dragged from (we need this to find a useful drag and drop target).
+        // FIXME: This is currently only correct on Win32. See what we do below with the WM_NCHITTEST, missing an equivalent for other systems.
+        // See https://github.com/glfw/glfw/issues/1236 if you want to help in making this a GLFW feature.
+#if GLFW_HAS_MOUSE_PASSTHROUGH
+        const bool window_no_input = (viewport->Flags & ImGuiViewportFlags_NoInputs) != 0;
+        glfwSetWindowAttrib(window, GLFW_MOUSE_PASSTHROUGH, window_no_input);
+#endif
+#if GLFW_HAS_MOUSE_PASSTHROUGH || GLFW_HAS_WINDOW_HOVERED
+        if (glfwGetWindowAttrib(window, GLFW_HOVERED))
+            mouse_viewport_id = viewport->ID;
+#else
+        // We cannot use bd->MouseWindow maintained from CursorEnter/Leave callbacks, because it is locked to the window capturing mouse.
+#endif
     }
+
+    if (io.BackendFlags & ImGuiBackendFlags_HasMouseHoveredViewport)
+        io.AddMouseViewportEvent(mouse_viewport_id);
 }
 
 static void ImGui_ImplGlfw_UpdateMouseCursor()
@@ -713,9 +780,10 @@ static void ImGui_ImplGlfw_UpdateMouseCursor()
         return;
 
     ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
-    // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int n = 0; n < platform_io.Viewports.Size; n++)
     {
-        GLFWwindow* window = bd->Window;
+        GLFWwindow* window = (GLFWwindow*)platform_io.Viewports[n]->PlatformHandle;
         if (imgui_cursor == ImGuiMouseCursor_None || io.MouseDrawCursor)
         {
             // Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
@@ -784,11 +852,53 @@ static void ImGui_ImplGlfw_UpdateGamepads()
     #undef MAP_ANALOG
 }
 
+static void ImGui_ImplGlfw_UpdateMonitors()
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    bd->WantUpdateMonitors = false;
+
+    int monitors_count = 0;
+    GLFWmonitor** glfw_monitors = glfwGetMonitors(&monitors_count);
+    if (monitors_count == 0) // Preserve existing monitor list if there are none. Happens on macOS sleeping (#5683)
+        return;
+
+    platform_io.Monitors.resize(0);
+    for (int n = 0; n < monitors_count; n++)
+    {
+        ImGuiPlatformMonitor monitor;
+        int x, y;
+        glfwGetMonitorPos(glfw_monitors[n], &x, &y);
+        const GLFWvidmode* vid_mode = glfwGetVideoMode(glfw_monitors[n]);
+        if (vid_mode == nullptr)
+            continue; // Failed to get Video mode (e.g. Emscripten does not support this function)
+        monitor.MainPos = monitor.WorkPos = ImVec2((float)x, (float)y);
+        monitor.MainSize = monitor.WorkSize = ImVec2((float)vid_mode->width, (float)vid_mode->height);
+#if GLFW_HAS_MONITOR_WORK_AREA
+        int w, h;
+        glfwGetMonitorWorkarea(glfw_monitors[n], &x, &y, &w, &h);
+        if (w > 0 && h > 0) // Workaround a small GLFW issue reporting zero on monitor changes: https://github.com/glfw/glfw/pull/1761
+        {
+            monitor.WorkPos = ImVec2((float)x, (float)y);
+            monitor.WorkSize = ImVec2((float)w, (float)h);
+        }
+#endif
+#if GLFW_HAS_PER_MONITOR_DPI
+        // 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.
+        float x_scale, y_scale;
+        glfwGetMonitorContentScale(glfw_monitors[n], &x_scale, &y_scale);
+        monitor.DpiScale = x_scale;
+#endif
+        monitor.PlatformHandle = (void*)glfw_monitors[n]; // [...] GLFW doc states: "guaranteed to be valid only until the monitor configuration changes"
+        platform_io.Monitors.push_back(monitor);
+    }
+}
+
 void ImGui_ImplGlfw_NewFrame()
 {
     ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplGlfw_InitForXXX()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplGlfw_InitForXXX()?");
 
     // Setup display size (every frame to accommodate for window resizing)
     int w, h;
@@ -798,6 +908,8 @@ void ImGui_ImplGlfw_NewFrame()
     io.DisplaySize = ImVec2((float)w, (float)h);
     if (w > 0 && h > 0)
         io.DisplayFramebufferScale = ImVec2((float)display_w / (float)w, (float)display_h / (float)h);
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplGlfw_UpdateMonitors();
 
     // Setup time step
     // (Accept glfwGetTime() not returning a monotonically increasing value. Seems to happens on disconnecting peripherals and probably on VMs and Emscripten, see #6491, #6189, #6114, #3644)
@@ -839,7 +951,7 @@ void ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_sel
 {
     IM_ASSERT(canvas_selector != nullptr);
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplGlfw_InitForXXX()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplGlfw_InitForXXX()?");
 
     bd->CanvasSelector = canvas_selector;
     emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW, bd, false, ImGui_ImplGlfw_OnCanvasSizeChange);
@@ -850,6 +962,399 @@ void ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_sel
 }
 #endif
 
+
+//--------------------------------------------------------------------------------------------------------
+// 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_ImplGlfw_ViewportData
+{
+    GLFWwindow* Window;
+    bool        WindowOwned;
+    int         IgnoreWindowPosEventFrame;
+    int         IgnoreWindowSizeEventFrame;
+#ifdef _WIN32
+    WNDPROC     PrevWndProc;
+#endif
+
+    ImGui_ImplGlfw_ViewportData()  { memset(this, 0, sizeof(*this)); IgnoreWindowSizeEventFrame = IgnoreWindowPosEventFrame = -1; }
+    ~ImGui_ImplGlfw_ViewportData() { IM_ASSERT(Window == nullptr); }
+};
+
+static void ImGui_ImplGlfw_WindowCloseCallback(GLFWwindow* window)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+        viewport->PlatformRequestClose = true;
+}
+
+// GLFW may dispatch window pos/size events after calling glfwSetWindowPos()/glfwSetWindowSize().
+// However: depending on the platform the callback may be invoked at different time:
+// - on Windows it appears to be called within the glfwSetWindowPos()/glfwSetWindowSize() call
+// - on Linux it is queued and invoked during glfwPollEvents()
+// Because the event doesn't always fire on glfwSetWindowXXX() we use a frame counter tag to only
+// ignore recent glfwSetWindowXXX() calls.
+static void ImGui_ImplGlfw_WindowPosCallback(GLFWwindow* window, int, int)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+    {
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+        {
+            bool ignore_event = (ImGui::GetFrameCount() <= vd->IgnoreWindowPosEventFrame + 1);
+            //data->IgnoreWindowPosEventFrame = -1;
+            if (ignore_event)
+                return;
+        }
+        viewport->PlatformRequestMove = true;
+    }
+}
+
+static void ImGui_ImplGlfw_WindowSizeCallback(GLFWwindow* window, int, int)
+{
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle(window))
+    {
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+        {
+            bool ignore_event = (ImGui::GetFrameCount() <= vd->IgnoreWindowSizeEventFrame + 1);
+            //data->IgnoreWindowSizeEventFrame = -1;
+            if (ignore_event)
+                return;
+        }
+        viewport->PlatformRequestResize = true;
+    }
+}
+
+static void ImGui_ImplGlfw_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = IM_NEW(ImGui_ImplGlfw_ViewportData)();
+    viewport->PlatformUserData = vd;
+
+    // GLFW 3.2 unfortunately always set focus on glfwCreateWindow() if GLFW_VISIBLE is set, regardless of GLFW_FOCUSED
+    // With GLFW 3.3, the hint GLFW_FOCUS_ON_SHOW fixes this problem
+    glfwWindowHint(GLFW_VISIBLE, false);
+    glfwWindowHint(GLFW_FOCUSED, false);
+#if GLFW_HAS_FOCUS_ON_SHOW
+    glfwWindowHint(GLFW_FOCUS_ON_SHOW, false);
+ #endif
+    glfwWindowHint(GLFW_DECORATED, (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? false : true);
+#if GLFW_HAS_WINDOW_TOPMOST
+    glfwWindowHint(GLFW_FLOATING, (viewport->Flags & ImGuiViewportFlags_TopMost) ? true : false);
+#endif
+    GLFWwindow* share_window = (bd->ClientApi == GlfwClientApi_OpenGL) ? bd->Window : nullptr;
+    vd->Window = glfwCreateWindow((int)viewport->Size.x, (int)viewport->Size.y, "No Title Yet", nullptr, share_window);
+    vd->WindowOwned = true;
+    viewport->PlatformHandle = (void*)vd->Window;
+#ifdef _WIN32
+    viewport->PlatformHandleRaw = glfwGetWin32Window(vd->Window);
+#elif defined(__APPLE__)
+    viewport->PlatformHandleRaw = (void*)glfwGetCocoaWindow(vd->Window);
+#endif
+    glfwSetWindowPos(vd->Window, (int)viewport->Pos.x, (int)viewport->Pos.y);
+
+    // Install GLFW callbacks for secondary viewports
+    glfwSetWindowFocusCallback(vd->Window, ImGui_ImplGlfw_WindowFocusCallback);
+    glfwSetCursorEnterCallback(vd->Window, ImGui_ImplGlfw_CursorEnterCallback);
+    glfwSetCursorPosCallback(vd->Window, ImGui_ImplGlfw_CursorPosCallback);
+    glfwSetMouseButtonCallback(vd->Window, ImGui_ImplGlfw_MouseButtonCallback);
+    glfwSetScrollCallback(vd->Window, ImGui_ImplGlfw_ScrollCallback);
+    glfwSetKeyCallback(vd->Window, ImGui_ImplGlfw_KeyCallback);
+    glfwSetCharCallback(vd->Window, ImGui_ImplGlfw_CharCallback);
+    glfwSetWindowCloseCallback(vd->Window, ImGui_ImplGlfw_WindowCloseCallback);
+    glfwSetWindowPosCallback(vd->Window, ImGui_ImplGlfw_WindowPosCallback);
+    glfwSetWindowSizeCallback(vd->Window, ImGui_ImplGlfw_WindowSizeCallback);
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+    {
+        glfwMakeContextCurrent(vd->Window);
+        glfwSwapInterval(0);
+    }
+}
+
+static void ImGui_ImplGlfw_DestroyWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+    {
+        if (vd->WindowOwned)
+        {
+#if !GLFW_HAS_MOUSE_PASSTHROUGH && GLFW_HAS_WINDOW_HOVERED && defined(_WIN32)
+            HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+            ::RemovePropA(hwnd, "IMGUI_VIEWPORT");
+#endif
+
+            // Release any keys that were pressed in the window being destroyed and are still held down,
+            // because we will not receive any release events after window is destroyed.
+            for (int i = 0; i < IM_ARRAYSIZE(bd->KeyOwnerWindows); i++)
+                if (bd->KeyOwnerWindows[i] == vd->Window)
+                    ImGui_ImplGlfw_KeyCallback(vd->Window, i, 0, GLFW_RELEASE, 0); // Later params are only used for main viewport, on which this function is never called.
+
+            glfwDestroyWindow(vd->Window);
+        }
+        vd->Window = nullptr;
+        IM_DELETE(vd);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = nullptr;
+}
+
+static void ImGui_ImplGlfw_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+
+#if defined(_WIN32)
+    // GLFW hack: Hide icon from task bar
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+    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);
+    }
+
+    // GLFW hack: install hook for WM_NCHITTEST message handler
+#if !GLFW_HAS_MOUSE_PASSTHROUGH && GLFW_HAS_WINDOW_HOVERED && defined(_WIN32)
+    ::SetPropA(hwnd, "IMGUI_VIEWPORT", viewport);
+    vd->PrevWndProc = (WNDPROC)::GetWindowLongPtrW(hwnd, GWLP_WNDPROC);
+    ::SetWindowLongPtrW(hwnd, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplGlfw_WndProc);
+#endif
+
+#if !GLFW_HAS_FOCUS_ON_SHOW
+    // GLFW hack: GLFW 3.2 has a bug where glfwShowWindow() also activates/focus the window.
+    // The fix was pushed to GLFW repository on 2018/01/09 and should be included in GLFW 3.3 via a GLFW_FOCUS_ON_SHOW window attribute.
+    // See https://github.com/glfw/glfw/issues/1189
+    // FIXME-VIEWPORT: Implement same work-around for Linux/OSX in the meanwhile.
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+    {
+        ::ShowWindow(hwnd, SW_SHOWNA);
+        return;
+    }
+#endif
+#endif
+
+    glfwShowWindow(vd->Window);
+}
+
+static ImVec2 ImGui_ImplGlfw_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    int x = 0, y = 0;
+    glfwGetWindowPos(vd->Window, &x, &y);
+    return ImVec2((float)x, (float)y);
+}
+
+static void ImGui_ImplGlfw_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    vd->IgnoreWindowPosEventFrame = ImGui::GetFrameCount();
+    glfwSetWindowPos(vd->Window, (int)pos.x, (int)pos.y);
+}
+
+static ImVec2 ImGui_ImplGlfw_GetWindowSize(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    int w = 0, h = 0;
+    glfwGetWindowSize(vd->Window, &w, &h);
+    return ImVec2((float)w, (float)h);
+}
+
+static void ImGui_ImplGlfw_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+#if __APPLE__ && !GLFW_HAS_OSX_WINDOW_POS_FIX
+    // Native OS windows are positioned from the bottom-left corner on macOS, whereas on other platforms they are
+    // positioned from the upper-left corner. GLFW makes an effort to convert macOS style coordinates, however it
+    // doesn't handle it when changing size. We are manually moving the window in order for changes of size to be based
+    // on the upper-left corner.
+    int x, y, width, height;
+    glfwGetWindowPos(vd->Window, &x, &y);
+    glfwGetWindowSize(vd->Window, &width, &height);
+    glfwSetWindowPos(vd->Window, x, y - height + size.y);
+#endif
+    vd->IgnoreWindowSizeEventFrame = ImGui::GetFrameCount();
+    glfwSetWindowSize(vd->Window, (int)size.x, (int)size.y);
+}
+
+static void ImGui_ImplGlfw_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwSetWindowTitle(vd->Window, title);
+}
+
+static void ImGui_ImplGlfw_SetWindowFocus(ImGuiViewport* viewport)
+{
+#if GLFW_HAS_FOCUS_WINDOW
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwFocusWindow(vd->Window);
+#else
+    // FIXME: What are the effect of not having this function? At the moment imgui doesn't actually call SetWindowFocus - we set that up ahead, will answer that question later.
+    (void)viewport;
+#endif
+}
+
+static bool ImGui_ImplGlfw_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    return glfwGetWindowAttrib(vd->Window, GLFW_FOCUSED) != 0;
+}
+
+static bool ImGui_ImplGlfw_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    return glfwGetWindowAttrib(vd->Window, GLFW_ICONIFIED) != 0;
+}
+
+#if GLFW_HAS_WINDOW_ALPHA
+static void ImGui_ImplGlfw_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    glfwSetWindowOpacity(vd->Window, alpha);
+}
+#endif
+
+static void ImGui_ImplGlfw_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+        glfwMakeContextCurrent(vd->Window);
+}
+
+static void ImGui_ImplGlfw_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    if (bd->ClientApi == GlfwClientApi_OpenGL)
+    {
+        glfwMakeContextCurrent(vd->Window);
+        glfwSwapBuffers(vd->Window);
+    }
+}
+
+//--------------------------------------------------------------------------------------------------------
+// Vulkan support (the Vulkan renderer needs to call a platform-side support function to create the surface)
+//--------------------------------------------------------------------------------------------------------
+
+// Avoid including <vulkan.h> so we can build without it
+#if GLFW_HAS_VULKAN
+#ifndef VULKAN_H_
+#define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;
+#if defined(__LP64__) || defined(_WIN64) || defined(__x86_64__) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
+#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
+#else
+#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
+#endif
+VK_DEFINE_HANDLE(VkInstance)
+VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSurfaceKHR)
+struct VkAllocationCallbacks;
+enum VkResult { VK_RESULT_MAX_ENUM = 0x7FFFFFFF };
+#endif // VULKAN_H_
+extern "C" { extern GLFWAPI VkResult glfwCreateWindowSurface(VkInstance instance, GLFWwindow* window, const VkAllocationCallbacks* allocator, VkSurfaceKHR* surface); }
+static int ImGui_ImplGlfw_CreateVkSurface(ImGuiViewport* viewport, ImU64 vk_instance, const void* vk_allocator, ImU64* out_vk_surface)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData;
+    IM_UNUSED(bd);
+    IM_ASSERT(bd->ClientApi == GlfwClientApi_Vulkan);
+    VkResult err = glfwCreateWindowSurface((VkInstance)vk_instance, vd->Window, (const VkAllocationCallbacks*)vk_allocator, (VkSurfaceKHR*)out_vk_surface);
+    return (int)err;
+}
+#endif // GLFW_HAS_VULKAN
+
+static void ImGui_ImplGlfw_InitPlatformInterface()
+{
+    // Register platform interface (will be coupled with a renderer interface)
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Platform_CreateWindow = ImGui_ImplGlfw_CreateWindow;
+    platform_io.Platform_DestroyWindow = ImGui_ImplGlfw_DestroyWindow;
+    platform_io.Platform_ShowWindow = ImGui_ImplGlfw_ShowWindow;
+    platform_io.Platform_SetWindowPos = ImGui_ImplGlfw_SetWindowPos;
+    platform_io.Platform_GetWindowPos = ImGui_ImplGlfw_GetWindowPos;
+    platform_io.Platform_SetWindowSize = ImGui_ImplGlfw_SetWindowSize;
+    platform_io.Platform_GetWindowSize = ImGui_ImplGlfw_GetWindowSize;
+    platform_io.Platform_SetWindowFocus = ImGui_ImplGlfw_SetWindowFocus;
+    platform_io.Platform_GetWindowFocus = ImGui_ImplGlfw_GetWindowFocus;
+    platform_io.Platform_GetWindowMinimized = ImGui_ImplGlfw_GetWindowMinimized;
+    platform_io.Platform_SetWindowTitle = ImGui_ImplGlfw_SetWindowTitle;
+    platform_io.Platform_RenderWindow = ImGui_ImplGlfw_RenderWindow;
+    platform_io.Platform_SwapBuffers = ImGui_ImplGlfw_SwapBuffers;
+#if GLFW_HAS_WINDOW_ALPHA
+    platform_io.Platform_SetWindowAlpha = ImGui_ImplGlfw_SetWindowAlpha;
+#endif
+#if GLFW_HAS_VULKAN
+    platform_io.Platform_CreateVkSurface = ImGui_ImplGlfw_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_ImplGlfw_ViewportData* vd = IM_NEW(ImGui_ImplGlfw_ViewportData)();
+    vd->Window = bd->Window;
+    vd->WindowOwned = false;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = (void*)bd->Window;
+}
+
+static void ImGui_ImplGlfw_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
+//-----------------------------------------------------------------------------
+
+// WndProc hook (declared here because we will need access to ImGui_ImplGlfw_ViewportData)
+#ifdef _WIN32
+static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
+{
+    LPARAM extra_info = ::GetMessageExtraInfo();
+    if ((extra_info & 0xFFFFFF80) == 0xFF515700)
+        return ImGuiMouseSource_Pen;
+    if ((extra_info & 0xFFFFFF80) == 0xFF515780)
+        return ImGuiMouseSource_TouchScreen;
+    return ImGuiMouseSource_Mouse;
+}
+static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    WNDPROC prev_wndproc = bd->PrevWndProc;
+    ImGuiViewport* viewport = (ImGuiViewport*)::GetPropA(hWnd, "IMGUI_VIEWPORT");
+    if (viewport != NULL)
+        if (ImGui_ImplGlfw_ViewportData* vd = (ImGui_ImplGlfw_ViewportData*)viewport->PlatformUserData)
+            prev_wndproc = vd->PrevWndProc;
+
+    switch (msg)
+    {
+        // GLFW doesn't allow to distinguish Mouse vs TouchScreen vs Pen.
+        // Add support for Win32 (based on imgui_impl_win32), because we rely on _TouchScreen info to trickle inputs differently.
+    case WM_MOUSEMOVE: case WM_NCMOUSEMOVE:
+    case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK: case WM_LBUTTONUP:
+    case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK: case WM_RBUTTONUP:
+    case WM_MBUTTONDOWN: case WM_MBUTTONDBLCLK: case WM_MBUTTONUP:
+    case WM_XBUTTONDOWN: case WM_XBUTTONDBLCLK: case WM_XBUTTONUP:
+        ImGui::GetIO().AddMouseSourceEvent(GetMouseSourceFromMessageExtraInfo());
+        break;
+
+        // We have submitted https://github.com/glfw/glfw/pull/1568 to allow GLFW to support "transparent inputs".
+        // In the meanwhile we implement custom per-platform workarounds here (FIXME-VIEWPORT: Implement same work-around for Linux/OSX!)
+#if !GLFW_HAS_MOUSE_PASSTHROUGH && GLFW_HAS_WINDOW_HOVERED
+    case WM_NCHITTEST:
+    {
+        // Let mouse pass-through the window. This will allow the backend to call io.AddMouseViewportEvent() properly (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 && (viewport->Flags & ImGuiViewportFlags_NoInputs))
+            return HTTRANSPARENT;
+        break;
+    }
+#endif
+    }
+    return ::CallWindowProcW(prev_wndproc, hWnd, msg, wParam, lParam);
+}
+#endif // #ifdef _WIN32
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

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.
@@ -8,6 +9,9 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange' (note: the resizing cursors requires GLFW 3.4+).
+//  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// Issues:
+//  [ ] 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.

backends/imgui_impl_glut.cpp

@@ -7,7 +7,7 @@
 
 // Implemented features:
 //  [X] Platform: Partial 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 GLUT values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
-// Issues:
+// Missing features:
 //  [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
 //  [ ] Platform: Missing horizontal mouse wheel support.
 //  [ ] Platform: Missing mouse cursor shape/visibility support.
@@ -167,7 +167,6 @@ static ImGuiKey ImGui_ImplGLUT_KeyToImGuiKey(int key)
 bool ImGui_ImplGLUT_Init()
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
 
 #ifdef FREEGLUT
     io.BackendPlatformName = "imgui_impl_glut (freeglut)";

backends/imgui_impl_glut.h

@@ -7,7 +7,7 @@
 
 // Implemented features:
 //  [X] Platform: Partial 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 GLUT values will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
-// Issues:
+// Missing features:
 //  [ ] Platform: GLUT is unable to distinguish e.g. Backspace from CTRL+H or TAB from CTRL+I
 //  [ ] Platform: Missing horizontal mouse wheel support.
 //  [ ] Platform: Missing mouse cursor shape/visibility support.

backends/imgui_impl_metal.h

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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.

backends/imgui_impl_metal.mm

@@ -4,6 +4,7 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [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 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Metal: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  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.
@@ -38,6 +40,12 @@
 #import <time.h>
 #import <Metal/Metal.h>
 
+// Forward Declarations
+static void ImGui_ImplMetal_InitPlatformInterface();
+static void ImGui_ImplMetal_ShutdownPlatformInterface();
+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
@@ -79,6 +87,7 @@ struct ImGui_ImplMetal_Data
     ImGui_ImplMetal_Data()      { memset(this, 0, sizeof(*this)); }
 };
 
+static ImGui_ImplMetal_Data*    ImGui_ImplMetal_CreateBackendData() { return IM_NEW(ImGui_ImplMetal_Data)(); }
 static ImGui_ImplMetal_Data*    ImGui_ImplMetal_GetBackendData()    { return ImGui::GetCurrentContext() ? (ImGui_ImplMetal_Data*)ImGui::GetIO().BackendRendererUserData : nullptr; }
 static void                     ImGui_ImplMetal_DestroyBackendData(){ IM_DELETE(ImGui_ImplMetal_GetBackendData()); }
 
@@ -124,18 +133,19 @@ bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
 
 bool ImGui_ImplMetal_Init(id<MTLDevice> device)
 {
+    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_CreateBackendData();
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
     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_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     bd->SharedMetalContext = [[MetalContext alloc] init];
     bd->SharedMetalContext.device = device;
 
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplMetal_InitPlatformInterface();
+
     return true;
 }
 
@@ -143,19 +153,20 @@ void ImGui_ImplMetal_Shutdown()
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGui_ImplMetal_ShutdownPlatformInterface();
     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_RendererHasViewports);
 }
 
 void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    IM_ASSERT(bd != nil && "Context or backend not initialized! Did you call ImGui_ImplMetal_Init()?");
+    IM_ASSERT(bd->SharedMetalContext != nil && "No Metal context. Did you call ImGui_ImplMetal_Init() ?");
     bd->SharedMetalContext.framebufferDescriptor = [[FramebufferDescriptor alloc] initWithRenderPassDescriptor:renderPassDescriptor];
 
     if (bd->SharedMetalContext.depthStencilState == nil)
@@ -367,6 +378,7 @@ bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device)
     depthStencilDescriptor.depthWriteEnabled = NO;
     depthStencilDescriptor.depthCompareFunction = MTLCompareFunctionAlways;
     bd->SharedMetalContext.depthStencilState = [device newDepthStencilStateWithDescriptor:depthStencilDescriptor];
+    ImGui_ImplMetal_CreateDeviceObjectsForPlatformWindows();
     ImGui_ImplMetal_CreateFontsTexture(device);
 
     return true;
@@ -376,9 +388,155 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
     ImGui_ImplMetal_DestroyFontsTexture();
+    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;
+
+    viewport->DpiScale = (float)window.backingScaleFactor;
+    if (data->MetalLayer.contentsScale != viewport->DpiScale)
+    {
+        data->MetalLayer.contentsScale = viewport->DpiScale;
+        data->MetalLayer.drawableSize = MakeScaledSize(window.frame.size, viewport->DpiScale);
+    }
+    viewport->DrawData->FramebufferScale = ImVec2(viewport->DpiScale, viewport->DpiScale);
+#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_InitPlatformInterface()
+{
+    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_ShutdownPlatformInterface()
+{
+    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

backends/imgui_impl_opengl2.cpp

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [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.
@@ -22,6 +23,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  2021-12-08: OpenGL: Fixed mishandling of the ImDrawCmd::IdxOffset field! This is an old bug but it never had an effect until some internal rendering changes in 1.86.
 //  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).
@@ -79,17 +81,24 @@ static ImGui_ImplOpenGL2_Data* ImGui_ImplOpenGL2_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL2_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL2_InitPlatformInterface();
+static void ImGui_ImplOpenGL2_ShutdownPlatformInterface();
+
 // Functions
 bool    ImGui_ImplOpenGL2_Init()
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
     ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_opengl2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;    // We can create multi-viewports on the Renderer side (optional)
+
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplOpenGL2_InitPlatformInterface();
 
     return true;
 }
@@ -100,16 +109,18 @@ void    ImGui_ImplOpenGL2_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplOpenGL2_ShutdownPlatformInterface();
     ImGui_ImplOpenGL2_DestroyDeviceObjects();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasViewports;
     IM_DELETE(bd);
 }
 
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplOpenGL2_Init()?");
 
     if (!bd->FontTexture)
         ImGui_ImplOpenGL2_CreateDeviceObjects();
@@ -294,6 +305,35 @@ void    ImGui_ImplOpenGL2_DestroyDeviceObjects()
     ImGui_ImplOpenGL2_DestroyFontsTexture();
 }
 
+
+//--------------------------------------------------------------------------------------------------------
+// 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_InitPlatformInterface()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL2_RenderWindow;
+}
+
+static void ImGui_ImplOpenGL2_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_opengl2.h

@@ -3,6 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
+//  [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.

backends/imgui_impl_opengl3.cpp

@@ -5,7 +5,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
+//  [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.
@@ -22,8 +23,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2024-05-07: OpenGL: Update loader for Linux to support EGL/GLVND. (#7562)
-//  2024-04-16: OpenGL: Detect ES3 contexts on desktop based on version string, to e.g. avoid calling glPolygonMode() on them. (#7447)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2024-01-09: OpenGL: Update GL3W based imgui_impl_opengl3_loader.h to load "libGL.so" and variants, fixing regression on distros missing a symlink.
 //  2023-11-08: OpenGL: Update GL3W based imgui_impl_opengl3_loader.h to load "libGL.so" instead of "libGL.so.1", accommodating for NetBSD systems having only "libGL.so.3" available. (#6983)
 //  2023-10-05: OpenGL: Rename symbols in our internal loader so that LTO compilation with another copy of gl3w is possible. (#6875, #6668, #4445)
@@ -179,10 +179,9 @@
 #endif
 
 // Desktop GL 2.0+ has extension and glPolygonMode() which GL ES and WebGL don't have..
-// A desktop ES context can technically compile fine with our loader, so we also perform a runtime checks
 #if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3)
 #define IMGUI_IMPL_OPENGL_HAS_EXTENSIONS        // has glGetIntegerv(GL_NUM_EXTENSIONS)
-#define IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE // may have glPolygonMode()
+#define IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE      // has glPolygonMode()
 #endif
 
 // Desktop GL 2.1+ and GL ES 3.0+ have glBindBuffer() with GL_PIXEL_UNPACK_BUFFER target.
@@ -233,7 +232,6 @@ struct ImGui_ImplOpenGL3_Data
     unsigned int    VboHandle, ElementsHandle;
     GLsizeiptr      VertexBufferSize;
     GLsizeiptr      IndexBufferSize;
-    bool            HasPolygonMode;
     bool            HasClipOrigin;
     bool            UseBufferSubData;
 
@@ -247,6 +245,10 @@ static ImGui_ImplOpenGL3_Data* ImGui_ImplOpenGL3_GetBackendData()
     return ImGui::GetCurrentContext() ? (ImGui_ImplOpenGL3_Data*)ImGui::GetIO().BackendRendererUserData : nullptr;
 }
 
+// Forward Declarations
+static void ImGui_ImplOpenGL3_InitPlatformInterface();
+static void ImGui_ImplOpenGL3_ShutdownPlatformInterface();
+
 // OpenGL vertex attribute state (for ES 1.0 and ES 2.0 only)
 #ifndef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
 struct ImGui_ImplOpenGL3_VtxAttribState
@@ -275,7 +277,6 @@ struct ImGui_ImplOpenGL3_VtxAttribState
 bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Initialize our loader
@@ -299,13 +300,16 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     bd->GlProfileIsES2 = true;
 #else
     // Desktop or GLES 3
-    const char* gl_version_str = (const char*)glGetString(GL_VERSION);
     GLint major = 0;
     GLint minor = 0;
     glGetIntegerv(GL_MAJOR_VERSION, &major);
     glGetIntegerv(GL_MINOR_VERSION, &minor);
     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>"
+    {
+        // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
+        const char* gl_version = (const char*)glGetString(GL_VERSION);
+        sscanf(gl_version, "%d.%d", &major, &minor);
+    }
     bd->GlVersion = (GLuint)(major * 100 + minor * 10);
 #if defined(GL_CONTEXT_PROFILE_MASK)
     if (bd->GlVersion >= 320)
@@ -315,9 +319,6 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 
 #if defined(IMGUI_IMPL_OPENGL_ES3)
     bd->GlProfileIsES3 = true;
-#else
-    if (strncmp(gl_version_str, "OpenGL ES 3", 11) == 0)
-        bd->GlProfileIsES3 = true;
 #endif
 
     bd->UseBufferSubData = false;
@@ -332,13 +333,14 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 #endif
 
 #ifdef IMGUI_IMPL_OPENGL_DEBUG
-    printf("GlVersion = %d, \"%s\"\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2 = %d, GlProfileIsES3 = %d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, gl_version_str, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
+    printf("GlVersion = %d\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2 = %d, GlProfileIsES3 = %d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
 #endif
 
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
     if (bd->GlVersion >= 320)
         io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 #endif
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     // 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.
@@ -364,9 +366,6 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
 
     // Detect extensions we support
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
-    bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
-#endif
     bd->HasClipOrigin = (bd->GlVersion >= 450);
 #ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
     GLint num_extensions = 0;
@@ -379,6 +378,9 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
     }
 #endif
 
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplOpenGL3_InitPlatformInterface();
+
     return true;
 }
 
@@ -388,17 +390,18 @@ void    ImGui_ImplOpenGL3_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplOpenGL3_ShutdownPlatformInterface();
     ImGui_ImplOpenGL3_DestroyDeviceObjects();
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 void    ImGui_ImplOpenGL3_NewFrame()
 {
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplOpenGL3_Init()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplOpenGL3_Init()?");
 
     if (!bd->ShaderHandle)
         ImGui_ImplOpenGL3_CreateDeviceObjects();
@@ -420,9 +423,8 @@ static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_wid
     if (bd->GlVersion >= 310)
         glDisable(GL_PRIMITIVE_RESTART);
 #endif
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
-    if (bd->HasPolygonMode)
-        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
+    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 #endif
 
     // Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
@@ -510,8 +512,8 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
     GLuint last_vertex_array_object; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (GLint*)&last_vertex_array_object);
 #endif
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
-    GLint last_polygon_mode[2]; if (bd->HasPolygonMode) { glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode); }
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
+    GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
 #endif
     GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
     GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
@@ -649,10 +651,18 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     if (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
+#ifdef IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
     // Desktop OpenGL 3.0 and OpenGL 3.1 had separate polygon draw modes for front-facing and back-facing faces of polygons
-    if (bd->HasPolygonMode) { if (bd->GlVersion <= 310 || bd->GlProfileIsCompat) { glPolygonMode(GL_FRONT, (GLenum)last_polygon_mode[0]); glPolygonMode(GL_BACK, (GLenum)last_polygon_mode[1]); } else { glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]); } }
-#endif // IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
+    if (bd->GlVersion <= 310 || bd->GlProfileIsCompat)
+    {
+        glPolygonMode(GL_FRONT, (GLenum)last_polygon_mode[0]);
+        glPolygonMode(GL_BACK, (GLenum)last_polygon_mode[1]);
+    }
+    else
+    {
+        glPolygonMode(GL_FRONT_AND_BACK, (GLenum)last_polygon_mode[0]);
+    }
+#endif // IMGUI_IMPL_OPENGL_HAS_POLYGON_MODE
 
     glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
     glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
@@ -750,7 +760,7 @@ bool    ImGui_ImplOpenGL3_CreateDeviceObjects()
     glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
     glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
 #ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_BUFFER_PIXEL_UNPACK
-    GLint last_pixel_unpack_buffer = 0;
+    GLint last_pixel_unpack_buffer;
     if (bd->GlVersion >= 210) { glGetIntegerv(GL_PIXEL_UNPACK_BUFFER_BINDING, &last_pixel_unpack_buffer); glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0); }
 #endif
 #ifdef IMGUI_IMPL_OPENGL_USE_VERTEX_ARRAY
@@ -945,6 +955,34 @@ void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
     ImGui_ImplOpenGL3_DestroyFontsTexture();
 }
 
+//--------------------------------------------------------------------------------------------------------
+// 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_InitPlatformInterface()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_RenderWindow = ImGui_ImplOpenGL3_RenderWindow;
+}
+
+static void ImGui_ImplOpenGL3_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__GNUC__)

backends/imgui_impl_opengl3.h

@@ -5,7 +5,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
+//  [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.
@@ -41,9 +42,9 @@ IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyFontsTexture();
 IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_CreateDeviceObjects();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_DestroyDeviceObjects();
 
-// 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)
+// Specific OpenGL ES versions
+//#define IMGUI_IMPL_OPENGL_ES2     // Auto-detected on Emscripten
+//#define IMGUI_IMPL_OPENGL_ES3     // Auto-detected on iOS/Android
 
 // You can explicitly select GLES2 or GLES3 API by using one of the '#define IMGUI_IMPL_OPENGL_LOADER_XXX' in imconfig.h or compiler command-line.
 #if !defined(IMGUI_IMPL_OPENGL_ES2) \

backends/imgui_impl_opengl3_loader.h

@@ -10,7 +10,7 @@
 // THE REST OF YOUR APP SHOULD USE A DIFFERENT GL LOADER: ANY GL LOADER OF YOUR CHOICE.
 //
 // IF YOU GET BUILD ERRORS IN THIS FILE (commonly macro redefinitions or function redefinitions):
-// IT LIKELY MEANS THAT YOU ARE BUILDING 'imgui_impl_opengl3.cpp' OR INCLUDING 'imgui_impl_opengl3_loader.h'
+// IT LIKELY MEANS THAT YOU ARE BUILDING 'imgui_impl_opengl3.cpp' OR INCUDING 'imgui_impl_opengl3_loader.h'
 // IN THE SAME COMPILATION UNIT AS ONE OF YOUR FILE WHICH IS USING A THIRD-PARTY OPENGL LOADER.
 // (e.g. COULD HAPPEN IF YOU ARE DOING A UNITY/JUMBO BUILD, OR INCLUDING .CPP FILES FROM OTHERS)
 // YOU SHOULD NOT BUILD BOTH IN THE SAME COMPILATION UNIT.
@@ -18,7 +18,7 @@
 // WILL NOT BE USING OUR LOADER, AND INSTEAD EXPECT ANOTHER/YOUR LOADER TO BE AVAILABLE IN THE COMPILATION UNIT.
 //
 // Regenerate with:
-//   python3 gl3w_gen.py --output ../imgui/backends/imgui_impl_opengl3_loader.h --ref ../imgui/backends/imgui_impl_opengl3.cpp ./extra_symbols.txt
+//   python gl3w_gen.py --output ../imgui/backends/imgui_impl_opengl3_loader.h --ref ../imgui/backends/imgui_impl_opengl3.cpp ./extra_symbols.txt
 //
 // More info:
 //   https://github.com/dearimgui/gl3w_stripped
@@ -118,7 +118,7 @@ extern "C" {
 ** included as <GL/glcorearb.h>.
 **
 ** glcorearb.h includes only APIs in the latest OpenGL core profile
-** implementation together with APIs in newer ARB extensions which 
+** implementation together with APIs in newer ARB extensions which
 ** can be supported by the core profile. It does not, and never will
 ** include functionality removed from the core profile, such as
 ** fixed-function vertex and fragment processing.
@@ -260,6 +260,8 @@ typedef khronos_intptr_t GLintptr;
 #define GL_ARRAY_BUFFER_BINDING           0x8894
 #define GL_ELEMENT_ARRAY_BUFFER_BINDING   0x8895
 #define GL_STREAM_DRAW                    0x88E0
+#define GL_PIXEL_UNPACK_BUFFER            0x88EC
+#define GL_PIXEL_UNPACK_BUFFER_BINDING    0x88EF
 typedef void (APIENTRYP PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
 typedef void (APIENTRYP PFNGLDELETEBUFFERSPROC) (GLsizei n, const GLuint *buffers);
 typedef void (APIENTRYP PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
@@ -346,10 +348,6 @@ GLAPI void APIENTRY glUniformMatrix4fv (GLint location, GLsizei count, GLboolean
 GLAPI void APIENTRY glVertexAttribPointer (GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const void *pointer);
 #endif
 #endif /* GL_VERSION_2_0 */
-#ifndef GL_VERSION_2_1
-#define GL_PIXEL_UNPACK_BUFFER            0x88EC
-#define GL_PIXEL_UNPACK_BUFFER_BINDING    0x88EF
-#endif /* GL_VERSION_2_1 */
 #ifndef GL_VERSION_3_0
 typedef khronos_uint16_t GLhalf;
 #define GL_MAJOR_VERSION                  0x821B
@@ -665,123 +663,31 @@ static GL3WglProc get_proc(const char *proc)
 #else
 #include <dlfcn.h>
 
-static void* libgl;  // OpenGL library
-static void* libglx;  // GLX library
-static void* libegl;  // EGL library
-static GL3WGetProcAddressProc gl_get_proc_address;
+static void *libgl;
+static GL3WglProc (*glx_get_proc_address)(const GLubyte *);
 
-static void close_libgl(void)
+static int open_libgl(void)
 {
-    if (libgl) {
-        dlclose(libgl);
-        libgl = NULL;
-    }
-    if (libegl) {
-        dlclose(libegl);
-        libegl = NULL;
-    }
-    if (libglx) {
-        dlclose(libglx);
-        libglx = NULL;
-    }
-}
-
-static int is_library_loaded(const char* name, void** lib)
-{
-    *lib = dlopen(name, RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
-    return *lib != NULL;
-}
-
-static int open_libs(void)
-{
-    // On Linux we have two APIs to get process addresses: EGL and GLX.
-    // EGL is supported under both X11 and Wayland, whereas GLX is X11-specific.
-
-    libgl = NULL;
-    libegl = NULL;
-    libglx = NULL;
-
-    // First check what's already loaded, the windowing library might have
-    // already loaded either EGL or GLX and we want to use the same one.
-
-    if (is_library_loaded("libEGL.so.1", &libegl) ||
-        is_library_loaded("libGLX.so.0", &libglx)) {
-        libgl = dlopen("libOpenGL.so.0", RTLD_LAZY | RTLD_LOCAL);
-        if (libgl)
-            return GL3W_OK;
-        else
-            close_libgl();
-    }
-
-    if (is_library_loaded("libGL.so", &libgl))
-        return GL3W_OK;
-    if (is_library_loaded("libGL.so.1", &libgl))
-        return GL3W_OK;
-    if (is_library_loaded("libGL.so.3", &libgl))
-        return GL3W_OK;
-
-    // Neither is already loaded, so we have to load one.  Try EGL first
-    // because it is supported under both X11 and Wayland.
-
-    // Load OpenGL + EGL
-    libgl = dlopen("libOpenGL.so.0", RTLD_LAZY | RTLD_LOCAL);
-    libegl = dlopen("libEGL.so.1", RTLD_LAZY | RTLD_LOCAL);
-    if (libgl && libegl)
-        return GL3W_OK;
-    else
-        close_libgl();
-
-    // Fall back to legacy libGL, which includes GLX
     // While most systems use libGL.so.1, NetBSD seems to use that libGL.so.3. See https://github.com/ocornut/imgui/issues/6983
     libgl = dlopen("libGL.so", RTLD_LAZY | RTLD_LOCAL);
     if (!libgl)
         libgl = dlopen("libGL.so.1", RTLD_LAZY | RTLD_LOCAL);
     if (!libgl)
         libgl = dlopen("libGL.so.3", RTLD_LAZY | RTLD_LOCAL);
-
-    if (libgl)
-        return GL3W_OK;
-
-    return GL3W_ERROR_LIBRARY_OPEN;
-}
-
-static int open_libgl(void)
-{
-    int res = open_libs();
-    if (res)
-        return res;
-
-    if (libegl)
-        *(void**)(&gl_get_proc_address) = dlsym(libegl, "eglGetProcAddress");
-    else if (libglx)
-        *(void**)(&gl_get_proc_address) = dlsym(libglx, "glXGetProcAddressARB");
-    else
-        *(void**)(&gl_get_proc_address) = dlsym(libgl, "glXGetProcAddressARB");
-
-    if (!gl_get_proc_address) {
-        close_libgl();
+    if (!libgl)
         return GL3W_ERROR_LIBRARY_OPEN;
-    }
-
+    *(void **)(&glx_get_proc_address) = dlsym(libgl, "glXGetProcAddressARB");
     return GL3W_OK;
 }
 
-static GL3WglProc get_proc(const char* proc)
+static void close_libgl(void) { dlclose(libgl); }
+
+static GL3WglProc get_proc(const char *proc)
 {
-    GL3WglProc res = NULL;
-
-    // Before EGL version 1.5, eglGetProcAddress doesn't support querying core
-    // functions and may return a dummy function if we try, so try to load the
-    // function from the GL library directly first.
-    if (libegl)
-        *(void**)(&res) = dlsym(libgl, proc);
-
+    GL3WglProc res;
+    res = glx_get_proc_address((const GLubyte *)proc);
     if (!res)
-        res = gl_get_proc_address(proc);
-
-    if (!libegl && !res)
-        *(void**)(&res) = dlsym(libgl, proc);
-
+        *(void **)(&res) = dlsym(libgl, proc);
     return res;
 }
 #endif

backends/imgui_impl_osx.h

@@ -10,6 +10,10 @@
 //  [X] Platform: OSX clipboard is supported within core Dear ImGui (no specific code in this backend).
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
+// Issues:
+//  [ ] Platform: Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] 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.

backends/imgui_impl_osx.mm

@@ -10,6 +10,10 @@
 //  [X] Platform: OSX clipboard is supported within core Dear ImGui (no specific code in this backend).
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: IME support.
+//  [x] Platform: Multi-viewport / platform windows.
+// Issues:
+//  [ ] Platform: Multi-viewport: Window size not correctly reported when enabling io.ConfigViewportsNoDecoration
+//  [ ] 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.
@@ -29,6 +33,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F20 function keys. Stopped mapping F13 into PrintScreen.
 //  2023-04-09: Inputs: Added support for io.AddMouseSourceEvent() to discriminate ImGuiMouseSource_Mouse/ImGuiMouseSource_Pen.
 //  2023-02-01: Fixed scroll wheel scaling for devices emitting events with hasPreciseScrollingDeltas==false (e.g. non-Apple mices).
@@ -80,16 +85,21 @@ struct ImGui_ImplOSX_Data
     KeyEventResponder*          KeyEventResponder;
     NSTextInputContext*         InputContext;
     id                          Monitor;
+    NSWindow*                   Window;
 
     ImGui_ImplOSX_Data()        { memset(this, 0, sizeof(*this)); }
 };
 
+static ImGui_ImplOSX_Data*      ImGui_ImplOSX_CreateBackendData()   { return IM_NEW(ImGui_ImplOSX_Data)(); }
 static ImGui_ImplOSX_Data*      ImGui_ImplOSX_GetBackendData()      { return (ImGui_ImplOSX_Data*)ImGui::GetIO().BackendPlatformUserData; }
 static void                     ImGui_ImplOSX_DestroyBackendData()  { IM_DELETE(ImGui_ImplOSX_GetBackendData()); }
 
 static inline CFTimeInterval    GetMachAbsoluteTimeInSeconds()      { return (CFTimeInterval)(double)(clock_gettime_nsec_np(CLOCK_UPTIME_RAW) / 1e9); }
 
 // Forward Declarations
+static void ImGui_ImplOSX_InitPlatformInterface();
+static void ImGui_ImplOSX_ShutdownPlatformInterface();
+static void ImGui_ImplOSX_UpdateMonitors();
 static void ImGui_ImplOSX_AddTrackingArea(NSView* _Nonnull view);
 static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
@@ -133,12 +143,28 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
 - (void)updateImePosWithView:(NSView *)view
 {
-    NSWindow *window = view.window;
+    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
@@ -233,6 +259,7 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
 
 - (void)onApplicationBecomeActive:(NSNotification*)aNotification;
 - (void)onApplicationBecomeInactive:(NSNotification*)aNotification;
+- (void)displaysDidChange:(NSNotification*)aNotification;
 
 @end
 
@@ -250,6 +277,11 @@ static bool ImGui_ImplOSX_HandleEvent(NSEvent* event, NSView* view);
     io.AddFocusEvent(false);
 }
 
+- (void)displaysDidChange:(NSNotification*)aNotification
+{
+    ImGui_ImplOSX_UpdateMonitors();
+}
+
 @end
 
 // Functions
@@ -391,17 +423,23 @@ IMGUI_IMPL_API void ImGui_ImplOSX_NewFrame(void* _Nullable view) {
 bool ImGui_ImplOSX_Init(NSView* view)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_CreateBackendData();
+    io.BackendPlatformUserData = (void*)bd;
 
     // Setup backend capabilities flags
-    ImGui_ImplOSX_Data* bd = IM_NEW(ImGui_ImplOSX_Data)();
-    io.BackendPlatformUserData = (void*)bd;
-    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)
+    io.BackendPlatformName = "imgui_impl_osx";
 
     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();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplOSX_InitPlatformInterface();
 
     // Load cursors. Some of them are undocumented.
     bd->MouseCursorHidden = false;
@@ -491,12 +529,12 @@ void ImGui_ImplOSX_Shutdown()
         bd->Monitor = nullptr;
     }
 
+    ImGui_ImplOSX_ShutdownPlatformInterface();
     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()
@@ -601,7 +639,6 @@ static void ImGui_ImplOSX_UpdateImePosWithView(NSView* view)
 void ImGui_ImplOSX_NewFrame(NSView* view)
 {
     ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplOSX_Init()?");
     ImGuiIO& io = ImGui::GetIO();
 
     // Setup display size
@@ -673,14 +710,23 @@ 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;
@@ -808,6 +854,294 @@ 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 ImGuiViewportDataOSX
+{
+    NSWindow*               Window;
+    bool                    WindowOwned;
+
+    ImGuiViewportDataOSX()  { WindowOwned = false; }
+    ~ImGuiViewportDataOSX() { 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();
+    ImGuiViewportDataOSX* data = IM_NEW(ImGuiViewportDataOSX)();
+    viewport->PlatformUserData = data;
+
+    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)
+        [view setWantsBestResolutionOpenGLSurface:YES];
+
+    window.contentView = view;
+
+    data->Window = window;
+    data->WindowOwned = true;
+    viewport->PlatformRequestResize = false;
+    viewport->PlatformHandle = viewport->PlatformHandleRaw = (__bridge_retained void*)window;
+}
+
+static void ImGui_ImplOSX_DestroyWindow(ImGuiViewport* viewport)
+{
+    NSWindow* window = (__bridge_transfer NSWindow*)viewport->PlatformHandleRaw;
+    window = nil;
+
+    if (ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData)
+    {
+        NSWindow* window = data->Window;
+        if (window != nil && data->WindowOwned)
+        {
+            window.contentView = nil;
+            window.contentViewController = nil;
+            [window orderOut:nil];
+        }
+        data->Window = nil;
+        IM_DELETE(data);
+    }
+    viewport->PlatformUserData = viewport->PlatformHandle = viewport->PlatformHandleRaw = nullptr;
+}
+
+static void ImGui_ImplOSX_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
+        [data->Window orderFront:nil];
+    else
+        [data->Window makeKeyAndOrderFront:nil];
+
+    [data->Window setIsVisible:YES];
+}
+
+static ImVec2 ImGui_ImplOSX_GetWindowPos(ImGuiViewport* viewport)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    NSWindow* window = data->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)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    NSWindow* window = data->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)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    NSWindow* window = data->Window;
+    NSSize size = window.contentLayoutRect.size;
+    return ImVec2(size.width, size.height);
+}
+
+static void ImGui_ImplOSX_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    NSWindow* window = data->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 void ImGui_ImplOSX_SetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGui_ImplOSX_Data* bd = ImGui_ImplOSX_GetBackendData();
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+    [data->Window makeKeyAndOrderFront:bd->Window];
+}
+
+static bool ImGui_ImplOSX_GetWindowFocus(ImGuiViewport* viewport)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    return data->Window.isKeyWindow;
+}
+
+static bool ImGui_ImplOSX_GetWindowMinimized(ImGuiViewport* viewport)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    return data->Window.isMiniaturized;
+}
+
+static void ImGui_ImplOSX_SetWindowTitle(ImGuiViewport* viewport, const char* title)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    data->Window.title = [NSString stringWithUTF8String:title];
+}
+
+static void ImGui_ImplOSX_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+    IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
+
+    data->Window.alphaValue = alpha;
+}
+
+static float ImGui_ImplOSX_GetWindowDpiScale(ImGuiViewport* viewport)
+{
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
+    IM_ASSERT(data->Window != 0);
+
+    return data->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_InitPlatformInterface()
+{
+    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_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();
+    ImGuiViewportDataOSX* data = IM_NEW(ImGuiViewportDataOSX)();
+    data->Window = bd->Window;
+    data->WindowOwned = false;
+    main_viewport->PlatformUserData = data;
+    main_viewport->PlatformHandle = (__bridge void*)bd->Window;
+
+    [NSNotificationCenter.defaultCenter addObserver:bd->Observer
+                                           selector:@selector(displaysDidChange:)
+                                               name:NSApplicationDidChangeScreenParametersNotification
+                                             object:nil];
+}
+
+static void ImGui_ImplOSX_ShutdownPlatformInterface()
+{
+    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();
+    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)main_viewport->PlatformUserData;
+    IM_DELETE(data);
+    main_viewport->PlatformUserData = nullptr;
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_sdl2.cpp

@@ -9,7 +9,11 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. 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'.
+// 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).
+//  [x] Platform: Basic IME support. 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.
@@ -21,6 +25,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2024-02-14: Inputs: Handle gamepad disconnection. Added ImGui_ImplSDL2_SetGamepadMode().
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F24 function keys, app back/forward keys.
 //  2023-04-06: Inputs: Avoid calling SDL_StartTextInput()/SDL_StopTextInput() as they don't only pertain to IME. It's unclear exactly what their relation is to IME. (#6306)
@@ -47,7 +52,7 @@
 //  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.
@@ -88,6 +93,7 @@
 #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>
 #if defined(__APPLE__)
@@ -99,7 +105,15 @@
 #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)
+#if !SDL_HAS_VULKAN
+static const Uint32 SDL_WINDOW_VULKAN = 0x10000000;
+#endif
 
 // SDL Data
 struct ImGui_ImplSDL2_Data
@@ -108,6 +122,8 @@ struct ImGui_ImplSDL2_Data
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // Mouse handling
     Uint32                  MouseWindowID;
@@ -116,6 +132,7 @@ struct ImGui_ImplSDL2_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MouseLastLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    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;
@@ -134,6 +151,11 @@ 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_InitPlatformInterface(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL2_ShutdownPlatformInterface();
+
 // Functions
 static const char* ImGui_ImplSDL2_GetClipboardText(void*)
 {
@@ -150,13 +172,13 @@ static void ImGui_ImplSDL2_SetClipboardText(void*, 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_SetPlatformImeData(ImGuiViewport*, ImGuiPlatformImeData* data)
+static void ImGui_ImplSDL2_SetPlatformImeData(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);
@@ -306,15 +328,21 @@ static void ImGui_ImplSDL2_UpdateKeyModifiers(SDL_Keymod sdl_key_mods)
 // 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();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDL2_Init()?");
     ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
 
     switch (event->type)
     {
         case SDL_MOUSEMOTION:
         {
             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;
@@ -366,6 +394,15 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
             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.
             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:
         {
             // - 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.
@@ -383,8 +420,19 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
                 bd->MouseLastLeaveFrame = ImGui::GetFrameCount() + 1;
             if (window_event == SDL_WINDOWEVENT_FOCUS_GAINED)
                 io.AddFocusEvent(true);
-            else if (event->window.event == SDL_WINDOWEVENT_FOCUS_LOST)
+            else if (window_event == SDL_WINDOWEVENT_FOCUS_LOST)
                 io.AddFocusEvent(false);
+            if (window_event == SDL_WINDOWEVENT_CLOSE || window_event == SDL_WINDOWEVENT_MOVED || window_event == SDL_WINDOWEVENT_RESIZED)
+                if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)SDL_GetWindowFromID(event->window.windowID)))
+                {
+                    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;
+                }
             return true;
         }
         case SDL_CONTROLLERDEVICEADDED:
@@ -397,10 +445,9 @@ bool ImGui_ImplSDL2_ProcessEvent(const SDL_Event* event)
     return false;
 }
 
-static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
+static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer, void* sdl_gl_context)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
 
     // Check and store if we are on a SDL backend that supports global mouse position
@@ -418,12 +465,23 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     ImGui_ImplSDL2_Data* bd = IM_NEW(ImGui_ImplSDL2_Data)();
     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.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
+    io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    if (mouse_can_use_global_state)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
 
     bd->Window = window;
     bd->Renderer = renderer;
+
+    // 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.
     bd->MouseCanUseGlobalState = mouse_can_use_global_state;
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
+    bd->WantUpdateMonitors = true;
 
     io.SetClipboardTextFn = ImGui_ImplSDL2_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplSDL2_GetClipboardText;
@@ -448,6 +506,7 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     // Set platform dependent data in viewport
     // Our mouse update function expect PlatformHandle to be filled for the main viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->PlatformHandle = (void*)window;
     main_viewport->PlatformHandleRaw = nullptr;
     SDL_SysWMinfo info;
     SDL_VERSION(&info.version);
@@ -481,13 +540,17 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
 #endif
 
+    // We need SDL_CaptureMouse(), SDL_GetGlobalMouseState() from SDL 2.0.4+ to support multiple viewports.
+    // We left the call to ImGui_ImplSDL2_InitPlatformInterface() outside of #ifdef to avoid unused-function warnings.
+    if ((io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) && (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports))
+        ImGui_ImplSDL2_InitPlatformInterface(window, sdl_gl_context);
+
     return true;
 }
 
 bool ImGui_ImplSDL2_InitForOpenGL(SDL_Window* window, void* sdl_gl_context)
 {
-    IM_UNUSED(sdl_gl_context); // Viewport branch will need this.
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, sdl_gl_context);
 }
 
 bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
@@ -495,7 +558,11 @@ bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
 #if !SDL_HAS_VULKAN
     IM_ASSERT(0 && "Unsupported");
 #endif
-    return ImGui_ImplSDL2_Init(window, 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)
@@ -503,22 +570,22 @@ bool ImGui_ImplSDL2_InitForD3D(SDL_Window* window)
 #if !defined(_WIN32)
     IM_ASSERT(0 && "Unsupported");
 #endif
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
 }
 
 bool ImGui_ImplSDL2_InitForMetal(SDL_Window* window)
 {
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
 }
 
 bool ImGui_ImplSDL2_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* renderer)
 {
-    return ImGui_ImplSDL2_Init(window, renderer);
+    return ImGui_ImplSDL2_Init(window, renderer, nullptr);
 }
 
 bool ImGui_ImplSDL2_InitForOther(SDL_Window* window)
 {
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
 }
 
 static void ImGui_ImplSDL2_CloseGamepads();
@@ -529,6 +596,8 @@ void ImGui_ImplSDL2_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplSDL2_ShutdownPlatformInterface();
+
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -537,10 +606,11 @@ 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();
@@ -551,25 +621,57 @@ static void ImGui_ImplSDL2_UpdateMouseData()
     // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger other operations outside
     SDL_CaptureMouse((bd->MouseButtonsDown != 0) ? 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::FindViewportByPlatformHandle((void*)focused_window)));
 #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 ImGuiConfigFlags_NavEnableSetMousePos 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)
         if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0)
         {
-            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));
+            // 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)
+            // 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 (SDL_Window* sdl_mouse_window = SDL_GetWindowFromID(bd->MouseWindowID))
+            if (ImGuiViewport* mouse_viewport = ImGui::FindViewportByPlatformHandle((void*)sdl_mouse_window))
+                mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL2_UpdateMouseCursor()
@@ -703,10 +805,43 @@ 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
+        SDL_GetDisplayUsableBounds(n, &r);
+        monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+#endif
+#if SDL_HAS_PER_MONITOR_DPI
+        // FIXME-VIEWPORT: On MacOS SDL reports actual monitor DPI scale, ignoring OS configuration. We may want to set
+        //  DpiScale to cocoa_window.backingScaleFactor here.
+        float dpi = 0.0f;
+        if (!SDL_GetDisplayDPI(n, &dpi, nullptr, nullptr))
+            monitor.DpiScale = dpi / 96.0f;
+#endif
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        platform_io.Monitors.push_back(monitor);
+    }
+}
+
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDL2_Init()?");
     ImGuiIO& io = ImGui::GetIO();
 
     // Setup display size (every frame to accommodate for window resizing)
@@ -723,6 +858,10 @@ void ImGui_ImplSDL2_NewFrame()
     if (w > 0 && h > 0)
         io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
 
+    // Update monitors
+    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)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
@@ -739,6 +878,13 @@ 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 rygorous, 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();
 
@@ -746,6 +892,253 @@ 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* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL2_ViewportData
+{
+    SDL_Window*     Window;
+    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*)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)
+    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);
+    }
+
+    // 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 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_InitPlatformInterface(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_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 = vd->Window;
+}
+
+static void ImGui_ImplSDL2_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl2.h

@@ -8,7 +8,11 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. 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'.
+// 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).
+//  [x] Platform: Basic IME support. 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_sdl3.cpp

@@ -9,8 +9,11 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Missing features:
-//  [ ] Platform: IME SUPPORT IS BROKEN IN SDL3 BECAUSE INPUTS GETS SENT TO BOTH APP AND IME + 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' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// 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).
+//  [x] Platform: Basic 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.
@@ -22,7 +25,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2024-04-15: Inputs: Re-enable calling SDL_StartTextInput()/SDL_StopTextInput() as SDL3 no longer enables it by default and should play nicer with IME.
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2024-02-13: Inputs: Fixed gamepad support. Handle gamepad disconnection. Added ImGui_ImplSDL3_SetGamepadMode().
 //  2023-11-13: Updated for recent SDL3 API changes.
 //  2023-10-05: Inputs: Added support for extra ImGuiKey values: F13 to F24 function keys, app back/forward keys.
@@ -60,14 +63,6 @@
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
 
-// FIXME-LEGACY: remove when SDL 3.1.3 preview is released.
-#ifndef SDLK_APOSTROPHE
-#define SDLK_APOSTROPHE SDLK_QUOTE
-#endif
-#ifndef SDLK_GRAVE
-#define SDLK_GRAVE SDLK_BACKQUOTE
-#endif
-
 // SDL Data
 struct ImGui_ImplSDL3_Data
 {
@@ -75,6 +70,8 @@ struct ImGui_ImplSDL3_Data
     SDL_Renderer*           Renderer;
     Uint64                  Time;
     char*                   ClipboardTextData;
+    bool                    UseVulkan;
+    bool                    WantUpdateMonitors;
 
     // Mouse handling
     Uint32                  MouseWindowID;
@@ -83,11 +80,12 @@ struct ImGui_ImplSDL3_Data
     SDL_Cursor*             MouseLastCursor;
     int                     MousePendingLeaveFrame;
     bool                    MouseCanUseGlobalState;
+    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)); }
 };
@@ -101,6 +99,11 @@ 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_InitPlatformInterface(SDL_Window* window, void* sdl_gl_context);
+static void ImGui_ImplSDL3_ShutdownPlatformInterface();
+
 // Functions
 static const char* ImGui_ImplSDL3_GetClipboardText(void*)
 {
@@ -116,21 +119,16 @@ static void ImGui_ImplSDL3_SetClipboardText(void*, const char* text)
     SDL_SetClipboardText(text);
 }
 
-static void ImGui_ImplSDL3_SetPlatformImeData(ImGuiViewport*, ImGuiPlatformImeData* data)
+static void ImGui_ImplSDL3_SetPlatformImeData(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);
-        SDL_StartTextInput();
-    }
-    else
-    {
-        SDL_StopTextInput();
     }
 }
 
@@ -153,7 +151,7 @@ static ImGuiKey ImGui_ImplSDL3_KeycodeToImGuiKey(int keycode)
         case SDLK_SPACE: return ImGuiKey_Space;
         case SDLK_RETURN: return ImGuiKey_Enter;
         case SDLK_ESCAPE: return ImGuiKey_Escape;
-        case SDLK_APOSTROPHE: return ImGuiKey_Apostrophe;
+        case SDLK_QUOTE: return ImGuiKey_Apostrophe;
         case SDLK_COMMA: return ImGuiKey_Comma;
         case SDLK_MINUS: return ImGuiKey_Minus;
         case SDLK_PERIOD: return ImGuiKey_Period;
@@ -163,7 +161,7 @@ static ImGuiKey ImGui_ImplSDL3_KeycodeToImGuiKey(int keycode)
         case SDLK_LEFTBRACKET: return ImGuiKey_LeftBracket;
         case SDLK_BACKSLASH: return ImGuiKey_Backslash;
         case SDLK_RIGHTBRACKET: return ImGuiKey_RightBracket;
-        case SDLK_GRAVE: return ImGuiKey_GraveAccent;
+        case SDLK_BACKQUOTE: return ImGuiKey_GraveAccent;
         case SDLK_CAPSLOCK: return ImGuiKey_CapsLock;
         case SDLK_SCROLLLOCK: return ImGuiKey_ScrollLock;
         case SDLK_NUMLOCKCLEAR: return ImGuiKey_NumLock;
@@ -277,15 +275,21 @@ static void ImGui_ImplSDL3_UpdateKeyModifiers(SDL_Keymod sdl_key_mods)
 // 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();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplSDL3_Init()?");
     ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplSDL3_Data* bd = ImGui_ImplSDL3_GetBackendData();
 
     switch (event->type)
     {
         case SDL_EVENT_MOUSE_MOTION:
         {
             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;
@@ -332,6 +336,15 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
             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.
             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:
         {
             bd->MouseWindowID = event->window.windowID;
@@ -353,6 +366,20 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
         case SDL_EVENT_WINDOW_FOCUS_LOST:
             io.AddFocusEvent(false);
             return true;
+        case SDL_EVENT_WINDOW_CLOSE_REQUESTED:
+        case SDL_EVENT_WINDOW_MOVED:
+        case SDL_EVENT_WINDOW_RESIZED:
+            if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)SDL_GetWindowFromID(event->window.windowID)))
+            {
+                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;
+            }
+            return true;
         case SDL_EVENT_GAMEPAD_ADDED:
         case SDL_EVENT_GAMEPAD_REMOVED:
         {
@@ -365,7 +392,7 @@ bool ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event)
 
 static void ImGui_ImplSDL3_SetupPlatformHandles(ImGuiViewport* viewport, SDL_Window* window)
 {
-    IM_UNUSED(window);
+    viewport->PlatformHandle = window;
     viewport->PlatformHandleRaw = nullptr;
 #if defined(__WIN32__) && !defined(__WINRT__)
     viewport->PlatformHandleRaw = (HWND)SDL_GetProperty(SDL_GetWindowProperties(window), "SDL.window.win32.hwnd", nullptr);
@@ -377,7 +404,6 @@ static void ImGui_ImplSDL3_SetupPlatformHandles(ImGuiViewport* viewport, SDL_Win
 static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void* sdl_gl_context)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
     IM_UNUSED(sdl_gl_context); // Unused in this branch
 
@@ -398,10 +424,21 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     io.BackendPlatformName = "imgui_impl_sdl3";
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;           // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;            // We can honor io.WantSetMousePos requests (optional, rarely used)
+    if (mouse_can_use_global_state)
+        io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;  // We can create multi-viewports on the Platform side (optional)
 
     bd->Window = window;
     bd->Renderer = renderer;
+
+    // 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.
     bd->MouseCanUseGlobalState = mouse_can_use_global_state;
+#ifndef __APPLE__
+    bd->MouseCanReportHoveredViewport = bd->MouseCanUseGlobalState;
+#else
+    bd->MouseCanReportHoveredViewport = false;
+#endif
+    bd->WantUpdateMonitors = true;
 
     io.SetClipboardTextFn = ImGui_ImplSDL3_SetClipboardText;
     io.GetClipboardTextFn = ImGui_ImplSDL3_GetClipboardText;
@@ -413,15 +450,15 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     bd->WantUpdateGamepadsList = true;
 
     // Load mouse cursors
-    bd->MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_DEFAULT);
-    bd->MouseCursors[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_TEXT);
-    bd->MouseCursors[ImGuiMouseCursor_ResizeAll] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_MOVE);
-    bd->MouseCursors[ImGuiMouseCursor_ResizeNS] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NS_RESIZE);
-    bd->MouseCursors[ImGuiMouseCursor_ResizeEW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_EW_RESIZE);
-    bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NESW_RESIZE);
-    bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NWSE_RESIZE);
-    bd->MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_POINTER);
-    bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NOT_ALLOWED);
+    bd->MouseCursors[ImGuiMouseCursor_Arrow] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_ARROW);
+    bd->MouseCursors[ImGuiMouseCursor_TextInput] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_IBEAM);
+    bd->MouseCursors[ImGuiMouseCursor_ResizeAll] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEALL);
+    bd->MouseCursors[ImGuiMouseCursor_ResizeNS] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENS);
+    bd->MouseCursors[ImGuiMouseCursor_ResizeEW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZEWE);
+    bd->MouseCursors[ImGuiMouseCursor_ResizeNESW] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENESW);
+    bd->MouseCursors[ImGuiMouseCursor_ResizeNWSE] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_SIZENWSE);
+    bd->MouseCursors[ImGuiMouseCursor_Hand] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_HAND);
+    bd->MouseCursors[ImGuiMouseCursor_NotAllowed] = SDL_CreateSystemCursor(SDL_SYSTEM_CURSOR_NO);
 
     // Set platform dependent data in viewport
     // Our mouse update function expect PlatformHandle to be filled for the main viewport
@@ -433,27 +470,34 @@ static bool ImGui_ImplSDL3_Init(SDL_Window* window, SDL_Renderer* renderer, void
     // (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
     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.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) && (io.BackendFlags & ImGuiBackendFlags_PlatformHasViewports))
+        ImGui_ImplSDL3_InitPlatformInterface(window, sdl_gl_context);
 
     return true;
 }
 
 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)
@@ -487,6 +531,8 @@ void ImGui_ImplSDL3_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplSDL3_ShutdownPlatformInterface();
+
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -495,10 +541,11 @@ 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();
@@ -509,7 +556,7 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     // SDL_CaptureMouse() let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't e.g. trigger other operations outside
     SDL_CaptureMouse((bd->MouseButtonsDown != 0) ? 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::FindViewportByPlatformHandle((void*)focused_window)));
 #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
@@ -518,19 +565,48 @@ static void ImGui_ImplSDL3_UpdateMouseData()
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos 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)
         if (bd->MouseCanUseGlobalState && bd->MouseButtonsDown == 0)
         {
             // 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 (SDL_Window* sdl_mouse_window = SDL_GetWindowFromID(bd->MouseWindowID))
+            if (ImGuiViewport* mouse_viewport = ImGui::FindViewportByPlatformHandle((void*)sdl_mouse_window))
+                mouse_viewport_id = mouse_viewport->ID;
+        io.AddMouseViewportEvent(mouse_viewport_id);
+    }
 }
 
 static void ImGui_ImplSDL3_UpdateMouseCursor()
@@ -639,36 +715,65 @@ static void ImGui_ImplSDL3_UpdateGamepads()
 
     // Update gamepad inputs
     const int thumb_dead_zone = 8000;           // SDL_gamepad.h suggests using this value.
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadStart,       SDL_GAMEPAD_BUTTON_START);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadBack,        SDL_GAMEPAD_BUTTON_BACK);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceLeft,    SDL_GAMEPAD_BUTTON_WEST);           // Xbox X, PS Square
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceRight,   SDL_GAMEPAD_BUTTON_EAST);           // Xbox B, PS Circle
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceUp,      SDL_GAMEPAD_BUTTON_NORTH);          // Xbox Y, PS Triangle
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceDown,    SDL_GAMEPAD_BUTTON_SOUTH);          // Xbox A, PS Cross
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadLeft,    SDL_GAMEPAD_BUTTON_DPAD_LEFT);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadRight,   SDL_GAMEPAD_BUTTON_DPAD_RIGHT);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadUp,      SDL_GAMEPAD_BUTTON_DPAD_UP);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadDown,    SDL_GAMEPAD_BUTTON_DPAD_DOWN);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadL1,          SDL_GAMEPAD_BUTTON_LEFT_SHOULDER);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadR1,          SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadL2,          SDL_GAMEPAD_AXIS_LEFT_TRIGGER,  0.0f, 32767);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadR2,          SDL_GAMEPAD_AXIS_RIGHT_TRIGGER, 0.0f, 32767);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadL3,          SDL_GAMEPAD_BUTTON_LEFT_STICK);
-    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadR3,          SDL_GAMEPAD_BUTTON_RIGHT_STICK);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickLeft,  SDL_GAMEPAD_AXIS_LEFTX,  -thumb_dead_zone, -32768);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickRight, SDL_GAMEPAD_AXIS_LEFTX,  +thumb_dead_zone, +32767);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickUp,    SDL_GAMEPAD_AXIS_LEFTY,  -thumb_dead_zone, -32768);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickDown,  SDL_GAMEPAD_AXIS_LEFTY,  +thumb_dead_zone, +32767);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickLeft,  SDL_GAMEPAD_AXIS_RIGHTX, -thumb_dead_zone, -32768);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickRight, SDL_GAMEPAD_AXIS_RIGHTX, +thumb_dead_zone, +32767);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickUp,    SDL_GAMEPAD_AXIS_RIGHTY, -thumb_dead_zone, -32768);
-    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickDown,  SDL_GAMEPAD_AXIS_RIGHTY, +thumb_dead_zone, +32767);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadStart,           SDL_GAMEPAD_BUTTON_START);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadBack,            SDL_GAMEPAD_BUTTON_BACK);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceLeft,        SDL_GAMEPAD_BUTTON_WEST);           // Xbox X, PS Square
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceRight,       SDL_GAMEPAD_BUTTON_EAST);           // Xbox B, PS Circle
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceUp,          SDL_GAMEPAD_BUTTON_NORTH);          // Xbox Y, PS Triangle
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadFaceDown,        SDL_GAMEPAD_BUTTON_SOUTH);          // Xbox A, PS Cross
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadLeft,        SDL_GAMEPAD_BUTTON_DPAD_LEFT);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadRight,       SDL_GAMEPAD_BUTTON_DPAD_RIGHT);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadUp,          SDL_GAMEPAD_BUTTON_DPAD_UP);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadDpadDown,        SDL_GAMEPAD_BUTTON_DPAD_DOWN);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadL1,              SDL_GAMEPAD_BUTTON_LEFT_SHOULDER);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadR1,              SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadL2,              SDL_GAMEPAD_AXIS_LEFT_TRIGGER,  0.0f, 32767);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadR2,              SDL_GAMEPAD_AXIS_RIGHT_TRIGGER, 0.0f, 32767);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadL3,              SDL_GAMEPAD_BUTTON_LEFT_STICK);
+    ImGui_ImplSDL3_UpdateGamepadButton(bd, io, ImGuiKey_GamepadR3,              SDL_GAMEPAD_BUTTON_RIGHT_STICK);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickLeft,      SDL_GAMEPAD_AXIS_LEFTX,  -thumb_dead_zone, -32768);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickRight,     SDL_GAMEPAD_AXIS_LEFTX,  +thumb_dead_zone, +32767);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickUp,        SDL_GAMEPAD_AXIS_LEFTY,  -thumb_dead_zone, -32768);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadLStickDown,      SDL_GAMEPAD_AXIS_LEFTY,  +thumb_dead_zone, +32767);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickLeft,      SDL_GAMEPAD_AXIS_RIGHTX, -thumb_dead_zone, -32768);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickRight,     SDL_GAMEPAD_AXIS_RIGHTX, +thumb_dead_zone, +32767);
+    ImGui_ImplSDL3_UpdateGamepadAnalog(bd, io, ImGuiKey_GamepadRStickUp,        SDL_GAMEPAD_AXIS_RIGHTY, -thumb_dead_zone, -32768);
+    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);
+        SDL_GetDisplayUsableBounds(display_id, &r);
+        monitor.WorkPos = ImVec2((float)r.x, (float)r.y);
+        monitor.WorkSize = ImVec2((float)r.w, (float)r.h);
+        // FIXME-VIEWPORT: On MacOS SDL reports actual monitor DPI scale, ignoring OS configuration. We may want to set
+        //  DpiScale to cocoa_window.backingScaleFactor here.
+        monitor.DpiScale = SDL_GetDisplayContentScale(display_id);
+        monitor.PlatformHandle = (void*)(intptr_t)n;
+        platform_io.Monitors.push_back(monitor);
+    }
 }
 
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDL3_Init()?");
     ImGuiIO& io = ImGui::GetIO();
 
     // Setup display size (every frame to accommodate for window resizing)
@@ -682,6 +787,10 @@ void ImGui_ImplSDL3_NewFrame()
     if (w > 0 && h > 0)
         io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
 
+    // Update monitors
+    if (bd->WantUpdateMonitors)
+        ImGui_ImplSDL3_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)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
@@ -698,6 +807,13 @@ 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 rygorous, 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();
 
@@ -705,6 +821,232 @@ 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* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplSDL3_ViewportData
+{
+    SDL_Window*     Window;
+    Uint32          WindowID;
+    bool            WindowOwned;
+    SDL_GLContext   GLContext;
+
+    ImGui_ImplSDL3_ViewportData() { Window = nullptr; WindowID = 0; WindowOwned = false; GLContext = nullptr; }
+    ~ImGui_ImplSDL3_ViewportData() { IM_ASSERT(Window == nullptr && GLContext == 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;
+
+    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);
+    }
+
+    Uint32 sdl_flags = 0;
+    sdl_flags |= use_opengl ? SDL_WINDOW_OPENGL : (bd->UseVulkan ? SDL_WINDOW_VULKAN : 0);
+    sdl_flags |= SDL_GetWindowFlags(bd->Window);
+    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_ImplSDL3_ShowWindow().
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_UTILITY : 0;
+#endif
+    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);
+    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_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_ImplSDL3_ShowWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplSDL3_ViewportData* vd = (ImGui_ImplSDL3_ViewportData*)viewport->PlatformUserData;
+#if defined(_WIN32)
+    HWND hwnd = (HWND)viewport->PlatformHandleRaw;
+
+    // SDL hack: Hide icon from task bar
+    // Note: SDL 3.0.0+ has a SDL_WINDOW_UTILITY 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);
+    }
+
+    // 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_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 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;
+    SDL_bool ret = SDL_Vulkan_CreateSurface(vd->Window, (VkInstance)vk_instance, (VkAllocationCallbacks*)vk_allocator, (VkSurfaceKHR*)out_vk_surface);
+    return ret ? 0 : 1; // ret ? VK_SUCCESS : VK_NOT_READY
+}
+
+static void ImGui_ImplSDL3_InitPlatformInterface(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_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_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_gl_context;
+    main_viewport->PlatformUserData = vd;
+    main_viewport->PlatformHandle = vd->Window;
+}
+
+static void ImGui_ImplSDL3_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdl3.h

@@ -9,8 +9,11 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
-// Missing features:
-//  [ ] Platform: IME SUPPORT IS BROKEN IN SDL3 BECAUSE INPUTS GETS SENT TO BOTH APP AND IME + 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' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// 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).
+//  [x] Platform: Basic 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_sdlrenderer2.cpp

@@ -10,6 +10,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// 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.
@@ -20,7 +22,6 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
-//  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
 //  2023-05-30: Renamed imgui_impl_sdlrenderer.h/.cpp to imgui_impl_sdlrenderer2.h/.cpp to accommodate for upcoming SDL3.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
 //  2021-12-21: Update SDL_RenderGeometryRaw() format to work with SDL 2.0.19.
@@ -48,9 +49,9 @@
 // SDL_Renderer data
 struct ImGui_ImplSDLRenderer2_Data
 {
-    SDL_Renderer*   Renderer;       // Main viewport's renderer
+    SDL_Renderer*   SDLRenderer;
     SDL_Texture*    FontTexture;
-    ImGui_ImplSDLRenderer2_Data()   { memset((void*)this, 0, sizeof(*this)); }
+    ImGui_ImplSDLRenderer2_Data() { memset((void*)this, 0, sizeof(*this)); }
 };
 
 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
@@ -64,7 +65,6 @@ static ImGui_ImplSDLRenderer2_Data* ImGui_ImplSDLRenderer2_GetBackendData()
 bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
     IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
 
@@ -74,7 +74,7 @@ bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
     io.BackendRendererName = "imgui_impl_sdlrenderer2";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
-    bd->Renderer = renderer;
+    bd->SDLRenderer = renderer;
 
     return true;
 }
@@ -93,31 +93,35 @@ void ImGui_ImplSDLRenderer2_Shutdown()
     IM_DELETE(bd);
 }
 
-static void ImGui_ImplSDLRenderer2_SetupRenderState(SDL_Renderer* renderer)
+static void ImGui_ImplSDLRenderer2_SetupRenderState()
 {
+	ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
+
 	// Clear out any viewports and cliprect set by the user
     // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
-	SDL_RenderSetViewport(renderer, nullptr);
-	SDL_RenderSetClipRect(renderer, nullptr);
+	SDL_RenderSetViewport(bd->SDLRenderer, nullptr);
+	SDL_RenderSetClipRect(bd->SDLRenderer, nullptr);
 }
 
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDLRenderer2_Init()?");
 
     if (!bd->FontTexture)
         ImGui_ImplSDLRenderer2_CreateDeviceObjects();
 }
 
-void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
+void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data)
 {
+	ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
+
 	// If there's a scale factor set by the user, use that instead
     // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
     // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
     float rsx = 1.0f;
 	float rsy = 1.0f;
-	SDL_RenderGetScale(renderer, &rsx, &rsy);
+	SDL_RenderGetScale(bd->SDLRenderer, &rsx, &rsy);
     ImVec2 render_scale;
 	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
 	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;
@@ -136,16 +140,16 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
         SDL_Rect    ClipRect;
     };
     BackupSDLRendererState old = {};
-    old.ClipEnabled = SDL_RenderIsClipEnabled(renderer) == SDL_TRUE;
-    SDL_RenderGetViewport(renderer, &old.Viewport);
-    SDL_RenderGetClipRect(renderer, &old.ClipRect);
+    old.ClipEnabled = SDL_RenderIsClipEnabled(bd->SDLRenderer) == SDL_TRUE;
+    SDL_RenderGetViewport(bd->SDLRenderer, &old.Viewport);
+    SDL_RenderGetClipRect(bd->SDLRenderer, &old.ClipRect);
 
 	// Will project scissor/clipping rectangles into framebuffer space
 	ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
 	ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    ImGui_ImplSDLRenderer2_SetupRenderState(renderer);
+    ImGui_ImplSDLRenderer2_SetupRenderState();
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -160,7 +164,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
                 // 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_ImplSDLRenderer2_SetupRenderState(renderer);
+                    ImGui_ImplSDLRenderer2_SetupRenderState();
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }
@@ -177,7 +181,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
                     continue;
 
                 SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
-                SDL_RenderSetClipRect(renderer, &r);
+                SDL_RenderSetClipRect(bd->SDLRenderer, &r);
 
                 const float* xy = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, pos));
                 const float* uv = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, uv));
@@ -189,7 +193,7 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
 
                 // Bind texture, Draw
 				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
-                SDL_RenderGeometryRaw(renderer, tex,
+                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
                     uv, (int)sizeof(ImDrawVert),
@@ -200,8 +204,8 @@ void ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     }
 
     // Restore modified SDL_Renderer state
-    SDL_RenderSetViewport(renderer, &old.Viewport);
-    SDL_RenderSetClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
+    SDL_RenderSetViewport(bd->SDLRenderer, &old.Viewport);
+    SDL_RenderSetClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
 // Called by Init/NewFrame/Shutdown
@@ -217,7 +221,7 @@ bool ImGui_ImplSDLRenderer2_CreateFontsTexture()
 
     // 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_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
+    bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
     if (bd->FontTexture == nullptr)
     {
         SDL_Log("error creating texture");

backends/imgui_impl_sdlrenderer2.h

@@ -10,6 +10,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// 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.
@@ -28,7 +30,7 @@ struct SDL_Renderer;
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer);
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_NewFrame();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer2_RenderDrawData(ImDrawData* draw_data);
 
 // Called by Init/NewFrame/Shutdown
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer2_CreateFontsTexture();

backends/imgui_impl_sdlrenderer3.cpp

@@ -10,6 +10,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// 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.
@@ -20,7 +22,6 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
-//  2024-05-14: *BREAKING CHANGE* ImGui_ImplSDLRenderer3_RenderDrawData() requires SDL_Renderer* passed as parameter.
 //  2024-02-12: Amend to query SDL_RenderViewportSet() and restore viewport accordingly.
 //  2023-05-30: Initial version.
 
@@ -44,9 +45,9 @@
 // SDL_Renderer data
 struct ImGui_ImplSDLRenderer3_Data
 {
-    SDL_Renderer*   Renderer;       // Main viewport's renderer
+    SDL_Renderer*   SDLRenderer;
     SDL_Texture*    FontTexture;
-    ImGui_ImplSDLRenderer3_Data()   { memset((void*)this, 0, sizeof(*this)); }
+    ImGui_ImplSDLRenderer3_Data() { memset((void*)this, 0, sizeof(*this)); }
 };
 
 // Backend data stored in io.BackendRendererUserData to allow support for multiple Dear ImGui contexts
@@ -60,7 +61,6 @@ static ImGui_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData()
 bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
     IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
 
@@ -70,7 +70,7 @@ bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
     io.BackendRendererName = "imgui_impl_sdlrenderer3";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
 
-    bd->Renderer = renderer;
+    bd->SDLRenderer = renderer;
 
     return true;
 }
@@ -89,31 +89,35 @@ void ImGui_ImplSDLRenderer3_Shutdown()
     IM_DELETE(bd);
 }
 
-static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
+static void ImGui_ImplSDLRenderer3_SetupRenderState()
 {
+	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
+
 	// Clear out any viewports and cliprect set by the user
     // FIXME: Technically speaking there are lots of other things we could backup/setup/restore during our render process.
-	SDL_SetRenderViewport(renderer, nullptr);
-	SDL_SetRenderClipRect(renderer, nullptr);
+	SDL_SetRenderViewport(bd->SDLRenderer, nullptr);
+	SDL_SetRenderClipRect(bd->SDLRenderer, nullptr);
 }
 
 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()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplSDLRenderer3_Init()?");
 
     if (!bd->FontTexture)
         ImGui_ImplSDLRenderer3_CreateDeviceObjects();
 }
 
-void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer)
+void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data)
 {
+	ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
+
 	// If there's a scale factor set by the user, use that instead
     // If the user has specified a scale factor to SDL_Renderer already via SDL_RenderSetScale(), SDL will scale whatever we pass
     // to SDL_RenderGeometryRaw() by that scale factor. In that case we don't want to be also scaling it ourselves here.
     float rsx = 1.0f;
 	float rsy = 1.0f;
-	SDL_GetRenderScale(renderer, &rsx, &rsy);
+	SDL_GetRenderScale(bd->SDLRenderer, &rsx, &rsy);
     ImVec2 render_scale;
 	render_scale.x = (rsx == 1.0f) ? draw_data->FramebufferScale.x : 1.0f;
 	render_scale.y = (rsy == 1.0f) ? draw_data->FramebufferScale.y : 1.0f;
@@ -133,17 +137,17 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
         SDL_Rect    ClipRect;
     };
     BackupSDLRendererState old = {};
-    old.ViewportEnabled = SDL_RenderViewportSet(renderer) == SDL_TRUE;
-    old.ClipEnabled = SDL_RenderClipEnabled(renderer) == SDL_TRUE;
-    SDL_GetRenderViewport(renderer, &old.Viewport);
-    SDL_GetRenderClipRect(renderer, &old.ClipRect);
+    old.ViewportEnabled = SDL_RenderViewportSet(bd->SDLRenderer) == SDL_TRUE;
+    old.ClipEnabled = SDL_RenderClipEnabled(bd->SDLRenderer) == SDL_TRUE;
+    SDL_GetRenderViewport(bd->SDLRenderer, &old.Viewport);
+    SDL_GetRenderClipRect(bd->SDLRenderer, &old.ClipRect);
 
 	// Will project scissor/clipping rectangles into framebuffer space
 	ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
 	ImVec2 clip_scale = render_scale;
 
     // Render command lists
-    ImGui_ImplSDLRenderer3_SetupRenderState(renderer);
+    ImGui_ImplSDLRenderer3_SetupRenderState();
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -158,7 +162,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
                 // 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_ImplSDLRenderer3_SetupRenderState(renderer);
+                    ImGui_ImplSDLRenderer3_SetupRenderState();
                 else
                     pcmd->UserCallback(cmd_list, pcmd);
             }
@@ -175,7 +179,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
                     continue;
 
                 SDL_Rect r = { (int)(clip_min.x), (int)(clip_min.y), (int)(clip_max.x - clip_min.x), (int)(clip_max.y - clip_min.y) };
-                SDL_SetRenderClipRect(renderer, &r);
+                SDL_SetRenderClipRect(bd->SDLRenderer, &r);
 
                 const float* xy = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, pos));
                 const float* uv = (const float*)(const void*)((const char*)(vtx_buffer + pcmd->VtxOffset) + offsetof(ImDrawVert, uv));
@@ -183,7 +187,7 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
 
                 // Bind texture, Draw
 				SDL_Texture* tex = (SDL_Texture*)pcmd->GetTexID();
-                SDL_RenderGeometryRaw(renderer, tex,
+                SDL_RenderGeometryRaw(bd->SDLRenderer, tex,
                     xy, (int)sizeof(ImDrawVert),
                     color, (int)sizeof(ImDrawVert),
                     uv, (int)sizeof(ImDrawVert),
@@ -194,8 +198,8 @@ void ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer*
     }
 
     // Restore modified SDL_Renderer state
-    SDL_SetRenderViewport(renderer, old.ViewportEnabled ? &old.Viewport : nullptr);
-    SDL_SetRenderClipRect(renderer, old.ClipEnabled ? &old.ClipRect : nullptr);
+    SDL_SetRenderViewport(bd->SDLRenderer, old.ViewportEnabled ? &old.Viewport : nullptr);
+    SDL_SetRenderClipRect(bd->SDLRenderer, old.ClipEnabled ? &old.ClipRect : nullptr);
 }
 
 // Called by Init/NewFrame/Shutdown
@@ -211,7 +215,7 @@ bool ImGui_ImplSDLRenderer3_CreateFontsTexture()
 
     // 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_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
+    bd->FontTexture = SDL_CreateTexture(bd->SDLRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STATIC, width, height);
     if (bd->FontTexture == nullptr)
     {
         SDL_Log("error creating texture");

backends/imgui_impl_sdlrenderer3.h

@@ -10,6 +10,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// 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.
@@ -28,7 +30,7 @@ struct SDL_Renderer;
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer);
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_NewFrame();
-IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data, SDL_Renderer* renderer);
+IMGUI_IMPL_API void     ImGui_ImplSDLRenderer3_RenderDrawData(ImDrawData* draw_data);
 
 // Called by Init/NewFrame/Shutdown
 IMGUI_IMPL_API bool     ImGui_ImplSDLRenderer3_CreateFontsTexture();

backends/imgui_impl_vulkan.cpp

@@ -2,8 +2,9 @@
 // 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. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
+//  [x] Renderer: User texture binding. Use 'VkDescriptorSet' as ImTextureID. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 
 // Important: on 32-bit systems, user texture binding is only supported if your imconfig file has '#define ImTextureID ImU64'.
 // This is because we need ImTextureID to carry a 64-bit value and by default ImTextureID is defined as void*.
@@ -33,7 +34,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2024-04-19: Vulkan: Added convenience support for Volk via IMGUI_IMPL_VULKAN_USE_VOLK define (you can also use IMGUI_IMPL_VULKAN_NO_PROTOTYPES + wrap Volk via ImGui_ImplVulkan_LoadFunctions().)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2024-02-14: *BREAKING CHANGE*: Moved RenderPass parameter from ImGui_ImplVulkan_Init() function to ImGui_ImplVulkan_InitInfo structure. Not required when using dynamic rendering.
 //  2024-02-12: *BREAKING CHANGE*: Dynamic rendering now require filling PipelineRenderingCreateInfo structure.
 //  2024-01-19: Vulkan: Fixed vkAcquireNextImageKHR() validation errors in VulkanSDK 1.3.275 by allocating one extra semaphore than in-flight frames. (#7236)
@@ -42,14 +43,14 @@
 //  2024-01-03: Vulkan: Stopped creating command pools with VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT as we don't reset them.
 //  2023-11-29: Vulkan: Fixed mismatching allocator passed to vkCreateCommandPool() vs vkDestroyCommandPool(). (#7075)
 //  2023-11-10: *BREAKING CHANGE*: Removed parameter from ImGui_ImplVulkan_CreateFontsTexture(): backend now creates its own command-buffer to upload fonts.
-//              *BREAKING CHANGE*: Removed ImGui_ImplVulkan_DestroyFontUploadObjects() which is now unnecessary as we create and destroy those objects in the backend.
+//              *BREAKING CHANGE*: Removed ImGui_ImplVulkan_DestroyFontUploadObjects() which is now unecessary as we create and destroy those objects in the backend.
 //              ImGui_ImplVulkan_CreateFontsTexture() is automatically called by NewFrame() the first time.
 //              You can call ImGui_ImplVulkan_CreateFontsTexture() again to recreate the font atlas texture.
 //              Added ImGui_ImplVulkan_DestroyFontsTexture() but you probably never need to call this.
 //  2023-07-04: Vulkan: Added optional support for VK_KHR_dynamic_rendering. User needs to set init_info->UseDynamicRendering = true and init_info->ColorAttachmentFormat.
 //  2023-01-02: Vulkan: Fixed sampler passed to ImGui_ImplVulkan_AddTexture() not being honored + removed a bunch of duplicate code.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
-//  2022-10-04: Vulkan: Added experimental ImGui_ImplVulkan_RemoveTexture() for api symmetry. (#914, #5738).
+//  2022-10-04: Vulkan: Added experimental ImGui_ImplVulkan_RemoveTexture() for api symetry. (#914, #5738).
 //  2022-01-20: Vulkan: Added support for ImTextureID as VkDescriptorSet. User need to call ImGui_ImplVulkan_AddTexture(). Building for 32-bit targets requires '#define ImTextureID ImU64'. (#914).
 //  2021-10-15: Vulkan: Call vkCmdSetScissor() at the end of render a full-viewport to reduce likehood of issues with people using VK_DYNAMIC_STATE_SCISSOR in their app without calling vkCmdSetScissor() explicitly every frame.
 //  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).
@@ -104,31 +105,34 @@ void ImGui_ImplVulkan_DestroyFrameRenderBuffers(VkDevice device, ImGui_ImplVulka
 void ImGui_ImplVulkan_DestroyWindowRenderBuffers(VkDevice device, ImGui_ImplVulkan_WindowRenderBuffers* buffers, const VkAllocationCallbacks* allocator);
 void ImGui_ImplVulkanH_DestroyFrame(VkDevice device, ImGui_ImplVulkanH_Frame* fd, const VkAllocationCallbacks* allocator);
 void ImGui_ImplVulkanH_DestroyFrameSemaphores(VkDevice device, ImGui_ImplVulkanH_FrameSemaphores* fsd, const VkAllocationCallbacks* allocator);
+void ImGui_ImplVulkanH_DestroyAllViewportsRenderBuffers(VkDevice device, const VkAllocationCallbacks* allocator);
 void ImGui_ImplVulkanH_CreateWindowSwapChain(VkPhysicalDevice physical_device, VkDevice device, ImGui_ImplVulkanH_Window* wd, const VkAllocationCallbacks* allocator, int w, int h, uint32_t min_image_count);
 void ImGui_ImplVulkanH_CreateWindowCommandBuffers(VkPhysicalDevice physical_device, VkDevice device, ImGui_ImplVulkanH_Window* wd, uint32_t queue_family, const VkAllocationCallbacks* allocator);
 
 // Vulkan prototypes for use with custom loaders
 // (see description of IMGUI_IMPL_VULKAN_NO_PROTOTYPES in imgui_impl_vulkan.h
-#if defined(VK_NO_PROTOTYPES) && !defined(VOLK_H_)
-#define IMGUI_IMPL_VULKAN_USE_LOADER
+#ifdef VK_NO_PROTOTYPES
 static bool g_FunctionsLoaded = false;
 #else
 static bool g_FunctionsLoaded = true;
 #endif
-#ifdef IMGUI_IMPL_VULKAN_USE_LOADER
+#ifdef VK_NO_PROTOTYPES
 #define IMGUI_VULKAN_FUNC_MAP(IMGUI_VULKAN_FUNC_MAP_MACRO) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkAllocateCommandBuffers) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkAllocateDescriptorSets) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkAllocateMemory) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkAcquireNextImageKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkBeginCommandBuffer) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkBindBufferMemory) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkBindImageMemory) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdBeginRenderPass) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdBindDescriptorSets) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdBindIndexBuffer) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdBindPipeline) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdBindVertexBuffers) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdCopyBufferToImage) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdDrawIndexed) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdEndRenderPass) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdPipelineBarrier) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdPushConstants) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkCmdSetScissor) \
@@ -174,19 +178,23 @@ static bool g_FunctionsLoaded = true;
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkGetPhysicalDeviceSurfaceCapabilitiesKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkGetPhysicalDeviceSurfaceFormatsKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkGetPhysicalDeviceSurfacePresentModesKHR) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkGetPhysicalDeviceSurfaceSupportKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkGetSwapchainImagesKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkMapMemory) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkQueuePresentKHR) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkQueueSubmit) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkQueueWaitIdle) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkResetCommandPool) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkResetFences) \
     IMGUI_VULKAN_FUNC_MAP_MACRO(vkUnmapMemory) \
-    IMGUI_VULKAN_FUNC_MAP_MACRO(vkUpdateDescriptorSets)
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkUpdateDescriptorSets) \
+    IMGUI_VULKAN_FUNC_MAP_MACRO(vkWaitForFences)
 
 // Define function pointers
 #define IMGUI_VULKAN_FUNC_DEF(func) static PFN_##func func;
 IMGUI_VULKAN_FUNC_MAP(IMGUI_VULKAN_FUNC_DEF)
 #undef IMGUI_VULKAN_FUNC_DEF
-#endif // IMGUI_IMPL_VULKAN_USE_LOADER
+#endif // VK_NO_PROTOTYPES
 
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
 static PFN_vkCmdBeginRenderingKHR   ImGuiImplVulkanFuncs_vkCmdBeginRenderingKHR;
@@ -214,6 +222,18 @@ struct ImGui_ImplVulkan_WindowRenderBuffers
     ImGui_ImplVulkan_FrameRenderBuffers* FrameRenderBuffers;
 };
 
+// For multi-viewport support:
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplVulkan_ViewportData
+{
+    bool                                    WindowOwned;
+    ImGui_ImplVulkanH_Window                Window;             // Used by secondary viewports only
+    ImGui_ImplVulkan_WindowRenderBuffers    RenderBuffers;      // Used by all viewports
+
+    ImGui_ImplVulkan_ViewportData()         { WindowOwned = false; memset(&RenderBuffers, 0, sizeof(RenderBuffers)); }
+    ~ImGui_ImplVulkan_ViewportData()        { }
+};
+
 // Vulkan data
 struct ImGui_ImplVulkan_Data
 {
@@ -249,6 +269,10 @@ struct ImGui_ImplVulkan_Data
 // SHADERS
 //-----------------------------------------------------------------------------
 
+// Forward Declarations
+static void ImGui_ImplVulkan_InitPlatformInterface();
+static void ImGui_ImplVulkan_ShutdownPlatformInterface();
+
 // backends/vulkan/glsl_shader.vert, compiled with:
 // # glslangValidator -V -x -o glsl_shader.vert.u32 glsl_shader.vert
 /*
@@ -486,8 +510,10 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
     if (pipeline == VK_NULL_HANDLE)
         pipeline = bd->Pipeline;
 
-    // Allocate array to store enough vertex/index buffers
-    ImGui_ImplVulkan_WindowRenderBuffers* wrb = &bd->MainWindowRenderBuffers;
+    // Allocate array to store enough vertex/index buffers. Each unique viewport gets its own storage.
+    ImGui_ImplVulkan_ViewportData* viewport_renderer_data = (ImGui_ImplVulkan_ViewportData*)draw_data->OwnerViewport->RendererUserData;
+    IM_ASSERT(viewport_renderer_data != nullptr);
+    ImGui_ImplVulkan_WindowRenderBuffers* wrb = &viewport_renderer_data->RenderBuffers;
     if (wrb->FrameRenderBuffers == nullptr)
     {
         wrb->Index = 0;
@@ -1032,7 +1058,7 @@ void    ImGui_ImplVulkan_DestroyDeviceObjects()
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
     ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
-    ImGui_ImplVulkan_DestroyWindowRenderBuffers(v->Device, &bd->MainWindowRenderBuffers, v->Allocator);
+    ImGui_ImplVulkanH_DestroyAllViewportsRenderBuffers(v->Device, v->Allocator);
     ImGui_ImplVulkan_DestroyFontsTexture();
 
     if (bd->FontCommandBuffer)    { vkFreeCommandBuffers(v->Device, bd->FontCommandPool, 1, &bd->FontCommandBuffer); bd->FontCommandBuffer = VK_NULL_HANDLE; }
@@ -1050,8 +1076,8 @@ bool    ImGui_ImplVulkan_LoadFunctions(PFN_vkVoidFunction(*loader_func)(const ch
     // Load function pointers
     // You can use the default Vulkan loader using:
     //      ImGui_ImplVulkan_LoadFunctions([](const char* function_name, void*) { return vkGetInstanceProcAddr(your_vk_isntance, function_name); });
-    // But this would be roughly equivalent to not setting VK_NO_PROTOTYPES.
-#ifdef IMGUI_IMPL_VULKAN_USE_LOADER
+    // But this would be equivalent to not setting VK_NO_PROTOTYPES.
+#ifdef VK_NO_PROTOTYPES
 #define IMGUI_VULKAN_FUNC_LOAD(func) \
     func = reinterpret_cast<decltype(func)>(loader_func(#func, user_data)); \
     if (func == nullptr)   \
@@ -1080,7 +1106,7 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info)
     if (info->UseDynamicRendering)
     {
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
-#ifndef IMGUI_IMPL_VULKAN_USE_LOADER
+#ifndef VK_NO_PROTOTYPES
         ImGuiImplVulkanFuncs_vkCmdBeginRenderingKHR = reinterpret_cast<PFN_vkCmdBeginRenderingKHR>(vkGetInstanceProcAddr(info->Instance, "vkCmdBeginRenderingKHR"));
         ImGuiImplVulkanFuncs_vkCmdEndRenderingKHR = reinterpret_cast<PFN_vkCmdEndRenderingKHR>(vkGetInstanceProcAddr(info->Instance, "vkCmdEndRenderingKHR"));
 #endif
@@ -1092,7 +1118,6 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info)
     }
 
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -1100,6 +1125,7 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info)
     io.BackendRendererUserData = (void*)bd;
     io.BackendRendererName = "imgui_impl_vulkan";
     io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasViewports;  // We can create multi-viewports on the Renderer side (optional)
 
     IM_ASSERT(info->Instance != VK_NULL_HANDLE);
     IM_ASSERT(info->PhysicalDevice != VK_NULL_HANDLE);
@@ -1115,6 +1141,13 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info)
 
     ImGui_ImplVulkan_CreateDeviceObjects();
 
+    // Our render function expect RendererUserData to be storing the window render buffer we need (for the main viewport we won't use ->Window)
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->RendererUserData = IM_NEW(ImGui_ImplVulkan_ViewportData)();
+
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplVulkan_InitPlatformInterface();
+
     return true;
 }
 
@@ -1124,17 +1157,28 @@ void ImGui_ImplVulkan_Shutdown()
     IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    // First destroy objects in all viewports
     ImGui_ImplVulkan_DestroyDeviceObjects();
+
+    // Manually delete main viewport render data in-case we haven't initialized for viewports
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    if (ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)main_viewport->RendererUserData)
+        IM_DELETE(vd);
+    main_viewport->RendererUserData = nullptr;
+
+    // Clean up windows
+    ImGui_ImplVulkan_ShutdownPlatformInterface();
+
     io.BackendRendererName = nullptr;
     io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasViewports);
     IM_DELETE(bd);
 }
 
 void ImGui_ImplVulkan_NewFrame()
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized! Did you call ImGui_ImplVulkan_Init()?");
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplVulkan_Init()?");
 
     if (!bd->FontDescriptorSet)
         ImGui_ImplVulkan_CreateFontsTexture();
@@ -1147,10 +1191,12 @@ void ImGui_ImplVulkan_SetMinImageCount(uint32_t min_image_count)
     if (bd->VulkanInitInfo.MinImageCount == min_image_count)
         return;
 
+    IM_ASSERT(0); // FIXME-VIEWPORT: Unsupported. Need to recreate all swap chains!
     ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
     VkResult err = vkDeviceWaitIdle(v->Device);
     check_vk_result(err);
-    ImGui_ImplVulkan_DestroyWindowRenderBuffers(v->Device, &bd->MainWindowRenderBuffers, v->Allocator);
+    ImGui_ImplVulkanH_DestroyAllViewportsRenderBuffers(v->Device, v->Allocator);
+
     bd->VulkanInitInfo.MinImageCount = min_image_count;
 }
 
@@ -1539,6 +1585,7 @@ void ImGui_ImplVulkanH_CreateOrResizeWindow(VkInstance instance, VkPhysicalDevic
     IM_ASSERT(g_FunctionsLoaded && "Need to call ImGui_ImplVulkan_LoadFunctions() if IMGUI_IMPL_VULKAN_NO_PROTOTYPES or VK_NO_PROTOTYPES are set!");
     (void)instance;
     ImGui_ImplVulkanH_CreateWindowSwapChain(physical_device, device, wd, allocator, width, height, min_image_count);
+    //ImGui_ImplVulkan_CreatePipeline(device, allocator, VK_NULL_HANDLE, wd->RenderPass, VK_SAMPLE_COUNT_1_BIT, &wd->Pipeline, g_VulkanInitInfo.Subpass);
     ImGui_ImplVulkanH_CreateWindowCommandBuffers(physical_device, device, wd, queue_family, allocator);
 }
 
@@ -1583,6 +1630,272 @@ void ImGui_ImplVulkanH_DestroyFrameSemaphores(VkDevice device, ImGui_ImplVulkanH
     fsd->ImageAcquiredSemaphore = fsd->RenderCompleteSemaphore = VK_NULL_HANDLE;
 }
 
+void ImGui_ImplVulkanH_DestroyAllViewportsRenderBuffers(VkDevice device, const VkAllocationCallbacks* allocator)
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    for (int n = 0; n < platform_io.Viewports.Size; n++)
+        if (ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)platform_io.Viewports[n]->RendererUserData)
+            ImGui_ImplVulkan_DestroyWindowRenderBuffers(device, &vd->RenderBuffers, allocator);
+}
+
+//--------------------------------------------------------------------------------------------------------
+// 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_ImplVulkan_CreateWindow(ImGuiViewport* viewport)
+{
+    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    ImGui_ImplVulkan_ViewportData* vd = IM_NEW(ImGui_ImplVulkan_ViewportData)();
+    viewport->RendererUserData = vd;
+    ImGui_ImplVulkanH_Window* wd = &vd->Window;
+    ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+
+    // Create surface
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    VkResult err = (VkResult)platform_io.Platform_CreateVkSurface(viewport, (ImU64)v->Instance, (const void*)v->Allocator, (ImU64*)&wd->Surface);
+    check_vk_result(err);
+
+    // Check for WSI support
+    VkBool32 res;
+    vkGetPhysicalDeviceSurfaceSupportKHR(v->PhysicalDevice, v->QueueFamily, wd->Surface, &res);
+    if (res != VK_TRUE)
+    {
+        IM_ASSERT(0); // Error: no WSI support on physical device
+        return;
+    }
+
+    // Select Surface Format
+    ImVector<VkFormat> requestSurfaceImageFormats;
+#ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
+    for (uint32_t n = 0; n < v->PipelineRenderingCreateInfo.colorAttachmentCount; n++)
+        requestSurfaceImageFormats.push_back(v->PipelineRenderingCreateInfo.pColorAttachmentFormats[n]);
+#endif
+    const VkFormat defaultFormats[] = { VK_FORMAT_B8G8R8A8_UNORM, VK_FORMAT_R8G8B8A8_UNORM, VK_FORMAT_B8G8R8_UNORM, VK_FORMAT_R8G8B8_UNORM };
+    for (VkFormat format : defaultFormats)
+        requestSurfaceImageFormats.push_back(format);
+
+    const VkColorSpaceKHR requestSurfaceColorSpace = VK_COLORSPACE_SRGB_NONLINEAR_KHR;
+    wd->SurfaceFormat = ImGui_ImplVulkanH_SelectSurfaceFormat(v->PhysicalDevice, wd->Surface, requestSurfaceImageFormats.Data, (size_t)requestSurfaceImageFormats.Size, requestSurfaceColorSpace);
+
+    // Select Present Mode
+    // FIXME-VULKAN: Even thought mailbox seems to get us maximum framerate with a single window, it halves framerate with a second window etc. (w/ Nvidia and SDK 1.82.1)
+    VkPresentModeKHR present_modes[] = { VK_PRESENT_MODE_MAILBOX_KHR, VK_PRESENT_MODE_IMMEDIATE_KHR, VK_PRESENT_MODE_FIFO_KHR };
+    wd->PresentMode = ImGui_ImplVulkanH_SelectPresentMode(v->PhysicalDevice, wd->Surface, &present_modes[0], IM_ARRAYSIZE(present_modes));
+    //printf("[vulkan] Secondary window selected PresentMode = %d\n", wd->PresentMode);
+
+    // Create SwapChain, RenderPass, Framebuffer, etc.
+    wd->ClearEnable = (viewport->Flags & ImGuiViewportFlags_NoRendererClear) ? false : true;
+    wd->UseDynamicRendering = v->UseDynamicRendering;
+    ImGui_ImplVulkanH_CreateOrResizeWindow(v->Instance, v->PhysicalDevice, v->Device, wd, v->QueueFamily, v->Allocator, (int)viewport->Size.x, (int)viewport->Size.y, v->MinImageCount);
+    vd->WindowOwned = true;
+}
+
+static void ImGui_ImplVulkan_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_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    if (ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData)
+    {
+        ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+        if (vd->WindowOwned)
+            ImGui_ImplVulkanH_DestroyWindow(v->Instance, v->Device, &vd->Window, v->Allocator);
+        ImGui_ImplVulkan_DestroyWindowRenderBuffers(v->Device, &vd->RenderBuffers, v->Allocator);
+        IM_DELETE(vd);
+    }
+    viewport->RendererUserData = nullptr;
+}
+
+static void ImGui_ImplVulkan_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
+{
+    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData;
+    if (vd == nullptr) // This is nullptr for the main viewport (which is left to the user/app to handle)
+        return;
+    ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+    vd->Window.ClearEnable = (viewport->Flags & ImGuiViewportFlags_NoRendererClear) ? false : true;
+    ImGui_ImplVulkanH_CreateOrResizeWindow(v->Instance, v->PhysicalDevice, v->Device, &vd->Window, v->QueueFamily, v->Allocator, (int)size.x, (int)size.y, v->MinImageCount);
+}
+
+static void ImGui_ImplVulkan_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData;
+    ImGui_ImplVulkanH_Window* wd = &vd->Window;
+    ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+    VkResult err;
+
+    ImGui_ImplVulkanH_Frame* fd = &wd->Frames[wd->FrameIndex];
+    ImGui_ImplVulkanH_FrameSemaphores* fsd = &wd->FrameSemaphores[wd->SemaphoreIndex];
+    {
+        {
+          err = vkAcquireNextImageKHR(v->Device, wd->Swapchain, UINT64_MAX, fsd->ImageAcquiredSemaphore, VK_NULL_HANDLE, &wd->FrameIndex);
+          check_vk_result(err);
+          fd = &wd->Frames[wd->FrameIndex];
+        }
+        for (;;)
+        {
+            err = vkWaitForFences(v->Device, 1, &fd->Fence, VK_TRUE, 100);
+            if (err == VK_SUCCESS) break;
+            if (err == VK_TIMEOUT) continue;
+            check_vk_result(err);
+        }
+        {
+            err = vkResetCommandPool(v->Device, fd->CommandPool, 0);
+            check_vk_result(err);
+            VkCommandBufferBeginInfo info = {};
+            info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
+            info.flags |= VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+            err = vkBeginCommandBuffer(fd->CommandBuffer, &info);
+            check_vk_result(err);
+        }
+        {
+            ImVec4 clear_color = ImVec4(0.0f, 0.0f, 0.0f, 1.0f);
+            memcpy(&wd->ClearValue.color.float32[0], &clear_color, 4 * sizeof(float));
+        }
+#ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
+        if (v->UseDynamicRendering)
+        {
+            // Transition swapchain image to a layout suitable for drawing.
+            VkImageMemoryBarrier barrier = {};
+            barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+            barrier.dstAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            barrier.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+            barrier.newLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+            barrier.image = fd->Backbuffer;
+            barrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
+            barrier.subresourceRange.levelCount = 1;
+            barrier.subresourceRange.layerCount = 1;
+            vkCmdPipelineBarrier(fd->CommandBuffer, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, 0, 0, nullptr, 0, nullptr, 1, &barrier);
+
+            VkRenderingAttachmentInfo attachmentInfo = {};
+            attachmentInfo.sType = VK_STRUCTURE_TYPE_RENDERING_ATTACHMENT_INFO_KHR;
+            attachmentInfo.imageView = fd->BackbufferView;
+            attachmentInfo.imageLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+            attachmentInfo.resolveMode = VK_RESOLVE_MODE_NONE;
+            attachmentInfo.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
+            attachmentInfo.storeOp = VK_ATTACHMENT_STORE_OP_STORE;
+            attachmentInfo.clearValue = wd->ClearValue;
+
+            VkRenderingInfo renderingInfo = {};
+            renderingInfo.sType = VK_STRUCTURE_TYPE_RENDERING_INFO_KHR;
+            renderingInfo.renderArea.extent.width = wd->Width;
+            renderingInfo.renderArea.extent.height = wd->Height;
+            renderingInfo.layerCount = 1;
+            renderingInfo.viewMask = 0;
+            renderingInfo.colorAttachmentCount = 1;
+            renderingInfo.pColorAttachments = &attachmentInfo;
+
+            ImGuiImplVulkanFuncs_vkCmdBeginRenderingKHR(fd->CommandBuffer, &renderingInfo);
+        }
+        else
+#endif
+        {
+            VkRenderPassBeginInfo info = {};
+            info.sType = VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO;
+            info.renderPass = wd->RenderPass;
+            info.framebuffer = fd->Framebuffer;
+            info.renderArea.extent.width = wd->Width;
+            info.renderArea.extent.height = wd->Height;
+            info.clearValueCount = (viewport->Flags & ImGuiViewportFlags_NoRendererClear) ? 0 : 1;
+            info.pClearValues = (viewport->Flags & ImGuiViewportFlags_NoRendererClear) ? nullptr : &wd->ClearValue;
+            vkCmdBeginRenderPass(fd->CommandBuffer, &info, VK_SUBPASS_CONTENTS_INLINE);
+        }
+    }
+
+    ImGui_ImplVulkan_RenderDrawData(viewport->DrawData, fd->CommandBuffer, wd->Pipeline);
+
+    {
+#ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
+        if (v->UseDynamicRendering)
+        {
+            ImGuiImplVulkanFuncs_vkCmdEndRenderingKHR(fd->CommandBuffer);
+
+            // Transition image to a layout suitable for presentation
+            VkImageMemoryBarrier barrier = {};
+            barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+            barrier.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            barrier.oldLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+            barrier.newLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
+            barrier.image = fd->Backbuffer;
+            barrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
+            barrier.subresourceRange.levelCount = 1;
+            barrier.subresourceRange.layerCount = 1;
+            vkCmdPipelineBarrier(fd->CommandBuffer, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT, 0, 0, nullptr, 0, nullptr, 1, &barrier);
+        }
+        else
+#endif
+        {
+            vkCmdEndRenderPass(fd->CommandBuffer);
+        }
+        {
+            VkPipelineStageFlags wait_stage = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
+            VkSubmitInfo info = {};
+            info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+            info.waitSemaphoreCount = 1;
+            info.pWaitSemaphores = &fsd->ImageAcquiredSemaphore;
+            info.pWaitDstStageMask = &wait_stage;
+            info.commandBufferCount = 1;
+            info.pCommandBuffers = &fd->CommandBuffer;
+            info.signalSemaphoreCount = 1;
+            info.pSignalSemaphores = &fsd->RenderCompleteSemaphore;
+
+            err = vkEndCommandBuffer(fd->CommandBuffer);
+            check_vk_result(err);
+            err = vkResetFences(v->Device, 1, &fd->Fence);
+            check_vk_result(err);
+            err = vkQueueSubmit(v->Queue, 1, &info, fd->Fence);
+            check_vk_result(err);
+        }
+    }
+}
+
+static void ImGui_ImplVulkan_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData;
+    ImGui_ImplVulkanH_Window* wd = &vd->Window;
+    ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
+
+    VkResult err;
+    uint32_t present_index = wd->FrameIndex;
+
+    ImGui_ImplVulkanH_FrameSemaphores* fsd = &wd->FrameSemaphores[wd->SemaphoreIndex];
+    VkPresentInfoKHR info = {};
+    info.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;
+    info.waitSemaphoreCount = 1;
+    info.pWaitSemaphores = &fsd->RenderCompleteSemaphore;
+    info.swapchainCount = 1;
+    info.pSwapchains = &wd->Swapchain;
+    info.pImageIndices = &present_index;
+    err = vkQueuePresentKHR(v->Queue, &info);
+    if (err == VK_ERROR_OUT_OF_DATE_KHR || err == VK_SUBOPTIMAL_KHR)
+        ImGui_ImplVulkanH_CreateOrResizeWindow(v->Instance, v->PhysicalDevice, v->Device, &vd->Window, v->QueueFamily, v->Allocator, (int)viewport->Size.x, (int)viewport->Size.y, v->MinImageCount);
+    else
+        check_vk_result(err);
+
+    wd->FrameIndex = (wd->FrameIndex + 1) % wd->ImageCount;             // This is for the next vkWaitForFences()
+    wd->SemaphoreIndex = (wd->SemaphoreIndex + 1) % wd->SemaphoreCount; // Now we can use the next set of semaphores
+}
+
+void ImGui_ImplVulkan_InitPlatformInterface()
+{
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        IM_ASSERT(platform_io.Platform_CreateVkSurface != nullptr && "Platform needs to setup the CreateVkSurface handler.");
+    platform_io.Renderer_CreateWindow = ImGui_ImplVulkan_CreateWindow;
+    platform_io.Renderer_DestroyWindow = ImGui_ImplVulkan_DestroyWindow;
+    platform_io.Renderer_SetWindowSize = ImGui_ImplVulkan_SetWindowSize;
+    platform_io.Renderer_RenderWindow = ImGui_ImplVulkan_RenderWindow;
+    platform_io.Renderer_SwapBuffers = ImGui_ImplVulkan_SwapBuffers;
+}
+
+void ImGui_ImplVulkan_ShutdownPlatformInterface()
+{
+    ImGui::DestroyPlatformWindows();
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_vulkan.h

@@ -2,8 +2,9 @@
 // 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. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
+//  [x] Renderer: User texture binding. Use 'VkDescriptorSet' as ImTextureID. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 
 // Important: on 32-bit systems, user texture binding is only supported if your imconfig file has '#define ImTextureID ImU64'.
 // See imgui_impl_vulkan.cpp file for details.
@@ -42,20 +43,13 @@
 // If you have no idea what this is, leave it alone!
 //#define IMGUI_IMPL_VULKAN_NO_PROTOTYPES
 
-// Convenience support for Volk
-// (you can also technically use IMGUI_IMPL_VULKAN_NO_PROTOTYPES + wrap Volk via ImGui_ImplVulkan_LoadFunctions().)
-//#define IMGUI_IMPL_VULKAN_USE_VOLK
-
+// Vulkan includes
 #if defined(IMGUI_IMPL_VULKAN_NO_PROTOTYPES) && !defined(VK_NO_PROTOTYPES)
 #define VK_NO_PROTOTYPES
 #endif
 #if defined(VK_USE_PLATFORM_WIN32_KHR) && !defined(NOMINMAX)
 #define NOMINMAX
-#endif
-
-// Vulkan includes
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-#include <Volk/volk.h>
+#include <vulkan/vulkan.h>
 #else
 #include <vulkan/vulkan.h>
 #endif

backends/imgui_impl_wgpu.cpp

@@ -5,6 +5,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows). Not meaningful on the web.
 
 // 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.
@@ -724,7 +726,6 @@ void ImGui_ImplWGPU_InvalidateDeviceObjects()
 bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
 
     // Setup backend capabilities flags
@@ -752,7 +753,7 @@ bool ImGui_ImplWGPU_Init(ImGui_ImplWGPU_InitInfo* init_info)
 
     // Create buffers with a default size (they will later be grown as needed)
     bd->pFrameResources = new FrameResources[bd->numFramesInFlight];
-    for (unsigned int i = 0; i < bd->numFramesInFlight; i++)
+    for (int i = 0; i < bd->numFramesInFlight; i++)
     {
         FrameResources* fr = &bd->pFrameResources[i];
         fr->IndexBuffer = nullptr;

backends/imgui_impl_wgpu.h

@@ -5,6 +5,8 @@
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
 //  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+// Missing features:
+//  [ ] Renderer: Multi-viewport support (multiple windows). Not meaningful on the web.
 
 // 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_win32.cpp

@@ -7,6 +7,7 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. 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.
@@ -16,11 +17,30 @@
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp
 
-// Configuration flags to add in your imconfig file:
+#include "imgui.h"
+#ifndef IMGUI_DISABLE
+#include "imgui_impl_win32.h"
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#include <windowsx.h> // GET_X_LPARAM(), GET_Y_LPARAM()
+#include <tchar.h>
+#include <dwmapi.h>
+
+// Configuration flags to add in your imconfig.h file:
 //#define IMGUI_IMPL_WIN32_DISABLE_GAMEPAD              // Disable gamepad support. This was meaningful before <1.81 but we now load XInput dynamically so the option is now less relevant.
 
+// Using XInput for gamepad (will load DLL dynamically)
+#ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
+#include <xinput.h>
+typedef DWORD (WINAPI *PFN_XInputGetCapabilities)(DWORD, DWORD, XINPUT_CAPABILITIES*);
+typedef DWORD (WINAPI *PFN_XInputGetState)(DWORD, XINPUT_STATE*);
+#endif
+
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  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).
 //  2023-09-07: Inputs: Added support for keyboard codepage conversion for when application is compiled in MBCS mode and using a non-Unicode window.
@@ -73,33 +93,10 @@
 //  2017-10-23: Inputs: Using Win32 ::SetCapture/::GetCapture() to retrieve mouse positions outside the client area when dragging.
 //  2016-11-12: Inputs: Only call Win32 ::SetCursor(nullptr) when io.MouseDrawCursor is set.
 
-#include "imgui.h"
-#ifndef IMGUI_DISABLE
-#include "imgui_impl_win32.h"
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#include <windows.h>
-#include <windowsx.h> // GET_X_LPARAM(), GET_Y_LPARAM()
-#include <tchar.h>
-#include <dwmapi.h>
-
-// Using XInput for gamepad (will load DLL dynamically)
-#ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
-#include <xinput.h>
-typedef DWORD(WINAPI* PFN_XInputGetCapabilities)(DWORD, DWORD, XINPUT_CAPABILITIES*);
-typedef DWORD(WINAPI* PFN_XInputGetState)(DWORD, XINPUT_STATE*);
-#endif
-
-// Clang/GCC warnings with -Weverything
-#if defined(__clang__)
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wcast-function-type"     // warning: cast between incompatible function types (for loader)
-#endif
-#if defined(__GNUC__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wcast-function-type"       // warning: cast between incompatible function types (for loader)
-#endif
+// Forward Declarations
+static void ImGui_ImplWin32_InitPlatformInterface(bool platformHasOwnDC);
+static void ImGui_ImplWin32_ShutdownPlatformInterface();
+static void ImGui_ImplWin32_UpdateMonitors();
 
 struct ImGui_ImplWin32_Data
 {
@@ -111,6 +108,7 @@ struct ImGui_ImplWin32_Data
     INT64                       TicksPerSecond;
     ImGuiMouseCursor            LastMouseCursor;
     UINT32                      KeyboardCodePage;
+    bool                        WantUpdateMonitors;
 
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     bool                        HasGamepad;
@@ -146,7 +144,6 @@ static void ImGui_ImplWin32_UpdateKeyboardCodePage()
 static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
 {
     ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
     IM_ASSERT(io.BackendPlatformUserData == nullptr && "Already initialized a platform backend!");
 
     INT64 perf_frequency, perf_counter;
@@ -161,16 +158,21 @@ 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->WantUpdateMonitors = true;
     bd->TicksPerSecond = perf_frequency;
     bd->Time = perf_counter;
     bd->LastMouseCursor = ImGuiMouseCursor_COUNT;
     ImGui_ImplWin32_UpdateKeyboardCodePage();
 
-    // Set platform dependent data in viewport
-    ImGui::GetMainViewport()->PlatformHandleRaw = (void*)hwnd;
-    IM_UNUSED(platform_has_own_dc); // Used in 'docking' branch
+    // 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;
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        ImGui_ImplWin32_InitPlatformInterface(platform_has_own_dc);
 
     // Dynamically load XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
@@ -213,6 +215,8 @@ void    ImGui_ImplWin32_Shutdown()
     IM_ASSERT(bd != nullptr && "No platform backend to shutdown, or already shutdown?");
     ImGuiIO& io = ImGui::GetIO();
 
+    ImGui_ImplWin32_ShutdownPlatformInterface();
+
     // Unload XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
     if (bd->XInputDLL)
@@ -221,7 +225,7 @@ 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);
 }
 
@@ -295,33 +299,59 @@ static void ImGui_ImplWin32_UpdateKeyModifiers()
     io.AddKeyEvent(ImGuiMod_Super, IsVkDown(VK_APPS));
 }
 
+// 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()
 {
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
     ImGuiIO& io = ImGui::GetIO();
     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::FindViewportByPlatformHandle((void*)focused_window)));
     if (is_app_focused)
     {
         // (Optional) Set OS mouse position from Dear ImGui if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos 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::FindViewportByPlatformHandle((void*)hovered_hwnd))
+                mouse_viewport_id = viewport->ID;
+    io.AddMouseViewportEvent(mouse_viewport_id);
 }
 
 // Gamepad navigation mapping
@@ -381,16 +411,47 @@ static void ImGui_ImplWin32_UpdateGamepads()
 #endif // #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
 }
 
-void    ImGui_ImplWin32_NewFrame()
+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;
+    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();
-    IM_ASSERT(bd != nullptr && "Context or backend not initialized? Did you call ImGui_ImplWin32_Init()?");
+    ImGui::GetPlatformIO().Monitors.resize(0);
+    ::EnumDisplayMonitors(nullptr, nullptr, ImGui_ImplWin32_UpdateMonitors_EnumFunc, 0);
+    bd->WantUpdateMonitors = false;
+}
+
+void    ImGui_ImplWin32_NewFrame()
+{
     ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    IM_ASSERT(bd != nullptr && "Did you call ImGui_ImplWin32_Init()?");
 
     // 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;
@@ -581,12 +642,11 @@ static ImGuiMouseSource GetMouseSourceFromMessageExtraInfo()
 
 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().
-    // We silently allow both context or just only backend data to be nullptr.
-    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
-    if (bd == nullptr)
+    if (ImGui::GetCurrentContext() == nullptr)
         return 0;
+
     ImGuiIO& io = ImGui::GetIO();
+    ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
 
     switch (msg)
     {
@@ -607,11 +667,14 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
             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;
+        break;
     }
     case WM_MOUSELEAVE:
     case WM_NCMOUSELEAVE:
@@ -624,7 +687,7 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
             bd->MouseTrackedArea = 0;
             io.AddMousePosEvent(-FLT_MAX, -FLT_MAX);
         }
-        return 0;
+        break;
     }
     case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK:
     case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK:
@@ -747,6 +810,9 @@ IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARA
             bd->WantUpdateHasGamepad = true;
 #endif
         return 0;
+    case WM_DISPLAYCHANGE:
+        bd->WantUpdateMonitors = true;
+        return 0;
     }
     return 0;
 }
@@ -811,6 +877,10 @@ 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
@@ -911,12 +981,357 @@ 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..
+//--------------------------------------------------------------------------------------------------------
 
-#if defined(__GNUC__)
-#pragma GCC diagnostic pop
-#endif
-#if defined(__clang__)
-#pragma clang diagnostic pop
+// Helper structure we store in the void* RendererUserData field of each ImGuiViewport to easily retrieve our backend data.
+struct ImGui_ImplWin32_ViewportData
+{
+    HWND    Hwnd;
+    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 = ::CreateWindowEx(
+        vd->DwExStyle, _T("ImGui Platform"), _T("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;
+}
+
+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_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 };
+    ::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 };
+    ::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);
+    ::SetWindowTextW(vd->Hwnd, 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 style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) | WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, style);
+        ::SetLayeredWindowAttributes(vd->Hwnd, 0, (BYTE)(255 * alpha), LWA_ALPHA);
+    }
+    else
+    {
+        DWORD style = ::GetWindowLongW(vd->Hwnd, GWL_EXSTYLE) & ~WS_EX_LAYERED;
+        ::SetWindowLongW(vd->Hwnd, GWL_EXSTYLE, 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
+}
+
+static LRESULT CALLBACK ImGui_ImplWin32_WndProcHandler_PlatformWindow(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+    if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))
+        return true;
+
+    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)hWnd))
+    {
+        switch (msg)
+        {
+        case WM_CLOSE:
+            viewport->PlatformRequestClose = true;
+            return 0;
+        case WM_MOVE:
+            viewport->PlatformRequestMove = true;
+            break;
+        case WM_SIZE:
+            viewport->PlatformRequestResize = true;
+            break;
+        case WM_MOUSEACTIVATE:
+            if (viewport->Flags & ImGuiViewportFlags_NoFocusOnClick)
+                return 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)
+                return HTTRANSPARENT;
+            break;
+        }
+    }
+
+    return DefWindowProc(hWnd, msg, wParam, lParam);
+}
+
+static void ImGui_ImplWin32_InitPlatformInterface(bool platform_has_own_dc)
+{
+    WNDCLASSEX wcex;
+    wcex.cbSize = sizeof(WNDCLASSEX);
+    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 = _T("ImGui Platform");
+    wcex.hIconSm = nullptr;
+    ::RegisterClassEx(&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;
+    main_viewport->PlatformHandle = (void*)bd->hWnd;
+}
+
+static void ImGui_ImplWin32_ShutdownPlatformInterface()
+{
+    ::UnregisterClass(_T("ImGui Platform"), ::GetModuleHandle(nullptr));
+    ImGui::DestroyPlatformWindows();
+}
+
+//---------------------------------------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_win32.h

@@ -7,6 +7,7 @@
 //  [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 will also be supported unless IMGUI_DISABLE_OBSOLETE_KEYIO is set]
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
 //  [X] Platform: Mouse cursor shape and visibility. 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

@@ -79,14 +79,14 @@ List of Renderer Backends:
     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_wgpu.cpp       ; WebGPU
 
 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.
+The SDL+GL, GLFW+GL and SDL+WebGPU examples are all ready to build and run with Emscripten.
 
 ### Backends for third-party frameworks, graphics API or other languages
 

docs/CHANGELOG.txt

@@ -35,214 +35,6 @@ HOW TO UPDATE?
   and API updates have been a little more frequent lately. They are documented below and in imgui.cpp and should not affect all users.
 - Please report any issue!
 
------------------------------------------------------------------------
- VERSION 1.90.8 (Released 2024-06-06)
------------------------------------------------------------------------
-
-Decorated log and release notes: https://github.com/ocornut/imgui/releases/tag/v1.90.8
-
-Breaking changes:
-
-- Reordered various ImGuiInputTextFlags values. This should NOT be breaking unless
-  you are using generated headers that have values not matching the main library.
-- Removed ImGuiButtonFlags_MouseButtonDefault_ = ImGuiButtonFlags_MouseButtonLeft
-  from imgui.h, was mostly unused and misleading.
-
-Other changes:
-
-- Inputs: fixed IsMouseClicked(..., repeat=true); broken in 1.90.7 on 2024/05/22.
-  (due to an internal api parameter swap, repeat wouldn't be honored and
-  ownership would be accidentally checked even though this api is meant to not
-  check ownership). (#7657) [@korenkonder]
-- Windows: fixed altering FramePadding mid-frame not correctly affecting logic
-  responsible for honoring io.ConfigWindowsMoveFromTitleBarOnly. (#7576, #899)
-- Scrollbar: made scrolling logic more standard: clicking above or below the
-  grab scrolls by one page, holding mouse button repeats scrolling. (#7328, #150)
-- Scrollbar: fixed miscalculation of vertical scrollbar visibility when required
-  solely by the presence of an horizontal scrollbar. (#1574)
-- InputScalar, InputInt, InputFloat: added ImGuiInputTextFlags_ParseEmptyRefVal
-  to parse an empty field as zero-value. (#7305) [@supermerill, @ocornut]
-- InputScalar, InputInt, InputFloat: added ImGuiInputTextFlags_DisplayEmptyRefVal
-  to display a zero-value as empty. (#7305) [@supermerill, @ocornut]
-- Popups: fixed an issue preventing to close a popup opened over a modal by clicking
-  over void (it required clicking over the visible part of the modal). (#7654)
-- Tables: fixed an issue where ideal size reported to parent container wouldn't
-  correctly take account of inner scrollbar, affecting potential auto-resize of
-  parent container. (#7651)
-- Tables: fixed a bug where after disabling the ScrollY flag for a table,
-  previous scrollbar width would be accounted for. (#5920)
-- Combo: simplified Combo() API uses a list clipper (due to its api it wasn't
-  previously trivial before we added clipper.IncludeItemByIndex() function).
-- Disabled: nested tooltips or other non-child window within a BeginDisabled()
-  block disable the disabled state. (#211, #7640)
-- Misc: made ImGuiDir and ImGuiSortDirection stronger-typed enums.
-- Backends: SDL3: Update for SDL_SYSTEM_CURSOR_xxx api renames. (#7653)
-
-
------------------------------------------------------------------------
- VERSION 1.90.7 (Released 2024-05-27)
------------------------------------------------------------------------
-
-Decorated log and release notes: https://github.com/ocornut/imgui/releases/tag/v1.90.7
-
-Breaking changes:
-
-- Inputs: on macOS X, Cmd and Ctrl keys are now automatically swapped by io.AddKeyEvent(),
-  as this naturally align with how macOS X uses those keys. (#2343, #4084, #5923, #456)
-  - Effectively it means that e.g. ImGuiMod_Ctrl | ImGuiKey_C is a valid idiomatic shortcut
-    for both Windows and Mac style users.
-  - It shouldn't really affect your code unless you had explicit/custom shortcut swapping in
-    place for macOS X apps in your input logic.
-  - Removed ImGuiMod_Shortcut which was previously dynamically remapping to Ctrl or Cmd/Super.
-    It is now unnecessary to specific cross-platform idiomatic shortcuts.
-    Kept symbols redirecting ImGuiMod_Shortcut to ImGuiMod_Ctrl (will obsolete).
-- Commented out obsolete symbols renamed in 1.88 (May 2022):
-    CaptureKeyboardFromApp() -> SetNextFrameWantCaptureKeyboard()
-    CaptureMouseFromApp()    -> SetNextFrameWantCaptureMouse()
-- Backends: SDL_Renderer2/SDL_Renderer3: ImGui_ImplSDLRenderer2_RenderDrawData() and
-  ImGui_ImplSDLRenderer3_RenderDrawData() now takes a SDL_Renderer* parameter. This was previously
-  overlooked from the API but it will allow eventual support for multi-viewports.
-
-Other changes:
-
-- Windows: BeginChild(): fixed visibility of fully clipped child windows and tables to Test Engine.
-- Windows: BeginChild(): fixed auto-fit calculation when using either (not both) ResizeX/ResizeY
-  and double-clicking on a border. Calculation incorrectly didn't always account for scrollbar as
-  it assumed the other axis would also be auto-fit. (#1710)
-- Inputs: added shortcut and routing system in public API. (#456, #2637) [BETA]
-  - The general idea is that several callers may register interest in a shortcut, and only one owner gets it.
-    - in Parent: call Shortcut(Ctrl+S)    // When Parent is focused, Parent gets the shortcut.
-    - in Child1: call Shortcut(Ctrl+S)    // When Child1 is focused, Child1 gets the shortcut (Child1 overrides Parent shortcuts)
-    - in Child2: no call                  // When Child2 is focused, Parent gets the shortcut.
-    The whole system is order independent, so if Child1 makes its calls before Parent, results will be identical.
-    This is an important property as it facilitate working with foreign code or larger codebase.
-  - Added Shortcut() function:
-    e.g. Using ImGui::Shortcut(ImGuiMod_Ctrl | ImGuiKey_C); with default policy:
-    - checks that CTRL+C is pressed,
-    - and that current window is in focus stack,
-    - and that no other requests for CTRL+C have been made from higher priority locations
-      (e.g. deeper in the window/item stack).
-  - Added SetNextItemShortcut() to set a shortcut to locally or remotely press or activate
-    an item (depending on specified routing policy: using ImGuiInputFlags_RouteGlobal the item
-    shortcut may be executed even if its window is not in focus stack).
-    Items like buttons are not fully activated, in the sense that they get pressed but another
-    active item, e.g. InputText() won't be deactivated.
-  - Added routing policies for Shortcut(), SetNextItemShortcut(): (#456, #2637)
-    - ImGuiInputFlags_RouteFocused: focus stack route (default)
-    - ImGuiInputFlags_RouteActive: only route to active item
-    - ImGuiInputFlags_RouteGlobal: route globally, unless a focus route claim shame shortcut.
-    - ImGuiInputFlags_RouteAlways: no routing submission, no routing check.
-  - Added other shortcut/routing options: (#456, #2637)
-    - ImGuiInputFlags_Repeat: for use by Shortcut() and by upcoming rework of various
-      input functions (which are still internal for now).
-    - ImGuiInputFlags_Tooltip: for SetNextItemShortcut() to show a tooltip when hovering item.
-    - ImGuiInputFlags_RouteOverFocused: global route takes priority over focus route.
-    - ImGuiInputFlags_RouteOverActive: global route takes priority over active item.
-    - ImGuiInputFlags_RouteUnlessBgFocused: global route disabled if no imgui window focused.
-    - ImGuiInputFlags_RouteFromRootWindow: route evaluated from the point of view of root window rather than current window.
-- Inputs: (OSX) Fixes variety of code which inconsistently required using Ctrl instead of Cmd.
-  - e.g. Drags/Sliders now use Cmd+Click to input a value. (#4084)
-  - Some shortcuts still uses Ctrl on Mac: e.g. Ctrl+Tab to switch windows. (#4828)
-- Inputs: (OSX) Ctrl+Left Click alias as a Right click. (#2343) [@haldean, @ocornut]
-- Inputs: Fixed ImGui::GetKeyName(ImGuiKey_None) from returning "N/A" or "None" depending
-  on value of IMGUI_DISABLE_OBSOLETE_KEYIO. It always returns "None".
-- Nav: fixed holding Ctrl or gamepad L1 from not slowing down keyboard/gamepad tweak speed.
-  Broken during a refactor refactor for 1.89. Holding Shift/R1 to speed up wasn't broken.
-- Tables: fixed cell background of fully clipped row overlapping with header. (#7575, #7041) [@prabuinet]
-- Demo: Added "Inputs & Focus -> Shortcuts" section. (#456, #2637)
-- Demo: Documents: Added shortcuts and renaming tabs/documents. (#7233)
-- Examples: Win32+DX9,DX10,DX11,DX12: rework main loop to handle minimization and screen
-  locking without burning resources by running unthrottled code. (#2496, #3907, #6308, #7615)
-- Backends: all backends + demo now call IMGUI_CHECKVERSION() to verify ABI compatibility between caller
-  code and compiled version of Dear ImGui. If you get an assert it most likely mean you have a build issue,
-  read comments near the assert. (#7568)
-- Backends: Win32: undo an assert introduced in 1.90.6 which didn't allow WndProc
-  handler to be called before backend initialization. Because of how ::CreateWindow()
-  calls in WndProc this is facilitating. (#6275) [@MennoVink]
-- Backends, Examples: SDL3: updates for latest SDL3 API changes. (#7580) [@kuvaus, @ocornut]
-
-Breaking changes IF you were using imgui_internal.h versions of Shortcut() or owner-aware
-versions of IsKeyPressed(), IsKeyChordPressed(), IsMouseClicked() prior to this version:
-
-- Inputs (Internals): Renamed ImGuiKeyOwner_None to ImGuiKeyOwner_NoOwner, to make use more
-  explicit and reduce confusion with the fact it is a non-zero value and cannot be a default.
-- Inputs (Internals): Renamed symbols global routes:
-      Renamed ImGuiInputFlags_RouteGlobalLow  -> ImGuiInputFlags_RouteGlobal (this is the suggested global route)
-      Renamed ImGuiInputFlags_RouteGlobal     -> ImGuiInputFlags_RouteGlobal | ImGuiInputFlags_RouteOverFocused
-      Renamed ImGuiInputFlags_RouteGlobalHigh -> ImGuiInputFlags_RouteGlobal | ImGuiInputFlags_RouteOverFocused | ImGuiInputFlags_RouteOverActive
-- Inputs (Internals): Shortcut(), SetShortcutRouting(): swapped last two parameters order
-  in function signatures:
-      Before: Shortcut(ImGuiKeyChord key_chord, ImGuiID owner_id = 0, ImGuiInputFlags flags = 0);
-      After:  Shortcut(ImGuiKeyChord key_chord, ImGuiInputFlags flags = 0, ImGuiID owner_id = 0);
-- Inputs (Internals): owner-aware versions of IsKeyPressed(), IsKeyChordPressed(), IsMouseClicked():
-  swapped last two parameters order in function signatures:
-      Before: IsKeyPressed(ImGuiKey key, ImGuiID owner_id, ImGuiInputFlags flags = 0);
-      After:  IsKeyPressed(ImGuiKey key, ImGuiInputFlags flags, ImGuiID owner_id = 0);
-      Before: IsMouseClicked(ImGuiMouseButton button, ImGuiID owner_id, ImGuiInputFlags flags = 0);
-      After:  IsMouseClicked(ImGuiMouseButton button, ImGuiInputFlags flags, ImGuiID owner_id = 0);
-- For several reasons those changes makes sense. They were all made before making some of
-  those API public. Only past users of imgui_internal.h with the extra parameters will be affected.
-  Added asserts for valid flags in various functions to detect _some_ misuses, BUT NOT ALL.
-
-
------------------------------------------------------------------------
- VERSION 1.90.6 (Released 2024-05-08)
------------------------------------------------------------------------
-
-Decorated log and release notes: https://github.com/ocornut/imgui/releases/tag/v1.90.6
-
-Breaking changes:
-
-- TreeNode: Fixed a layout inconsistency when using a empty/hidden label followed
-  by a SameLine() call. (#7505, #282)
-     Before: TreeNode("##Hidden"); SameLine(); Text("Hello");
-             // This was actually incorrect! BUT appeared to look ok with the default style
-             // where ItemSpacing.x == FramePadding.x * 2 (it didn't look aligned otherwise).
-     After:  TreeNode("##Hidden"); SameLine(0, 0); Text("Hello");
-             // This is correct for all values in style.
-  With the fix, IF you were successfully using TreeNode("")+SameLine(); you will now
-  have extra spacing between your TreeNode and the following item. You'll need to change
-  the SameLine() call to SameLine(0,0) to remove this extraneous spacing.
-  This seemed like the more sensible fix that's not making things less consistent.
-  (Note: when using this idiom you are likely to also use ImGuiTreeNodeFlags_SpanAvailWidth).
-
-Other changes:
-
-- Windows: Changed default ClipRect to extend to windows' left and right borders,
-  instead of adding arbitrary WindowPadding.x * 0.5f space on left and right.
-  That ClipRect half-padding was arbitrary/confusing and inconsistent with Y axis.
-  It also made it harder to draw items covering whole window without pushing an
-  extended ClipRect. Some items near windows left and right edge that used to be clipped
-  may be partly more visible. (#3312, #7540, #3756, #6170, #6365)
-- Windows: Fixed subsequent Begin() append calls from setting last item information
-  for title bar, making it impossible to use IsItemHovered() on a Begin()-to-append,
-  and causing issue bypassing hover detection on collapsed windows. (#7506, #823)
-- Fonts: Fixed font ascent and descent calculation when a font hits exact integer values.
-  It is possible that some prior manual use of ImFontConfig::GlyphOffset may become
-  duplicate with this fix. (#7399, #7404) [@GamingMinds-DanielC]
-- TreeNode: Added ImGuiTreeNodeFlags_SpanTextWidth to make hitbox and highlight only
-  cover the label. (#6937) [@dimateos]
-- Tables: Angled headers: fixed multi-line label display when angle is flipped. (#6917)
-- Tables: Angled headers: added style.TableAngledHeadersTextAlign and corresponding
-  ImGuiStyleVar_TableAngledHeadersTextAlign variable. Default to horizontal center. (#6917)
-  [@thedmd, @ocornut]
-- ProgressBar: Added support for indeterminate progress bar by passing an animated
-  negative fraction, e.g. ProgressBar(-1.0f * GetTime()). (#5316, #5370, #1901)[@gan74]
-- Text, DrawList: Improved handling of long single-line wrapped text. Faster and
-  mitigate issues with reading vertex indexing limits with 16-bit indices. (#7496, #5720)
-- Backends: OpenGL3: Detect ES3 contexts on desktop based on version string,
-  to e.g. avoid calling glPolygonMode() on them. (#7447) [@afraidofdark, @ocornut]
-- Backends: OpenGL3: Update loader for Linux to support EGL/GLVND. (#7562) [@ShadowNinja, @vanfanel]
-- Backends: Vulkan: Added convenience support for Volk via IMGUI_IMPL_VULKAN_USE_VOLK define.
-  (you could always use IMGUI_IMPL_VULKAN_NO_PROTOTYPES + ImGui_ImplVulkan_LoadFunctions() as well).
-  (#6582, #4854) [@adalsteinnh, @kennyalive, @ocornut]
-- Backends: SDL3: Fixed text inputs. Re-enable calling SDL_StartTextInput()/SDL_StopTextInput()
-  as SDL3 no longer enables it by default. (#7452, #6306, #6071, #1953) [@Green-Sky]
-- Examples: GLFW+Vulkan, SDL+Vulkan: Added optional support for Volk. (#6582, #4854)
-- Examples: GLFW+WebGPU: Added support for WebGPU-native/Dawn (#7435, #7132) [@eliasdaler, @Zelif]
-- Examples: GLFW+WebGPU: Renamed example_emscripten_wgpu/ to example_glfw_wgpu/. (#7435, #7132)
-
-
 -----------------------------------------------------------------------
  VERSION 1.90.5 (Released 2024-04-11)
 -----------------------------------------------------------------------
@@ -298,6 +90,11 @@ Other changes:
     Adding a link to the crawlable version, even though it is not intended for humans,
     to increase its search rank.
 
+Docking+Viewports Branch:
+
+- Backends: Win32: made it so that an appearing viewport showing up doesn't bring
+  its parent to front. (#7354)
+
 
 -----------------------------------------------------------------------
  VERSION 1.90.4 (Released 2024-02-22)
@@ -331,6 +128,13 @@ Other changes:
 - Demo: Custom Rendering: better demonstrate PathArcTo(), PathBezierQuadraticCurveTo(),
   PathBezierCubicCurveTo(), PathStroke(), PathFillConvex() functions.
 
+Docking+Viewports Branch:
+
+- Backends: GLFW: enable ImGuiBackendFlags_HasMouseHoveredViewport support with GLFW 3.3.x,
+  as required specs for it was relaxed in 1.87. This enable better viewport hovering detection
+  without GLFW 3.4's GLFW_MOUSE_PASSTHROUGH, with less reliance on dear imgui's own heuristic
+  of platform windows order. (#7316)
+
 
 -----------------------------------------------------------------------
  VERSION 1.90.3 (Released 2024-02-14)
@@ -419,6 +223,18 @@ Other changes:
   Often requested in some form (#6962, #5219, #3290, #4627, #5054, #3878, #2881, #1506, #1216, #968),
   and useful for interactive completion/suggestions popups (#2057, #718)
 
+Docking+Viewports Branch:
+
+- Added ImGuiWindowClass::FocusRouteParentWindowId as a way to connect the focus route between
+  a tool window to a parent document window, so that Shortcuts in the documents are routed when the
+  tool is focused (regardless of whether the tool is docked or in a floating viewport, etc.) (#6798)
+- Added ImGuiDockNodeFlags_DockedWindowsInFocusRoute to automatically make a dockspace connect
+  the focus route of its docked window. This is provided a convenience in case you have windows
+  where a connection is not explicit. (#6798)
+- Viewports: Fixed moving accross monitors when io.ConfigWindowsMoveFromTitleBarOnly is set. (#7299, #3071)
+- Backends: OSX: Fixed not submitting Monitors info when viewports are not enabled, leading to
+  missing e.g. DpiScale info. (#7257) [@actboy168]
+
 
 -----------------------------------------------------------------------
  VERSION 1.90.1 (Released 2024-01-10)
@@ -523,6 +339,15 @@ Other changes:
     (#6751) [@Traveller23, @ypujante]
   - Examples: SDL3: Minor fixes following recent SDL3 in-progress development.
 
+Docking+Viewports Branch:
+
+- Windows: Fixed ImGuiCol_TitleBg/Active alpha being used for viewport-owned windows. (#7181) [@PathogenDavid]
+- Backends: DX12: Changed swapchain scaling mode to DXGI_SCALING_NONE to reduce artifacts as
+  queued frames aren't synchronized with platform window resizes. (#7152, #7153) [@SuperWangKai]
+- Backends: OSX: Fixed monitor and window position by correctly transforming Y origin on multi-viewports
+  multi-monitor setups. (#7028, #7101, #6009, #6432) [@dmirty-kuzmenko, @734vin]
+- Backends: OSX: Fixed IME position in multi-monitor multi-viewports setups. (#7028) [@734vin]
+
 
 -----------------------------------------------------------------------
  VERSION 1.90.0 (Released 2023-11-15)
@@ -715,6 +540,8 @@ Other changes:
   Fixed leaks, and added ImGui_ImplVulkan_DestroyFontsTexture() (probably no need to call this directly).
   (#6943, #6715, #6327, #3743, #4618)
   [@helynranta, @thomasherzog, @guybrush77, @albin-johansson, @MiroKaku, @benbatya-fb, @ocornut]
+- Backends: Vulkan: use specified ColorAttachmentFormat when creating a secondary window when enabling
+  UseDynamicRendering option. (#6999, #5446, #5037) [@raaaviol]
 - Backends: GLFW: Clear emscripten's MouseWheel callback before shutdown. (#6790, #6096, #4019) [@halx99]
 - Backends: GLFW: Added support for F13 to F24 function keys. (#6891)
 - Backends: SDL2, SDL3: Added support for F13 to F24 function keys, AppBack, AppForward. (#6891)
@@ -732,6 +559,31 @@ Other changes:
 - Examples: GLFW+Vulkan, SDL+Vulkan: Simplified and removed code due to backend improvements.
 - Internals: Renamed ImFloor() to ImTrunc(). Renamed ImFloorSigned() to ImFloor(). (#6861)
 
+Docking+Viewports Branch:
+
+- Viewports: Fixed window inner clipping rectangle off by one when window is located on a monitor
+  with negative coordinates. While it is expected that other small issues with arise from this
+  situation, at the moment we are fixing the most noticeable one. (#6861, #2884) [@Vuhdo, @alektron]
+- Docking: revised undocking to reduce accidental whole-node undocking:
+  - cannot undock a whole node by dragging from empty space in tab-bar.
+  - can undock whole node by dragging from window/collapse menu button.
+  - can undock single window by dragging from its tab.
+  - can still move (but not undock) whole node or whole hierarchy when node is part of a
+    floating hierarchy.
+  - added tooltip when hovering the collapse/window menu button, to faciliate understanding
+    that whole dock node may be undocked or grabbed from here.
+- Docking: Fixed an issue leading to incorrect restoration of selected tab in dock nodes that
+  don't carry the currently focused window. (#2304)
+- Docking: added ImGuiDockNodeFlags_NoUndocking. (#2999, #6823, #6780, #3492)
+- Docking: renamed ImGuiDockNodeFlags_NoSplit to ImGuiDockNodeFlags_NoDockingSplit.
+- Docking: renamed ImGuiDockNodeFlags_NoDockingInCentralNode to ImGuiDockNodeFlags_NoDockingOverCentralNode.
+- Docking: Internals: renamed ImGuiDockNodeFlags_NoDockingSplitMe to ImGuiDockNodeFlags_NoDockingSplit.
+- Docking: Fixed a bug where ClassId compare tests (when using SetNextWindowClass) on success would
+  prevent further filter from running, namely the one that prevent docking over a popup.
+- Backends: GLFW: Fixed an assertion in situation where the WndProc handler is different between
+  main and secondary viewport (may happen due to third-party hooks). (#6889)
+- Backends: DX9: Fixed incorrect assert triggering on reopening session with minimized windows. (#3424)
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.9 (Released 2023-09-04)
@@ -789,6 +641,11 @@ Other changes:
 - Examples: Emscripten+WebGPU: Fixed WGPUInstance creation process + use preferred
   framebuffer format. (#6640, #6748) [@smileorigin]
 
+Docking+Viewports Branch:
+
+- Docking: when io.ConfigDockingWithShift is enabled, staying stationary while moving
+  a window displays an help tooltip to increase affordance. (#6709, #4643)
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.8 (Released 2023-08-01)
@@ -857,6 +714,16 @@ Other changes:
 - Examples: Vulkan: Creating minimal descriptor pools to fit only what is needed by
   example. (#6642) [@SaschaWillem]
 
+Docking+Viewports Branch:
+
+- Docking, Style: resizing separators use same colors as window borders (ImGuiCol_Border)
+  for consistency. With default styles it doesn't make a big difference. (#2522) [@rmitton]
+  In the future if we promote using thick value for inner/outer docking padding we may
+  need to introduce new colors for it.
+- Docking: added style.DockingSeparatorSize, ImGuiStyleVar_DockingSeparatorSize. Now
+  also scaled by style.ScaleAllSizes(). (#3481, #4721, #2522) [@PossiblyAShrub, @wobbier]
+- Docking: fixed rendering of docked-window scrollbar above outer border. (#2522)
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.7 (Released 2023-07-04)
@@ -952,6 +819,23 @@ Other changes:
 - Examples: Win32+OpenGL3: Changed DefWindowProc() to DefWindowProcW() to match other examples
   and support the example app being compiled without UNICODE. (#6516, #5725, #5961, #5975) [@yenixing]
 
+Docking+Viewports Branch:
+
+- Viewports+Docking: Fixed extraneous viewport+platform-window recreation in various
+  combination of showing or hiding windows, docking with/without split, undocking.
+  While with some backends and without OS decorations, some extraneous window recreation
+  were visibly not noticeable, they would typically become noticeable when enabling
+  OS decorations on those windows (e.g. Windows title bar fade-in/animation).
+- Viewports: Closing a viewport via OS/platform means (e.g. OS close button or task-bar menu),
+  mark all windows in this viewport as closed.
+- Docking: Fixed one-frame flickering on reappearing windows binding to a dock node
+  where a later-submitted window was already bound.
+- Docking: Fixed dragging from title-bar empty space (regression from 1.88 related to
+  keeping ID alive when calling low-level ButtonBehavior() directly). (#5181, #2645)
+- Docking: [Internal] DockBuilderDockWindow() API calls don't clear docking order
+  if the target node is same as existing one.
+- Backends: Win32: Added support for changing ParentViewportID after viewport creation.
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.6 (Released 2023-05-31)
@@ -970,7 +854,7 @@ Breaking changes:
    - ListBoxFooter()  -> use EndListBox()
    - Note how two variants of ListBoxHeader() existed. Check commented versions in imgui.h for refeence.
 - Backends: SDL_Renderer: Renamed 'imgui_impl_sdlrenderer.h/cpp' to 'imgui_impl_sdlrenderer2.h/cpp',
-  in order to accommodate for upcoming SDL3 and change in its SDL_Renderer API. (#6286)
+  in order to accomodate for upcoming SDL3 and change in its SDL_Renderer API. (#6286)
 - Backends: GLUT: Removed call to ImGui::NewFrame() from ImGui_ImplGLUT_NewFrame().
   It needs to be called from the main app loop, like with every other backends. (#6337) [@GereonV]
 
@@ -1021,6 +905,23 @@ Other changes:
 - Examples: Added SDL3+SDL_Renderer example. (#6286)
 - Examples: Updated all Visual Studio projects and batches to use /utf-8 argument.
 
+Docking+Viewports Branch:
+
+- Viewports: Fixed platform-side focus (e.g. Alt+Tab) from leading to accidental
+  closure of Modal windows. Regression from 1.89.5. (#6357, #6299)
+- Viewports: Fixed loss of imgui-side focus when dragging a secondary viewport back in
+  main viewport, due to platform-side handling changes. Regression from 1.89.5 (#6299)
+- Viewports: Avoid applying imgui-side focus when focus change is due to a viewport
+  destruction. Fixes erroneous popup closure on closing a previous popup. (#6462, #6299)
+- Viewports: Added void* ImGuiPlatformMonitor::PlatformHandle field (backend-dependant),
+  for usage by user code.
+- Backends: GLFW: Preserve monitor list when there are no monitor, may briefly
+  happen when recovering from macOS sleeping mode. (#5683) [@Guistac]
+- Backends: SDL2: Update monitor list when receiving a display event. (#6348)
+  Note however that SDL2 currently doesn't have an event for a DPI/Scaling change,
+  so monitor data won't be updated in this situation.
+- Backends: SDL3: Update monitor list when receiving a display event. (#6348)
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.5 (Released 2023-04-13)
@@ -1078,7 +979,6 @@ Other changes:
   is to other IME function such as SDL_SetTextInputRect(). (#6306, #6071, #1953)
 - Backends: GLFW: Added support on Win32 only for io.AddMouseSourceEvent() to discriminate
   Mouse/TouchScreen/Pen. (#2334, #2702)
-- Backends: GLFW: Fixed key modifiers handling on secondary viewports. (#6248, #6034) [@aiekick]
 - Backends: Android: Added support for io.AddMouseSourceEvent() to discriminate Mouse/TouchScreen/Pen.
   (#6315) [@PathogenDavid]
 - Backends: OSX: Added support for io.AddMouseSourceEvent() to discriminate Mouse/Pen.
@@ -1094,6 +994,16 @@ Other changes:
 - TestSuite: Added variety of new regression tests and improved/amended existing ones
   in imgui_test_engine/ repo. [@PathogenDavid, @ocornut]
 
+Docking+Viewports Branch:
+
+- Viewports: Setting focus from Platform/OS (e.g. via decoration, or Alt-Tab) sets corresponding
+  focus at Dear ImGui level (generally last focused window in the viewport). (#6299)
+- Docking: Fixed using GetItemXXX() or IsItemXXX() functions after a DockSpace(). (#6217)
+- Backends: GLFW: Fixed key modifiers handling on secondary viewports. (#6248, #6034) [@aiekick]
+- Backends: GLFW: Fixed Emscripten erroneously enabling multi-viewport support, leading to assert. (#5683)
+- Backends: SDL2/SDL3: Fixed IME text input rectangle position with viewports. (#6071, #1953)
+- Backends: SDL3: Fixed for compilation with multi-viewports. (#6255) [@P3RK4N]
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.4 (Released 2023-03-14)
@@ -1168,7 +1078,6 @@ Other changes:
   and ImGuiConfigFlags_NavEnableGamepad by default. (#787)
 - Internals: Misc tweaks to facilitate applying an explicit-context patch. (#5856) [@Dragnalith]
 
-
 -----------------------------------------------------------------------
  VERSION 1.89.3 (Released 2023-02-14)
 -----------------------------------------------------------------------
@@ -1269,6 +1178,10 @@ Other changes:
 - Examples: SDL2+SDL_Renderer: Added call to SDL_RenderSetScale() to fix display on a
   Retina display (albeit lower-res as our other unmodified examples). (#6121, #6065, #5931).
 
+Docking+Viewports Branch:
+
+- Backends: GLFW: Handle unsupported glfwGetVideoMode() for Emscripten. (#6096)
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.2 (Released 2023-01-05)
@@ -1319,6 +1232,17 @@ All changes:
 - Backends: Vulkan: Fixed sampler passed to ImGui_ImplVulkan_AddTexture() not being honored as we were using
   an immutable sampler. (#5502, #6001, #914) [@martin-ejdestig, @rytisss]
 
+Docking+Viewports Branch:
+
+- Docking: Internals: fixed DockBuilderCopyDockSpace() crashing when windows not in the
+  remapping list are docked on the left or top side of a split. (#6035)
+- Docking: fixed DockSpace() with ImGuiDockNodeFlags_KeepAliveOnly marking current window
+  as written to, even if it doesn't technically submit an item. This allow using KeepAliveOnly
+  from any window location. (#6037)
+- Backends: OSX: fixed typo in ImGui_ImplOSX_GetWindowSize that would cause issues when resiing
+  from OS decorations, if they are enabled on secondary viewports. (#6009) [@sivu]
+- Backends: Metal: fixed secondary viewport rendering. (#6015) [@dmirty-kuzmenko]
+
 
 -----------------------------------------------------------------------
  VERSION 1.89.1 (Released 2022-11-24)
@@ -1345,6 +1269,13 @@ Other changes:
 - Backends: GLFW: cancel out errors emitted by glfwGetKeyName() when a name is missing. (#5908)
 - Backends: WebGPU: fixed validation error with default depth buffer settings. (#5869, #5914) [@kdchambers]
 
+Docking+Viewports Branch:
+
+- Viewports: Fixed collapsed windows setting ImGuiViewportFlags_NoRendererClear without
+  making title bar color opaque, leading to potential texture/fb garbage being visible.
+  Right now as we don't fully support transparent viewports (#2766), so we turn that
+  'TitleBgCollapsed' color opaque just lke we do for 'WindowBG' on uncollapsed windows.
+
 
 -----------------------------------------------------------------------
  VERSION 1.89 (Released 2022-11-15)
@@ -1533,9 +1464,26 @@ Other Changes:
 - Backends: Metal: Use __bridge for ARC based systems. (#5403) [@stack]
 - Backends: Metal: Add dispatch synchronization. (#5447) [@luigifcruz]
 - Backends: Metal: Update deprecated property 'sampleCount'->'rasterSampleCount'. (#5603) [@dcvz]
-- Backends: Vulkan: Added experimental ImGui_ImplVulkan_RemoveTexture() for api symmetry. (#914, #5738).
+- Backends: Vulkan: Added experimental ImGui_ImplVulkan_RemoveTexture() for api symetry. (#914, #5738).
 - Backends: WebGPU: fixed rendering when a depth buffer is enabled. (#5869) [@brainlag]
 
+Docking+Viewports Branch:
+
+- Docking: Fixed incorrect focus highlight on docking node when focusing a menu. (#5702)
+- Docking, Nav: Fixed using gamepad/keyboard navigation not being able enter menu layer when
+  it only contained the standard Collapse/Close buttons and no actual menu. (#5463, #4792)
+- Docking: Fixed regression introduced in v1.87 when docked window content not rendered
+  while switching between with CTRL+Tab. [@rokups]
+- Docking: Fixed amending into an existing tab bar from rendering invisible items. (#5515)
+- Docking: Made spacing between dock nodes not a dropping gap. When hovering it only
+  outer-docking drop markers are visible.
+- Docking+Viewports: Fixed undocking window node causing parent viewports to become unresponsive
+  in certain situation (e.g. hidden tab bar). (#5503) [@rokups]
+- Backends: SDL: Fixed building backend under non-OSX Apple targets (e.g. iPhone). (#5665)
+- Backends: SDL: Fixed drag'n drop crossing a viewport border losing mouse coordinates. (#5710, #5012)
+- Backends: GLFW: Fixed leftover static variable preventing from changing or
+  reinitializing backend while application is running. (#4616, #5434) [@rtoumazet]
+
 
 -----------------------------------------------------------------------
  VERSION 1.88 (Released 2022-06-21)
@@ -1670,6 +1618,26 @@ Other Changes:
 - Examples: Emscripten+WebGPU: Fix building for latest WebGPU specs. (#3632)
 - Examples: OSX+Metal, OSX+OpenGL: Removed now-unnecessary calls to ImGui_ImplOSX_HandleEvent(). (#4821)
 
+Docking+Viewports Branch:
+
+- Docking: Fixed floating docked nodes not being clamped into viewport workrect to stay reachable
+  when io.ConfigWindowsMoveFromTitleBarOnly is true and multi-viewports are disabled. (#5044)
+- Docking: Fixed a regression where moving window would be interrupted after undocking a tab
+  when io.ConfigDockingAlwaysTabBar is true. (#5324) [@rokups]
+- Docking: Fixed incorrect focus highlight on docking node when focusing empty central node
+  or a child window which was manually injected into a dockspace window.
+- Docking, Modal: Fixed a crash when opening popup from a parent which is being docked on the same frame. (#5401)
+- Viewports: Fixed an issue where MouseViewport was lagging by a frame when using 1.87 Input Queue.
+  A common side-effect would be that when releasing a window drag the underlying window would highlight
+  for a frame. (#5837, #4921) [@cfillion]
+- Viewports: Fixed translating a host viewport from briefly altering the size of AlwaysAutoResize windows. (#5057)
+- Viewports: Fixed main viewport size not matching ImDrawData::DisplaySize for one frame during resize
+  when multi-viewports are disabled. (#4900)
+- Backends: SDL: Fixed dragging out main viewport broken on some SDL setups. (#5012) [@rokups]
+- Backends: OSX: Added support for multi-viewports. [@stuartcarnie, @metarutaiga] (#4821, #2778)
+- Backends: Metal: Added support for multi-viewports. [@stuartcarnie, @metarutaiga] (#4821, #2778)
+- Examples: OSX+Metal, SDL+Metal, GLFW+Metal: Added support for multi-viewports. [@rokups]
+
 
 -----------------------------------------------------------------------
  VERSION 1.87 (Released 2022-02-07)
@@ -1812,6 +1780,29 @@ Other Changes:
 - Backends: WebGPU: Fixed incorrect size parameters in wgpuRenderPassEncoderSetIndexBuffer() and
   wgpuRenderPassEncoderSetVertexBuffer() calls. (#4891) [@FeepsDev]
 
+Docking+Viewports Branch:
+
+- Docking: Fixed a CTRL+TAB crash when aiming at an empty docked window. (#4792)
+- Docking: Tabs use their own identifier instead of the Window identifier.
+  (This will invalidate some stored .ini data such as last selected tab, sorry!)
+- Docking: Fixed size constraints not working on single window holding on a dock id (still doesn't work on docked windows).
+- Docking: Fixed CTRL+TAB back into a docked window not selecting menu layer when no item are on main layer.
+- Viewports, IO: Added io.AddMouseViewportEvent() function to queue hovered viewport change (when known by backend).
+- Viewports: Relaxed specs for backend supporting ImGuiBackendFlags_HasMouseHoveredViewport: it is now _optional_
+  for the backend to have to ignore viewports with the _NoInputs flag when call io.AddMouseViewportEvent(). It is
+  much better if they can (Win32 and GLFW 3.3+ backends can, SDL and GLFW 3.2 backends cannot, they are lacking data).
+  A concrete example is: when dragging a viewport for docking, the viewport is marked with _NoInputs to allow us
+  to pick the target viewports for docking. If the backend reports a viewport with _NoInputs when calling the
+  io.AddMouseViewportEvent() function, then Dear ImGui will revert to its flawed heuristic to find the viewport under.
+  By lowering those specs, we allow the SDL and more backend to support this, only relying on the heuristic in a few
+  drag and drop situations rather that relying on it everywhere.
+- Viewports: Fixed a CTRL+TAB crash with viewports enabled when the window list needs to appears in
+  its own viewport (regression from 1.86). (#4023, #787)
+- Viewports: Fixed active InputText() from preventing viewports to merge. (#4212)
+- Backends: SDL: Added support for ImGuiBackendFlags_HasMouseHoveredViewport now that its specs have been lowered.
+- (Breaking) Removed ImGuiPlatformIO::Platform_SetImeInputPos() in favor of newly standardized
+  io.SetPlatformImeDataFn() function. Should not affect more than default backends.
+
 
 -----------------------------------------------------------------------
  VERSION 1.86 (Released 2021-12-22)
@@ -1910,6 +1901,24 @@ Other Changes:
   wgpuRenderPassEncoderSetIndexBuffer() functions as validation layers appears to not do what the
   in-flux specs says. (#4766) [@meshula]
 
+Docking+Viewports Branch:
+
+- Docking: Revert removal of io.ConfigDockingWithShift config option (removed in 1.83). (#4643)
+- Docking: Fixed a bug undocking windows docked into a non-visible or _KeepAliveOnly dockspace
+  when unrelated windows submitted before the dockspace have dynamic visibility. (#4757)
+- Docking, Style: Docked windows honor ImGuiCol_WindowBg. (#2700, #2539)
+- Docking, Style: Docked windows honor display their border properly. (#2522)
+- Docking: Fixed incorrectly rounded tab bars for dock node that are not at the top of their dock tree.
+- Docking: Fixed single-frame node pos/size inconsistencies when window stop or start being submitted.
+- Docking: Prevent docking any window created above a popup/modal. (#4317)
+- Viewports: Made it possible to explicitly assign ImGuiWindowClass::ParentViewportId to 0 in order
+  to ensure a window is not parented. Previously this would use the global default (which might be 0,
+  but not always as it would depend on io.ConfigViewportsNoDefaultParent). (#3152, #2871)
+- Viewports: Fixed tooltip in own viewport over modal from being incorrectly dimmed. (#4729)
+- Viewports: Fixed CTRL+TAB highlight outline on docked windows not always fitting in host viewport.
+- Backends: Made it possible to shutdown default Platform Backends before the Renderer backends. (#4656)
+- Disabled: Fixed nested BeginDisabled()/EndDisabled() bug in Docking branch due to bad merge. (#4655, #4452, #4453, #4462)
+
 
 -----------------------------------------------------------------------
  VERSION 1.85 (Released 2021-10-12)
@@ -1928,6 +1937,10 @@ Breaking Changes:
   Can use 'GetWindowContentRegionMax().x - GetWindowContentRegionMin().x' instead but it's not
   very useful in practice, and the only use of it in the demo was illfit.
   Using 'GetContentRegionAvail().x' is generally a better choice.
+- (Docking branch) IsWindowFocused() and IsWindowHovered() with only the _ChildWindows flag
+  and without the _RootWindow flag used to leak docking hierarchy, so a docked window would
+  return as the child of the window hosting the dockspace. This was inconsistent and incorrect
+  with other behaviors so we fixed it. Added a new _DockHierarchy flag to opt-in this behavior.
 
 Other Changes:
 
@@ -2001,6 +2014,29 @@ Other Changes:
 - Backends: All renderers: Normalize clipping rect handling across backends. (#4464)
 - Examples: Added SDL + SDL_Renderer example in "examples/example_sdl_sdlrenderer/" folder. (#3926) [@1bsyl]
 
+Docking+Viewports Branch:
+
+- IsWindowFocused: Fixed using ImGuiFocusedFlags_ChildWindows (without _RootWindow) from leaking the
+  docking hierarchy. Added ImGuiFocusedFlags_DockHierarchy flag to consider docking hierarchy in the test.
+- IsWindowHovered: Fixed using ImGuiHoveredFlags_ChildWindows (without _RootWindow) from leaking the
+  docking hierarchy. Added ImGuiHoveredFlags_DockHierarchy flag to consider docking hierarchy in the test.
+- Nav: Fixed an issue with losing focus on docked windows when pressing Alt while keyboard navigation
+  is disabled. (#4547, #4439) [@PathogenDavid]
+- Docking: Fixed IsItemHovered() and functions depending on it (e.g. BeginPopupContextItem()) when
+  called after Begin() on a docked window (broken 2021/03/04). (#3851)
+- Docking: Improved resizing system so that non-central zone are better at keeping their fixed size.
+  The algorithm is still not handling the allocation of size ideally for nested sibling, but it got better.
+- Docking: Fixed settings load issue when mouse wheeling. (#4310)
+- Docking: Fixed manually created floating node with a central node from not hiding when windows are gone.
+- Docking + Drag and Drop: Fixed using BeginDragDropSource() or BeginDragDropTarget() inside a Begin()
+  that returned false because the window is docked. (#4515)
+- Viewports: Fixed a crash while a window owning its viewport disappear while being dragged.
+  It would manifest when e.g. reconfiguring dock nodes while dragging.
+- Viewports: Fixed unnecessary creation of temporary viewports when multiple docked windows
+  got reassigned to a new node (created mid-frame) which already has a HostWindow.
+- Viewports: Fixed window with viewport ini data immediately merged into a host viewport from
+  leaving a temporary viewport alive for a frame (would leak into backend).
+
 
 -----------------------------------------------------------------------
  VERSION 1.84.2 (Released 2021-08-23)
@@ -2137,6 +2173,25 @@ Other Changes:
 - Examples: Updated all .vcxproj to VS2015 (toolset v140) to facilitate usage with vcpkg.
 - Examples: SDL2: Accommodate  for vcpkg install having headers in SDL2/SDL.h vs SDL.h.
 
+Docking+Viewports Branch:
+
+- Docking: Clicking on the right-most close button of a docking node closes all windows. (#4186)
+- Docking: Fix IsWindowAppearing() and ImGuiCond_Appearing on docked windows. (#4177, #3982, #1497, #1061)
+- Docking: Fix crash using DockBuilderRemoveNode() in some situations. (#3111, #3179, #3203, #4295) [@hsimyu]
+- Docking: Fix crash when a dock node gets re-qualified as dockspace>floating>dockspace, which tends to happen
+  when incorrectly calling DockBuilderAddNode() without ImGuiDockNodeFlags_Dockspace and using it as a Dockspace
+  on the next frame after the floating window hosting the node has been automatically created. (#3203, #4295)
+- Docking: Reworked node flags saving/inheritance so that flags enforced by docked windows via the
+  DockNodeFlagsOverrideSet mechanism are are not left in empty dockspace nodes once the windows gets undocked.
+  (#4292, #3834, #3633, #3521, #3492, #3335, #2999, #2648)
+- Docking: (Internal/Experimental) Removed DockNodeFlagsOverrideClear flags from ImGuiWindowClass as
+  it is ambiguous how to apply them and we haven't got a use out of them yet.
+- Docking: Fixed ImGuiWindowFlags_UnsavedDocument clipping label in docked windows when there are
+  no close button. (#5745)
+- Viewports: Fix popup/tooltip created without a parent window from being given a ParentViewportId value
+  from the implicit/fallback window. (#4236, #2409)
+- Backends: Vulkan: Fix the use of the incorrect fence for secondary viewports. (#4208) [@FunMiles]
+
 
 -----------------------------------------------------------------------
  VERSION 1.83 (Released 2021-05-24)
@@ -2221,6 +2276,22 @@ Other Changes:
 - Docs: Improvements to description of using colored glyphs/emojis. (#4169, #3369)
 - Docs: Improvements to minor mistakes in documentation comments (#3923) [@ANF-Studios]
 
+Docking+Viewports Branch:
+
+- [Breaking] Removed io.ConfigDockingWithShift config option. Behavior always equivalent to having the
+  option set to false (dock/undock by default, hold shift to avoid docking). (#2109)
+- Docking: DockSpace() returns its node ID.
+- Docking: Dockspace() never draws a background. (#3924)
+- Docking: Undocking nodes/windows covering most of the monitor max their size down to 90% to ease manipulations.
+- Docking: Docking node tab bar honors ItemInnerSpacing.x before first tab. (#4130)
+- Docking: Tweak rendering and alignment of dock node menu marker. (#4130)
+- Docking: Fixed restoring of tab order within a dockspace or a split node.
+- Docking: Fixed reappearing docked windows with no close button showing a tab with extraneous space for one frame.
+- Docking: Fixed multiple simultaneously reappearing window from appearing undocked for one frame.
+- Viewports: Hotfix for crash in monitor array access, caused by 4b9bc4902. (#3967)
+- Backends, Viewports: GLFW: Add a workaround for stuck keys after closing a GLFW window (#3837).
+- Backends, Viewports: Vulkan: Rebuild swapchain on VK_SUBOPTIMAL_KHR. (#3881)
+
 
 -----------------------------------------------------------------------
  VERSION 1.82 (Released 2021-02-15)
@@ -2306,7 +2377,7 @@ Other Changes:
   alpha compositing and transparent windows. (#2766, #3447 etc.).
 - Backends: OpenGL, Vulkan, DX9, DX10, DX11, DX12, Metal, WebGPU, Allegro: Rework blending equation to
   preserve alpha in output buffer (using SrcBlendAlpha = ONE, DstBlendAlpha = ONE_MINUS_SRC_ALPHA consistently
-  across all backends), facilitating compositing of the output buffer with another buffer.
+  accross all backends), facilitating compositing of the output buffer with another buffer.
   (#2693, #2764, #2766, #2873, #3447, #3813, #3816) [@ocornut, @thedmd, @ShawnM427, @Ubpa, @aiekick]
 - Backends: DX9: Fix to support IMGUI_USE_BGRA_PACKED_COLOR. (#3844) [@Xiliusha]
 - Backends: DX9: Fix to support colored glyphs, using newly introduced 'TexPixelsUseColors' info. (#3844)
@@ -2316,6 +2387,13 @@ Other Changes:
   scheduled builds builds are not required. [@rokups]
 - Log/Capture: Added LogTextV, a va_list variant of LogText. [@PathogenDavid]
 
+Docking+Viewports Branch:
+
+- Viewports: Fix setting of ImGuiViewportFlags_NoRendererClear. (#3213)
+- Viewports: Added GetViewportPlatformMonitor() with a safety net to keep code portable.
+- Viewports, Backends: SDL: Fix missing ImGuiBackendFlags_HasSetMousePos flag in docking branch.
+- Viewports, Backends: GLFW: Fix application of WantSetMousePos. (#1542, #787)
+
 
 -----------------------------------------------------------------------
  VERSION 1.81 (Released 2021-02-10)
@@ -2397,6 +2475,17 @@ Other Changes:
 - Examples: WebGPU: Added Emscripten+WebGPU example. (#3632) [@bfierz]
 - Backends: GLFW: Added ImGui_ImplGlfw_InitForOther() initialization call to use with non OpenGL API. (#3632)
 
+Docking+Viewports Branch:
+
+- Docking: Fix losing docking information on closed windows for which the hosting node was split. (#3716) [@GamingMinds-DanielC]
+- Docking: Fix gap in hit test hole when using ImGuiDockNodeFlags_PassthruCentralNode touching the edge of a viewport. (#3733)
+- Viewports: (Breaking) removed ImGuiPlatformIO::MainViewport which is now pretty much unused and duplicate
+  (and misleading as we will evolve the concept).
+- Viewports: (Breaking) turned ImGuiViewport::GetWorkPos(), ImGuiViewport::GetWorkSize() into regular fields
+  (WorkPos, WorkSize) before exposing in master branch.
+- Viewports: Fix issue inferring viewport z-order when new popups gets created. (#3734) + Metrics updates.
+- Viewports, Backends: Vulkan: handle VK_ERROR_OUT_OF_DATE_KHR when resizing secondary viewport (#3766, #3758)
+
 
 -----------------------------------------------------------------------
  VERSION 1.80 (Released 2021-01-21)
@@ -2516,6 +2605,14 @@ Other Changes:
 - Docs: Split examples/README.txt into docs/BACKENDS.md and docs/EXAMPLES.md, and improved them.
 - Docs: Consistently renamed all occurrences of "binding" and "back-end" to "backend" in comments and docs.
 
+Docking+Viewports Branch:
+
+- Docking: Docked windows honor change of tab and text colors. (#2771)
+- Docking: Support for appending into existing tab-bar made to work with Docking + internal helper DockNodeBeginAmendTabBar().
+- Docking: Added experimental TabItemFlagsOverrideSet to ImGuiWindowClass.
+- Viewports: Fixed incorrect whitening of popups above a modal if both use their own viewport.
+- Viewports: Backends: Vulkan: Fixed build, removed extraneous pipeline creation. (#3459, #3579)
+
 
 -----------------------------------------------------------------------
  VERSION 1.79 (Released 2020-10-08)
@@ -2610,6 +2707,21 @@ Other Changes:
 - Examples: DX12: Added '#define ImTextureID ImU64' in project and build files to also allow building
   on 32-bit systems. Added project to default Visual Studio solution file. (#301)
 
+Docking+Viewports Branch:
+
+- Docking: DockSpace() emits ItemSize() properly (useful when not filling all space).
+- Docking: Fixed docking while hovering a child window. (#3420) broken by 85a661d. Improve metrics debugging.
+- Docking: Fix honoring payload filter with overlapping nodes (we incorrectly over-relied on g.HoveredDockNode
+  when making change for #3398).
+- Docking: Fix handling of WindowMenuButtonPosition == ImGuiDir_None in Docking Nodes. (#3499)
+- Viewports: Fixed a rare edge-case if the window targeted by CTRL+Tab stops being rendered.
+- Viewports, Backends: DX12: Make secondary viewport format match main viewport one (#3462) {@BeastLe9enD]
+- Viewports: Backends: Vulkan: Removed unused shader code. Fix leaks. Avoid unnecessary pipeline creation for main
+  viewport. (#3459) + Add ImGui_ImplVulkanH_CreateWindowSwapChain in ImGui_ImplVulkanH_CreateOrResizeWindow().
+- Viewports: Backends: DirectX9: Recover from D3DERR_DEVICELOST on secondary viewports. (#3424)
+- Viewports, Backends: Win32: Fix toggling of ImGuiViewportFlags_TopMost (#3477) [@Kodokuna]
+- Viewports: Backends: GLFW: Workaround for cases where glfwGetMonitorWorkarea fails (#3457) [@dougbinks]
+
 
 -----------------------------------------------------------------------
  VERSION 1.78 (Released 2020-08-18)
@@ -2711,6 +2823,23 @@ Other Changes:
 - Examples: Vulkan: Fixed GLFW+Vulkan and SDL+Vulkan clear color not being set. (#3390) [@RoryO]
 - CI: Emscripten has stopped their support for their fastcomp backend, switching to latest sdk [@Xipiryon]
 
+Docking+Viewports Branch:
+
+- Docking: Made DockBuilderAddNode() automatically call DockBuilderRemoveNode(). (#3399, #2109)
+- Docking: Storing HoveredDockNode in context which can be useful for easily detecting e.g. hovering an
+  empty node. (#3398)
+- Docking: Fixed docking overlay bits appearing at (0,0), because of 43bd80a. Most typically noticeable
+  when disabling multi-viewport.
+- Docking: Workaround recovery for node created without the _DockSpace flags later becoming a DockSpace. (#3340)
+- Docking: Rework size allocations to recover when there's no enough room for nodes + do not hold on
+  _WantLockSizeOnce forever. (#3328)
+- Docking: Rework size allocation to allow user code to override node sizes. Not all edge cases will be
+  properly handled but this is a step toward toolbar emitting size constraints.
+- Docking: Added experimental flags to perform more docking filtering and disable resize per axis.
+  Designed for toolbar patterns.
+- Viewports, Backends, GLFW: Use GLFW_MOUSE_PASSTHROUGH when available.
+- Viewports, Backends: DX12: Fixed issue on shutdown when viewports are disabled. (#3347)
+
 
 -----------------------------------------------------------------------
  VERSION 1.77 (Released 2020-06-29)
@@ -2802,6 +2931,17 @@ Other Changes:
 - Examples: Apple: Fixed example_apple_metal and example_apple_opengl2 using imgui_impl_osx.mm
   not forwarding right and center mouse clicks. (#3260) [@nburrus]
 
+Docking+Viewports Branch:
+
+- Viewports: Don't set ImGuiViewportFlags_NoRendererClear when ImGuiWindowFlags_NoBackground is set. (#3213)
+- Viewports: Report minimized viewports as zero DisplaySize to be consistent with main branch. (#1542)
+- Docking, Settings: Allow reload of settings data at runtime. (#2573)
+- Backends, GLFW: Fix windows resizing incorrectly on Linux due to GLFW firing window positioning
+  callbacks on next frame after window is resized manually. (#2117)
+- Backends: DX12: Fix OBJECT_DELETED_WHILE_STILL_IN_USE on viewport resizing. (#3210)
+- Backends: DX12: Fix for crash caused by early resource release. (#3121)
+- Backends, Win32: Request monitor update when DPI awareness is enabled to make sure they have the correct DPI settings.
+
 
 -----------------------------------------------------------------------
  VERSION 1.76 (Released 2020-04-12)
@@ -2874,6 +3014,20 @@ Other Changes:
 - Examples: SDL+DX11: Fixed resizing main window. (#3057) [@joeslay]
 - Examples: Added SDL+Metal example application. (#3017) [@coding-jackalope]
 
+Docking+Viewports Branch:
+
+- Docking: Fixed assert preventing dockspace from being created instead a hidden tab. (#3101)
+- Viewports: Fixed secondary viewports accidentally merging into a minimized host viewport. (#3118)
+- Viewports, Docking: Added per-viewport work area system for e.g. menu-bars. Fixed DockspaceOverViewport()
+  and demo code (overlay etc) accordingly. (#3035, #2889, #2474, #1542, #2109)
+- Viewports: Improve menu positioning in multi-monitor setups. [@rokups]
+- Viewports: Software mouse cursor is also scaled by current DpiScale. (amend #939)
+- Viewports: Avoid manually clipping resize grips and borders, which messes up with automation ability
+  to locate those items. Also simpler and more standard.
+- Viewports: Fix for UWP in the imgui_impl_win32.cpp IME handler. (#2895, #2892).
+- Viewports: Bunch of extra of comments to facilitate setting up multi-viewports.
+- Viewports, GLFW: Avoid using window positioning workaround for GLFW 3.3+ versions that have it fixed.
+
 
 -----------------------------------------------------------------------
  VERSION 1.75 (Released 2020-02-10)
@@ -2972,6 +3126,21 @@ Other Changes:
 - Examples: Metal: Wrapped main loop in @autoreleasepool block to ensure allocations get freed
   even if underlying system event loop gets paused due to app nap. (#2910, #2917) [@bear24rw]
 
+Docking+Viewports Branch:
+
+- Docking + Nav: Fixed messed up Ctrl+Tab order with docked windows.
+- Docking + Nav: Fixed failing to restore NavId when refocusing a child within a docked window.
+- Docking + Nav: Fixed failing to restore NavId when refocusing due to missing nav window (when
+  it stops being submitted).
+- Docking: Fixed a bug where the tab bar of a hidden dockspace would keep requesting focus. (#2960)
+- Docking: Added experimental DockNodeFlagsOverrideSet/DockNodeFlagsOverrideClear flags in ImGuiWindowClass
+  (currently experimenting with toolbar idioms).
+- Viewports: Fix resizing viewport-owning windows when mouse pos is outside the InnerClipRect
+  (can happen with OS decoration enabled).
+- Viewports: Preserve last known size for minimized main viewport to be consistent with secondary viewports.
+- Backends: SDL: Honor NoTaskBarIcon flag under non Win32 OS. (#2117)
+- Backends: GLFW, SDL: Platform monitors declared properly even if multi-viewport is not enabled.
+
 
 -----------------------------------------------------------------------
  VERSION 1.74 (Released 2019-11-25)
@@ -3051,6 +3220,14 @@ Other Changes:
 - CI: Set up a bunch of continuous-integration tests using GitHub Actions. We now compile many of the example
   applications on Windows, Linux, MacOS, iOS, Emscripten. Removed Travis integration. (#2865) [@rokups]
 
+Docking+Viewports Branch:
+
+- Docking: Can undock from the small triangle button. (#2109,. #2645)
+- Docking: Fixed node->HasCloseButton not honoring ImGuiDockNodeFlags_NoCloseButton in a floating node,
+  leading to empty space at the right of tab-bars with those flags. (#2109)
+- Docking: Made docked windows not use style.ChildRounding.
+- Multi-viewports: Added multi-viewport support in the DX12 back-end. (#2851) [@obfuscate]
+
 
 -----------------------------------------------------------------------
  VERSION 1.73 (Released 2019-09-24)
@@ -3113,6 +3290,28 @@ Other Changes:
 - Misc: Updated stb_rect_pack.h from 0.99 to 1.00 (fixes by @rygorous: off-by-1 bug in best-fit heuristic,
   fix handling of rectangles too large to fit inside texture). (#2762) [@tido64]
 
+Docking+Viewports Branch:
+
+- Docking: Fix BeginDocked() path that creates node so that SetNextWindowDockID() doesn't immediately discard the node. (#2109)
+- Docking: Fix for node created at the same time as windows that are still resizing (typically with
+  io.ConfigDockingAlwaysTabBar) to not be zero/min sized. (#2109). The fix delays their visibility by one frame,
+  which is not ideal but not very problematic as the .ini data gets populated after that.
+- Docking: Fix a crash that could occur with a malformed ini file (DockNode Parent value pointing to a missing node).
+- Viewport: Fix modal/popup window being stuck in unowned hidden viewport associated to fallback window without stealing
+  it back. Fix modal reference viewport when opened outside of another window. (#1542)
+- Viewport: Modals don't need to set ImGuiViewportFlags_NoFocusOnClick, this also mitigate the issue described by #2445,
+  which becomes particularly bad with unfocused modal. (#1542)
+- Viewport: better case case where host window gets moved and resized simultaneous (toggling maximized state).
+  There's no perfect solution there, than using io.ConfigViewportsNoAutoMerge = false. (#1542)
+- Viewport, Docking: Fixed incorrect assignment of IsFallbackWindow which would tag dock node host windows created
+  in NewFrame() as such, messing with popup viewport inheritance.
+- Viewport: Fixed issue where resize grip would display as hovered while mouse is still off the OS bounds so a click
+  would miss it and focus the OS window behind expected one. (#1542)
+- Viewport: Fix to allow multiple shutdown / calls to DestroyPlatformWindows(). (#2769)
+- Viewport: Backends: GLFW: Fix setting window size on macOS (#2767, #2117) [@rokups]
+- Viewport: Backends: GLFW+Linux: Fix window having incorrect size after uncollapse. (#2756, #2117) [@rokups]
+- Viewport: Backends: DirectX9: Workaround for windows not refreshing when main viewport has no draw call. (#2560)
+
 
 -----------------------------------------------------------------------
  VERSION 1.72b (Released 2019-07-31)
@@ -3215,6 +3414,25 @@ Other Changes:
   (#2482, #2632) [@josiahmanson]
 - Examples: Added SDL2+DirectX11 example application. (#2632, #2612, #2482) [@vincenthamm]
 
+Docking+Viewports Branch:
+
+- Docking: Making it possible to undock a node by clicking on the tab bar / title bar for the node. (#2645).
+- Docking: Explicitly inhibit constraint when docked for now. Fix clipping issue related to constraints. (#2690).
+- Docking: Fixed dragging/resizing from OS decoration not marking settings as dirty.
+- Docking: Renamed io.ConfigDockingTabBarOnSingleWindows to io.ConfigDockingAlwaysTabBar.
+  Added ImGuiWindowClass::DockingAlwaysTabBar to set on individual windows.
+- Docking: Perform simple check: assert if Docking or Viewport are enabled exactly on frame 1 (instead of frame 0
+  or later), which is a common user error leading to loss of .ini data on load.
+- Docking: Fix so that an appearing window making a dock node reappear won't have a zero-size on its first frame.
+- Docking: Fixed using ImGuiDockNodeFlags_AutoHideTabBar with io.ConfigDockingTabBarOnSingleWindows.
+- Docking: Added ImGuiDockNode to .natvis file.
+- Docking: Fixed support for large meshes in GetBackgroundDrawList(), GetForegroundDrawList(). (#2638)
+- Viewport: Fix monitor dpi info not being copied to main viewport when multi-viewports are not enabled. (#2621, #1676)
+- Viewport: Refactored ImGuiWindowClass's ViewportFlagsOverrideMask + ViewportFlagsOverrideValue into
+  ViewportFlagsOverrideSet + ViewportFlagsOverrideClear which appears easier to grasp. (#1542)
+- Viewport: Added ImGuiViewportFlags_NoAutoMerge to prevent merging into host viewport in a per-window basis
+  via the ImGuiWindowClass override mechanism. (#1542)
+
 
 -----------------------------------------------------------------------
  VERSION 1.71 (Released 2019-06-12)
@@ -3554,6 +3772,7 @@ Breaking Changes:
 - Renamed ImFontAtlas::GlyphRangesBuilder to ImFontGlyphRangesBuilder. Kept redirection typedef (will obsolete).
 
 Other Changes:
+
 - Added BETA api for Tab Bar/Tabs widgets: (#261, #351)
   - Added BeginTabBar(), EndTabBar(), BeginTabItem(), EndTabItem(), SetTabItemClosed() API.
   - Added ImGuiTabBarFlags flags for BeginTabBar().
@@ -5715,7 +5934,7 @@ Other Changes:
  VERSION 1.08 (2014-08-25)
 -----------------------------------------------------------------------
 
-Decorated log and release notes: https://github.com/ocornut/imgui/releases/tag/v1.08
+Decorated log and release notes: https://github.com/ocornut/imgui/releases/tag/v1.09
 
 - Fixed ImGuiTextFilter trimming of leading/trailing blanks.
 - Fixed file descriptor leak on LoadSettings() failure.

docs/EXAMPLES.md

@@ -104,8 +104,8 @@ OSX + OpenGL2 example. <BR>
 (NB: imgui_impl_osx.mm is currently not as feature complete as other platforms backends.
  You may prefer to use the GLFW Or SDL backends, which will also support Windows and Linux.)
 
-[example_glfw_wgpu/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_wgpu/) <BR>
-GLFW + WebGPU example. Supports Emscripten (web) or Dawn (desktop) <BR>
+[example_emscripten_wgpu/](https://github.com/ocornut/imgui/blob/master/examples/example_emscripten_wgpu/) <BR>
+Emcripten + GLFW + WebGPU example. <BR>
 = main.cpp + imgui_impl_glfw.cpp + imgui_impl_wgpu.cpp
 Note that the 'example_glfw_opengl3' and 'example_sdl2_opengl3' examples also supports Emscripten!
 
@@ -126,7 +126,7 @@ state, and might confuse your GPU driver. One star, not recommended.
 GLFW (Win32, Mac, Linux) + OpenGL3+/ES2/ES3 example (modern, programmable pipeline). <BR>
 = main.cpp + imgui_impl_glfw.cpp + imgui_impl_opengl3.cpp <BR>
 This uses more modern GL calls and custom shaders.<BR>
-This support building with Emscripten and targeting WebGL.<BR>
+This support building with Emscripten and targetting WebGL.<BR>
 Prefer using that if you are using modern GL or WebGL in your application.
 
 [example_glfw_vulkan/](https://github.com/ocornut/imgui/blob/master/examples/example_glfw_vulkan/) <BR>
@@ -168,7 +168,7 @@ state, and might confuse your GPU driver. One star, not recommended.
 SDL2 (Win32, Mac, Linux, etc.) + OpenGL3+/ES2/ES3 example. <BR>
 = main.cpp + imgui_impl_sdl2.cpp + imgui_impl_opengl3.cpp <BR>
 This uses more modern GL calls and custom shaders. <BR>
-This support building with Emscripten and targeting WebGL.<BR>
+This support building with Emscripten and targetting WebGL.<BR>
 Prefer using that if you are using modern GL or WebGL in your application.
 
 [example_sdl2_sdlrenderer2/](https://github.com/ocornut/imgui/blob/master/examples/example_sdl2_sdlrenderer2/) <BR>

docs/FAQ.md

@@ -23,7 +23,7 @@ or view this file with any Markdown viewer.
 | [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)** |
+| **[About the ID Stack system..<br>Why is my widget not reacting when I click on it?<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 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) |
@@ -199,42 +199,10 @@ ctx->RSSetScissorRects(1, &r);
 
 ### Q: About the ID Stack system...
 ### Q: Why is my widget not reacting when I click on it?
-### Q: Why is the wrong widget reacting when I click on one?
 ### Q: How can I have widgets with an empty label?
 ### Q: How can I have multiple widgets with the same label?
 ### Q: How can I have multiple windows with the same label?
 
-**USING THE SAME LABEL+ID IS THE MOST COMMON USER MISTAKE:**
-<table>
-<tr>
-<td><img src="https://github.com/ocornut/imgui/assets/8225057/76eb9467-74d1-4e95-9f56-be81c6dd029d"></td>
-<td>
-<pre lang="cpp">
-ImGui::Begin("Incorrect!");
-ImGui::DragFloat2("My value", &objects[0]->pos.x);
-ImGui::DragFloat2("My value", &objects[1]->pos.x);
-ImGui::DragFloat2("My value", &objects[2]->pos.x);
-ImGui::End();
-&nbsp;
-ImGui::Begin("Correct!");
-ImGui::DragFloat2("My value", &objects[0]->pos.x);
-ImGui::DragFloat2("My value##2", &objects[1]->pos.x);
-ImGui::DragFloat2("My value##3", &objects[2]->pos.x);
-ImGui::End();
-&nbsp;
-ImGui::Begin("Also Correct!");
-for (int n = 0; n < 3; n++)
-{
-    ImGui::PushID(n);
-    ImGui::DragFloat2("My value", &objects[n]->pos.x);
-    ImGui::PopID();
-}
-ImGui::End();
-</pre>
-</td>
-</tr>    
-</table>
-
 A primer on labels and the ID Stack...
 
 Dear ImGui internally needs to uniquely identify UI elements.
@@ -654,7 +622,7 @@ You may take a look at:
 - [Quotes](https://github.com/ocornut/imgui/wiki/Quotes)
 - [Software using Dear ImGui](https://github.com/ocornut/imgui/wiki/Software-using-dear-imgui)
 - [Funding & Sponsors](https://github.com/ocornut/imgui/wiki/Funding)
-- [Gallery](https://github.com/ocornut/imgui/issues/7503)
+- [Gallery](https://github.com/ocornut/imgui/issues/6897)
 
 ##### [Return to Index](#index)
 
@@ -700,7 +668,7 @@ There is an auto-generated [c-api for Dear ImGui (cimgui)](https://github.com/ci
 - Individuals: you can support continued maintenance and development via PayPal donations. See [README](https://github.com/ocornut/imgui/blob/master/docs/README.md).
 - If you are experienced with Dear ImGui and C++, look at [GitHub Issues](https://github.com/ocornut/imgui/issues), [GitHub Discussions](https://github.com/ocornut/imgui/discussions), the [Wiki](https://github.com/ocornut/imgui/wiki), read [docs/TODO.txt](https://github.com/ocornut/imgui/blob/master/docs/TODO.txt), and see how you want to help and can help!
 - Disclose your usage of Dear ImGui via a dev blog post, a tweet, a screenshot, a mention somewhere, etc.
-You may post screenshots or links in the [gallery threads](https://github.com/ocornut/imgui/issues/7503). Visuals are ideal as they inspire other programmers. Disclosing your use of Dear ImGui helps the library grow credibility, and helps other teams and programmers with taking decisions.
+You may post screenshots or links in the [gallery threads](https://github.com/ocornut/imgui/issues/6897). Visuals are ideal as they inspire other programmers. Disclosing your use of Dear ImGui helps the library grow credibility, and helps other teams and programmers with taking decisions.
 - If you have issues or if you need to hack into the library, even if you don't expect any support it is useful that you share your issues or sometimes incomplete PR.
 
 ##### [Return to Index](#index)

docs/README.md

@@ -141,7 +141,7 @@ Also see [Wiki](https://github.com/ocornut/imgui/wiki) for more links and ideas.
 
 Examples projects using Dear ImGui: [Tracy](https://github.com/wolfpld/tracy) (profiler), [ImHex](https://github.com/WerWolv/ImHex) (hex editor/data analysis), [RemedyBG](https://remedybg.itch.io/remedybg) (debugger) and [hundreds of others](https://github.com/ocornut/imgui/wiki/Software-using-Dear-ImGui).
 
-For more user-submitted screenshots of projects using Dear ImGui, check out the [Gallery Threads](https://github.com/ocornut/imgui/issues/7503)!
+For more user-submitted screenshots of projects using Dear ImGui, check out the [Gallery Threads](https://github.com/ocornut/imgui/issues/6897)!
 
 For a list of third-party widgets and extensions, check out the [Useful Extensions/Widgets](https://github.com/ocornut/imgui/wiki/Useful-Extensions) wiki page.
 
@@ -162,7 +162,7 @@ See: [Upcoming Changes](https://github.com/ocornut/imgui/wiki/Upcoming-Changes).
 
 See: [Dear ImGui Test Engine + Test Suite](https://github.com/ocornut/imgui_test_engine) for Automation & Testing.
 
-For the purposes of getting search engines to crawl the wiki, here's a link to the [Crawlable Wiki](https://github-wiki-see.page/m/ocornut/imgui/wiki) (not for humans, [here's why](https://github-wiki-see.page/)).
+For the purposes of getting search engines to crawl the wiki, here's a link to the [Crawable Wiki](https://github-wiki-see.page/m/ocornut/imgui/wiki) (not for humans, [here's why](https://github-wiki-see.page/)).
 
 Getting started? For first-time users having issues compiling/linking/running or issues loading fonts, please use [GitHub Discussions](https://github.com/ocornut/imgui/discussions). For ANY other questions, bug reports, requests, feedback, please post on [GitHub Issues](https://github.com/ocornut/imgui/issues). Please read and fill the New Issue template carefully.
 
@@ -174,7 +174,7 @@ We occasionally tag [Releases](https://github.com/ocornut/imgui/releases) (with
 
 **Who uses Dear ImGui?**
 
-See the [Quotes](https://github.com/ocornut/imgui/wiki/Quotes), [Funding & Sponsors](https://github.com/ocornut/imgui/wiki/Funding), and [Software using Dear ImGui](https://github.com/ocornut/imgui/wiki/Software-using-dear-imgui) Wiki pages for an idea of who is using Dear ImGui. Please add your game/software if you can! Also, see the [Gallery Threads](https://github.com/ocornut/imgui/issues/7503)!
+See the [Quotes](https://github.com/ocornut/imgui/wiki/Quotes), [Funding & Sponsors](https://github.com/ocornut/imgui/wiki/Funding), and [Software using Dear ImGui](https://github.com/ocornut/imgui/wiki/Software-using-dear-imgui) Wiki pages for an idea of who is using Dear ImGui. Please add your game/software if you can! Also, see the [Gallery Threads](https://github.com/ocornut/imgui/issues/6897)!
 
 How to help
 -----------

docs/TODO.txt

@@ -39,7 +39,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - scrolling: forward mouse wheel scrolling to parent window when at the edge of scrolling limits? (useful for listbox,tables?)
  - scrolling/style: shadows on scrollable areas to denote that there is more contents (see e.g. DaVinci Resolve ui)
 
- - drawdata: make it easy to deep-copy (or swap?) a full ImDrawData so user can easily save that data if they use threaded rendering. (#1860 see ImDrawDataSnapshot)
+ - drawdata: make it easy to deep-copy (or swap?) a full ImDrawData so user can easily save that data if they use threaded rendering. (e.g. #2646)
  ! drawlist: add CalcTextSize() func to facilitate consistent code from user pov (currently need to use ImGui or ImFont alternatives!)
  - drawlist: maintaining bounding box per command would allow to merge draw command when clipping isn't relied on (typical non-scrolling window or non-overflowing column would merge with previous command). (WIP branch)
  - drawlist: make it easier to toggle AA per primitive, so we can use e.g. non-AA fill + AA borders more naturally
@@ -117,7 +117,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
 !- color: the color conversion helpers/types are a mess and needs sorting out.
  - color: (api breaking) ImGui::ColorConvertXXX functions should be loose ImColorConvertXX to match imgui_internals.h
 
- - plot: full featured plot/graph api w/ scrolling, zooming etc. --> promote using ImPlot
+ - plot: full featured plot/graph api w/ scrolling, zooming etc. --> ImPlot
  - (plot: deleted all other todo lines on 2023-06-28)
 
  - clipper: ability to disable the clipping through a simple flag/bool.
@@ -129,7 +129,35 @@ 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.
@@ -150,6 +178,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - drag float: power != 0.0f with current value being outside the range keeps the value stuck.
  - drag float: added leeway on edge (e.g. a few invisible steps past the clamp limits)
 
+ - combo: use clipper.
  - combo: a way/helper to customize the combo preview (#1658) -> experimental BeginComboPreview()
  - combo/listbox: keyboard control. need InputText-like non-active focus + key handling. considering keyboard for custom listbox (pr #203)
  - listbox: multiple selection (WIP range-select branch)
@@ -172,14 +201,13 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - tooltip: drag and drop with tooltip near monitor edges lose/changes its last direction instead of locking one. The drag and drop tooltip should always follow without changing direction.
  - tooltip: allow to set the width of a tooltip to allow TextWrapped() etc. while keeping the height automatic.
  - tooltip: drag tooltip hovering over source widget with IsItemHovered/SetTooltip flickers (WIP branch)
- - tooltip: tooltip priorities to override a stock tooltip (e.g. shortcut tooltip)
 
  - status-bar: add a per-window status bar helper similar to what menu-bar does. generalize concept of layer0 rect in window (can make _MenuBar window flag obsolete too).
- - shortcuts: store multiple keychords in ImGuiKeyChord
- - shortcuts: Hovered route (lower than Focused, higher than Global)
  - shortcuts: local-style shortcut api, e.g. parse "&Save"
  - shortcuts,menus: global-style shortcut api e.g. "Save (CTRL+S)" -> explicit flag for recursing into closed menu
- - menus: hovering from menu to menu on a menu-bar has 1 frame without any menu, which is a little annoying. ideally zero.
+ - shortcuts: programmatically access shortcuts "Focus("&Save"))
+ - menus: menu-bar: main menu-bar could affect clamping of windows position (~ akin to modifying DisplayMin)
+ - menus: hovering from menu to menu on a menu-bar has 1 frame without any menu, which is a little annoying. ideally either 0 either longer.
  - menus: would be nice if the Selectable() supported horizontal alignment (must be given the equivalent of WorkRect.Max.x matching the position of the shortcut column)
 
  - tree node: add treenode/treepush int variants? not there because (void*) cast from int warns on some platforms/settings?
@@ -275,6 +303,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - 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?
 
+ - nav: visual feedback on button press.
  - nav: some features such as PageUp/Down/Home/End should probably work without ImGuiConfigFlags_NavEnableKeyboard? (where do we draw the line? how about CTRL+Tab)
  ! nav: never clear NavId on some setup (e.g. gamepad centric)
  - nav: there's currently no way to completely clear focus with the keyboard. depending on patterns used by the application to dispatch inputs, it may be desirable.
@@ -302,6 +331,20 @@ 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
+ - 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.
+ - 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)
@@ -314,7 +357,8 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - misc: make the ImGuiCond values linear (non-power-of-two). internal storage for ImGuiWindow can use integers to combine into flags (Why?)
  - misc: PushItemFlag(): add a flag to disable keyboard capture when used with mouse? (#1682)
  - misc: use more size_t in public api?
- - misc: support for string view/range instead of char* would e.g. facilitate usage with Rust (#683, #3038, WIP string_view branch)
+ - misc: possible compile-time support for string view/range instead of char* would e.g. facilitate usage with Rust (#683, #3038, WIP string_view branch)
+ - misc: possible compile-time support for wchar_t instead of char*?
 
  - demo: demonstrate using PushStyleVar() in more details.
  - demo: add vertical separator demo
@@ -334,7 +378,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - backends: bgfx: https://gist.github.com/RichardGale/6e2b74bc42b3005e08397236e4be0fd0
  - backends: emscriptem: with refactored examples, we could provide a direct imgui_impl_emscripten platform layer (see eg. https://github.com/floooh/sokol-samples/blob/master/html5/imgui-emsc.cc#L42)
 
- - bindings: ways to use clang ast dump to generate bindings or helpers for bindings? (e.g. clang++ -Xclang -ast-dump=json imgui.h) (--> use https://github.com/dearimgui/dear_bindings)
+ - bindings: ways to use clang ast dump to generate bindings or helpers for bindings? (e.g. clang++ -Xclang -ast-dump=json imgui.h) (WIP project "dear-bindings" still private)
 
  - optimization: replace vsnprintf with stb_printf? using IMGUI_USE_STB_SPRINTF. (#1038 + needed for string_view)
  - optimization: add clipping for multi-component widgets (SliderFloatX, ColorEditX, etc.). one problem is that nav branch can't easily clip parent group when there is a move request.

examples/example_allegro5/main.cpp

@@ -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();

examples/example_android_opengl3/main.cpp

@@ -161,7 +161,7 @@ void Init(struct android_app* app)
 
     // We load the default font with increased size to improve readability on many devices with "high" DPI.
     // FIXME: Put some effort into DPI awareness.
-    // Important: when calling AddFontFromMemoryTTF(), ownership of font_data is transferred by Dear ImGui by default (deleted is handled by Dear ImGui), unless we set FontDataOwnedByAtlas=false in ImFontConfig
+    // Important: when calling AddFontFromMemoryTTF(), ownership of font_data is transfered by Dear ImGui by default (deleted is handled by Dear ImGui), unless we set FontDataOwnedByAtlas=false in ImFontConfig
     ImFontConfig font_cfg;
     font_cfg.SizePixels = 22.0f;
     io.Fonts->AddFontDefault(&font_cfg);

examples/example_apple_metal/example_apple_metal.xcodeproj/project.pbxproj

@@ -7,7 +7,10 @@
 	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 */,
@@ -268,9 +281,9 @@
 				8309BDBB253CCCAD0045E2A1 /* imgui_impl_metal.mm in Sources */,
 				83BBEA0920EB54E700295997 /* imgui.cpp in Sources */,
 				83BBEA0720EB54E700295997 /* imgui_demo.cpp in Sources */,
-                83BBEA0520EB54E700295997 /* imgui_draw.cpp in Sources */,
+				83BBEA0520EB54E700295997 /* imgui_draw.cpp in Sources */,
 				5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */,
-                07A82ED82139413D0078D120 /* imgui_widgets.cpp in Sources */,
+				07A82ED82139413D0078D120 /* imgui_widgets.cpp in Sources */,
 				8309BDA5253CCC070045E2A1 /* main.mm in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -281,10 +294,10 @@
 			files = (
 				8309BDBE253CCCB60045E2A1 /* imgui_impl_metal.mm in Sources */,
 				8309BDBF253CCCB60045E2A1 /* imgui_impl_osx.mm in Sources */,
-                83BBEA0A20EB54E700295997 /* imgui.cpp in Sources */,
-                83BBEA0820EB54E700295997 /* imgui_demo.cpp in Sources */,
-                83BBEA0620EB54E700295997 /* imgui_draw.cpp in Sources */,
-                5079822E257677DB0038A28D /* imgui_tables.cpp in Sources */,
+				83BBEA0A20EB54E700295997 /* imgui.cpp in Sources */,
+				83BBEA0820EB54E700295997 /* imgui_demo.cpp in Sources */,
+				83BBEA0620EB54E700295997 /* imgui_draw.cpp in Sources */,
+				050450AB2768052600AB6805 /* imgui_tables.cpp in Sources */,
 				07A82ED92139418F0078D120 /* imgui_widgets.cpp in Sources */,
 				8309BDA8253CCC080045E2A1 /* main.mm in Sources */,
 			);

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);
 
@@ -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

examples/example_apple_opengl2/main.mm

@@ -47,11 +47,21 @@
     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();
@@ -136,6 +146,13 @@
 
     ImGui_ImplOpenGL2_RenderDrawData(draw_data);
 
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
+
     // Present
     [[self openGLContext] flushBuffer];
 

examples/example_emscripten_wgpu/README.md

@@ -6,7 +6,7 @@
 
 - You may also refer to our [Continuous Integration setup](https://github.com/ocornut/imgui/tree/master/.github/workflows) for Emscripten setup.
 
-- Then build using `make -f Makefile.emscripten` while in the `example_glfw_wgpu/` directory.
+- Then build using `make -f Makefile.emscripten` while in the `example_emscripten_wgpu/` directory.
 
 - Requires recent Emscripten as WGPU is still a work-in-progress API.
 
@@ -18,7 +18,7 @@ To run on a local machine:
 - Otherwise, generally you will need a local webserver:
   - Quoting [https://emscripten.org/docs/getting_started](https://emscripten.org/docs/getting_started/Tutorial.html#generating-html):<br>
 _"Unfortunately several browsers (including Chrome, Safari, and Internet Explorer) do not support file:// [XHR](https://emscripten.org/docs/site/glossary.html#term-xhr) requests, and can’t load extra files needed by the HTML (like a .wasm file, or packaged file data as mentioned lower down). For these browsers you’ll need to serve the files using a [local webserver](https://emscripten.org/docs/getting_started/FAQ.html#faq-local-webserver) and then open http://localhost:8000/hello.html."_
-  - Emscripten SDK has a handy `emrun` command: `emrun web/example_glfw_wgpu.html --browser firefox` which will spawn a temporary local webserver (in Firefox). See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
+  - Emscripten SDK has a handy `emrun` command: `emrun web/example_emscripten_opengl3.html --browser firefox` which will spawn a temporary local webserver (in Firefox). See https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html for details.
   - You may use Python 3 builtin webserver: `python -m http.server -d web` (this is what `make serve` uses).
   - You may use Python 2 builtin webserver: `cd web && python -m SimpleHTTPServer`.
   - If you are accessing the files over a network, certain browsers, such as Firefox, will restrict Gamepad API access to secure contexts only (e.g. https only).

examples/example_emscripten_wgpu/main.cpp

@@ -1,6 +1,5 @@
-// Dear ImGui: standalone example application for using GLFW + WebGPU
-// - Emscripten is supported for publishing on web. See https://emscripten.org.
-// - Dawn is used as a WebGPU implementation on desktop.
+// Dear ImGui: standalone example application for Emscripten, using GLFW + WebGPU
+// (Emscripten is a C++-to-javascript compiler, used to publish executables for the web. See https://emscripten.org/)
 
 // Learn about Dear ImGui:
 // - FAQ                  https://dearimgui.com/faq
@@ -12,15 +11,11 @@
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_wgpu.h"
 #include <stdio.h>
-
 #ifdef __EMSCRIPTEN__
 #include <emscripten.h>
 #include <emscripten/html5.h>
 #include <emscripten/html5_webgpu.h>
-#else
-#include <webgpu/webgpu_glfw.h>
 #endif
-
 #include <GLFW/glfw3.h>
 #include <webgpu/webgpu.h>
 #include <webgpu/webgpu_cpp.h>
@@ -31,16 +26,15 @@
 #endif
 
 // Global WebGPU required states
-static WGPUInstance      wgpu_instance = nullptr;
 static WGPUDevice        wgpu_device = nullptr;
 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_width = 0;
+static int               wgpu_swap_chain_height = 0;
 
 // Forward declarations
-static bool InitWGPU(GLFWwindow* window);
+static bool InitWGPU();
 static void CreateSwapChain(int width, int height);
 
 static void glfw_error_callback(int error, const char* description)
@@ -72,19 +66,18 @@ int main(int, char**)
     // Make sure GLFW does not initialize any graphics context.
     // This needs to be done explicitly later.
     glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
-    GLFWwindow* window = glfwCreateWindow(wgpu_swap_chain_width, wgpu_swap_chain_height, "Dear ImGui GLFW+WebGPU example", nullptr, nullptr);
+    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+WebGPU example", nullptr, nullptr);
     if (window == nullptr)
         return 1;
 
     // Initialize the WebGPU environment
-    if (!InitWGPU(window))
+    if (!InitWGPU())
     {
         if (window)
             glfwDestroyWindow(window);
         glfwTerminate();
         return 1;
     }
-    CreateSwapChain(wgpu_swap_chain_width, wgpu_swap_chain_height);
     glfwShowWindow(window);
 
     // Setup Dear ImGui context
@@ -122,7 +115,7 @@ int main(int, char**)
     //io.Fonts->AddFontDefault();
 #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/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);
@@ -155,7 +148,7 @@ int main(int, char**)
         // React to changes in screen size
         int width, height;
         glfwGetFramebufferSize((GLFWwindow*)window, &width, &height);
-        if (width != wgpu_swap_chain_width || height != wgpu_swap_chain_height)
+        if (width != wgpu_swap_chain_width && height != wgpu_swap_chain_height)
         {
             ImGui_ImplWGPU_InvalidateDeviceObjects();
             CreateSwapChain(width, height);
@@ -207,11 +200,6 @@ int main(int, char**)
         // Rendering
         ImGui::Render();
 
-#ifndef __EMSCRIPTEN__
-        // Tick needs to be called in Dawn to display validation errors
-        wgpuDeviceTick(wgpu_device);
-#endif
-
         WGPURenderPassColorAttachment color_attachments = {};
         color_attachments.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
         color_attachments.loadOp = WGPULoadOp_Clear;
@@ -235,15 +223,6 @@ int main(int, char**)
         WGPUCommandBuffer cmd_buffer = wgpuCommandEncoderFinish(encoder, &cmd_buffer_desc);
         WGPUQueue queue = wgpuDeviceGetQueue(wgpu_device);
         wgpuQueueSubmit(queue, 1, &cmd_buffer);
-
-#ifndef __EMSCRIPTEN__
-        wgpuSwapChainPresent(wgpu_swap_chain);
-#endif
-
-        wgpuTextureViewRelease(color_attachments.view);
-        wgpuRenderPassEncoderRelease(pass);
-        wgpuCommandEncoderRelease(encoder);
-        wgpuCommandBufferRelease(cmd_buffer);
     }
 #ifdef __EMSCRIPTEN__
     EMSCRIPTEN_MAINLOOP_END;
@@ -260,72 +239,29 @@ int main(int, char**)
     return 0;
 }
 
-#ifndef __EMSCRIPTEN__
-static WGPUAdapter RequestAdapter(WGPUInstance instance)
+static bool InitWGPU()
 {
-    auto onAdapterRequestEnded = [](WGPURequestAdapterStatus status, WGPUAdapter adapter, const char* message, void* pUserData)
-    {
-        if (status == WGPURequestAdapterStatus_Success)
-            *(WGPUAdapter*)(pUserData) = adapter;
-        else
-            printf("Could not get WebGPU adapter: %s\n", message);
-};
-    WGPUAdapter adapter;
-    wgpuInstanceRequestAdapter(instance, nullptr, onAdapterRequestEnded, (void*)&adapter);
-    return adapter;
-}
-
-static WGPUDevice RequestDevice(WGPUAdapter& adapter)
-{
-    auto onDeviceRequestEnded = [](WGPURequestDeviceStatus status, WGPUDevice device, const char* message, void* pUserData)
-    {
-        if (status == WGPURequestDeviceStatus_Success)
-            *(WGPUDevice*)(pUserData) = device;
-        else
-            printf("Could not get WebGPU device: %s\n", message);
-    };
-    WGPUDevice device;
-    wgpuAdapterRequestDevice(adapter, nullptr, onDeviceRequestEnded, (void*)&device);
-    return device;
-}
-#endif
-
-static bool InitWGPU(GLFWwindow* window)
-{
-    wgpu::Instance instance = wgpuCreateInstance(nullptr);
-
-#ifdef __EMSCRIPTEN__
     wgpu_device = emscripten_webgpu_get_device();
     if (!wgpu_device)
         return false;
-#else
-    WGPUAdapter adapter = RequestAdapter(instance.Get());
-    if (!adapter)
-        return false;
-    wgpu_device = RequestDevice(adapter);
-#endif
-
-#ifdef __EMSCRIPTEN__
-    wgpu::SurfaceDescriptorFromCanvasHTMLSelector html_surface_desc = {};
-    html_surface_desc.selector = "#canvas";
-    wgpu::SurfaceDescriptor surface_desc = {};
-    surface_desc.nextInChain = &html_surface_desc;
-    wgpu::Surface surface = instance.CreateSurface(&surface_desc);
-
-    wgpu::Adapter adapter = {};
-    wgpu_preferred_fmt = (WGPUTextureFormat)surface.GetPreferredFormat(adapter);
-#else
-    wgpu::Surface surface = wgpu::glfw::CreateSurfaceForWindow(instance, window);
-    if (!surface)
-        return false;
-    wgpu_preferred_fmt = WGPUTextureFormat_BGRA8Unorm;
-#endif
-
-    wgpu_instance = instance.MoveToCHandle();
-    wgpu_surface = surface.MoveToCHandle();
 
     wgpuDeviceSetUncapturedErrorCallback(wgpu_device, wgpu_error_callback, nullptr);
 
+    // Use C++ wrapper due to misbehavior in Emscripten.
+    // Some offset computation for wgpuInstanceCreateSurface in JavaScript
+    // seem to be inline with struct alignments in the C++ structure
+    wgpu::SurfaceDescriptorFromCanvasHTMLSelector html_surface_desc = {};
+    html_surface_desc.selector = "#canvas";
+
+    wgpu::SurfaceDescriptor surface_desc = {};
+    surface_desc.nextInChain = &html_surface_desc;
+
+    wgpu::Instance instance = wgpuCreateInstance(nullptr);
+    wgpu::Surface surface = instance.CreateSurface(&surface_desc);
+    wgpu::Adapter adapter = {};
+    wgpu_preferred_fmt = (WGPUTextureFormat)surface.GetPreferredFormat(adapter);
+    wgpu_surface = surface.MoveToCHandle();
+
     return true;
 }
 

examples/example_emscripten_wgpu/web/index.html

@@ -3,7 +3,7 @@
   <head>
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"/>
-    <title>Dear ImGui Emscripten+GLFW+WebGPU example</title>
+    <title>Dear ImGui Emscripten+WebGPU example</title>
     <style>
         body { margin: 0; background-color: black }
         .emscripten {
@@ -63,10 +63,6 @@
 
       // Initialize the graphics adapter
       {
-          if (!navigator.gpu) {
-            throw Error("WebGPU not supported.");
-          }
-
           const adapter = await navigator.gpu.requestAdapter();
           const device = await adapter.requestDevice();
           Module.preinitializedWebGPUDevice = device;

examples/example_glfw_metal/main.mm

@@ -33,11 +33,21 @@ 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.
@@ -69,7 +79,7 @@ int main(int, char**)
     id <MTLCommandQueue> commandQueue = [device newCommandQueue];
 
     // Setup Platform/Renderer backends
-    ImGui_ImplGlfw_InitForOpenGL(window, true);
+    ImGui_ImplGlfw_InitForOther(window, true);
     ImGui_ImplMetal_Init(device);
 
     NSWindow *nswin = glfwGetCocoaWindow(window);
@@ -157,6 +167,13 @@ 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/main.cpp

@@ -52,11 +52,23 @@ 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();
 
+    // 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_ImplGlfw_InitForOpenGL(window, true);
     ImGui_ImplOpenGL2_Init();
@@ -150,6 +162,17 @@ 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/main.cpp

@@ -77,11 +77,23 @@ 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();
 
+    // 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_ImplGlfw_InitForOpenGL(window, true);
 #ifdef __EMSCRIPTEN__
@@ -179,6 +191,17 @@ 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/main.cpp

@@ -21,12 +21,8 @@
 #define GLFW_INCLUDE_NONE
 #define GLFW_INCLUDE_VULKAN
 #include <GLFW/glfw3.h>
-
-// Volk headers
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-#define VOLK_IMPLEMENTATION
-#include <Volk/volk.h>
-#endif
+#include <vulkan/vulkan.h>
+//#include <vulkan/vulkan_beta.h>
 
 // [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
 // To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
@@ -117,9 +113,6 @@ static VkPhysicalDevice SetupVulkan_SelectPhysicalDevice()
 static void SetupVulkan(ImVector<const char*> instance_extensions)
 {
     VkResult err;
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-    volkInitialize();
-#endif
 
     // Create Vulkan Instance
     {
@@ -158,20 +151,17 @@ static void SetupVulkan(ImVector<const char*> instance_extensions)
         create_info.ppEnabledExtensionNames = instance_extensions.Data;
         err = vkCreateInstance(&create_info, g_Allocator, &g_Instance);
         check_vk_result(err);
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-        volkLoadInstance(g_Instance);
-#endif
 
         // Setup the debug report callback
 #ifdef APP_USE_VULKAN_DEBUG_REPORT
-        auto f_vkCreateDebugReportCallbackEXT = (PFN_vkCreateDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkCreateDebugReportCallbackEXT");
-        IM_ASSERT(f_vkCreateDebugReportCallbackEXT != nullptr);
+        auto vkCreateDebugReportCallbackEXT = (PFN_vkCreateDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkCreateDebugReportCallbackEXT");
+        IM_ASSERT(vkCreateDebugReportCallbackEXT != nullptr);
         VkDebugReportCallbackCreateInfoEXT debug_report_ci = {};
         debug_report_ci.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT;
         debug_report_ci.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT | VK_DEBUG_REPORT_WARNING_BIT_EXT | VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT;
         debug_report_ci.pfnCallback = debug_report;
         debug_report_ci.pUserData = nullptr;
-        err = f_vkCreateDebugReportCallbackEXT(g_Instance, &debug_report_ci, g_Allocator, &g_DebugReport);
+        err = vkCreateDebugReportCallbackEXT(g_Instance, &debug_report_ci, g_Allocator, &g_DebugReport);
         check_vk_result(err);
 #endif
     }
@@ -287,8 +277,8 @@ static void CleanupVulkan()
 
 #ifdef APP_USE_VULKAN_DEBUG_REPORT
     // Remove the debug report callback
-    auto f_vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkDestroyDebugReportCallbackEXT");
-    f_vkDestroyDebugReportCallbackEXT(g_Instance, g_DebugReport, g_Allocator);
+    auto vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkDestroyDebugReportCallbackEXT");
+    vkDestroyDebugReportCallbackEXT(g_Instance, g_DebugReport, g_Allocator);
 #endif // APP_USE_VULKAN_DEBUG_REPORT
 
     vkDestroyDevice(g_Device, g_Allocator);
@@ -429,11 +419,23 @@ 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();
 
+    // 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_ImplGlfw_InitForVulkan(window, true);
     ImGui_ImplVulkan_InitInfo init_info = {};
@@ -542,17 +544,25 @@ 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/CMakeLists.txt

@@ -1,100 +0,0 @@
-# Building for desktop (WebGPU-native) with Dawn:
-#  1. git clone https://github.com/google/dawn dawn
-#  2. cmake -B build -DIMGUI_DAWN_DIR=dawn
-#  3. cmake --build build
-# The resulting binary will be found at one of the following locations:
-#   * build/Debug/example_glfw_wgpu[.exe]
-#   * build/example_glfw_wgpu[.exe]
-
-# Building for Emscripten:
-#  1. Install Emscripten SDK following the instructions: https://emscripten.org/docs/getting_started/downloads.html
-#  2. Install Ninja build system
-#  3. emcmake cmake -G Ninja -B build
-#  3. cmake --build build
-#  4. emrun build/index.html
-
-cmake_minimum_required(VERSION 3.10.2)
-project(imgui_example_glfw_wgpu C CXX)
-
-if(NOT CMAKE_BUILD_TYPE)
-  set(CMAKE_BUILD_TYPE Debug CACHE STRING "" FORCE)
-endif()
-
-set(CMAKE_CXX_STANDARD 17) # Dawn requires C++17
-
-# Dear ImGui
-set(IMGUI_DIR ../../)
-
-# Libraries
-if(EMSCRIPTEN)
-  set(LIBRARIES glfw)
-  add_compile_options(-sDISABLE_EXCEPTION_CATCHING=1 -DIMGUI_DISABLE_FILE_FUNCTIONS=1)
-else()
-  # Dawn wgpu desktop
-  set(DAWN_FETCH_DEPENDENCIES ON)
-  set(IMGUI_DAWN_DIR CACHE PATH "Path to Dawn repository")
-  if (NOT IMGUI_DAWN_DIR)
-    message(FATAL_ERROR "Please specify the Dawn repository by setting IMGUI_DAWN_DIR")
-  endif()
-
-  option(DAWN_FETCH_DEPENDENCIES "Use fetch_dawn_dependencies.py as an alternative to using depot_tools" ON)
-
-  # Dawn builds many things by default - disable things we don't need
-  option(DAWN_BUILD_SAMPLES "Enables building Dawn's samples" OFF)
-  option(TINT_BUILD_CMD_TOOLS "Build the Tint command line tools" OFF)
-  option(TINT_BUILD_DOCS "Build documentation" OFF)
-  option(TINT_BUILD_TESTS "Build tests" OFF)
-  if (NOT APPLE)
-    option(TINT_BUILD_MSL_WRITER "Build the MSL output writer" OFF)
-  endif()
-  if(WIN32)
-    option(TINT_BUILD_SPV_READER "Build the SPIR-V input reader" OFF)
-    option(TINT_BUILD_WGSL_READER "Build the WGSL input reader" ON)
-    option(TINT_BUILD_GLSL_WRITER "Build the GLSL output writer" OFF)
-    option(TINT_BUILD_GLSL_VALIDATOR "Build the GLSL output validator" OFF)
-    option(TINT_BUILD_SPV_WRITER "Build the SPIR-V output writer" OFF)
-    option(TINT_BUILD_WGSL_WRITER "Build the WGSL output writer" ON)
-  endif()
-
-  add_subdirectory("${IMGUI_DAWN_DIR}" "${CMAKE_CURRENT_BINARY_DIR}/dawn" EXCLUDE_FROM_ALL)
-
-  set(LIBRARIES webgpu_dawn webgpu_cpp webgpu_glfw glfw)
-endif()
-
-add_executable(example_glfw_wgpu
-  main.cpp
-  # backend files
-  ${IMGUI_DIR}/backends/imgui_impl_glfw.cpp
-  ${IMGUI_DIR}/backends/imgui_impl_wgpu.cpp
-  # Dear ImGui files
-  ${IMGUI_DIR}/imgui.cpp
-  ${IMGUI_DIR}/imgui_draw.cpp
-  ${IMGUI_DIR}/imgui_demo.cpp
-  ${IMGUI_DIR}/imgui_tables.cpp
-  ${IMGUI_DIR}/imgui_widgets.cpp
-)
-target_include_directories(example_glfw_wgpu PUBLIC
-  ${IMGUI_DIR}
-  ${IMGUI_DIR}/backends
-)
-
-target_link_libraries(example_glfw_wgpu PUBLIC ${LIBRARIES})
-
-# Emscripten settings
-if(EMSCRIPTEN)
-  target_link_options(example_glfw_wgpu PRIVATE
-    "-sUSE_WEBGPU=1"
-    "-sUSE_GLFW=3"
-    "-sWASM=1"
-    "-sALLOW_MEMORY_GROWTH=1"
-    "-sNO_EXIT_RUNTIME=0"
-    "-sASSERTIONS=1"
-    "-sDISABLE_EXCEPTION_CATCHING=1"
-    "-sNO_FILESYSTEM=1"
-  )
-  set_target_properties(example_glfw_wgpu PROPERTIES OUTPUT_NAME "index")
-  # copy our custom index.html to build directory
-  add_custom_command(TARGET example_glfw_wgpu POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy_if_different "${CMAKE_CURRENT_LIST_DIR}/web/index.html" $<TARGET_FILE_DIR:example_glfw_wgpu>
-  )
-endif()

examples/example_glut_opengl2/main.cpp

@@ -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();
@@ -78,7 +79,6 @@ 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.

examples/example_sdl2_directx11/main.cpp

@@ -71,11 +71,23 @@ 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();
 
+    // 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_ImplSDL2_InitForD3D(window);
     ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
@@ -176,6 +188,13 @@ 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

@@ -24,11 +24,21 @@ 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.
@@ -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

@@ -57,11 +57,23 @@ 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();
 
+    // 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_ImplSDL2_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL2_Init();
@@ -155,6 +167,19 @@ 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

@@ -84,11 +84,23 @@ 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();
 
+    // 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_ImplSDL2_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL3_Init(glsl_version);
@@ -189,6 +201,19 @@ 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

@@ -155,7 +155,7 @@ int main(int, char**)
         SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
         SDL_SetRenderDrawColor(renderer, (Uint8)(clear_color.x * 255), (Uint8)(clear_color.y * 255), (Uint8)(clear_color.z * 255), (Uint8)(clear_color.w * 255));
         SDL_RenderClear(renderer);
-        ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData(), renderer);
+        ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData());
         SDL_RenderPresent(renderer);
     }
 

examples/example_sdl2_vulkan/main.cpp

@@ -20,12 +20,8 @@
 #include <stdlib.h>         // abort
 #include <SDL.h>
 #include <SDL_vulkan.h>
-
-// Volk headers
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-#define VOLK_IMPLEMENTATION
-#include <Volk/volk.h>
-#endif
+#include <vulkan/vulkan.h>
+//#include <vulkan/vulkan_beta.h>
 
 //#define APP_USE_UNLIMITED_FRAME_RATE
 #ifdef _DEBUG
@@ -105,9 +101,6 @@ static VkPhysicalDevice SetupVulkan_SelectPhysicalDevice()
 static void SetupVulkan(ImVector<const char*> instance_extensions)
 {
     VkResult err;
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-    volkInitialize();
-#endif
 
     // Create Vulkan Instance
     {
@@ -146,20 +139,17 @@ static void SetupVulkan(ImVector<const char*> instance_extensions)
         create_info.ppEnabledExtensionNames = instance_extensions.Data;
         err = vkCreateInstance(&create_info, g_Allocator, &g_Instance);
         check_vk_result(err);
-#ifdef IMGUI_IMPL_VULKAN_USE_VOLK
-        volkLoadInstance(g_Instance);
-#endif
 
         // Setup the debug report callback
 #ifdef APP_USE_VULKAN_DEBUG_REPORT
-        auto f_vkCreateDebugReportCallbackEXT = (PFN_vkCreateDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkCreateDebugReportCallbackEXT");
-        IM_ASSERT(f_vkCreateDebugReportCallbackEXT != nullptr);
+        auto vkCreateDebugReportCallbackEXT = (PFN_vkCreateDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkCreateDebugReportCallbackEXT");
+        IM_ASSERT(vkCreateDebugReportCallbackEXT != nullptr);
         VkDebugReportCallbackCreateInfoEXT debug_report_ci = {};
         debug_report_ci.sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT;
         debug_report_ci.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT | VK_DEBUG_REPORT_WARNING_BIT_EXT | VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT;
         debug_report_ci.pfnCallback = debug_report;
         debug_report_ci.pUserData = nullptr;
-        err = f_vkCreateDebugReportCallbackEXT(g_Instance, &debug_report_ci, g_Allocator, &g_DebugReport);
+        err = vkCreateDebugReportCallbackEXT(g_Instance, &debug_report_ci, g_Allocator, &g_DebugReport);
         check_vk_result(err);
 #endif
     }
@@ -275,8 +265,8 @@ static void CleanupVulkan()
 
 #ifdef APP_USE_VULKAN_DEBUG_REPORT
     // Remove the debug report callback
-    auto f_vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkDestroyDebugReportCallbackEXT");
-    f_vkDestroyDebugReportCallbackEXT(g_Instance, g_DebugReport, g_Allocator);
+    auto vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT)vkGetInstanceProcAddr(g_Instance, "vkDestroyDebugReportCallbackEXT");
+    vkDestroyDebugReportCallbackEXT(g_Instance, g_DebugReport, g_Allocator);
 #endif // APP_USE_VULKAN_DEBUG_REPORT
 
     vkDestroyDevice(g_Device, g_Allocator);
@@ -429,11 +419,23 @@ 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();
 
+    // 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_ImplSDL2_InitForVulkan(window);
     ImGui_ImplVulkan_InitInfo init_info = {};
@@ -551,17 +553,25 @@ 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_opengl3/Makefile

@@ -37,9 +37,9 @@ LIBS =
 
 ifeq ($(UNAME_S), Linux) #LINUX
 	ECHO_MESSAGE = "Linux"
-	LIBS += $(LINUX_GL_LIBS) -ldl `pkg-config sdl3 --libs`
+	LIBS += $(LINUX_GL_LIBS) -ldl `sdl3-config --libs`
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `sdl3-config --cflags`
 	CFLAGS = $(CXXFLAGS)
 endif
 
@@ -48,7 +48,7 @@ ifeq ($(UNAME_S), Darwin) #APPLE
 	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo `sdl3-config --libs`
 	LIBS += -L/usr/local/lib -L/opt/local/lib
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `sdl3-config --cflags`
 	CXXFLAGS += -I/usr/local/include -I/opt/local/include
 	CFLAGS = $(CXXFLAGS)
 endif

examples/example_sdl3_opengl3/main.cpp

@@ -83,11 +83,23 @@ 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();
 
+    // 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_ImplSDL3_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL3_Init(glsl_version);
@@ -188,6 +200,19 @@ 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_sdlrenderer3/Makefile

@@ -26,9 +26,9 @@ LIBS =
 
 ifeq ($(UNAME_S), Linux) #LINUX
 	ECHO_MESSAGE = "Linux"
-	LIBS += -ldl `pkg-config sdl3  --libs`
+	LIBS += -ldl `sdl3-config --libs`
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `sdl3-config --cflags`
 	CFLAGS = $(CXXFLAGS)
 endif
 
@@ -37,7 +37,7 @@ ifeq ($(UNAME_S), Darwin) #APPLE
 	LIBS += -framework OpenGL -framework Cocoa -framework IOKit -framework CoreVideo `sdl3-config --libs`
 	LIBS += -L/usr/local/lib -L/opt/local/lib
 
-	CXXFLAGS += `pkg-config sdl3 --cflags`
+	CXXFLAGS += `sdl3-config --cflags`
 	CXXFLAGS += -I/usr/local/include -I/opt/local/include
 	CFLAGS = $(CXXFLAGS)
 endif

examples/example_sdl3_sdlrenderer3/main.cpp

@@ -42,8 +42,7 @@ int main(int, char**)
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
         return -1;
     }
-    SDL_Renderer* renderer = SDL_CreateRenderer(window, nullptr);
-    SDL_SetRenderVSync(renderer, 1);
+    SDL_Renderer* renderer = SDL_CreateRenderer(window, nullptr, SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED);
     if (renderer == nullptr)
     {
         SDL_Log("Error: SDL_CreateRenderer(): %s\n", SDL_GetError());
@@ -160,9 +159,9 @@ int main(int, char**)
         // Rendering
         ImGui::Render();
         //SDL_RenderSetScale(renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
-        SDL_SetRenderDrawColorFloat(renderer, clear_color.x, clear_color.y, clear_color.z, clear_color.w);
+        SDL_SetRenderDrawColor(renderer, (Uint8)(clear_color.x * 255), (Uint8)(clear_color.y * 255), (Uint8)(clear_color.z * 255), (Uint8)(clear_color.w * 255));
         SDL_RenderClear(renderer);
-        ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData(), renderer);
+        ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData());
         SDL_RenderPresent(renderer);
     }
 

examples/example_win32_directx10/main.cpp

@@ -16,7 +16,6 @@
 // Data
 static ID3D10Device*            g_pd3dDevice = nullptr;
 static IDXGISwapChain*          g_pSwapChain = nullptr;
-static bool                     g_SwapChainOccluded = false;
 static UINT                     g_ResizeWidth = 0, g_ResizeHeight = 0;
 static ID3D10RenderTargetView*  g_mainRenderTargetView = nullptr;
 
@@ -54,11 +53,23 @@ 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();
 
+    // 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_ImplWin32_Init(hwnd);
     ImGui_ImplDX10_Init(g_pd3dDevice);
@@ -101,14 +112,6 @@ int main(int, char**)
         if (done)
             break;
 
-        // Handle window being minimized or screen locked
-        if (g_SwapChainOccluded && g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED)
-        {
-            ::Sleep(10);
-            continue;
-        }
-        g_SwapChainOccluded = false;
-
         // Handle window resize (we don't resize directly in the WM_SIZE handler)
         if (g_ResizeWidth != 0 && g_ResizeHeight != 0)
         {
@@ -167,13 +170,17 @@ int main(int, char**)
         g_pd3dDevice->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX10_RenderDrawData(ImGui::GetDrawData());
 
-        // Present
-        HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
-        //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
-        g_SwapChainOccluded = (hr == DXGI_STATUS_OCCLUDED);
+        // 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
     }
 
-    // Cleanup
     ImGui_ImplDX10_Shutdown();
     ImGui_ImplWin32_Shutdown();
     ImGui::DestroyContext();
@@ -186,7 +193,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain

examples/example_win32_directx11/main.cpp

@@ -16,7 +16,6 @@
 static ID3D11Device*            g_pd3dDevice = nullptr;
 static ID3D11DeviceContext*     g_pd3dDeviceContext = nullptr;
 static IDXGISwapChain*          g_pSwapChain = nullptr;
-static bool                     g_SwapChainOccluded = false;
 static UINT                     g_ResizeWidth = 0, g_ResizeHeight = 0;
 static ID3D11RenderTargetView*  g_mainRenderTargetView = nullptr;
 
@@ -54,11 +53,28 @@ 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;
+    //io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleFonts;     // FIXME-DPI: Experimental. THIS CURRENTLY DOESN'T WORK AS EXPECTED. DON'T USE IN USER APP!
+    //io.ConfigFlags |= ImGuiConfigFlags_DpiEnableScaleViewports; // FIXME-DPI: Experimental.
 
     // 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_ImplWin32_Init(hwnd);
     ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);
@@ -101,14 +117,6 @@ int main(int, char**)
         if (done)
             break;
 
-        // Handle window being minimized or screen locked
-        if (g_SwapChainOccluded && g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED)
-        {
-            ::Sleep(10);
-            continue;
-        }
-        g_SwapChainOccluded = false;
-
         // Handle window resize (we don't resize directly in the WM_SIZE handler)
         if (g_ResizeWidth != 0 && g_ResizeHeight != 0)
         {
@@ -167,10 +175,15 @@ int main(int, char**)
         g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
         ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
 
-        // Present
-        HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
-        //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
-        g_SwapChainOccluded = (hr == DXGI_STATUS_OCCLUDED);
+        // 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
     }
 
     // Cleanup
@@ -186,7 +199,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain
@@ -241,6 +253,10 @@ void CleanupRenderTarget()
     if (g_mainRenderTargetView) { g_mainRenderTargetView->Release(); g_mainRenderTargetView = nullptr; }
 }
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED 0x02E0 // From Windows SDK 8.1+ headers
+#endif
+
 // Forward declare message handler from imgui_impl_win32.cpp
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
@@ -269,6 +285,15 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
     case WM_DESTROY:
         ::PostQuitMessage(0);
         return 0;
+    case WM_DPICHANGED:
+        if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_DpiEnableScaleViewports)
+        {
+            //const int dpi = HIWORD(wParam);
+            //printf("WM_DPICHANGED to %d (%.0f%%)\n", dpi, (float)dpi / 96.0f * 100.0f);
+            const RECT* suggested_rect = (RECT*)lParam;
+            ::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);
+        }
+        break;
     }
     return ::DefWindowProcW(hWnd, msg, wParam, lParam);
 }

examples/example_win32_directx12/main.cpp

@@ -26,8 +26,6 @@
 #pragma comment(lib, "dxguid.lib")
 #endif
 
-#include "imgui_internal.h"
-
 struct FrameContext
 {
     ID3D12CommandAllocator* CommandAllocator;
@@ -49,7 +47,6 @@ static ID3D12Fence*                 g_fence = nullptr;
 static HANDLE                       g_fenceEvent = nullptr;
 static UINT64                       g_fenceLastSignaledValue = 0;
 static IDXGISwapChain3*             g_pSwapChain = nullptr;
-static bool                         g_SwapChainOccluded = false;
 static HANDLE                       g_hSwapChainWaitableObject = nullptr;
 static ID3D12Resource*              g_mainRenderTargetResource[NUM_BACK_BUFFERS] = {};
 static D3D12_CPU_DESCRIPTOR_HANDLE  g_mainRenderTargetDescriptor[NUM_BACK_BUFFERS] = {};
@@ -90,11 +87,23 @@ 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();
 
+    // 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_ImplWin32_Init(hwnd);
     ImGui_ImplDX12_Init(g_pd3dDevice, NUM_FRAMES_IN_FLIGHT,
@@ -140,14 +149,6 @@ int main(int, char**)
         if (done)
             break;
 
-        // Handle window screen locked
-        if (g_SwapChainOccluded && g_pSwapChain->Present(0, DXGI_PRESENT_TEST) == DXGI_STATUS_OCCLUDED)
-        {
-            ::Sleep(10);
-            continue;
-        }
-        g_SwapChainOccluded = false;
-
         // Start the Dear ImGui frame
         ImGui_ImplDX12_NewFrame();
         ImGui_ImplWin32_NewFrame();
@@ -220,10 +221,15 @@ int main(int, char**)
 
         g_pd3dCommandQueue->ExecuteCommandLists(1, (ID3D12CommandList* const*)&g_pd3dCommandList);
 
-        // Present
-        HRESULT hr = g_pSwapChain->Present(1, 0);   // Present with vsync
-        //HRESULT hr = g_pSwapChain->Present(0, 0); // Present without vsync
-        g_SwapChainOccluded = (hr == DXGI_STATUS_OCCLUDED);
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault(nullptr, (void*)g_pd3dCommandList);
+        }
+
+        g_pSwapChain->Present(1, 0); // Present with vsync
+        //g_pSwapChain->Present(0, 0); // Present without vsync
 
         UINT64 fenceValue = g_fenceLastSignaledValue + 1;
         g_pd3dCommandQueue->Signal(g_fence, fenceValue);
@@ -246,7 +252,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     // Setup swap chain

examples/example_win32_directx9/main.cpp

@@ -15,7 +15,6 @@
 // Data
 static LPDIRECT3D9              g_pD3D = nullptr;
 static LPDIRECT3DDEVICE9        g_pd3dDevice = nullptr;
-static bool                     g_DeviceLost = false;
 static UINT                     g_ResizeWidth = 0, g_ResizeHeight = 0;
 static D3DPRESENT_PARAMETERS    g_d3dpp = {};
 
@@ -52,11 +51,23 @@ 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();
 
+    // 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_ImplWin32_Init(hwnd);
     ImGui_ImplDX9_Init(g_pd3dDevice);
@@ -99,20 +110,6 @@ int main(int, char**)
         if (done)
             break;
 
-        // Handle lost D3D9 device
-        if (g_DeviceLost)
-        {
-            HRESULT hr = g_pd3dDevice->TestCooperativeLevel();
-            if (hr == D3DERR_DEVICELOST)
-            {
-                ::Sleep(10);
-                continue;
-            }
-            if (hr == D3DERR_DEVICENOTRESET)
-                ResetDevice();
-            g_DeviceLost = false;
-        }
-
         // Handle window resize (we don't resize directly in the WM_SIZE handler)
         if (g_ResizeWidth != 0 && g_ResizeHeight != 0)
         {
@@ -177,12 +174,21 @@ 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;
+
+        // Handle loss of D3D9 device
+        if (result == D3DERR_DEVICELOST && g_pd3dDevice->TestCooperativeLevel() == D3DERR_DEVICENOTRESET)
+            ResetDevice();
     }
 
-    // Cleanup
     ImGui_ImplDX9_Shutdown();
     ImGui_ImplWin32_Shutdown();
     ImGui::DestroyContext();
@@ -195,7 +201,6 @@ int main(int, char**)
 }
 
 // Helper functions
-
 bool CreateDeviceD3D(HWND hWnd)
 {
     if ((g_pD3D = Direct3DCreate9(D3D_SDK_VERSION)) == nullptr)
@@ -231,6 +236,10 @@ void ResetDevice()
     ImGui_ImplDX9_CreateDeviceObjects();
 }
 
+#ifndef WM_DPICHANGED
+#define WM_DPICHANGED 0x02E0 // From Windows SDK 8.1+ headers
+#endif
+
 // Forward declare message handler from imgui_impl_win32.cpp
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
@@ -259,6 +268,15 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
     case WM_DESTROY:
         ::PostQuitMessage(0);
         return 0;
+    case WM_DPICHANGED:
+        if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_DpiEnableScaleViewports)
+        {
+            //const int dpi = HIWORD(wParam);
+            //printf("WM_DPICHANGED to %d (%.0f%%)\n", dpi, (float)dpi / 96.0f * 100.0f);
+            const RECT* suggested_rect = (RECT*)lParam;
+            ::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);
+        }
+        break;
     }
     return ::DefWindowProcW(hWnd, msg, wParam, lParam);
 }

examples/example_win32_opengl3/main.cpp

@@ -33,6 +33,42 @@ void CleanupDeviceWGL(HWND hWnd, WGL_WindowData* data);
 void ResetDeviceWGL();
 LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
+// Support function for multi-viewports
+// Unlike most other backend combination, we need specific hooks to combine Win32+OpenGL.
+// We could in theory decide to support Win32-specific code in OpenGL backend via e.g. an hypothetical ImGui_ImplOpenGL3_InitForRawWin32().
+static void Hook_Renderer_CreateWindow(ImGuiViewport* viewport)
+{
+    assert(viewport->RendererUserData == NULL);
+
+    WGL_WindowData* data = IM_NEW(WGL_WindowData);
+    CreateDeviceWGL((HWND)viewport->PlatformHandle, data);
+    viewport->RendererUserData = data;
+}
+
+static void Hook_Renderer_DestroyWindow(ImGuiViewport* viewport)
+{
+    if (viewport->RendererUserData != NULL)
+    {
+        WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData;
+        CleanupDeviceWGL((HWND)viewport->PlatformHandle, data);
+        IM_DELETE(data);
+        viewport->RendererUserData = NULL;
+    }
+}
+
+static void Hook_Platform_RenderWindow(ImGuiViewport* viewport, void*)
+{
+    // Activate the platform window DC in the OpenGL rendering context
+    if (WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData)
+        wglMakeCurrent(data->hDC, g_hRC);
+}
+
+static void Hook_Renderer_SwapBuffers(ImGuiViewport* viewport, void*)
+{
+    if (WGL_WindowData* data = (WGL_WindowData*)viewport->RendererUserData)
+        ::SwapBuffers(data->hDC);
+}
+
 // Main code
 int main(int, char**)
 {
@@ -62,15 +98,39 @@ 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::StyleColorsClassic();
 
+    // 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_ImplWin32_InitForOpenGL(hwnd);
     ImGui_ImplOpenGL3_Init();
 
+    // Win32+GL needs specific hooks for viewport, as there are specific things needed to tie Win32 and GL api.
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+        IM_ASSERT(platform_io.Renderer_CreateWindow == NULL);
+        IM_ASSERT(platform_io.Renderer_DestroyWindow == NULL);
+        IM_ASSERT(platform_io.Renderer_SwapBuffers == NULL);
+        IM_ASSERT(platform_io.Platform_RenderWindow == NULL);
+        platform_io.Renderer_CreateWindow = Hook_Renderer_CreateWindow;
+        platform_io.Renderer_DestroyWindow = Hook_Renderer_DestroyWindow;
+        platform_io.Renderer_SwapBuffers = Hook_Renderer_SwapBuffers;
+        platform_io.Platform_RenderWindow = Hook_Platform_RenderWindow;
+    }
+
     // 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.
@@ -158,6 +218,16 @@ int main(int, char**)
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
 
+        // Update and Render additional Platform Windows
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+
+            // Restore the OpenGL rendering context to the main window DC, since platform windows might have changed it.
+            wglMakeCurrent(g_MainWindow.hDC, g_hRC);
+        }
+
         // Present
         ::SwapBuffers(g_MainWindow.hDC);
     }

examples/libs/usynergy/uSynergy.h

@@ -200,7 +200,7 @@ typedef void		(*uSynergySleepFunc)(uSynergyCookie cookie, int timeMs);
 @brief Get time function
 
 This function is called when uSynergy needs to know the current time. This is used to determine when timeouts
-have occurred. The time base should be a cyclic millisecond time value.
+have occured. The time base should be a cyclic millisecond time value.
 
 @returns			Time value in milliseconds
 **/

imgui.h

@@ -1,4 +1,4 @@
-// dear imgui, v1.90.8
+// dear imgui, v1.90.5
 // (headers)
 
 // Help:
@@ -10,7 +10,7 @@
 // - FAQ ........................ https://dearimgui.com/faq (in repository as docs/FAQ.md)
 // - Homepage ................... https://github.com/ocornut/imgui
 // - Releases & changelog ....... https://github.com/ocornut/imgui/releases
-// - Gallery .................... https://github.com/ocornut/imgui/issues/7503 (please post your screenshots/video there!)
+// - Gallery .................... https://github.com/ocornut/imgui/issues/6897 (please post your screenshots/video there!)
 // - Wiki ....................... https://github.com/ocornut/imgui/wiki (lots of good stuff there)
 //   - Getting Started            https://github.com/ocornut/imgui/wiki/Getting-Started (how to integrate in an existing app by adding ~25 lines of code)
 //   - Third-party Extensions     https://github.com/ocornut/imgui/wiki/Useful-Extensions (ImPlot & many more)
@@ -27,9 +27,11 @@
 
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
-#define IMGUI_VERSION       "1.90.8"
-#define IMGUI_VERSION_NUM   19080
+#define IMGUI_VERSION       "1.90.5"
+#define IMGUI_VERSION_NUM   19050
 #define IMGUI_HAS_TABLE
+#define IMGUI_HAS_VIEWPORT          // Viewport WIP branch
+#define IMGUI_HAS_DOCK              // Docking WIP branch
 
 /*
 
@@ -42,12 +44,12 @@ Index of this file:
 // [SECTION] Helpers: Memory allocations macros, ImVector<>
 // [SECTION] ImGuiStyle
 // [SECTION] ImGuiIO
-// [SECTION] Misc data structures (ImGuiInputTextCallbackData, ImGuiSizeCallbackData, ImGuiPayload)
+// [SECTION] Misc data structures (ImGuiInputTextCallbackData, ImGuiSizeCallbackData, ImGuiWindowClass, ImGuiPayload)
 // [SECTION] Helpers (ImGuiOnceUponAFrame, ImGuiTextFilter, ImGuiTextBuffer, ImGuiStorage, ImGuiListClipper, Math Operators, ImColor)
 // [SECTION] Drawing API (ImDrawCallback, ImDrawCmd, ImDrawIdx, ImDrawVert, ImDrawChannel, ImDrawListSplitter, ImDrawFlags, ImDrawListFlags, ImDrawList, ImDrawData)
 // [SECTION] Font API (ImFontConfig, ImFontGlyph, ImFontGlyphRangesBuilder, ImFontAtlasFlags, ImFontAtlas, ImFont)
 // [SECTION] Viewports (ImGuiViewportFlags, ImGuiViewport)
-// [SECTION] Platform Dependent Interfaces (ImGuiPlatformImeData)
+// [SECTION] Platform Dependent Interfaces (ImGuiPlatformIO, ImGuiPlatformMonitor, ImGuiPlatformImeData)
 // [SECTION] Obsolete functions and types
 
 */
@@ -90,8 +92,6 @@ Index of this file:
 #endif
 #define IM_ARRAYSIZE(_ARR)          ((int)(sizeof(_ARR) / sizeof(*(_ARR))))     // Size of a static C-style array. Don't use on pointers!
 #define IM_UNUSED(_VAR)             ((void)(_VAR))                              // Used to silence "unused variable warnings". Often useful as asserts may be stripped out from final builds.
-
-// Check that version and structures layouts are matching between compiled imgui code and caller. Read comments above DebugCheckVersionAndDataLayout() for details.
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 
 // Helper Macros - IM_FMTARGS, IM_FMTLIST: Apply printf-style warnings to our formatting functions.
@@ -132,7 +132,6 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wfloat-equal"                    // warning: comparing floating point with == or != is unsafe
 #pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
 #pragma clang diagnostic ignored "-Wreserved-identifier"            // warning: identifier '_Xxx' is reserved because it starts with '_' followed by a capital letter
-#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
 #elif defined(__GNUC__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wpragmas"          // warning: unknown option after '#pragma GCC diagnostic' kind
@@ -143,17 +142,6 @@ Index of this file:
 // [SECTION] Forward declarations and basic types
 //-----------------------------------------------------------------------------
 
-// Scalar data types
-typedef unsigned int        ImGuiID;// A unique ID used by widgets (typically the result of hashing a stack of string)
-typedef signed char         ImS8;   // 8-bit signed integer
-typedef unsigned char       ImU8;   // 8-bit unsigned integer
-typedef signed short        ImS16;  // 16-bit signed integer
-typedef unsigned short      ImU16;  // 16-bit unsigned integer
-typedef signed int          ImS32;  // 32-bit signed integer == int
-typedef unsigned int        ImU32;  // 32-bit unsigned integer (often used to store packed colors)
-typedef signed   long long  ImS64;  // 64-bit signed integer
-typedef unsigned long long  ImU64;  // 64-bit unsigned integer
-
 // Forward declarations
 struct ImDrawChannel;               // Temporary storage to output draw commands out of order, used by ImDrawListSplitter and ImDrawList::ChannelsSplit()
 struct ImDrawCmd;                   // A single draw command within a parent ImDrawList (generally maps to 1 GPU draw call, unless it is a callback)
@@ -176,6 +164,8 @@ struct ImGuiKeyData;                // Storage for ImGuiIO and IsKeyDown(), IsKe
 struct ImGuiListClipper;            // Helper to manually clip large list of items
 struct ImGuiOnceUponAFrame;         // Helper for running a block of code not more than once a frame
 struct ImGuiPayload;                // User data payload for drag and drop operations
+struct ImGuiPlatformIO;             // Multi-viewport support: interface for Platform/Renderer backends + viewports to render
+struct ImGuiPlatformMonitor;        // Multi-viewport support: user-provided bounds for each connected monitor/display. Used when positioning popups and tooltips to avoid them straddling monitors
 struct ImGuiPlatformImeData;        // Platform IME data for io.SetPlatformImeDataFn() function.
 struct ImGuiSizeCallbackData;       // Callback data when using SetNextWindowSizeConstraints() (rare/advanced use)
 struct ImGuiStorage;                // Helper for key->value storage
@@ -184,7 +174,8 @@ struct ImGuiTableSortSpecs;         // Sorting specifications for a table (often
 struct ImGuiTableColumnSortSpecs;   // Sorting specification for one column of a table
 struct ImGuiTextBuffer;             // Helper to hold and append into a text buffer (~string builder)
 struct ImGuiTextFilter;             // Helper to parse and apply text filters (e.g. "aaaaa[,bbbbb][,ccccc]")
-struct ImGuiViewport;               // A Platform Window (always only one in 'master' branch), in the future may represent Platform Monitor
+struct ImGuiViewport;               // A Platform Window (always 1 unless multi-viewport are enabled. One per platform window to output to). In the future may represent Platform Monitor
+struct ImGuiWindowClass;            // Window class (rare/advanced uses: provide hints to the platform backend via altered viewport flags and parent/child info)
 
 // Enumerations
 // - We don't use strongly typed enums much because they add constraints (can't extend in private code, can't store typed in bit fields, extra casting on iteration)
@@ -192,15 +183,15 @@ struct ImGuiViewport;               // A Platform Window (always only one in 'ma
 //   - In Visual Studio: CTRL+comma ("Edit.GoToAll") can follow symbols inside comments, whereas CTRL+F12 ("Edit.GoToImplementation") cannot.
 //   - In Visual Studio w/ Visual Assist installed: ALT+G ("VAssistX.GoToImplementation") can also follow symbols inside comments.
 //   - In VS Code, CLion, etc.: CTRL+click can follow symbols inside comments.
-enum ImGuiDir : int;                // -> enum ImGuiDir              // Enum: A cardinal direction (Left, Right, Up, Down)
 enum ImGuiKey : int;                // -> enum ImGuiKey              // Enum: A key identifier (ImGuiKey_XXX or ImGuiMod_XXX value)
 enum ImGuiMouseSource : int;        // -> enum ImGuiMouseSource      // Enum; A mouse input source identifier (Mouse, TouchScreen, Pen)
-enum ImGuiSortDirection : ImU8;     // -> enum ImGuiSortDirection    // Enum: A sorting direction (ascending or descending)
 typedef int ImGuiCol;               // -> enum ImGuiCol_             // Enum: A color identifier for styling
 typedef int ImGuiCond;              // -> enum ImGuiCond_            // Enum: A condition for many Set*() functions
 typedef int ImGuiDataType;          // -> enum ImGuiDataType_        // Enum: A primary data type
+typedef int ImGuiDir;               // -> enum ImGuiDir_             // Enum: A cardinal direction
 typedef int ImGuiMouseButton;       // -> enum ImGuiMouseButton_     // Enum: A mouse button identifier (0=left, 1=right, 2=middle)
 typedef int ImGuiMouseCursor;       // -> enum ImGuiMouseCursor_     // Enum: A mouse cursor shape
+typedef int ImGuiSortDirection;     // -> enum ImGuiSortDirection_   // Enum: A sorting direction (ascending or descending)
 typedef int ImGuiStyleVar;          // -> enum ImGuiStyleVar_        // Enum: A variable identifier for styling
 typedef int ImGuiTableBgTarget;     // -> enum ImGuiTableBgTarget_   // Enum: A color target for TableSetBgColor()
 
@@ -218,10 +209,10 @@ typedef int ImGuiChildFlags;        // -> enum ImGuiChildFlags_      // Flags: f
 typedef int ImGuiColorEditFlags;    // -> enum ImGuiColorEditFlags_  // Flags: for ColorEdit4(), ColorPicker4() etc.
 typedef int ImGuiConfigFlags;       // -> enum ImGuiConfigFlags_     // Flags: for io.ConfigFlags
 typedef int ImGuiComboFlags;        // -> enum ImGuiComboFlags_      // Flags: for BeginCombo()
+typedef int ImGuiDockNodeFlags;     // -> enum ImGuiDockNodeFlags_   // Flags: for DockSpace()
 typedef int ImGuiDragDropFlags;     // -> enum ImGuiDragDropFlags_   // Flags: for BeginDragDropSource(), AcceptDragDropPayload()
 typedef int ImGuiFocusedFlags;      // -> enum ImGuiFocusedFlags_    // Flags: for IsWindowFocused()
 typedef int ImGuiHoveredFlags;      // -> enum ImGuiHoveredFlags_    // Flags: for IsItemHovered(), IsWindowHovered() etc.
-typedef int ImGuiInputFlags;        // -> enum ImGuiInputFlags_      // Flags: for Shortcut(), SetNextItemShortcut()
 typedef int ImGuiInputTextFlags;    // -> enum ImGuiInputTextFlags_  // Flags: for InputText(), InputTextMultiline()
 typedef int ImGuiKeyChord;          // -> ImGuiKey | ImGuiMod_XXX    // Flags: for IsKeyChordPressed(), Shortcut() etc. an ImGuiKey optionally OR-ed with one or more ImGuiMod_XXX values.
 typedef int ImGuiPopupFlags;        // -> enum ImGuiPopupFlags_      // Flags: for OpenPopup*(), BeginPopupContext*(), IsPopupOpen()
@@ -250,6 +241,17 @@ typedef void* ImTextureID;          // Default: store a pointer or an integer fi
 typedef unsigned short ImDrawIdx;   // Default: 16-bit (for maximum compatibility with renderer backends)
 #endif
 
+// Scalar data types
+typedef unsigned int        ImGuiID;// A unique ID used by widgets (typically the result of hashing a stack of string)
+typedef signed char         ImS8;   // 8-bit signed integer
+typedef unsigned char       ImU8;   // 8-bit unsigned integer
+typedef signed short        ImS16;  // 16-bit signed integer
+typedef unsigned short      ImU16;  // 16-bit unsigned integer
+typedef signed int          ImS32;  // 32-bit signed integer == int
+typedef unsigned int        ImU32;  // 32-bit unsigned integer (often used to store packed colors)
+typedef signed   long long  ImS64;  // 64-bit signed integer
+typedef unsigned long long  ImU64;  // 64-bit unsigned integer
+
 // Character types
 // (we generally use UTF-8 encoded string in the API. This is storage specifically for a decoded character used for keyboard input and display)
 typedef unsigned int ImWchar32;     // A single decoded U32 character/code point. We encode them as multi bytes UTF-8 when used in strings.
@@ -379,10 +381,12 @@ namespace ImGui
     IMGUI_API bool          IsWindowFocused(ImGuiFocusedFlags flags=0); // is current window focused? or its root/child, depending on flags. see flags for options.
     IMGUI_API bool          IsWindowHovered(ImGuiHoveredFlags flags=0); // is current window hovered and hoverable (e.g. not blocked by a popup/modal)? See ImGuiHoveredFlags_ for options. IMPORTANT: If you are trying to check whether your mouse should be dispatched to Dear ImGui or to your underlying app, you should not use this function! Use the 'io.WantCaptureMouse' boolean for that! Refer to FAQ entry "How can I tell whether to dispatch mouse/keyboard to Dear ImGui or my application?" for details.
     IMGUI_API ImDrawList*   GetWindowDrawList();                        // get draw list associated to the current window, to append your own drawing primitives
+    IMGUI_API float         GetWindowDpiScale();                        // get DPI scale currently associated to the current window's viewport.
     IMGUI_API ImVec2        GetWindowPos();                             // get current window position in screen space (note: it is unlikely you need to use this. Consider using current layout pos instead, GetCursorScreenPos())
     IMGUI_API ImVec2        GetWindowSize();                            // get current window size (note: it is unlikely you need to use this. Consider using GetCursorScreenPos() and e.g. GetContentRegionAvail() instead)
     IMGUI_API float         GetWindowWidth();                           // get current window width (shortcut for GetWindowSize().x)
     IMGUI_API float         GetWindowHeight();                          // get current window height (shortcut for GetWindowSize().y)
+    IMGUI_API ImGuiViewport*GetWindowViewport();                        // get viewport currently associated to the current window.
 
     // Window manipulation
     // - Prefer using SetNextXXX functions (before Begin) rather that SetXXX functions (after Begin).
@@ -394,6 +398,7 @@ namespace ImGui
     IMGUI_API void          SetNextWindowFocus();                                                       // set next window to be focused / top-most. call before Begin()
     IMGUI_API void          SetNextWindowScroll(const ImVec2& scroll);                                  // set next window scrolling value (use < 0.0f to not affect a given axis).
     IMGUI_API void          SetNextWindowBgAlpha(float alpha);                                          // set next window background color alpha. helper to easily override the Alpha component of ImGuiCol_WindowBg/ChildBg/PopupBg. you may also use ImGuiWindowFlags_NoBackground.
+    IMGUI_API void          SetNextWindowViewport(ImGuiID viewport_id);                                 // set next window viewport
     IMGUI_API void          SetWindowPos(const ImVec2& pos, ImGuiCond cond = 0);                        // (not recommended) set current window position - call within Begin()/End(). prefer using SetNextWindowPos(), as this may incur tearing and side-effects.
     IMGUI_API void          SetWindowSize(const ImVec2& size, ImGuiCond cond = 0);                      // (not recommended) set current window size - call within Begin()/End(). set to ImVec2(0, 0) to force an auto-fit. prefer using SetNextWindowSize(), as this may incur tearing and minor side-effects.
     IMGUI_API void          SetWindowCollapsed(bool collapsed, ImGuiCond cond = 0);                     // (not recommended) set current window collapsed state. prefer using SetNextWindowCollapsed().
@@ -700,8 +705,7 @@ namespace ImGui
 
     // Tooltips
     // - Tooltips are windows following the mouse. They do not take focus away.
-    // - A tooltip window can contain items of any types.
-    // - SetTooltip() is more or less a shortcut for the 'if (BeginTooltip()) { Text(...); EndTooltip(); }' idiom (with a subtlety that it discard any previously submitted tooltip)
+    // - A tooltip window can contain items of any types. SetTooltip() is a shortcut for the 'if (BeginTooltip()) { Text(...); EndTooltip(); }' idiom.
     IMGUI_API bool          BeginTooltip();                                                     // begin/append a tooltip window.
     IMGUI_API void          EndTooltip();                                                       // only call EndTooltip() if BeginTooltip()/BeginItemTooltip() returns true!
     IMGUI_API void          SetTooltip(const char* fmt, ...) IM_FMTARGS(1);                     // set a text-only tooltip. Often used after a ImGui::IsItemHovered() check. Override any previous call to SetTooltip().
@@ -712,7 +716,7 @@ namespace ImGui
     // - SetItemTooltip() is a shortcut for the 'if (IsItemHovered(ImGuiHoveredFlags_ForTooltip)) { SetTooltip(...); }' idiom.
     // - Where 'ImGuiHoveredFlags_ForTooltip' itself is a shortcut to use 'style.HoverFlagsForTooltipMouse' or 'style.HoverFlagsForTooltipNav' depending on active input type. For mouse it defaults to 'ImGuiHoveredFlags_Stationary | ImGuiHoveredFlags_DelayShort'.
     IMGUI_API bool          BeginItemTooltip();                                                 // begin/append a tooltip window if preceding item was hovered.
-    IMGUI_API void          SetItemTooltip(const char* fmt, ...) IM_FMTARGS(1);                 // set a text-only tooltip if preceding item was hovered. override any previous call to SetTooltip().
+    IMGUI_API void          SetItemTooltip(const char* fmt, ...) IM_FMTARGS(1);                 // set a text-only tooltip if preceeding item was hovered. override any previous call to SetTooltip().
     IMGUI_API void          SetItemTooltipV(const char* fmt, va_list args) IM_FMTLIST(1);
 
     // Popups, Modals
@@ -833,6 +837,26 @@ namespace ImGui
     IMGUI_API bool          TabItemButton(const char* label, ImGuiTabItemFlags flags = 0);      // create a Tab behaving like a button. return true when clicked. cannot be selected in the tab bar.
     IMGUI_API void          SetTabItemClosed(const char* tab_or_docked_window_label);           // notify TabBar or Docking system of a closed tab/window ahead (useful to reduce visual flicker on reorderable tab bars). For tab-bar: call after BeginTabBar() and before Tab submissions. Otherwise call with a window name.
 
+    // Docking
+    // [BETA API] Enable with io.ConfigFlags |= ImGuiConfigFlags_DockingEnable.
+    // Note: You can use most Docking facilities without calling any API. You DO NOT need to call DockSpace() to use Docking!
+    // - Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking.
+    // - Drag from window menu button (upper-left button) to undock an entire node (all windows).
+    // - When io.ConfigDockingWithShift == true, you instead need to hold SHIFT to enable docking.
+    // About dockspaces:
+    // - Use DockSpaceOverViewport() to create an explicit dock node covering the screen or a specific viewport.
+    //   This is often used with ImGuiDockNodeFlags_PassthruCentralNode to make it transparent.
+    // - Use DockSpace() to create an explicit dock node _within_ an existing window. See Docking demo for details.
+    // - Important: Dockspaces need to be submitted _before_ any window they can host. Submit it early in your frame!
+    // - Important: Dockspaces need to be kept alive if hidden, otherwise windows docked into it will be undocked.
+    //   e.g. if you have multiple tabs with a dockspace inside each tab: submit the non-visible dockspaces with ImGuiDockNodeFlags_KeepAliveOnly.
+    IMGUI_API ImGuiID       DockSpace(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
+    IMGUI_API ImGuiID       DockSpaceOverViewport(const ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
+    IMGUI_API void          SetNextWindowDockID(ImGuiID dock_id, ImGuiCond cond = 0);           // set next window dock id
+    IMGUI_API void          SetNextWindowClass(const ImGuiWindowClass* window_class);           // set next window class (control docking compatibility + provide hints to platform backend via custom viewport flags and platform parent/child relationship)
+    IMGUI_API ImGuiID       GetWindowDockID();
+    IMGUI_API bool          IsWindowDocked();                                                   // is current window docked into another window?
+
     // Logging/Capture
     // - All text output from the interface can be captured into tty/file/clipboard. By default, tree nodes are automatically opened during logging.
     IMGUI_API void          LogToTTY(int auto_open_depth = -1);                                 // start logging to tty (stdout)
@@ -904,8 +928,10 @@ namespace ImGui
     IMGUI_API ImGuiViewport* GetMainViewport();                                                 // return primary/default viewport. This can never be NULL.
 
     // Background/Foreground Draw Lists
-    IMGUI_API ImDrawList*   GetBackgroundDrawList();                                            // this draw list will be the first rendered one. Useful to quickly draw shapes/text behind dear imgui contents.
-    IMGUI_API ImDrawList*   GetForegroundDrawList();                                            // this draw list will be the last rendered one. Useful to quickly draw shapes/text over dear imgui contents.
+    IMGUI_API ImDrawList*   GetBackgroundDrawList();                                            // get background draw list for the viewport associated to the current window. this draw list will be the first rendering one. Useful to quickly draw shapes/text behind dear imgui contents.
+    IMGUI_API ImDrawList*   GetForegroundDrawList();                                            // get foreground draw list for the viewport associated to the current window. this draw list will be the last rendered one. Useful to quickly draw shapes/text over dear imgui contents.
+    IMGUI_API ImDrawList*   GetBackgroundDrawList(ImGuiViewport* viewport);                     // get background draw list for the given viewport. this draw list will be the first rendering one. Useful to quickly draw shapes/text behind dear imgui contents.
+    IMGUI_API ImDrawList*   GetForegroundDrawList(ImGuiViewport* viewport);                     // get foreground draw list for the given viewport. this draw list will be the last rendered one. Useful to quickly draw shapes/text over dear imgui contents.
 
     // Miscellaneous Utilities
     IMGUI_API bool          IsRectVisible(const ImVec2& size);                                  // test if rectangle (of given size, starting from cursor position) is visible / not clipped.
@@ -939,24 +965,6 @@ namespace ImGui
     IMGUI_API const char*   GetKeyName(ImGuiKey key);                                           // [DEBUG] returns English name of the key. Those names a provided for debugging purpose and are not meant to be saved persistently not compared.
     IMGUI_API void          SetNextFrameWantCaptureKeyboard(bool want_capture_keyboard);        // Override io.WantCaptureKeyboard flag next frame (said flag is left for your application to handle, typically when true it instructs your app to ignore inputs). e.g. force capture keyboard when your widget is being hovered. This is equivalent to setting "io.WantCaptureKeyboard = want_capture_keyboard"; after the next NewFrame() call.
 
-    // Inputs Utilities: Shortcut Testing & Routing [BETA]
-    // - ImGuiKeyChord = a ImGuiKey + optional ImGuiMod_Alt/ImGuiMod_Ctrl/ImGuiMod_Shift/ImGuiMod_Super.
-    //       ImGuiKey_C                          // Accepted by functions taking ImGuiKey or ImGuiKeyChord arguments)
-    //       ImGuiMod_Ctrl | ImGuiKey_C          // Accepted by functions taking ImGuiKeyChord arguments)
-    //   only ImGuiMod_XXX values are legal to combine with an ImGuiKey. You CANNOT combine two ImGuiKey values.
-    // - The general idea is that several callers may register interest in a shortcut, and only one owner gets it.
-    //      Parent   -> call Shortcut(Ctrl+S)    // When Parent is focused, Parent gets the shortcut.
-    //        Child1 -> call Shortcut(Ctrl+S)    // When Child1 is focused, Child1 gets the shortcut (Child1 overrides Parent shortcuts)
-    //        Child2 -> no call                  // When Child2 is focused, Parent gets the shortcut.
-    //   The whole system is order independent, so if Child1 makes its calls before Parent, results will be identical.
-    //   This is an important property as it facilitate working with foreign code or larger codebase.
-    // - To understand the difference:
-    //   - IsKeyChordPressed() compares mods and call IsKeyPressed() -> function has no side-effect.
-    //   - Shortcut() submits a route, routes are resolved, if it currently can be routed it calls IsKeyChordPressed() -> function has (desirable) side-effects as it can prevents another call from getting the route.
-    // - Visualize registered routes in 'Metrics/Debugger->Inputs'.
-    IMGUI_API bool          Shortcut(ImGuiKeyChord key_chord, ImGuiInputFlags flags = 0);
-    IMGUI_API void          SetNextItemShortcut(ImGuiKeyChord key_chord, ImGuiInputFlags flags = 0);
-
     // Inputs Utilities: Mouse specific
     // - To refer to a mouse button, you may use named enums in your code e.g. ImGuiMouseButton_Left, ImGuiMouseButton_Right.
     // - You can also use regular integer: it is forever guaranteed that 0=Left, 1=Right, 2=Middle.
@@ -971,8 +979,8 @@ namespace ImGui
     IMGUI_API bool          IsAnyMouseDown();                                                   // [WILL OBSOLETE] is any mouse button held? This was designed for backends, but prefer having backend maintain a mask of held mouse buttons, because upcoming input queue system will make this invalid.
     IMGUI_API ImVec2        GetMousePos();                                                      // shortcut to ImGui::GetIO().MousePos provided by user, to be consistent with other calls
     IMGUI_API ImVec2        GetMousePosOnOpeningCurrentPopup();                                 // retrieve mouse position at the time of opening popup we have BeginPopup() into (helper to avoid user backing that value themselves)
-    IMGUI_API bool          IsMouseDragging(ImGuiMouseButton button, float lock_threshold = -1.0f);         // is mouse dragging? (uses io.MouseDraggingThreshold if lock_threshold < 0.0f)
-    IMGUI_API ImVec2        GetMouseDragDelta(ImGuiMouseButton button = 0, float lock_threshold = -1.0f);   // return the delta from the initial clicking position while the mouse button is pressed or was just released. This is locked and return 0.0f until the mouse moves past a distance threshold at least once (uses io.MouseDraggingThreshold if lock_threshold < 0.0f)
+    IMGUI_API bool          IsMouseDragging(ImGuiMouseButton button, float lock_threshold = -1.0f);         // is mouse dragging? (if lock_threshold < -1.0f, uses io.MouseDraggingThreshold)
+    IMGUI_API ImVec2        GetMouseDragDelta(ImGuiMouseButton button = 0, float lock_threshold = -1.0f);   // return the delta from the initial clicking position while the mouse button is pressed or was just released. This is locked and return 0.0f until the mouse moves past a distance threshold at least once (if lock_threshold < -1.0f, uses io.MouseDraggingThreshold)
     IMGUI_API void          ResetMouseDragDelta(ImGuiMouseButton button = 0);                   //
     IMGUI_API ImGuiMouseCursor GetMouseCursor();                                                // get desired mouse cursor shape. Important: reset in ImGui::NewFrame(), this is updated during the frame. valid before Render(). If you use software rendering by setting io.MouseDrawCursor ImGui will render those for you
     IMGUI_API void          SetMouseCursor(ImGuiMouseCursor cursor_type);                       // set desired mouse cursor shape
@@ -1008,6 +1016,16 @@ namespace ImGui
     IMGUI_API void*         MemAlloc(size_t size);
     IMGUI_API void          MemFree(void* ptr);
 
+    // (Optional) Platform/OS interface for multi-viewport support
+    // Read comments around the ImGuiPlatformIO structure for more details.
+    // Note: You may use GetWindowViewport() to get the current viewport of the current window.
+    IMGUI_API ImGuiPlatformIO&  GetPlatformIO();                                                // platform/renderer functions, for backend to setup + viewports list.
+    IMGUI_API void              UpdatePlatformWindows();                                        // call in main loop. will call CreateWindow/ResizeWindow/etc. platform functions for each secondary viewport, and DestroyWindow for each inactive viewport.
+    IMGUI_API void              RenderPlatformWindowsDefault(void* platform_render_arg = NULL, void* renderer_render_arg = NULL); // call in main loop. will call RenderWindow/SwapBuffers platform functions for each secondary viewport which doesn't have the ImGuiViewportFlags_Minimized flag set. May be reimplemented by user for custom rendering needs.
+    IMGUI_API void              DestroyPlatformWindows();                                       // call DestroyWindow platform functions for all viewports. call from backend Shutdown() if you need to close platform windows before imgui shutdown. otherwise will be called by DestroyContext().
+    IMGUI_API ImGuiViewport*    FindViewportByID(ImGuiID id);                                   // this is a helper for backends.
+    IMGUI_API ImGuiViewport*    FindViewportByPlatformHandle(void* platform_handle);            // this is a helper for backends. the type platform_handle is decided by the backend (e.g. HWND, MyWindow*, GLFWwindow* etc.)
+
 } // namespace ImGui
 
 //-----------------------------------------------------------------------------
@@ -1038,6 +1056,7 @@ enum ImGuiWindowFlags_
     ImGuiWindowFlags_NoNavInputs            = 1 << 16,  // No gamepad/keyboard navigation within the window
     ImGuiWindowFlags_NoNavFocus             = 1 << 17,  // No focusing toward this window with gamepad/keyboard navigation (e.g. skipped by CTRL+TAB)
     ImGuiWindowFlags_UnsavedDocument        = 1 << 18,  // Display a dot next to the title. When used in a tab/docking context, tab is selected when clicking the X + closure is not assumed (will wait for user to stop submitting the tab). Otherwise closure is assumed when pressing the X, so if you keep submitting the tab may reappear at end of tab bar.
+    ImGuiWindowFlags_NoDocking              = 1 << 19,  // Disable docking of this window
     ImGuiWindowFlags_NoNav                  = ImGuiWindowFlags_NoNavInputs | ImGuiWindowFlags_NoNavFocus,
     ImGuiWindowFlags_NoDecoration           = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoCollapse,
     ImGuiWindowFlags_NoInputs               = ImGuiWindowFlags_NoMouseInputs | ImGuiWindowFlags_NoNavInputs | ImGuiWindowFlags_NoNavFocus,
@@ -1049,6 +1068,7 @@ enum ImGuiWindowFlags_
     ImGuiWindowFlags_Popup                  = 1 << 26,  // Don't use! For internal use by BeginPopup()
     ImGuiWindowFlags_Modal                  = 1 << 27,  // Don't use! For internal use by BeginPopupModal()
     ImGuiWindowFlags_ChildMenu              = 1 << 28,  // Don't use! For internal use by BeginMenu()
+    ImGuiWindowFlags_DockNodeHost           = 1 << 29,  // Don't use! For internal use by Begin()/NewFrame()
 
     // Obsolete names
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
@@ -1082,37 +1102,28 @@ enum ImGuiChildFlags_
 // (Those are per-item flags. There are shared flags in ImGuiIO: io.ConfigInputTextCursorBlink and io.ConfigInputTextEnterKeepActive)
 enum ImGuiInputTextFlags_
 {
-    // Basic filters (also see ImGuiInputTextFlags_CallbackCharFilter)
     ImGuiInputTextFlags_None                = 0,
     ImGuiInputTextFlags_CharsDecimal        = 1 << 0,   // Allow 0123456789.+-*/
     ImGuiInputTextFlags_CharsHexadecimal    = 1 << 1,   // Allow 0123456789ABCDEFabcdef
-    ImGuiInputTextFlags_CharsScientific     = 1 << 2,   // Allow 0123456789.+-*/eE (Scientific notation input)
-    ImGuiInputTextFlags_CharsUppercase      = 1 << 3,   // Turn a..z into A..Z
-    ImGuiInputTextFlags_CharsNoBlank        = 1 << 4,   // Filter out spaces, tabs
-
-    // Inputs
-    ImGuiInputTextFlags_AllowTabInput       = 1 << 5,   // Pressing TAB input a '\t' character into the text field
-    ImGuiInputTextFlags_EnterReturnsTrue    = 1 << 6,   // Return 'true' when Enter is pressed (as opposed to every time the value was modified). Consider looking at the IsItemDeactivatedAfterEdit() function.
-    ImGuiInputTextFlags_EscapeClearsAll     = 1 << 7,   // Escape key clears content if not empty, and deactivate otherwise (contrast to default behavior of Escape to revert)
-    ImGuiInputTextFlags_CtrlEnterForNewLine = 1 << 8,   // In multi-line mode, validate with Enter, add new line with Ctrl+Enter (default is opposite: validate with Ctrl+Enter, add line with Enter).
-
-    // Other options
-    ImGuiInputTextFlags_ReadOnly            = 1 << 9,   // Read-only mode
-    ImGuiInputTextFlags_Password            = 1 << 10,  // Password mode, display all characters as '*', disable copy
-    ImGuiInputTextFlags_AlwaysOverwrite     = 1 << 11,  // Overwrite mode
-    ImGuiInputTextFlags_AutoSelectAll       = 1 << 12,  // Select entire text when first taking mouse focus
-    ImGuiInputTextFlags_ParseEmptyRefVal    = 1 << 13,  // InputFloat(), InputInt(), InputScalar() etc. only: parse empty string as zero value.
-    ImGuiInputTextFlags_DisplayEmptyRefVal  = 1 << 14,  // InputFloat(), InputInt(), InputScalar() etc. only: when value is zero, do not display it. Generally used with ImGuiInputTextFlags_ParseEmptyRefVal.
-    ImGuiInputTextFlags_NoHorizontalScroll  = 1 << 15,  // Disable following the cursor horizontally
+    ImGuiInputTextFlags_CharsUppercase      = 1 << 2,   // Turn a..z into A..Z
+    ImGuiInputTextFlags_CharsNoBlank        = 1 << 3,   // Filter out spaces, tabs
+    ImGuiInputTextFlags_AutoSelectAll       = 1 << 4,   // Select entire text when first taking mouse focus
+    ImGuiInputTextFlags_EnterReturnsTrue    = 1 << 5,   // Return 'true' when Enter is pressed (as opposed to every time the value was modified). Consider looking at the IsItemDeactivatedAfterEdit() function.
+    ImGuiInputTextFlags_CallbackCompletion  = 1 << 6,   // Callback on pressing TAB (for completion handling)
+    ImGuiInputTextFlags_CallbackHistory     = 1 << 7,   // Callback on pressing Up/Down arrows (for history handling)
+    ImGuiInputTextFlags_CallbackAlways      = 1 << 8,   // Callback on each iteration. User code may query cursor position, modify text buffer.
+    ImGuiInputTextFlags_CallbackCharFilter  = 1 << 9,   // Callback on character inputs to replace or discard them. Modify 'EventChar' to replace or discard, or return 1 in callback to discard.
+    ImGuiInputTextFlags_AllowTabInput       = 1 << 10,  // Pressing TAB input a '\t' character into the text field
+    ImGuiInputTextFlags_CtrlEnterForNewLine = 1 << 11,  // In multi-line mode, unfocus with Enter, add new line with Ctrl+Enter (default is opposite: unfocus with Ctrl+Enter, add line with Enter).
+    ImGuiInputTextFlags_NoHorizontalScroll  = 1 << 12,  // Disable following the cursor horizontally
+    ImGuiInputTextFlags_AlwaysOverwrite     = 1 << 13,  // Overwrite mode
+    ImGuiInputTextFlags_ReadOnly            = 1 << 14,  // Read-only mode
+    ImGuiInputTextFlags_Password            = 1 << 15,  // Password mode, display all characters as '*'
     ImGuiInputTextFlags_NoUndoRedo          = 1 << 16,  // Disable undo/redo. Note that input text owns the text data while active, if you want to provide your own undo/redo stack you need e.g. to call ClearActiveID().
-
-    // Callback features
-    ImGuiInputTextFlags_CallbackCompletion  = 1 << 17,  // Callback on pressing TAB (for completion handling)
-    ImGuiInputTextFlags_CallbackHistory     = 1 << 18,  // Callback on pressing Up/Down arrows (for history handling)
-    ImGuiInputTextFlags_CallbackAlways      = 1 << 19,  // Callback on each iteration. User code may query cursor position, modify text buffer.
-    ImGuiInputTextFlags_CallbackCharFilter  = 1 << 20,  // Callback on character inputs to replace or discard them. Modify 'EventChar' to replace or discard, or return 1 in callback to discard.
-    ImGuiInputTextFlags_CallbackResize      = 1 << 21,  // Callback on buffer capacity changes request (beyond 'buf_size' parameter value), allowing the string to grow. Notify when the string wants to be resized (for string types which hold a cache of their Size). You will be provided a new BufSize in the callback and NEED to honor it. (see misc/cpp/imgui_stdlib.h for an example of using this)
-    ImGuiInputTextFlags_CallbackEdit        = 1 << 22,  // Callback on any edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active)
+    ImGuiInputTextFlags_CharsScientific     = 1 << 17,  // Allow 0123456789.+-*/eE (Scientific notation input)
+    ImGuiInputTextFlags_CallbackResize      = 1 << 18,  // Callback on buffer capacity changes request (beyond 'buf_size' parameter value), allowing the string to grow. Notify when the string wants to be resized (for string types which hold a cache of their Size). You will be provided a new BufSize in the callback and NEED to honor it. (see misc/cpp/imgui_stdlib.h for an example of using this)
+    ImGuiInputTextFlags_CallbackEdit        = 1 << 19,  // Callback on any edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active)
+    ImGuiInputTextFlags_EscapeClearsAll     = 1 << 20,  // Escape key clears content if not empty, and deactivate otherwise (contrast to default behavior of Escape to revert)
 
     // Obsolete names
     //ImGuiInputTextFlags_AlwaysInsertMode  = ImGuiInputTextFlags_AlwaysOverwrite   // [renamed in 1.82] name was not matching behavior
@@ -1132,13 +1143,12 @@ enum ImGuiTreeNodeFlags_
     ImGuiTreeNodeFlags_OpenOnArrow          = 1 << 7,   // Only open when clicking on the arrow part. If ImGuiTreeNodeFlags_OpenOnDoubleClick is also set, single-click arrow or double-click all box to open.
     ImGuiTreeNodeFlags_Leaf                 = 1 << 8,   // No collapsing, no arrow (use as a convenience for leaf nodes).
     ImGuiTreeNodeFlags_Bullet               = 1 << 9,   // Display a bullet instead of arrow. IMPORTANT: node can still be marked open/close if you don't set the _Leaf flag!
-    ImGuiTreeNodeFlags_FramePadding         = 1 << 10,  // Use FramePadding (even for an unframed text node) to vertically align text baseline to regular widget height. Equivalent to calling AlignTextToFramePadding() before the node.
-    ImGuiTreeNodeFlags_SpanAvailWidth       = 1 << 11,  // Extend hit box to the right-most edge, even if not framed. This is not the default in order to allow adding other items on the same line without using AllowOverlap mode.
-    ImGuiTreeNodeFlags_SpanFullWidth        = 1 << 12,  // Extend hit box to the left-most and right-most edges (cover the indent area).
-    ImGuiTreeNodeFlags_SpanTextWidth        = 1 << 13,  // Narrow hit box + narrow hovering highlight, will only cover the label text.
-    ImGuiTreeNodeFlags_SpanAllColumns       = 1 << 14,  // Frame will span all columns of its container table (text will still fit in current column)
-    ImGuiTreeNodeFlags_NavLeftJumpsBackHere = 1 << 15,  // (WIP) Nav: left direction may move to this TreeNode() from any of its child (items submitted between TreeNode and TreePop)
-    //ImGuiTreeNodeFlags_NoScrollOnOpen     = 1 << 16,  // FIXME: TODO: Disable automatic scroll on TreePop() if node got just open and contents is not visible
+    ImGuiTreeNodeFlags_FramePadding         = 1 << 10,  // Use FramePadding (even for an unframed text node) to vertically align text baseline to regular widget height. Equivalent to calling AlignTextToFramePadding().
+    ImGuiTreeNodeFlags_SpanAvailWidth       = 1 << 11,  // Extend hit box to the right-most edge, even if not framed. This is not the default in order to allow adding other items on the same line. In the future we may refactor the hit system to be front-to-back, allowing natural overlaps and then this can become the default.
+    ImGuiTreeNodeFlags_SpanFullWidth        = 1 << 12,  // Extend hit box to the left-most and right-most edges (bypass the indented area).
+    ImGuiTreeNodeFlags_SpanAllColumns       = 1 << 13,  // Frame will span all columns of its container table (text will still fit in current column)
+    ImGuiTreeNodeFlags_NavLeftJumpsBackHere = 1 << 14,  // (WIP) Nav: left direction may move to this TreeNode() from any of its child (items submitted between TreeNode and TreePop)
+    //ImGuiTreeNodeFlags_NoScrollOnOpen     = 1 << 15,  // FIXME: TODO: Disable automatic scroll on TreePop() if node got just open and contents is not visible
     ImGuiTreeNodeFlags_CollapsingHeader     = ImGuiTreeNodeFlags_Framed | ImGuiTreeNodeFlags_NoTreePushOnOpen | ImGuiTreeNodeFlags_NoAutoOpenOnLog,
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
@@ -1240,7 +1250,7 @@ enum ImGuiFocusedFlags_
     ImGuiFocusedFlags_RootWindow                    = 1 << 1,   // Test from root window (top most parent of the current hierarchy)
     ImGuiFocusedFlags_AnyWindow                     = 1 << 2,   // Return true if any window is focused. Important: If you are trying to tell how to dispatch your low-level inputs, do NOT use this. Use 'io.WantCaptureMouse' instead! Please read the FAQ!
     ImGuiFocusedFlags_NoPopupHierarchy              = 1 << 3,   // Do not consider popup hierarchy (do not treat popup emitter as parent of popup) (when used with _ChildWindows or _RootWindow)
-    //ImGuiFocusedFlags_DockHierarchy               = 1 << 4,   // Consider docking hierarchy (treat dockspace host as parent of docked window) (when used with _ChildWindows or _RootWindow)
+    ImGuiFocusedFlags_DockHierarchy                 = 1 << 4,   // Consider docking hierarchy (treat dockspace host as parent of docked window) (when used with _ChildWindows or _RootWindow)
     ImGuiFocusedFlags_RootAndChildWindows           = ImGuiFocusedFlags_RootWindow | ImGuiFocusedFlags_ChildWindows,
 };
 
@@ -1254,7 +1264,7 @@ enum ImGuiHoveredFlags_
     ImGuiHoveredFlags_RootWindow                    = 1 << 1,   // IsWindowHovered() only: Test from root window (top most parent of the current hierarchy)
     ImGuiHoveredFlags_AnyWindow                     = 1 << 2,   // IsWindowHovered() only: Return true if any window is hovered
     ImGuiHoveredFlags_NoPopupHierarchy              = 1 << 3,   // IsWindowHovered() only: Do not consider popup hierarchy (do not treat popup emitter as parent of popup) (when used with _ChildWindows or _RootWindow)
-    //ImGuiHoveredFlags_DockHierarchy               = 1 << 4,   // IsWindowHovered() only: Consider docking hierarchy (treat dockspace host as parent of docked window) (when used with _ChildWindows or _RootWindow)
+    ImGuiHoveredFlags_DockHierarchy                 = 1 << 4,   // IsWindowHovered() only: Consider docking hierarchy (treat dockspace host as parent of docked window) (when used with _ChildWindows or _RootWindow)
     ImGuiHoveredFlags_AllowWhenBlockedByPopup       = 1 << 5,   // Return true even if a popup window is normally blocking access to this item/window
     //ImGuiHoveredFlags_AllowWhenBlockedByModal     = 1 << 6,   // Return true even if a modal popup window is normally blocking access to this item/window. FIXME-TODO: Unavailable yet.
     ImGuiHoveredFlags_AllowWhenBlockedByActiveItem  = 1 << 7,   // Return true even if an active item is blocking access to this item/window. Useful for Drag and Drop patterns.
@@ -1284,6 +1294,27 @@ enum ImGuiHoveredFlags_
     ImGuiHoveredFlags_NoSharedDelay                 = 1 << 17,  // IsItemHovered() only: Disable shared delay system where moving from one item to the next keeps the previous timer for a short time (standard for tooltips with long delays)
 };
 
+// Flags for ImGui::DockSpace(), shared/inherited by child nodes.
+// (Some flags can be applied to individual nodes directly)
+// FIXME-DOCK: Also see ImGuiDockNodeFlagsPrivate_ which may involve using the WIP and internal DockBuilder api.
+enum ImGuiDockNodeFlags_
+{
+    ImGuiDockNodeFlags_None                         = 0,
+    ImGuiDockNodeFlags_KeepAliveOnly                = 1 << 0,   //       // Don't display the dockspace node but keep it alive. Windows docked into this dockspace node won't be undocked.
+    //ImGuiDockNodeFlags_NoCentralNode              = 1 << 1,   //       // Disable Central Node (the node which can stay empty)
+    ImGuiDockNodeFlags_NoDockingOverCentralNode     = 1 << 2,   //       // Disable docking over the Central Node, which will be always kept empty.
+    ImGuiDockNodeFlags_PassthruCentralNode          = 1 << 3,   //       // Enable passthru dockspace: 1) DockSpace() will render a ImGuiCol_WindowBg background covering everything excepted the Central Node when empty. Meaning the host window should probably use SetNextWindowBgAlpha(0.0f) prior to Begin() when using this. 2) When Central Node is empty: let inputs pass-through + won't display a DockingEmptyBg background. See demo for details.
+    ImGuiDockNodeFlags_NoDockingSplit               = 1 << 4,   //       // Disable other windows/nodes from splitting this node.
+    ImGuiDockNodeFlags_NoResize                     = 1 << 5,   // Saved // Disable resizing node using the splitter/separators. Useful with programmatically setup dockspaces.
+    ImGuiDockNodeFlags_AutoHideTabBar               = 1 << 6,   //       // Tab bar will automatically hide when there is a single window in the dock node.
+    ImGuiDockNodeFlags_NoUndocking                  = 1 << 7,   //       // Disable undocking this node.
+
+#ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+    ImGuiDockNodeFlags_NoSplit                      = ImGuiDockNodeFlags_NoDockingSplit, // Renamed in 1.90
+    ImGuiDockNodeFlags_NoDockingInCentralNode       = ImGuiDockNodeFlags_NoDockingOverCentralNode, // Renamed in 1.90
+#endif
+};
+
 // Flags for ImGui::BeginDragDropSource(), ImGui::AcceptDragDropPayload()
 enum ImGuiDragDropFlags_
 {
@@ -1323,7 +1354,7 @@ enum ImGuiDataType_
 };
 
 // A cardinal direction
-enum ImGuiDir : int
+enum ImGuiDir_
 {
     ImGuiDir_None    = -1,
     ImGuiDir_Left    = 0,
@@ -1334,7 +1365,7 @@ enum ImGuiDir : int
 };
 
 // A sorting direction
-enum ImGuiSortDirection : ImU8
+enum ImGuiSortDirection_
 {
     ImGuiSortDirection_None         = 0,
     ImGuiSortDirection_Ascending    = 1,    // Ascending = 0->9, A->Z etc.
@@ -1453,13 +1484,13 @@ enum ImGuiKey : int
     // - In theory the value of keyboard modifiers should be roughly equivalent to a logical or of the equivalent left/right keys.
     //   In practice: it's complicated; mods are often provided from different sources. Keyboard layout, IME, sticky keys and
     //   backends tend to interfere and break that equivalence. The safer decision is to relay that ambiguity down to the end-user...
-    // - On macOS, we swap Cmd(Super) and Ctrl keys at the time of the io.AddKeyEvent() call.
     ImGuiMod_None                   = 0,
-    ImGuiMod_Ctrl                   = 1 << 12, // Ctrl (non-macOS), Cmd (macOS)
+    ImGuiMod_Ctrl                   = 1 << 12, // Ctrl
     ImGuiMod_Shift                  = 1 << 13, // Shift
     ImGuiMod_Alt                    = 1 << 14, // Option/Menu
-    ImGuiMod_Super                  = 1 << 15, // Windows/Super (non-macOS), Ctrl (macOS)
-    ImGuiMod_Mask_                  = 0xF000,  // 4-bits
+    ImGuiMod_Super                  = 1 << 15, // Cmd/Super/Windows
+    ImGuiMod_Shortcut               = 1 << 11, // Alias for Ctrl (non-macOS) _or_ Super (macOS).
+    ImGuiMod_Mask_                  = 0xF800,  // 5-bits
 
     // [Internal] Prior to 1.87 we required user to fill io.KeysDown[512] using their own native index + the io.KeyMap[] array.
     // We are ditching this method but keeping a legacy path for user code doing e.g. IsKeyPressed(MY_NATIVE_KEY_CODE)
@@ -1476,37 +1507,11 @@ enum ImGuiKey : int
 #endif
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
-    ImGuiMod_Shortcut               = ImGuiMod_Ctrl,            // Removed in 1.90.7, you can now simply use ImGuiMod_Ctrl
     ImGuiKey_ModCtrl = ImGuiMod_Ctrl, ImGuiKey_ModShift = ImGuiMod_Shift, ImGuiKey_ModAlt = ImGuiMod_Alt, ImGuiKey_ModSuper = ImGuiMod_Super, // Renamed in 1.89
     //ImGuiKey_KeyPadEnter = ImGuiKey_KeypadEnter,              // Renamed in 1.87
 #endif
 };
 
-// Flags for Shortcut(), SetNextItemShortcut(),
-// (and for upcoming extended versions of IsKeyPressed(), IsMouseClicked(), Shortcut(), SetKeyOwner(), SetItemKeyOwner() that are still in imgui_internal.h)
-// Don't mistake with ImGuiInputTextFlags! (which is for ImGui::InputText() function)
-enum ImGuiInputFlags_
-{
-    ImGuiInputFlags_None                    = 0,
-    ImGuiInputFlags_Repeat                  = 1 << 0,   // Enable repeat. Return true on successive repeats. Default for legacy IsKeyPressed(). NOT Default for legacy IsMouseClicked(). MUST BE == 1.
-
-    // Flags for Shortcut(), SetNextItemShortcut()
-    // - Routing policies: RouteGlobal+OverActive >> RouteActive or RouteFocused (if owner is active item) >> RouteGlobal+OverFocused >> RouteFocused (if in focused window stack) >> RouteGlobal.
-    // - Default policy is RouteFocused. Can select only 1 policy among all available.
-    ImGuiInputFlags_RouteActive             = 1 << 10,  // Route to active item only.
-    ImGuiInputFlags_RouteFocused            = 1 << 11,  // Route to windows in the focus stack (DEFAULT). Deep-most focused window takes inputs. Active item takes inputs over deep-most focused window.
-    ImGuiInputFlags_RouteGlobal             = 1 << 12,  // Global route (unless a focused window or active item registered the route).
-    ImGuiInputFlags_RouteAlways             = 1 << 13,  // Do not register route, poll keys directly.
-    // - Routing options
-    ImGuiInputFlags_RouteOverFocused        = 1 << 14,  // Option: global route: higher priority than focused route (unless active item in focused route).
-    ImGuiInputFlags_RouteOverActive         = 1 << 15,  // Option: global route: higher priority than active item. Unlikely you need to use that: will interfere with every active items, e.g. CTRL+A registered by InputText will be overridden by this. May not be fully honored as user/internal code is likely to always assume they can access keys when active.
-    ImGuiInputFlags_RouteUnlessBgFocused    = 1 << 16,  // Option: global route: will not be applied if underlying background/void is focused (== no Dear ImGui windows are focused). Useful for overlay applications.
-    ImGuiInputFlags_RouteFromRootWindow     = 1 << 17,  // Option: route evaluated from the point of view of root window rather than current window.
-
-    // Flags for SetNextItemShortcut()
-    ImGuiInputFlags_Tooltip                 = 1 << 18,  // Automatically display a tooltip when hovering item [BETA] Unsure of right api (opt-in/opt-out)
-};
-
 #ifndef IMGUI_DISABLE_OBSOLETE_KEYIO
 // OBSOLETED in 1.88 (from July 2022): ImGuiNavInput and io.NavInputs[].
 // Official backends between 1.60 and 1.86: will keep working and feed gamepad inputs as long as IMGUI_DISABLE_OBSOLETE_KEYIO is not set.
@@ -1530,6 +1535,15 @@ enum ImGuiConfigFlags_
     ImGuiConfigFlags_NoMouse                = 1 << 4,   // Instruct imgui to clear mouse position/buttons in NewFrame(). This allows ignoring the mouse information set by the backend.
     ImGuiConfigFlags_NoMouseCursorChange    = 1 << 5,   // Instruct backend to not alter mouse cursor shape and visibility. Use if the backend cursor changes are interfering with yours and you don't want to use SetMouseCursor() to change mouse cursor. You may want to honor requests from imgui by reading GetMouseCursor() yourself instead.
 
+    // [BETA] Docking
+    ImGuiConfigFlags_DockingEnable          = 1 << 6,   // Docking enable flags.
+
+    // [BETA] Viewports
+    // When using viewports it is recommended that your default value for ImGuiCol_WindowBg is opaque (Alpha=1.0) so transition to a viewport won't be noticeable.
+    ImGuiConfigFlags_ViewportsEnable        = 1 << 10,  // Viewport enable flags (require both ImGuiBackendFlags_PlatformHasViewports + ImGuiBackendFlags_RendererHasViewports set by the respective backends)
+    ImGuiConfigFlags_DpiEnableScaleViewports= 1 << 14,  // [BETA: Don't use] FIXME-DPI: Reposition and resize imgui windows when the DpiScale of a viewport changed (mostly useful for the main viewport hosting other window). Note that resizing the main window itself is up to your application.
+    ImGuiConfigFlags_DpiEnableScaleFonts    = 1 << 15,  // [BETA: Don't use] FIXME-DPI: Request bitmap-scaled fonts to match DpiScale. This is a very low-quality workaround. The correct way to handle DPI is _currently_ to replace the atlas and/or fonts in the Platform_OnChangedViewport callback, but this is all early work in progress.
+
     // User storage (to allow your backend/engine to communicate to code that may be shared between multiple projects. Those flags are NOT used by core Dear ImGui)
     ImGuiConfigFlags_IsSRGB                 = 1 << 20,  // Application is SRGB-aware.
     ImGuiConfigFlags_IsTouchScreen          = 1 << 21,  // Application is using a touch screen instead of a mouse.
@@ -1543,6 +1557,11 @@ enum ImGuiBackendFlags_
     ImGuiBackendFlags_HasMouseCursors       = 1 << 1,   // Backend Platform supports honoring GetMouseCursor() value to change the OS cursor shape.
     ImGuiBackendFlags_HasSetMousePos        = 1 << 2,   // Backend Platform supports io.WantSetMousePos requests to reposition the OS mouse position (only used if ImGuiConfigFlags_NavEnableSetMousePos is set).
     ImGuiBackendFlags_RendererHasVtxOffset  = 1 << 3,   // Backend Renderer supports ImDrawCmd::VtxOffset. This enables output of large meshes (64K+ vertices) while still using 16-bit indices.
+
+    // [BETA] Viewports
+    ImGuiBackendFlags_PlatformHasViewports  = 1 << 10,  // Backend Platform supports multiple viewports.
+    ImGuiBackendFlags_HasMouseHoveredViewport=1 << 11,  // Backend Platform supports calling io.AddMouseViewportEvent() with the viewport under the mouse. IF POSSIBLE, ignore viewports with the ImGuiViewportFlags_NoInputs flag (Win32 backend, GLFW 3.30+ backend can do this, SDL backend cannot). If this cannot be done, Dear ImGui needs to use a flawed heuristic to find the viewport under.
+    ImGuiBackendFlags_RendererHasViewports  = 1 << 12,  // Backend Renderer supports multiple viewports.
 };
 
 // Enumeration for PushStyleColor() / PopStyleColor()
@@ -1586,6 +1605,8 @@ enum ImGuiCol_
     ImGuiCol_TabActive,
     ImGuiCol_TabUnfocused,
     ImGuiCol_TabUnfocusedActive,
+    ImGuiCol_DockingPreview,        // Preview overlay color when about to docking something
+    ImGuiCol_DockingEmptyBg,        // Background color for empty node (e.g. CentralNode with no window docked into it)
     ImGuiCol_PlotLines,
     ImGuiCol_PlotLinesHovered,
     ImGuiCol_PlotHistogram,
@@ -1614,39 +1635,39 @@ enum ImGuiCol_
 // - When changing this enum, you need to update the associated internal table GStyleVarInfo[] accordingly. This is where we link enum values to members offset/type.
 enum ImGuiStyleVar_
 {
-    // Enum name -------------------------- // Member in ImGuiStyle structure (see ImGuiStyle for descriptions)
-    ImGuiStyleVar_Alpha,                    // float     Alpha
-    ImGuiStyleVar_DisabledAlpha,            // float     DisabledAlpha
-    ImGuiStyleVar_WindowPadding,            // ImVec2    WindowPadding
-    ImGuiStyleVar_WindowRounding,           // float     WindowRounding
-    ImGuiStyleVar_WindowBorderSize,         // float     WindowBorderSize
-    ImGuiStyleVar_WindowMinSize,            // ImVec2    WindowMinSize
-    ImGuiStyleVar_WindowTitleAlign,         // ImVec2    WindowTitleAlign
-    ImGuiStyleVar_ChildRounding,            // float     ChildRounding
-    ImGuiStyleVar_ChildBorderSize,          // float     ChildBorderSize
-    ImGuiStyleVar_PopupRounding,            // float     PopupRounding
-    ImGuiStyleVar_PopupBorderSize,          // float     PopupBorderSize
-    ImGuiStyleVar_FramePadding,             // ImVec2    FramePadding
-    ImGuiStyleVar_FrameRounding,            // float     FrameRounding
-    ImGuiStyleVar_FrameBorderSize,          // float     FrameBorderSize
-    ImGuiStyleVar_ItemSpacing,              // ImVec2    ItemSpacing
-    ImGuiStyleVar_ItemInnerSpacing,         // ImVec2    ItemInnerSpacing
-    ImGuiStyleVar_IndentSpacing,            // float     IndentSpacing
-    ImGuiStyleVar_CellPadding,              // ImVec2    CellPadding
-    ImGuiStyleVar_ScrollbarSize,            // float     ScrollbarSize
-    ImGuiStyleVar_ScrollbarRounding,        // float     ScrollbarRounding
-    ImGuiStyleVar_GrabMinSize,              // float     GrabMinSize
-    ImGuiStyleVar_GrabRounding,             // float     GrabRounding
-    ImGuiStyleVar_TabRounding,              // float     TabRounding
-    ImGuiStyleVar_TabBorderSize,            // float     TabBorderSize
-    ImGuiStyleVar_TabBarBorderSize,         // float     TabBarBorderSize
-    ImGuiStyleVar_TableAngledHeadersAngle,  // float  TableAngledHeadersAngle
-    ImGuiStyleVar_TableAngledHeadersTextAlign,// ImVec2 TableAngledHeadersTextAlign
-    ImGuiStyleVar_ButtonTextAlign,          // ImVec2    ButtonTextAlign
-    ImGuiStyleVar_SelectableTextAlign,      // ImVec2    SelectableTextAlign
-    ImGuiStyleVar_SeparatorTextBorderSize,  // float  SeparatorTextBorderSize
-    ImGuiStyleVar_SeparatorTextAlign,       // ImVec2    SeparatorTextAlign
-    ImGuiStyleVar_SeparatorTextPadding,     // ImVec2    SeparatorTextPadding
+    // Enum name --------------------- // Member in ImGuiStyle structure (see ImGuiStyle for descriptions)
+    ImGuiStyleVar_Alpha,               // float     Alpha
+    ImGuiStyleVar_DisabledAlpha,       // float     DisabledAlpha
+    ImGuiStyleVar_WindowPadding,       // ImVec2    WindowPadding
+    ImGuiStyleVar_WindowRounding,      // float     WindowRounding
+    ImGuiStyleVar_WindowBorderSize,    // float     WindowBorderSize
+    ImGuiStyleVar_WindowMinSize,       // ImVec2    WindowMinSize
+    ImGuiStyleVar_WindowTitleAlign,    // ImVec2    WindowTitleAlign
+    ImGuiStyleVar_ChildRounding,       // float     ChildRounding
+    ImGuiStyleVar_ChildBorderSize,     // float     ChildBorderSize
+    ImGuiStyleVar_PopupRounding,       // float     PopupRounding
+    ImGuiStyleVar_PopupBorderSize,     // float     PopupBorderSize
+    ImGuiStyleVar_FramePadding,        // ImVec2    FramePadding
+    ImGuiStyleVar_FrameRounding,       // float     FrameRounding
+    ImGuiStyleVar_FrameBorderSize,     // float     FrameBorderSize
+    ImGuiStyleVar_ItemSpacing,         // ImVec2    ItemSpacing
+    ImGuiStyleVar_ItemInnerSpacing,    // ImVec2    ItemInnerSpacing
+    ImGuiStyleVar_IndentSpacing,       // float     IndentSpacing
+    ImGuiStyleVar_CellPadding,         // ImVec2    CellPadding
+    ImGuiStyleVar_ScrollbarSize,       // float     ScrollbarSize
+    ImGuiStyleVar_ScrollbarRounding,   // float     ScrollbarRounding
+    ImGuiStyleVar_GrabMinSize,         // float     GrabMinSize
+    ImGuiStyleVar_GrabRounding,        // float     GrabRounding
+    ImGuiStyleVar_TabRounding,         // float     TabRounding
+    ImGuiStyleVar_TabBorderSize,       // float     TabBorderSize
+    ImGuiStyleVar_TabBarBorderSize,    // float     TabBarBorderSize
+    ImGuiStyleVar_TableAngledHeadersAngle,// float  TableAngledHeadersAngle
+    ImGuiStyleVar_ButtonTextAlign,     // ImVec2    ButtonTextAlign
+    ImGuiStyleVar_SelectableTextAlign, // ImVec2    SelectableTextAlign
+    ImGuiStyleVar_SeparatorTextBorderSize,// float  SeparatorTextBorderSize
+    ImGuiStyleVar_SeparatorTextAlign,  // ImVec2    SeparatorTextAlign
+    ImGuiStyleVar_SeparatorTextPadding,// ImVec2    SeparatorTextPadding
+    ImGuiStyleVar_DockingSeparatorSize,// float     DockingSeparatorSize
     ImGuiStyleVar_COUNT
 };
 
@@ -1657,8 +1678,10 @@ enum ImGuiButtonFlags_
     ImGuiButtonFlags_MouseButtonLeft        = 1 << 0,   // React on left mouse button (default)
     ImGuiButtonFlags_MouseButtonRight       = 1 << 1,   // React on right mouse button
     ImGuiButtonFlags_MouseButtonMiddle      = 1 << 2,   // React on center mouse button
-    ImGuiButtonFlags_MouseButtonMask_       = ImGuiButtonFlags_MouseButtonLeft | ImGuiButtonFlags_MouseButtonRight | ImGuiButtonFlags_MouseButtonMiddle, // [Internal]
-    //ImGuiButtonFlags_MouseButtonDefault_  = ImGuiButtonFlags_MouseButtonLeft,
+
+    // [Internal]
+    ImGuiButtonFlags_MouseButtonMask_       = ImGuiButtonFlags_MouseButtonLeft | ImGuiButtonFlags_MouseButtonRight | ImGuiButtonFlags_MouseButtonMiddle,
+    ImGuiButtonFlags_MouseButtonDefault_    = ImGuiButtonFlags_MouseButtonLeft,
 };
 
 // Flags for ColorEdit3() / ColorEdit4() / ColorPicker3() / ColorPicker4() / ColorButton()
@@ -1931,7 +1954,7 @@ struct ImGuiTableColumnSortSpecs
     ImGuiID                     ColumnUserID;       // User id of the column (if specified by a TableSetupColumn() call)
     ImS16                       ColumnIndex;        // Index of the column
     ImS16                       SortOrder;          // Index within parent ImGuiTableSortSpecs (always stored in order starting from 0, tables sorted on a single criteria will always have a 0 here)
-    ImGuiSortDirection          SortDirection;      // ImGuiSortDirection_Ascending or ImGuiSortDirection_Descending
+    ImGuiSortDirection          SortDirection : 8;  // ImGuiSortDirection_Ascending or ImGuiSortDirection_Descending
 
     ImGuiTableColumnSortSpecs() { memset(this, 0, sizeof(*this)); }
 };
@@ -2073,15 +2096,15 @@ struct ImGuiStyle
     float       TabMinWidthForCloseButton;  // Minimum width for close button to appear on an unselected tab when hovered. Set to 0.0f to always show when hovering, set to FLT_MAX to never show close button unless selected.
     float       TabBarBorderSize;           // Thickness of tab-bar separator, which takes on the tab active color to denote focus.
     float       TableAngledHeadersAngle;    // Angle of angled headers (supported values range from -50.0f degrees to +50.0f degrees).
-    ImVec2      TableAngledHeadersTextAlign;// Alignment of angled headers within the cell
     ImGuiDir    ColorButtonPosition;        // Side of the color button in the ColorEdit4 widget (left/right). Defaults to ImGuiDir_Right.
     ImVec2      ButtonTextAlign;            // Alignment of button text when button is larger than text. Defaults to (0.5f, 0.5f) (centered).
     ImVec2      SelectableTextAlign;        // Alignment of selectable text. Defaults to (0.0f, 0.0f) (top-left aligned). It's generally important to keep this left-aligned if you want to lay multiple items on a same line.
     float       SeparatorTextBorderSize;    // Thickkness of border in SeparatorText()
     ImVec2      SeparatorTextAlign;         // Alignment of text within the separator. Defaults to (0.0f, 0.5f) (left aligned, center).
     ImVec2      SeparatorTextPadding;       // Horizontal offset of text from each edge of the separator + spacing on other axis. Generally small values. .y is recommended to be == FramePadding.y.
-    ImVec2      DisplayWindowPadding;       // Apply to regular windows: amount which we enforce to keep visible when moving near edges of your screen.
-    ImVec2      DisplaySafeAreaPadding;     // Apply to every windows, menus, popups, tooltips: amount where we avoid displaying contents. Adjust if you cannot see the edges of your screen (e.g. on a TV where scaling has not been configured).
+    ImVec2      DisplayWindowPadding;       // Window position are clamped to be visible within the display area or monitors by at least this amount. Only applies to regular windows.
+    ImVec2      DisplaySafeAreaPadding;     // If you cannot see the edges of your screen (e.g. on a TV) increase the safe area padding. Apply to popups/tooltips as well regular windows. NB: Prefer configuring your TV sets correctly!
+    float       DockingSeparatorSize;       // Thickness of resizing border between docked windows
     float       MouseCursorScale;           // Scale software rendered mouse cursor (when io.MouseDrawCursor is enabled). We apply per-monitor DPI scaling over this scale. May be removed later.
     bool        AntiAliasedLines;           // Enable anti-aliased lines/borders. Disable if you are really tight on CPU/GPU. Latched at the beginning of the frame (copied to ImDrawList).
     bool        AntiAliasedLinesUseTex;     // Enable anti-aliased lines/borders using textures where possible. Require backend to render with bilinear filtering (NOT point/nearest filtering). Latched at the beginning of the frame (copied to ImDrawList).
@@ -2143,9 +2166,21 @@ struct ImGuiIO
     ImFont*     FontDefault;                    // = NULL           // Font to use on NewFrame(). Use NULL to uses Fonts->Fonts[0].
     ImVec2      DisplayFramebufferScale;        // = (1, 1)         // For retina display or other situations where window coordinates are different from framebuffer coordinates. This generally ends up in ImDrawData::FramebufferScale.
 
+    // Docking options (when ImGuiConfigFlags_DockingEnable is set)
+    bool        ConfigDockingNoSplit;           // = false          // Simplified docking mode: disable window splitting, so docking is limited to merging multiple windows together into tab-bars.
+    bool        ConfigDockingWithShift;         // = false          // Enable docking with holding Shift key (reduce visual noise, allows dropping in wider space)
+    bool        ConfigDockingAlwaysTabBar;      // = false          // [BETA] [FIXME: This currently creates regression with auto-sizing and general overhead] Make every single floating window display within a docking node.
+    bool        ConfigDockingTransparentPayload;// = false          // [BETA] Make window or viewport transparent when docking and only display docking boxes on the target viewport. Useful if rendering of multiple viewport cannot be synced. Best used with ConfigViewportsNoAutoMerge.
+
+    // Viewport options (when ImGuiConfigFlags_ViewportsEnable is set)
+    bool        ConfigViewportsNoAutoMerge;     // = false;         // Set to make all floating imgui windows always create their own viewport. Otherwise, they are merged into the main host viewports when overlapping it. May also set ImGuiViewportFlags_NoAutoMerge on individual viewport.
+    bool        ConfigViewportsNoTaskBarIcon;   // = false          // Disable default OS task bar icon flag for secondary viewports. When a viewport doesn't want a task bar icon, ImGuiViewportFlags_NoTaskBarIcon will be set on it.
+    bool        ConfigViewportsNoDecoration;    // = true           // Disable default OS window decoration flag for secondary viewports. When a viewport doesn't want window decorations, ImGuiViewportFlags_NoDecoration will be set on it. Enabling decoration can create subsequent issues at OS levels (e.g. minimum window size).
+    bool        ConfigViewportsNoDefaultParent; // = false          // Disable default OS parenting to main viewport for secondary viewports. By default, viewports are marked with ParentViewportId = <main_viewport>, expecting the platform backend to setup a parent/child relationship between the OS windows (some backend may ignore this). Set to true if you want the default to be 0, then all viewports will be top-level OS windows.
+
     // Miscellaneous options
     bool        MouseDrawCursor;                // = false          // Request ImGui to draw a mouse cursor for you (if you are on a platform without a mouse cursor). Cannot be easily renamed to 'io.ConfigXXX' because this is frequently used by backend implementations.
-    bool        ConfigMacOSXBehaviors;          // = defined(__APPLE__) // Swap Cmd<>Ctrl keys + OS X style text editing cursor movement using Alt instead of Ctrl, Shortcuts using Cmd/Super instead of Ctrl, Line/Text Start and End using Cmd+Arrows instead of Home/End, Double click selects by word instead of selecting whole text, Multi-selection in lists uses Cmd/Super instead of Ctrl.
+    bool        ConfigMacOSXBehaviors;          // = defined(__APPLE__) // OS X style: Text editing cursor movement using Alt instead of Ctrl, Shortcuts using Cmd/Super instead of Ctrl, Line/Text Start and End using Cmd+Arrows instead of Home/End, Double click selects by word instead of selecting whole text, Multi-selection in lists uses Cmd/Super instead of Ctrl.
     bool        ConfigInputTrickleEventQueue;   // = true           // Enable input queue trickling: some types of events submitted during the same frame (e.g. button down + up) will be spread over multiple frames, improving interactions with low framerates.
     bool        ConfigInputTextCursorBlink;     // = true           // Enable blinking cursor (optional as some users consider it to be distracting).
     bool        ConfigInputTextEnterKeepActive; // = false          // [BETA] Pressing Enter will keep item active and select contents (single-line only).
@@ -2184,7 +2219,7 @@ struct ImGuiIO
     // - Backends may have other side-effects on focus loss, so this will reduce side-effects but not necessary remove all of them.
     bool        ConfigDebugIgnoreFocusLoss;     // = false          // Ignore io.AddFocusEvent(false), consequently not calling io.ClearInputKeys() in input processing.
 
-    // Options to audit .ini data
+    // Option to audit .ini data
     bool        ConfigDebugIniSettings;         // = false          // Save .ini data with extra comments (particularly helpful for Docking, but makes saving slower)
 
     //------------------------------------------------------------------
@@ -2223,6 +2258,7 @@ struct ImGuiIO
     IMGUI_API void  AddMouseButtonEvent(int button, bool down);             // Queue a mouse button change
     IMGUI_API void  AddMouseWheelEvent(float wheel_x, float wheel_y);       // Queue a mouse wheel update. wheel_y<0: scroll down, wheel_y>0: scroll up, wheel_x<0: scroll right, wheel_x>0: scroll left.
     IMGUI_API void  AddMouseSourceEvent(ImGuiMouseSource source);           // Queue a mouse source change (Mouse/TouchScreen/Pen)
+    IMGUI_API void  AddMouseViewportEvent(ImGuiID id);                      // Queue a mouse hovered viewport. Requires backend to set ImGuiBackendFlags_HasMouseHoveredViewport to call this (for multi-viewport support).
     IMGUI_API void  AddFocusEvent(bool focused);                            // Queue a gain/loss of focus for the application (generally based on OS/platform focus of your window)
     IMGUI_API void  AddInputCharacter(unsigned int c);                      // Queue a new character input
     IMGUI_API void  AddInputCharacterUTF16(ImWchar16 c);                    // Queue a new character input from a UTF-16 character, it can be a surrogate
@@ -2256,6 +2292,16 @@ struct ImGuiIO
     int         MetricsActiveWindows;               // Number of active windows
     ImVec2      MouseDelta;                         // Mouse delta. Note that this is zero if either current or previous position are invalid (-FLT_MAX,-FLT_MAX), so a disappearing/reappearing mouse won't have a huge delta.
 
+    // Legacy: before 1.87, we required backend to fill io.KeyMap[] (imgui->native map) during initialization and io.KeysDown[] (native indices) every frame.
+    // This is still temporarily supported as a legacy feature. However the new preferred scheme is for backend to call io.AddKeyEvent().
+    //   Old (<1.87):  ImGui::IsKeyPressed(ImGui::GetIO().KeyMap[ImGuiKey_Space]) --> New (1.87+) ImGui::IsKeyPressed(ImGuiKey_Space)
+#ifndef IMGUI_DISABLE_OBSOLETE_KEYIO
+    int         KeyMap[ImGuiKey_COUNT];             // [LEGACY] Input: map of indices into the KeysDown[512] entries array which represent your "native" keyboard state. The first 512 are now unused and should be kept zero. Legacy backend will write into KeyMap[] using ImGuiKey_ indices which are always >512.
+    bool        KeysDown[ImGuiKey_COUNT];           // [LEGACY] Input: Keyboard keys that are pressed (ideally left in the "native" order your engine has access to keyboard keys, so you can use your own defines/enums for keys). This used to be [512] sized. It is now ImGuiKey_COUNT to allow legacy io.KeysDown[GetKeyIndex(...)] to work without an overflow.
+    float       NavInputs[ImGuiNavInput_COUNT];     // [LEGACY] Since 1.88, NavInputs[] was removed. Backends from 1.60 to 1.86 won't build. Feed gamepad inputs via io.AddKeyEvent() and ImGuiKey_GamepadXXX enums.
+    //void*     ImeWindowHandle;                    // [Obsoleted in 1.87] Set ImGuiViewport::PlatformHandleRaw instead. Set this to your HWND to get automatic IME cursor positioning.
+#endif
+
     //------------------------------------------------------------------
     // [Internal] Dear ImGui will maintain those fields. Forward compatibility not guaranteed!
     //------------------------------------------------------------------
@@ -2270,13 +2316,14 @@ struct ImGuiIO
     float       MouseWheel;                         // Mouse wheel Vertical: 1 unit scrolls about 5 lines text. >0 scrolls Up, <0 scrolls Down. Hold SHIFT to turn vertical scroll into horizontal scroll.
     float       MouseWheelH;                        // Mouse wheel Horizontal. >0 scrolls Left, <0 scrolls Right. Most users don't have a mouse with a horizontal wheel, may not be filled by all backends.
     ImGuiMouseSource MouseSource;                   // Mouse actual input peripheral (Mouse/TouchScreen/Pen).
+    ImGuiID     MouseHoveredViewport;               // (Optional) Modify using io.AddMouseViewportEvent(). With multi-viewports: viewport the OS mouse is hovering. If possible _IGNORING_ viewports with the ImGuiViewportFlags_NoInputs flag is much better (few backends can handle that). Set io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport if you can provide this info. If you don't imgui will infer the value using the rectangles and last focused time of the viewports it knows about (ignoring other OS windows).
     bool        KeyCtrl;                            // Keyboard modifier down: Control
     bool        KeyShift;                           // Keyboard modifier down: Shift
     bool        KeyAlt;                             // Keyboard modifier down: Alt
     bool        KeySuper;                           // Keyboard modifier down: Cmd/Super/Windows
 
     // Other state maintained from data above + IO function calls
-    ImGuiKeyChord KeyMods;                          // Key mods flags (any of ImGuiMod_Ctrl/ImGuiMod_Shift/ImGuiMod_Alt/ImGuiMod_Super flags, same as io.KeyCtrl/KeyShift/KeyAlt/KeySuper but merged into flags. Read-only, updated by NewFrame()
+    ImGuiKeyChord KeyMods;                          // Key mods flags (any of ImGuiMod_Ctrl/ImGuiMod_Shift/ImGuiMod_Alt/ImGuiMod_Super flags, same as io.KeyCtrl/KeyShift/KeyAlt/KeySuper but merged into flags. DOES NOT CONTAINS ImGuiMod_Shortcut which is pretranslated). Read-only, updated by NewFrame()
     ImGuiKeyData  KeysData[ImGuiKey_KeysData_SIZE]; // Key state for all known keys. Use IsKeyXXX() functions to access this.
     bool        WantCaptureMouseUnlessPopupClose;   // Alternative to WantCaptureMouse: (WantCaptureMouse == true && WantCaptureMouseUnlessPopupClose == false) when a click over void is expected to close a popup.
     ImVec2      MousePosPrev;                       // Previous mouse position (note that MouseDelta is not necessary == MousePos-MousePosPrev, in case either position is invalid)
@@ -2290,9 +2337,9 @@ struct ImGuiIO
     bool        MouseDownOwned[5];                  // Track if button was clicked inside a dear imgui window or over void blocked by a popup. We don't request mouse capture from the application if click started outside ImGui bounds.
     bool        MouseDownOwnedUnlessPopupClose[5];  // Track if button was clicked inside a dear imgui window.
     bool        MouseWheelRequestAxisSwap;          // On a non-Mac system, holding SHIFT requests WheelY to perform the equivalent of a WheelX event. On a Mac system this is already enforced by the system.
-    bool        MouseCtrlLeftAsRightClick;          // (OSX) Set to true when the current click was a ctrl-click that spawned a simulated right click
     float       MouseDownDuration[5];               // Duration the mouse button has been down (0.0f == just clicked)
     float       MouseDownDurationPrev[5];           // Previous time the mouse button has been down
+    ImVec2      MouseDragMaxDistanceAbs[5];         // Maximum distance, absolute, on each axis, of how much mouse has traveled from the clicking point
     float       MouseDragMaxDistanceSqr[5];         // Squared maximum distance of how much mouse has traveled from the clicking point (used for moving thresholds)
     float       PenPressure;                        // Touch/Pen pressure (0.0f to 1.0f, should be >0.0f only when MouseDown[0] == true). Helper storage currently unused by Dear ImGui.
     bool        AppFocusLost;                       // Only modify via AddFocusEvent()
@@ -2302,16 +2349,6 @@ struct ImGuiIO
     ImWchar16   InputQueueSurrogate;                // For AddInputCharacterUTF16()
     ImVector<ImWchar> InputQueueCharacters;         // Queue of _characters_ input (obtained by platform backend). Fill using AddInputCharacter() helper.
 
-    // Legacy: before 1.87, we required backend to fill io.KeyMap[] (imgui->native map) during initialization and io.KeysDown[] (native indices) every frame.
-    // This is still temporarily supported as a legacy feature. However the new preferred scheme is for backend to call io.AddKeyEvent().
-    //   Old (<1.87):  ImGui::IsKeyPressed(ImGui::GetIO().KeyMap[ImGuiKey_Space]) --> New (1.87+) ImGui::IsKeyPressed(ImGuiKey_Space)
-#ifndef IMGUI_DISABLE_OBSOLETE_KEYIO
-    int         KeyMap[ImGuiKey_COUNT];             // [LEGACY] Input: map of indices into the KeysDown[512] entries array which represent your "native" keyboard state. The first 512 are now unused and should be kept zero. Legacy backend will write into KeyMap[] using ImGuiKey_ indices which are always >512.
-    bool        KeysDown[ImGuiKey_COUNT];           // [LEGACY] Input: Keyboard keys that are pressed (ideally left in the "native" order your engine has access to keyboard keys, so you can use your own defines/enums for keys). This used to be [512] sized. It is now ImGuiKey_COUNT to allow legacy io.KeysDown[GetKeyIndex(...)] to work without an overflow.
-    float       NavInputs[ImGuiNavInput_COUNT];     // [LEGACY] Since 1.88, NavInputs[] was removed. Backends from 1.60 to 1.86 won't build. Feed gamepad inputs via io.AddKeyEvent() and ImGuiKey_GamepadXXX enums.
-    //void*     ImeWindowHandle;                    // [Obsoleted in 1.87] Set ImGuiViewport::PlatformHandleRaw instead. Set this to your HWND to get automatic IME cursor positioning.
-#endif
-
     IMGUI_API   ImGuiIO();
 };
 
@@ -2370,6 +2407,28 @@ struct ImGuiSizeCallbackData
     ImVec2  DesiredSize;    // Read-write.  Desired size, based on user's mouse position. Write to this field to restrain resizing.
 };
 
+// [ALPHA] Rarely used / very advanced uses only. Use with SetNextWindowClass() and DockSpace() functions.
+// Important: the content of this class is still highly WIP and likely to change and be refactored
+// before we stabilize Docking features. Please be mindful if using this.
+// Provide hints:
+// - To the platform backend via altered viewport flags (enable/disable OS decoration, OS task bar icons, etc.)
+// - To the platform backend for OS level parent/child relationships of viewport.
+// - To the docking system for various options and filtering.
+struct ImGuiWindowClass
+{
+    ImGuiID             ClassId;                    // User data. 0 = Default class (unclassed). Windows of different classes cannot be docked with each others.
+    ImGuiID             ParentViewportId;           // Hint for the platform backend. -1: use default. 0: request platform backend to not parent the platform. != 0: request platform backend to create a parent<>child relationship between the platform windows. Not conforming backends are free to e.g. parent every viewport to the main viewport or not.
+    ImGuiID             FocusRouteParentWindowId;   // ID of parent window for shortcut focus route evaluation, e.g. Shortcut() call from Parent Window will succeed when this window is focused.
+    ImGuiViewportFlags  ViewportFlagsOverrideSet;   // Viewport flags to set when a window of this class owns a viewport. This allows you to enforce OS decoration or task bar icon, override the defaults on a per-window basis.
+    ImGuiViewportFlags  ViewportFlagsOverrideClear; // Viewport flags to clear when a window of this class owns a viewport. This allows you to enforce OS decoration or task bar icon, override the defaults on a per-window basis.
+    ImGuiTabItemFlags   TabItemFlagsOverrideSet;    // [EXPERIMENTAL] TabItem flags to set when a window of this class gets submitted into a dock node tab bar. May use with ImGuiTabItemFlags_Leading or ImGuiTabItemFlags_Trailing.
+    ImGuiDockNodeFlags  DockNodeFlagsOverrideSet;   // [EXPERIMENTAL] Dock node flags to set when a window of this class is hosted by a dock node (it doesn't have to be selected!)
+    bool                DockingAlwaysTabBar;        // Set to true to enforce single floating windows of this class always having their own docking node (equivalent of setting the global io.ConfigDockingAlwaysTabBar)
+    bool                DockingAllowUnclassed;      // Set to true to allow windows of this class to be docked/merged with an unclassed window. // FIXME-DOCK: Move to DockNodeFlags override?
+
+    ImGuiWindowClass() { memset(this, 0, sizeof(*this)); ParentViewportId = (ImGuiID)-1; DockingAllowUnclassed = true; }
+};
+
 // Data payload for Drag and Drop operations: AcceptDragDropPayload(), GetDragDropPayload()
 struct ImGuiPayload
 {
@@ -2781,15 +2840,15 @@ struct ImDrawList
     // [Internal, used while building lists]
     unsigned int            _VtxCurrentIdx;     // [Internal] generally == VtxBuffer.Size unless we are past 64K vertices, in which case this gets reset to 0.
     ImDrawListSharedData*   _Data;              // Pointer to shared draw data (you can use ImGui::GetDrawListSharedData() to get the one from current ImGui context)
+    const char*             _OwnerName;         // Pointer to owner window's name for debugging
     ImDrawVert*             _VtxWritePtr;       // [Internal] point within VtxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
     ImDrawIdx*              _IdxWritePtr;       // [Internal] point within IdxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
+    ImVector<ImVec4>        _ClipRectStack;     // [Internal]
+    ImVector<ImTextureID>   _TextureIdStack;    // [Internal]
     ImVector<ImVec2>        _Path;              // [Internal] current path building
     ImDrawCmdHeader         _CmdHeader;         // [Internal] template of active commands. Fields should match those of CmdBuffer.back().
     ImDrawListSplitter      _Splitter;          // [Internal] for channels api (note: prefer using your own persistent instance of ImDrawListSplitter!)
-    ImVector<ImVec4>        _ClipRectStack;     // [Internal]
-    ImVector<ImTextureID>   _TextureIdStack;    // [Internal]
     float                   _FringeScale;       // [Internal] anti-alias fringe is scaled by this value, this helps to keep things sharp while zooming at vertex buffer content
-    const char*             _OwnerName;         // Pointer to owner window's name for debugging
 
     // If you want to create ImDrawList instances, pass them ImGui::GetDrawListSharedData() or create and use your own ImDrawListSharedData (so you can use ImDrawList without ImGui)
     ImDrawList(ImDrawListSharedData* shared_data) { memset(this, 0, sizeof(*this)); _Data = shared_data; }
@@ -2913,7 +2972,7 @@ struct ImDrawList
 struct ImDrawData
 {
     bool                Valid;              // Only valid after Render() is called and before the next NewFrame() is called.
-    int                 CmdListsCount;      // Number of ImDrawList* to render (should always be == CmdLists.size)
+    int                 CmdListsCount;      // Number of ImDrawList* to render
     int                 TotalIdxCount;      // For convenience, sum of all ImDrawList's IdxBuffer.Size
     int                 TotalVtxCount;      // For convenience, sum of all ImDrawList's VtxBuffer.Size
     ImVector<ImDrawList*> CmdLists;         // Array of ImDrawList* to render. The ImDrawLists are owned by ImGuiContext and only pointed to from here.
@@ -3079,7 +3138,7 @@ struct ImFontAtlas
 
     // You can request arbitrary rectangles to be packed into the atlas, for your own purposes.
     // - After calling Build(), you can query the rectangle position and render your pixels.
-    // - If you render colored output, set 'atlas->TexPixelsUseColors = true' as this may help some backends decide of preferred texture format.
+    // - If you render colored output, set 'atlas->TexPixelsUseColors = true' as this may help some backends decide of prefered texture format.
     // - You can also request your rectangles to be mapped as font glyph (given a font + Unicode point),
     //   so you can render e.g. custom colorful icons and use them as regular glyphs.
     // - Read docs/FONTS.md for more details about using colorful icons.
@@ -3196,11 +3255,24 @@ enum ImGuiViewportFlags_
     ImGuiViewportFlags_None                     = 0,
     ImGuiViewportFlags_IsPlatformWindow         = 1 << 0,   // Represent a Platform Window
     ImGuiViewportFlags_IsPlatformMonitor        = 1 << 1,   // Represent a Platform Monitor (unused yet)
-    ImGuiViewportFlags_OwnedByApp               = 1 << 2,   // Platform Window: is created/managed by the application (rather than a dear imgui backend)
+    ImGuiViewportFlags_OwnedByApp               = 1 << 2,   // Platform Window: Was created/managed by the user application? (rather than our backend)
+    ImGuiViewportFlags_NoDecoration             = 1 << 3,   // Platform Window: Disable platform decorations: title bar, borders, etc. (generally set all windows, but if ImGuiConfigFlags_ViewportsDecoration is set we only set this on popups/tooltips)
+    ImGuiViewportFlags_NoTaskBarIcon            = 1 << 4,   // Platform Window: Disable platform task bar icon (generally set on popups/tooltips, or all windows if ImGuiConfigFlags_ViewportsNoTaskBarIcon is set)
+    ImGuiViewportFlags_NoFocusOnAppearing       = 1 << 5,   // Platform Window: Don't take focus when created.
+    ImGuiViewportFlags_NoFocusOnClick           = 1 << 6,   // Platform Window: Don't take focus when clicked on.
+    ImGuiViewportFlags_NoInputs                 = 1 << 7,   // Platform Window: Make mouse pass through so we can drag this window while peaking behind it.
+    ImGuiViewportFlags_NoRendererClear          = 1 << 8,   // Platform Window: Renderer doesn't need to clear the framebuffer ahead (because we will fill it entirely).
+    ImGuiViewportFlags_NoAutoMerge              = 1 << 9,   // Platform Window: Avoid merging this window into another host window. This can only be set via ImGuiWindowClass viewport flags override (because we need to now ahead if we are going to create a viewport in the first place!).
+    ImGuiViewportFlags_TopMost                  = 1 << 10,  // Platform Window: Display on top (for tooltips only).
+    ImGuiViewportFlags_CanHostOtherWindows      = 1 << 11,  // Viewport can host multiple imgui windows (secondary viewports are associated to a single window). // FIXME: In practice there's still probably code making the assumption that this is always and only on the MainViewport. Will fix once we add support for "no main viewport".
+
+    // Output status flags (from Platform)
+    ImGuiViewportFlags_IsMinimized              = 1 << 12,  // Platform Window: Window is minimized, can skip render. When minimized we tend to avoid using the viewport pos/size for clipping window or testing if they are contained in the viewport.
+    ImGuiViewportFlags_IsFocused                = 1 << 13,  // Platform Window: Window is focused (last call to Platform_GetWindowFocus() returned true)
 };
 
 // - Currently represents the Platform Window created by the application which is hosting our Dear ImGui windows.
-// - In 'docking' branch with multi-viewport enabled, we extend this concept to have multiple active viewports.
+// - With multi-viewport enabled, we extend this concept to have multiple active viewports.
 // - In the future we will extend this concept further to also represent Platform Monitor and support a "no main platform window" operation mode.
 // - About Main Area vs Work Area:
 //   - Main Area = entire viewport.
@@ -3214,11 +3286,26 @@ struct ImGuiViewport
     ImVec2              Size;                   // Main Area: Size of the viewport.
     ImVec2              WorkPos;                // Work Area: Position of the viewport minus task bars, menus bars, status bars (>= Pos)
     ImVec2              WorkSize;               // Work Area: Size of the viewport minus task bars, menu bars, status bars (<= Size)
+    float               DpiScale;               // 1.0f = 96 DPI = No extra scale.
+    ImGuiID             ParentViewportId;       // (Advanced) 0: no parent. Instruct the platform backend to setup a parent/child relationship between platform windows.
+    ImDrawData*         DrawData;               // The ImDrawData corresponding to this viewport. Valid after Render() and until the next call to NewFrame().
 
     // Platform/Backend Dependent Data
-    void*               PlatformHandleRaw;      // void* to hold lower-level, platform-native window handle (under Win32 this is expected to be a HWND, unused for other platforms)
+    // Our design separate the Renderer and Platform backends to facilitate combining default backends with each others.
+    // When our create your own backend for a custom engine, it is possible that both Renderer and Platform will be handled
+    // by the same system and you may not need to use all the UserData/Handle fields.
+    // The library never uses those fields, they are merely storage to facilitate backend implementation.
+    void*               RendererUserData;       // void* to hold custom data structure for the renderer (e.g. swap chain, framebuffers etc.). generally set by your Renderer_CreateWindow function.
+    void*               PlatformUserData;       // void* to hold custom data structure for the OS / platform (e.g. windowing info, render context). generally set by your Platform_CreateWindow function.
+    void*               PlatformHandle;         // void* for FindViewportByPlatformHandle(). (e.g. suggested to use natural platform handle such as HWND, GLFWWindow*, SDL_Window*)
+    void*               PlatformHandleRaw;      // void* to hold lower-level, platform-native window handle (under Win32 this is expected to be a HWND, unused for other platforms), when using an abstraction layer like GLFW or SDL (where PlatformHandle would be a SDL_Window*)
+    bool                PlatformWindowCreated;  // Platform window has been created (Platform_CreateWindow() has been called). This is false during the first frame where a viewport is being created.
+    bool                PlatformRequestMove;    // Platform window requested move (e.g. window was moved by the OS / host window manager, authoritative position will be OS window position)
+    bool                PlatformRequestResize;  // Platform window requested resize (e.g. window was resized by the OS / host window manager, authoritative size will be OS window size)
+    bool                PlatformRequestClose;   // Platform window requested closure (e.g. window was moved by the OS / host window manager, e.g. pressing ALT-F4)
 
     ImGuiViewport()     { memset(this, 0, sizeof(*this)); }
+    ~ImGuiViewport()    { IM_ASSERT(PlatformUserData == NULL && RendererUserData == NULL); }
 
     // Helpers
     ImVec2              GetCenter() const       { return ImVec2(Pos.x + Size.x * 0.5f, Pos.y + Size.y * 0.5f); }
@@ -3226,8 +3313,126 @@ struct ImGuiViewport
 };
 
 //-----------------------------------------------------------------------------
-// [SECTION] Platform Dependent Interfaces
+// [SECTION] Platform Dependent Interfaces (for e.g. multi-viewport support)
 //-----------------------------------------------------------------------------
+// [BETA] (Optional) This is completely optional, for advanced users!
+// If you are new to Dear ImGui and trying to integrate it into your engine, you can probably ignore this for now.
+//
+// This feature allows you to seamlessly drag Dear ImGui windows outside of your application viewport.
+// This is achieved by creating new Platform/OS windows on the fly, and rendering into them.
+// Dear ImGui manages the viewport structures, and the backend create and maintain one Platform/OS window for each of those viewports.
+//
+// See Glossary https://github.com/ocornut/imgui/wiki/Glossary for details about some of the terminology.
+// See Thread https://github.com/ocornut/imgui/issues/1542 for gifs, news and questions about this evolving feature.
+//
+// About the coordinates system:
+// - When multi-viewports are enabled, all Dear ImGui coordinates become absolute coordinates (same as OS coordinates!)
+// - So e.g. ImGui::SetNextWindowPos(ImVec2(0,0)) will position a window relative to your primary monitor!
+// - If you want to position windows relative to your main application viewport, use ImGui::GetMainViewport()->Pos as a base position.
+//
+// Steps to use multi-viewports in your application, when using a default backend from the examples/ folder:
+// - Application:  Enable feature with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// - Backend:      The backend initialization will setup all necessary ImGuiPlatformIO's functions and update monitors info every frame.
+// - Application:  In your main loop, call ImGui::UpdatePlatformWindows(), ImGui::RenderPlatformWindowsDefault() after EndFrame() or Render().
+// - Application:  Fix absolute coordinates used in ImGui::SetWindowPos() or ImGui::SetNextWindowPos() calls.
+//
+// Steps to use multi-viewports in your application, when using a custom backend:
+// - Important:    THIS IS NOT EASY TO DO and comes with many subtleties not described here!
+//                 It's also an experimental feature, so some of the requirements may evolve.
+//                 Consider using default backends if you can. Either way, carefully follow and refer to examples/ backends for details.
+// - Application:  Enable feature with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+// - Backend:      Hook ImGuiPlatformIO's Platform_* and Renderer_* callbacks (see below).
+//                 Set 'io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports' and 'io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports'.
+//                 Update ImGuiPlatformIO's Monitors list every frame.
+//                 Update MousePos every frame, in absolute coordinates.
+// - Application:  In your main loop, call ImGui::UpdatePlatformWindows(), ImGui::RenderPlatformWindowsDefault() after EndFrame() or Render().
+//                 You may skip calling RenderPlatformWindowsDefault() if its API is not convenient for your needs. Read comments below.
+// - Application:  Fix absolute coordinates used in ImGui::SetWindowPos() or ImGui::SetNextWindowPos() calls.
+//
+// About ImGui::RenderPlatformWindowsDefault():
+// - This function is a mostly a _helper_ for the common-most cases, and to facilitate using default backends.
+// - You can check its simple source code to understand what it does.
+//   It basically iterates secondary viewports and call 4 functions that are setup in ImGuiPlatformIO, if available:
+//     Platform_RenderWindow(), Renderer_RenderWindow(), Platform_SwapBuffers(), Renderer_SwapBuffers()
+//   Those functions pointers exists only for the benefit of RenderPlatformWindowsDefault().
+// - If you have very specific rendering needs (e.g. flipping multiple swap-chain simultaneously, unusual sync/threading issues, etc.),
+//   you may be tempted to ignore RenderPlatformWindowsDefault() and write customized code to perform your renderingg.
+//   You may decide to setup the platform_io's *RenderWindow and *SwapBuffers pointers and call your functions through those pointers,
+//   or you may decide to never setup those pointers and call your code directly. They are a convenience, not an obligatory interface.
+//-----------------------------------------------------------------------------
+
+// (Optional) Access via ImGui::GetPlatformIO()
+struct ImGuiPlatformIO
+{
+    //------------------------------------------------------------------
+    // Input - Backend interface/functions + Monitor List
+    //------------------------------------------------------------------
+
+    // (Optional) Platform functions (e.g. Win32, GLFW, SDL2)
+    // For reference, the second column shows which function are generally calling the Platform Functions:
+    //   N = ImGui::NewFrame()                        ~ beginning of the dear imgui frame: read info from platform/OS windows (latest size/position)
+    //   F = ImGui::Begin(), ImGui::EndFrame()        ~ during the dear imgui frame
+    //   U = ImGui::UpdatePlatformWindows()           ~ after the dear imgui frame: create and update all platform/OS windows
+    //   R = ImGui::RenderPlatformWindowsDefault()    ~ render
+    //   D = ImGui::DestroyPlatformWindows()          ~ shutdown
+    // The general idea is that NewFrame() we will read the current Platform/OS state, and UpdatePlatformWindows() will write to it.
+    //
+    // The functions are designed so we can mix and match 2 imgui_impl_xxxx files, one for the Platform (~window/input handling), one for Renderer.
+    // Custom engine backends will often provide both Platform and Renderer interfaces and so may not need to use all functions.
+    // Platform functions are typically called before their Renderer counterpart, apart from Destroy which are called the other way.
+
+    // Platform function --------------------------------------------------- Called by -----
+    void    (*Platform_CreateWindow)(ImGuiViewport* vp);                    // . . U . .  // Create a new platform window for the given viewport
+    void    (*Platform_DestroyWindow)(ImGuiViewport* vp);                   // N . U . D  //
+    void    (*Platform_ShowWindow)(ImGuiViewport* vp);                      // . . U . .  // Newly created windows are initially hidden so SetWindowPos/Size/Title can be called on them before showing the window
+    void    (*Platform_SetWindowPos)(ImGuiViewport* vp, ImVec2 pos);        // . . U . .  // Set platform window position (given the upper-left corner of client area)
+    ImVec2  (*Platform_GetWindowPos)(ImGuiViewport* vp);                    // N . . . .  //
+    void    (*Platform_SetWindowSize)(ImGuiViewport* vp, ImVec2 size);      // . . U . .  // Set platform window client area size (ignoring OS decorations such as OS title bar etc.)
+    ImVec2  (*Platform_GetWindowSize)(ImGuiViewport* vp);                   // N . . . .  // Get platform window client area size
+    void    (*Platform_SetWindowFocus)(ImGuiViewport* vp);                  // N . . . .  // Move window to front and set input focus
+    bool    (*Platform_GetWindowFocus)(ImGuiViewport* vp);                  // . . U . .  //
+    bool    (*Platform_GetWindowMinimized)(ImGuiViewport* vp);              // N . . . .  // Get platform window minimized state. When minimized, we generally won't attempt to get/set size and contents will be culled more easily
+    void    (*Platform_SetWindowTitle)(ImGuiViewport* vp, const char* str); // . . U . .  // Set platform window title (given an UTF-8 string)
+    void    (*Platform_SetWindowAlpha)(ImGuiViewport* vp, float alpha);     // . . U . .  // (Optional) Setup global transparency (not per-pixel transparency)
+    void    (*Platform_UpdateWindow)(ImGuiViewport* vp);                    // . . U . .  // (Optional) Called by UpdatePlatformWindows(). Optional hook to allow the platform backend from doing general book-keeping every frame.
+    void    (*Platform_RenderWindow)(ImGuiViewport* vp, void* render_arg);  // . . . R .  // (Optional) Main rendering (platform side! This is often unused, or just setting a "current" context for OpenGL bindings). 'render_arg' is the value passed to RenderPlatformWindowsDefault().
+    void    (*Platform_SwapBuffers)(ImGuiViewport* vp, void* render_arg);   // . . . R .  // (Optional) Call Present/SwapBuffers (platform side! This is often unused!). 'render_arg' is the value passed to RenderPlatformWindowsDefault().
+    float   (*Platform_GetWindowDpiScale)(ImGuiViewport* vp);               // N . . . .  // (Optional) [BETA] FIXME-DPI: DPI handling: Return DPI scale for this viewport. 1.0f = 96 DPI.
+    void    (*Platform_OnChangedViewport)(ImGuiViewport* vp);               // . F . . .  // (Optional) [BETA] FIXME-DPI: DPI handling: Called during Begin() every time the viewport we are outputting into changes, so backend has a chance to swap fonts to adjust style.
+    int     (*Platform_CreateVkSurface)(ImGuiViewport* vp, ImU64 vk_inst, const void* vk_allocators, ImU64* out_vk_surface); // (Optional) For a Vulkan Renderer to call into Platform code (since the surface creation needs to tie them both).
+
+    // (Optional) Renderer functions (e.g. DirectX, OpenGL, Vulkan)
+    void    (*Renderer_CreateWindow)(ImGuiViewport* vp);                    // . . U . .  // Create swap chain, frame buffers etc. (called after Platform_CreateWindow)
+    void    (*Renderer_DestroyWindow)(ImGuiViewport* vp);                   // N . U . D  // Destroy swap chain, frame buffers etc. (called before Platform_DestroyWindow)
+    void    (*Renderer_SetWindowSize)(ImGuiViewport* vp, ImVec2 size);      // . . U . .  // Resize swap chain, frame buffers etc. (called after Platform_SetWindowSize)
+    void    (*Renderer_RenderWindow)(ImGuiViewport* vp, void* render_arg);  // . . . R .  // (Optional) Clear framebuffer, setup render target, then render the viewport->DrawData. 'render_arg' is the value passed to RenderPlatformWindowsDefault().
+    void    (*Renderer_SwapBuffers)(ImGuiViewport* vp, void* render_arg);   // . . . R .  // (Optional) Call Present/SwapBuffers. 'render_arg' is the value passed to RenderPlatformWindowsDefault().
+
+    // (Optional) Monitor list
+    // - Updated by: app/backend. Update every frame to dynamically support changing monitor or DPI configuration.
+    // - Used by: dear imgui to query DPI info, clamp popups/tooltips within same monitor and not have them straddle monitors.
+    ImVector<ImGuiPlatformMonitor>  Monitors;
+
+    //------------------------------------------------------------------
+    // Output - List of viewports to render into platform windows
+    //------------------------------------------------------------------
+
+    // Viewports list (the list is updated by calling ImGui::EndFrame or ImGui::Render)
+    // (in the future we will attempt to organize this feature to remove the need for a "main viewport")
+    ImVector<ImGuiViewport*>        Viewports;                              // Main viewports, followed by all secondary viewports.
+    ImGuiPlatformIO()               { memset(this, 0, sizeof(*this)); }     // Zero clear
+};
+
+// (Optional) This is required when enabling multi-viewport. Represent the bounds of each connected monitor/display and their DPI.
+// We use this information for multiple DPI support + clamping the position of popups and tooltips so they don't straddle multiple monitors.
+struct ImGuiPlatformMonitor
+{
+    ImVec2  MainPos, MainSize;      // Coordinates of the area displayed on this monitor (Min = upper left, Max = bottom right)
+    ImVec2  WorkPos, WorkSize;      // Coordinates without task bars / side bars / menu bars. Used to avoid positioning popups/tooltips inside this region. If you don't have this info, please copy the value for MainPos/MainSize.
+    float   DpiScale;               // 1.0f = 96 DPI
+    void*   PlatformHandle;         // Backend dependant data (e.g. HMONITOR, GLFWmonitor*, SDL Display Index, NSScreen*)
+    ImGuiPlatformMonitor()          { MainPos = MainSize = WorkPos = WorkSize = ImVec2(0, 0); DpiScale = 1.0f; PlatformHandle = NULL; }
+};
 
 // (Optional) Support for IME (Input Method Editor) via the io.SetPlatformImeDataFn() function.
 struct ImGuiPlatformImeData
@@ -3263,14 +3468,14 @@ namespace ImGui
     static inline void  PopAllowKeyboardFocus()                                             { PopTabStop(); }
     // OBSOLETED in 1.89 (from August 2022)
     IMGUI_API bool      ImageButton(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0 = ImVec2(0, 0), const ImVec2& uv1 = ImVec2(1, 1), int frame_padding = -1, const ImVec4& bg_col = ImVec4(0, 0, 0, 0), const ImVec4& tint_col = ImVec4(1, 1, 1, 1)); // Use new ImageButton() signature (explicit item id, regular FramePadding)
-    // OBSOLETED in 1.87 (from February 2022 but more formally obsoleted April 2024)
+    // OBSOLETED in 1.88 (from May 2022)
+    static inline void  CaptureKeyboardFromApp(bool want_capture_keyboard = true)           { SetNextFrameWantCaptureKeyboard(want_capture_keyboard); } // Renamed as name was misleading + removed default value.
+    static inline void  CaptureMouseFromApp(bool want_capture_mouse = true)                 { SetNextFrameWantCaptureMouse(want_capture_mouse); }       // Renamed as name was misleading + removed default value.
+    // OBSOLETED in 1.87 (from February 2022)
     IMGUI_API ImGuiKey  GetKeyIndex(ImGuiKey key);                                          // Map ImGuiKey_* values into legacy native key index. == io.KeyMap[key]. When using a 1.87+ backend using io.AddKeyEvent(), calling GetKeyIndex() with ANY ImGuiKey_XXXX values will return the same value!
     //static inline ImGuiKey GetKeyIndex(ImGuiKey key)                                      { IM_ASSERT(key >= ImGuiKey_NamedKey_BEGIN && key < ImGuiKey_NamedKey_END); return key; }
 
     // Some of the older obsolete names along with their replacement (commented out so they are not reported in IDE)
-    //-- OBSOLETED in 1.88 (from May 2022)
-    //static inline void  CaptureKeyboardFromApp(bool want_capture_keyboard = true)         { SetNextFrameWantCaptureKeyboard(want_capture_keyboard); } // Renamed as name was misleading + removed default value.
-    //static inline void  CaptureMouseFromApp(bool want_capture_mouse = true)               { SetNextFrameWantCaptureMouse(want_capture_mouse); }       // Renamed as name was misleading + removed default value.
     //-- OBSOLETED in 1.86 (from November 2021)
     //IMGUI_API void      CalcListClipping(int items_count, float items_height, int* out_items_display_start, int* out_items_display_end); // Code removed, see 1.90 for last version of the code. Calculate range of visible items for large list of evenly sized items. Prefer using ImGuiListClipper.
     //-- OBSOLETED in 1.85 (from August 2021)

imgui_draw.cpp

@@ -1,4 +1,4 @@
-// dear imgui, v1.90.8
+// dear imgui, v1.90.5
 // (drawing and font code)
 
 /*
@@ -65,7 +65,6 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wdouble-promotion"               // warning: implicit conversion from 'float' to 'double' when passing argument to function  // using printf() is a misery with this as C++ va_arg ellipsis changes float to double.
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #pragma clang diagnostic ignored "-Wreserved-identifier"            // warning: identifier '_Xxx' is reserved because it starts with '_' followed by a capital letter
-#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                  // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wunused-function"          // warning: 'xxxx' defined but not used
@@ -216,6 +215,8 @@ void ImGui::StyleColorsDark(ImGuiStyle* dst)
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
+    colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_HeaderActive] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(0.61f, 0.61f, 0.61f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(1.00f, 0.43f, 0.35f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
@@ -276,6 +277,8 @@ void ImGui::StyleColorsClassic(ImGuiStyle* dst)
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
+    colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(1.00f, 1.00f, 1.00f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
@@ -337,6 +340,8 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
+    colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(0.39f, 0.39f, 0.39f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(1.00f, 0.43f, 0.35f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
@@ -385,7 +390,6 @@ void ImDrawListSharedData::SetCircleTessellationMaxError(float max_error)
 }
 
 // Initialize before use in a new frame. We always have a command ready in the buffer.
-// In the majority of cases, you would want to call PushClipRect() and PushTextureID() after this.
 void ImDrawList::_ResetForNewFrame()
 {
     // Verify that the ImDrawCmd fields we want to memcmp() are contiguous in memory.
@@ -2985,8 +2989,8 @@ static bool ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
         int unscaled_ascent, unscaled_descent, unscaled_line_gap;
         stbtt_GetFontVMetrics(&src_tmp.FontInfo, &unscaled_ascent, &unscaled_descent, &unscaled_line_gap);
 
-        const float ascent = ImCeil(unscaled_ascent * font_scale);
-        const float descent = ImFloor(unscaled_descent * font_scale);
+        const float ascent = ImTrunc(unscaled_ascent * font_scale + ((unscaled_ascent > 0.0f) ? +1 : -1));
+        const float descent = ImTrunc(unscaled_descent * font_scale + ((unscaled_descent > 0.0f) ? +1 : -1));
         ImFontAtlasBuildSetupFont(atlas, dst_font, &cfg, ascent, descent);
         const float font_off_x = cfg.GlyphOffset.x;
         const float font_off_y = cfg.GlyphOffset.y + IM_ROUND(dst_font->Ascent);
@@ -4081,8 +4085,6 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, Im
             {
                 x = start_x;
                 y += line_height;
-                if (y > clip_rect.w)
-                    break; // break out of main loop
                 word_wrap_eol = NULL;
                 s = CalcWordWrapNextLineStartA(s, text_end); // Wrapping skips upcoming blanks
                 continue;
@@ -4196,6 +4198,7 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, Im
 // - RenderArrow()
 // - RenderBullet()
 // - RenderCheckMark()
+// - RenderArrowDockMenu()
 // - RenderArrowPointingAt()
 // - RenderRectFilledRangeH()
 // - RenderRectFilledWithHole()
@@ -4270,6 +4273,14 @@ void ImGui::RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half
     }
 }
 
+// This is less wide than RenderArrow() and we use in dock nodes instead of the regular RenderArrow() to denote a change of functionality,
+// and because the saved space means that the left-most tab label can stay at exactly the same position as the label of a loose window.
+void ImGui::RenderArrowDockMenu(ImDrawList* draw_list, ImVec2 p_min, float sz, ImU32 col)
+{
+    draw_list->AddRectFilled(p_min + ImVec2(sz * 0.20f, sz * 0.15f), p_min + ImVec2(sz * 0.80f, sz * 0.30f), col);
+    RenderArrowPointingAt(draw_list, p_min + ImVec2(sz * 0.50f, sz * 0.85f), ImVec2(sz * 0.30f, sz * 0.40f), ImGuiDir_Down, col);
+}
+
 static inline float ImAcos01(float x)
 {
     if (x <= 0.0f) return IM_PI * 0.5f;
@@ -4355,6 +4366,17 @@ void ImGui::RenderRectFilledWithHole(ImDrawList* draw_list, const ImRect& outer,
     if (fill_R && fill_D) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, ImDrawFlags_RoundCornersBottomRight);
 }
 
+ImDrawFlags ImGui::CalcRoundingFlagsForRectInRect(const ImRect& r_in, const ImRect& r_outer, float threshold)
+{
+    bool round_l = r_in.Min.x <= r_outer.Min.x + threshold;
+    bool round_r = r_in.Max.x >= r_outer.Max.x - threshold;
+    bool round_t = r_in.Min.y <= r_outer.Min.y + threshold;
+    bool round_b = r_in.Max.y >= r_outer.Max.y - threshold;
+    return ImDrawFlags_RoundCornersNone
+        | ((round_t && round_l) ? ImDrawFlags_RoundCornersTopLeft : 0) | ((round_t && round_r) ? ImDrawFlags_RoundCornersTopRight : 0)
+        | ((round_b && round_l) ? ImDrawFlags_RoundCornersBottomLeft : 0) | ((round_b && round_r) ? ImDrawFlags_RoundCornersBottomRight : 0);
+}
+
 // Helper for ColorPicker4()
 // NB: This is rather brittle and will show artifact when rounding this enabled if rounded corners overlap multiple cells. Caller currently responsible for avoiding that.
 // Spent a non reasonable amount of time trying to getting this right for ColorButton with rounding+anti-aliasing+ImGuiColorEditFlags_HalfAlphaPreview flag + various grid sizes and offsets, and eventually gave up... probably more reasonable to disable rounding altogether.

imgui_tables.cpp

@@ -1,4 +1,4 @@
-// dear imgui, v1.90.8
+// dear imgui, v1.90.5
 // (tables and columns code)
 
 /*
@@ -228,7 +228,6 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wenum-enum-conversion"           // warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_')
 #pragma clang diagnostic ignored "-Wdeprecated-enum-enum-conversion"// warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_') is deprecated
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
-#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"                // warning: format not a string literal, format string not checked
@@ -320,12 +319,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
         IM_ASSERT(inner_width >= 0.0f);
 
     // If an outer size is specified ahead we will be able to early out when not visible. Exact clipping criteria may evolve.
-    // FIXME: coarse clipping because access to table data causes two issues:
-    // - instance numbers varying/unstable. may not be a direct problem for users, but could make outside access broken or confusing, e.g. TestEngine.
-    // - can't implement support for ImGuiChildFlags_ResizeY as we need to somehow pull the height data from somewhere. this also needs stable instance numbers.
-    // The side-effects of accessing table data on coarse clip would be:
-    // - always reserving the pooled ImGuiTable data ahead for a fully clipped table (minor IMHO). Also the 'outer_window_is_measuring_size' criteria may already be defeating this in some situations.
-    // - always performing the GetOrAddByKey() O(log N) query in g.Tables.Map[].
     const bool use_child_window = (flags & (ImGuiTableFlags_ScrollX | ImGuiTableFlags_ScrollY)) != 0;
     const ImVec2 avail_size = GetContentRegionAvail();
     const ImVec2 actual_outer_size = CalcItemSize(outer_size, ImMax(avail_size.x, 1.0f), use_child_window ? ImMax(avail_size.y, 1.0f) : 0.0f);
@@ -334,7 +327,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     if (use_child_window && IsClippedEx(outer_rect, 0) && !outer_window_is_measuring_size)
     {
         ItemSize(outer_rect);
-        ItemAdd(outer_rect, id);
         return false;
     }
 
@@ -344,6 +336,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
 
     // Acquire storage for the table
     ImGuiTable* table = g.Tables.GetOrAddByKey(id);
+    const ImGuiTableFlags table_last_flags = table->Flags;
 
     // Acquire temporary buffers
     const int table_idx = g.Tables.GetIndex(table);
@@ -361,7 +354,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     // Initialize
     const int previous_frame_active = table->LastFrameActive;
     const int instance_no = (previous_frame_active != g.FrameCount) ? 0 : table->InstanceCurrent + 1;
-    const ImGuiTableFlags previous_flags = table->Flags;
     table->ID = id;
     table->Flags = flags;
     table->LastFrameActive = g.FrameCount;
@@ -408,7 +400,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
             SetNextWindowContentSize(ImVec2(override_content_size.x != FLT_MAX ? override_content_size.x : 0.0f, override_content_size.y != FLT_MAX ? override_content_size.y : 0.0f));
 
         // Reset scroll if we are reactivating it
-        if ((previous_flags & (ImGuiTableFlags_ScrollX | ImGuiTableFlags_ScrollY)) == 0)
+        if ((table_last_flags & (ImGuiTableFlags_ScrollX | ImGuiTableFlags_ScrollY)) == 0)
             SetNextWindowScroll(ImVec2(0.0f, 0.0f));
 
         // Create scrolling region (without border and zero window padding)
@@ -437,7 +429,6 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
         // For non-scrolling tables, WorkRect == OuterRect == InnerRect.
         // But at this point we do NOT have a correct value for .Max.y (unless a height has been explicitly passed in). It will only be updated in EndTable().
         table->WorkRect = table->OuterRect = table->InnerRect = outer_rect;
-        table->HasScrollbarYPrev = table->HasScrollbarYCurr = false;
     }
 
     // Push a standardized ID for both child-using and not-child-using tables
@@ -522,7 +513,7 @@ bool    ImGui::BeginTableEx(const char* name, ImGuiID id, int columns_count, ImG
     if (inner_window != outer_window) // So EndChild() within the inner window can restore the table properly.
         inner_window->DC.CurrentTableIdx = table_idx;
 
-    if ((previous_flags & ImGuiTableFlags_Reorderable) && (flags & ImGuiTableFlags_Reorderable) == 0)
+    if ((table_last_flags & ImGuiTableFlags_Reorderable) && (flags & ImGuiTableFlags_Reorderable) == 0)
         table->IsResetDisplayOrderRequest = true;
 
     // Mark as used to avoid GC
@@ -1264,7 +1255,7 @@ void ImGui::TableUpdateBorders(ImGuiTable* table)
     // really problematic (whereas the actual visual will be displayed in EndTable() and using the current frame height).
     // Actual columns highlight/render will be performed in EndTable() and not be affected.
     ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
-    const float hit_half_width = ImTrunc(TABLE_RESIZE_SEPARATOR_HALF_THICKNESS * g.CurrentDpiScale);
+    const float hit_half_width = TABLE_RESIZE_SEPARATOR_HALF_THICKNESS;
     const float hit_y1 = (table->FreezeRowsCount >= 1 ? table->OuterRect.Min.y : table->WorkRect.Min.y) + table->AngledHeadersHeight;
     const float hit_y2_body = ImMax(table->OuterRect.Max.y, hit_y1 + table_instance->LastOuterHeight - table->AngledHeadersHeight);
     const float hit_y2_head = hit_y1 + table_instance->LastTopHeadersRowHeight;
@@ -1441,7 +1432,7 @@ void    ImGui::EndTable()
     if (table->ResizedColumn != -1 && table->InstanceCurrent == table->InstanceInteracted)
     {
         ImGuiTableColumn* column = &table->Columns[table->ResizedColumn];
-        const float new_x2 = (g.IO.MousePos.x - g.ActiveIdClickOffset.x + ImTrunc(TABLE_RESIZE_SEPARATOR_HALF_THICKNESS * g.CurrentDpiScale));
+        const float new_x2 = (g.IO.MousePos.x - g.ActiveIdClickOffset.x + TABLE_RESIZE_SEPARATOR_HALF_THICKNESS);
         const float new_width = ImTrunc(new_x2 - column->MinX - table->CellSpacingX1 - table->CellPaddingX * 2.0f);
         table->ResizedColumnNextWidth = new_width;
     }
@@ -1470,10 +1461,7 @@ void    ImGui::EndTable()
     // CursorPosPrevLine and CursorMaxPos manually. That should be a more general layout feature, see same problem e.g. #3414)
     if (inner_window != outer_window)
     {
-        short backup_nav_layers_active_mask = inner_window->DC.NavLayersActiveMask;
-        inner_window->DC.NavLayersActiveMask |= 1 << ImGuiNavLayer_Main; // So empty table don't appear to navigate differently.
         EndChild();
-        inner_window->DC.NavLayersActiveMask = backup_nav_layers_active_mask;
     }
     else
     {
@@ -1491,13 +1479,9 @@ void    ImGui::EndTable()
     }
     else if (temp_data->UserOuterSize.x <= 0.0f)
     {
-        // Some references for this: #7651 + tests "table_reported_size", "table_reported_size_outer" equivalent Y block
-        // - Checking for ImGuiTableFlags_ScrollX/ScrollY flag makes us a frame ahead when disabling those flags.
-        // - FIXME-TABLE: Would make sense to pre-compute expected scrollbar visibility/sizes to generally save a frame of feedback.
-        const float inner_content_max_x = table->OuterRect.Min.x + table->ColumnsAutoFitWidth; // Slightly misleading name but used for code symmetry with inner_content_max_y
-        const float decoration_size = table->TempData->AngledHeadersExtraWidth + ((table->Flags & ImGuiTableFlags_ScrollY) ? inner_window->ScrollbarSizes.x : 0.0f);
-        outer_window->DC.IdealMaxPos.x = ImMax(outer_window->DC.IdealMaxPos.x, inner_content_max_x + decoration_size - temp_data->UserOuterSize.x);
-        outer_window->DC.CursorMaxPos.x = ImMax(backup_outer_max_pos.x, ImMin(table->OuterRect.Max.x, inner_content_max_x + decoration_size));
+        const float decoration_size = table->TempData->AngledHeadersExtraWidth + ((table->Flags & ImGuiTableFlags_ScrollX) ? inner_window->ScrollbarSizes.x : 0.0f);
+        outer_window->DC.IdealMaxPos.x = ImMax(outer_window->DC.IdealMaxPos.x, table->OuterRect.Min.x + table->ColumnsAutoFitWidth + decoration_size - temp_data->UserOuterSize.x);
+        outer_window->DC.CursorMaxPos.x = ImMax(backup_outer_max_pos.x, ImMin(table->OuterRect.Max.x, table->OuterRect.Min.x + table->ColumnsAutoFitWidth));
     }
     else
     {
@@ -1505,9 +1489,9 @@ void    ImGui::EndTable()
     }
     if (temp_data->UserOuterSize.y <= 0.0f)
     {
-        const float decoration_size = (table->Flags & ImGuiTableFlags_ScrollX) ? inner_window->ScrollbarSizes.y : 0.0f;
+        const float decoration_size = (table->Flags & ImGuiTableFlags_ScrollY) ? inner_window->ScrollbarSizes.y : 0.0f;
         outer_window->DC.IdealMaxPos.y = ImMax(outer_window->DC.IdealMaxPos.y, inner_content_max_y + decoration_size - temp_data->UserOuterSize.y);
-        outer_window->DC.CursorMaxPos.y = ImMax(backup_outer_max_pos.y, ImMin(table->OuterRect.Max.y, inner_content_max_y + decoration_size));
+        outer_window->DC.CursorMaxPos.y = ImMax(backup_outer_max_pos.y, ImMin(table->OuterRect.Max.y, inner_content_max_y));
     }
     else
     {
@@ -1978,8 +1962,7 @@ void ImGui::TableEndRow(ImGuiTable* table)
                 cell_bg_rect.ClipWith(table->BgClipRect);
                 cell_bg_rect.Min.x = ImMax(cell_bg_rect.Min.x, column->ClipRect.Min.x);     // So that first column after frozen one gets clipped when scrolling
                 cell_bg_rect.Max.x = ImMin(cell_bg_rect.Max.x, column->MaxX);
-                if (cell_bg_rect.Min.y < cell_bg_rect.Max.y)
-                    window->DrawList->AddRectFilled(cell_bg_rect.Min, cell_bg_rect.Max, cell_data->BgColor);
+                window->DrawList->AddRectFilled(cell_bg_rect.Min, cell_bg_rect.Max, cell_data->BgColor);
             }
         }
 
@@ -2800,7 +2783,7 @@ ImGuiTableSortSpecs* ImGui::TableGetSortSpecs()
 static inline ImGuiSortDirection TableGetColumnAvailSortDirection(ImGuiTableColumn* column, int n)
 {
     IM_ASSERT(n < column->SortDirectionsAvailCount);
-    return (ImGuiSortDirection)((column->SortDirectionsAvailList >> (n << 1)) & 0x03);
+    return (column->SortDirectionsAvailList >> (n << 1)) & 0x03;
 }
 
 // Fix sort direction if currently set on a value which is unavailable (e.g. activating NoSortAscending/NoSortDescending)
@@ -2941,7 +2924,6 @@ void ImGui::TableSortSpecsBuild(ImGuiTable* table)
     }
 
     // Write output
-    // May be able to move all SortSpecs data from table (48 bytes) to ImGuiTableTempData if we decide to write it back on every BeginTable()
     ImGuiTableColumnSortSpecs* sort_specs = (table->SortSpecsCount == 0) ? NULL : (table->SortSpecsCount == 1) ? &table->SortSpecsSingle : table->SortSpecsMulti.Data;
     if (dirty && sort_specs != NULL)
         for (int column_n = 0; column_n < table->ColumnsCount; column_n++)
@@ -2954,7 +2936,7 @@ void ImGui::TableSortSpecsBuild(ImGuiTable* table)
             sort_spec->ColumnUserID = column->UserID;
             sort_spec->ColumnIndex = (ImGuiTableColumnIdx)column_n;
             sort_spec->SortOrder = (ImGuiTableColumnIdx)column->SortOrder;
-            sort_spec->SortDirection = (ImGuiSortDirection)column->SortDirection;
+            sort_spec->SortDirection = column->SortDirection;
         }
 
     table->SortSpecs.Specs = sort_specs;
@@ -3002,7 +2984,7 @@ float ImGui::TableGetHeaderAngledMaxLabelWidth()
 
 // [Public] This is a helper to output TableHeader() calls based on the column names declared in TableSetupColumn().
 // The intent is that advanced users willing to create customized headers would not need to use this helper
-// and can create their own! For example: TableHeader() may be preceded by Checkbox() or other custom widgets.
+// and can create their own! For example: TableHeader() may be preceeded by Checkbox() or other custom widgets.
 // See 'Demo->Tables->Custom headers' for a demonstration of implementing a custom version of this.
 // This code is constructed to not make much use of internal functions, as it is intended to be a template to copy.
 // FIXME-TABLE: TableOpenContextMenu() and TableGetHeaderRowHeight() are not public.
@@ -3188,43 +3170,15 @@ void ImGui::TableHeader(const char* label)
 }
 
 // Unlike TableHeadersRow() it is not expected that you can reimplement or customize this with custom widgets.
+// FIXME: highlight without ImGuiTableFlags_HighlightHoveredColumn
 // FIXME: No hit-testing/button on the angled header.
 void ImGui::TableAngledHeadersRow()
 {
     ImGuiContext& g = *GImGui;
-    ImGuiTable* table = g.CurrentTable;
-    ImGuiTableTempData* temp_data = table->TempData;
-    temp_data->AngledHeadersRequests.resize(0);
-    temp_data->AngledHeadersRequests.reserve(table->ColumnsEnabledCount);
-
-    // Which column needs highlight?
-    const ImGuiID row_id = GetID("##AngledHeaders");
-    ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
-    int highlight_column_n = table->HighlightColumnHeader;
-    if (highlight_column_n == -1 && table->HoveredColumnBody != -1)
-        if (table_instance->HoveredRowLast == 0 && table->HoveredColumnBorder == -1 && (g.ActiveId == 0 || g.ActiveId == row_id || (table->IsActiveIdInTable || g.DragDropActive)))
-            highlight_column_n = table->HoveredColumnBody;
-
-    // Build up request
-    ImU32 col_header_bg = GetColorU32(ImGuiCol_TableHeaderBg);
-    ImU32 col_text = GetColorU32(ImGuiCol_Text);
-    for (int order_n = 0; order_n < table->ColumnsCount; order_n++)
-        if (IM_BITARRAY_TESTBIT(table->EnabledMaskByDisplayOrder, order_n))
-        {
-            const int column_n = table->DisplayOrderToIndex[order_n];
-            ImGuiTableColumn* column = &table->Columns[column_n];
-            if ((column->Flags & ImGuiTableColumnFlags_AngledHeader) == 0) // Note: can't rely on ImGuiTableColumnFlags_IsVisible test here.
-                continue;
-            ImGuiTableHeaderData request = { (ImGuiTableColumnIdx)column_n, col_text, col_header_bg, (column_n == highlight_column_n) ? GetColorU32(ImGuiCol_Header) : 0 };
-            temp_data->AngledHeadersRequests.push_back(request);
-        }
-
-    // Render row
-    TableAngledHeadersRowEx(row_id, g.Style.TableAngledHeadersAngle, 0.0f, temp_data->AngledHeadersRequests.Data, temp_data->AngledHeadersRequests.Size);
+    TableAngledHeadersRowEx(g.Style.TableAngledHeadersAngle, 0.0f);
 }
 
-// Important: data must be fed left to right
-void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label_width, const ImGuiTableHeaderData* data, int data_count)
+void ImGui::TableAngledHeadersRowEx(float angle, float max_label_width)
 {
     ImGuiContext& g = *GImGui;
     ImGuiTable* table = g.CurrentTable;
@@ -3266,22 +3220,28 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
     draw_list->AddRectFilled(ImVec2(table->BgClipRect.Min.x, row_r.Min.y), ImVec2(table->BgClipRect.Max.x, row_r.Max.y), GetColorU32(ImGuiCol_TableHeaderBg, 0.25f)); // FIXME-STYLE: Change row background with an arbitrary color.
     PushClipRect(ImVec2(clip_rect_min_x, table->BgClipRect.Min.y), table->BgClipRect.Max, true); // Span all columns
 
+    const ImGuiID row_id = GetID("##AngledHeaders");
     ButtonBehavior(row_r, row_id, NULL, NULL);
     KeepAliveID(row_id);
 
-    const float ascent_scaled = g.Font->Ascent * (g.FontSize / g.Font->FontSize); // FIXME: Standardize those scaling factors better
-    const float line_off_for_ascent_x = (ImMax((g.FontSize - ascent_scaled) * 0.5f, 0.0f) / -sin_a) * (flip_label ? -1.0f : 1.0f);
-    const ImVec2 padding = g.Style.CellPadding; // We will always use swapped component
-    const ImVec2 align = g.Style.TableAngledHeadersTextAlign;
+    ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
+    int highlight_column_n = table->HighlightColumnHeader;
+    if (highlight_column_n == -1 && table->HoveredColumnBody != -1)
+        if (table_instance->HoveredRowLast == 0 && table->HoveredColumnBorder == -1 && (g.ActiveId == 0 || g.ActiveId == row_id || (table->IsActiveIdInTable || g.DragDropActive)))
+            highlight_column_n = table->HoveredColumnBody;
 
     // Draw background and labels in first pass, then all borders.
     float max_x = 0.0f;
+    ImVec2 padding = g.Style.CellPadding; // We will always use swapped component
     for (int pass = 0; pass < 2; pass++)
-        for (int order_n = 0; order_n < data_count; order_n++)
+        for (int order_n = 0; order_n < table->ColumnsCount; order_n++)
         {
-            const ImGuiTableHeaderData* request = &data[order_n];
-            const int column_n = request->Index;
+            if (!IM_BITARRAY_TESTBIT(table->EnabledMaskByDisplayOrder, order_n))
+                continue;
+            const int column_n = table->DisplayOrderToIndex[order_n];
             ImGuiTableColumn* column = &table->Columns[column_n];
+            if ((column->Flags & ImGuiTableColumnFlags_AngledHeader) == 0) // Note: can't rely on ImGuiTableColumnFlags_IsVisible test here.
+                continue;
 
             ImVec2 bg_shape[4];
             bg_shape[0] = ImVec2(column->MaxX, row_r.Max.y);
@@ -3291,8 +3251,9 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
             if (pass == 0)
             {
                 // Draw shape
-                draw_list->AddQuadFilled(bg_shape[0], bg_shape[1], bg_shape[2], bg_shape[3], request->BgColor0);
-                draw_list->AddQuadFilled(bg_shape[0], bg_shape[1], bg_shape[2], bg_shape[3], request->BgColor1); // Optional highlight
+                draw_list->AddQuadFilled(bg_shape[0], bg_shape[1], bg_shape[2], bg_shape[3], GetColorU32(ImGuiCol_TableHeaderBg));
+                if (column_n == highlight_column_n)
+                    draw_list->AddQuadFilled(bg_shape[0], bg_shape[1], bg_shape[2], bg_shape[3], GetColorU32(ImGuiCol_Header)); // Highlight on hover
                 max_x = ImMax(max_x, bg_shape[3].x);
 
                 // Draw label
@@ -3300,17 +3261,8 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
                 // - Handle multiple lines manually, as we want each lines to follow on the horizontal border, rather than see a whole block rotated.
                 const char* label_name = TableGetColumnName(table, column_n);
                 const char* label_name_end = FindRenderedTextEnd(label_name);
-                const float line_off_step_x = (g.FontSize / -sin_a);
-                const int label_lines = ImTextCountLines(label_name, label_name_end);
-
-                // Left<>Right alignment
-                float line_off_curr_x = flip_label ? (label_lines - 1) * line_off_step_x : 0.0f;
-                float line_off_for_align_x = ImMax((((column->MaxX - column->MinX) - padding.x * 2.0f) - (label_lines * line_off_step_x)), 0.0f) * align.x;
-                line_off_curr_x += line_off_for_align_x - line_off_for_ascent_x;
-
-                // Register header width
-                column->ContentMaxXHeadersUsed = column->ContentMaxXHeadersIdeal = column->WorkMinX + ImCeil(label_lines * line_off_step_x - line_off_for_align_x);
-
+                const float line_off_step_x = g.FontSize / -sin_a;
+                float line_off_curr_x = 0.0f;
                 while (label_name < label_name_end)
                 {
                     const char* label_name_eol = strchr(label_name, '\n');
@@ -3319,30 +3271,26 @@ void ImGui::TableAngledHeadersRowEx(ImGuiID row_id, float angle, float max_label
 
                     // FIXME: Individual line clipping for right-most column is broken for negative angles.
                     ImVec2 label_size = CalcTextSize(label_name, label_name_eol);
-                    float clip_width = max_label_width - padding.y; // Using padding.y*2.0f would be symmetrical but hide more text.
+                    float clip_width = max_label_width - padding.y; // Using padding.y*2.0f would be symetrical but hide more text.
                     float clip_height = ImMin(label_size.y, column->ClipRect.Max.x - column->WorkMinX - line_off_curr_x);
                     ImRect clip_r(window->ClipRect.Min, window->ClipRect.Min + ImVec2(clip_width, clip_height));
                     int vtx_idx_begin = draw_list->_VtxCurrentIdx;
-                    PushStyleColor(ImGuiCol_Text, request->TextColor);
                     RenderTextEllipsis(draw_list, clip_r.Min, clip_r.Max, clip_r.Max.x, clip_r.Max.x, label_name, label_name_eol, &label_size);
-                    PopStyleColor();
                     int vtx_idx_end = draw_list->_VtxCurrentIdx;
 
-                    // Up<>Down alignment
-                    const float available_space = ImMax(clip_width - label_size.x + ImAbs(padding.x * cos_a) * 2.0f - ImAbs(padding.y * sin_a) * 2.0f, 0.0f);
-                    const float vertical_offset = available_space * align.y * (flip_label ? -1.0f : 1.0f);
-
                     // Rotate and offset label
-                    ImVec2 pivot_in = ImVec2(window->ClipRect.Min.x - vertical_offset, window->ClipRect.Min.y + label_size.y);
+                    ImVec2 pivot_in = ImVec2(window->ClipRect.Min.x, window->ClipRect.Min.y + label_size.y);
                     ImVec2 pivot_out = ImVec2(column->WorkMinX, row_r.Max.y);
-                    line_off_curr_x += flip_label ? -line_off_step_x : line_off_step_x;
+                    line_off_curr_x += line_off_step_x;
                     pivot_out += unit_right * padding.y;
                     if (flip_label)
                         pivot_out += unit_right * (clip_width - ImMax(0.0f, clip_width - label_size.x));
-                    pivot_out.x += flip_label ? line_off_curr_x + line_off_step_x : line_off_curr_x;
+                    pivot_out.x += flip_label ? line_off_curr_x - line_off_step_x : line_off_curr_x;
                     ShadeVertsTransformPos(draw_list, vtx_idx_begin, vtx_idx_end, pivot_in, label_cos_a, label_sin_a, pivot_out); // Rotate and offset
-                    //if (g.IO.KeyShift) { ImDrawList* fg_dl = GetForegroundDrawList(); vtx_idx_begin = fg_dl->_VtxCurrentIdx; fg_dl->AddRect(clip_r.Min, clip_r.Max, IM_COL32(0, 255, 0, 255), 0.0f, 0, 1.0f); ShadeVertsTransformPos(fg_dl, vtx_idx_begin, fg_dl->_VtxCurrentIdx, pivot_in, label_cos_a, label_sin_a, pivot_out); }
+                    //if (g.IO.KeyShift) { ImDrawList* fg_dl = GetForegroundDrawList(); vtx_idx_begin = fg_dl->_VtxCurrentIdx; fg_dl->AddRect(clip_r.Min, clip_r.Max, IM_COL32(0, 255, 0, 255), 0.0f, 0, 2.0f); ShadeVertsTransformPos(fg_dl, vtx_idx_begin, fg_dl->_VtxCurrentIdx, pivot_in, label_cos_a, label_sin_a, pivot_out); }
 
+                    // Register header width
+                    column->ContentMaxXHeadersUsed = column->ContentMaxXHeadersIdeal = column->WorkMinX + ImCeil(line_off_curr_x);
                     label_name = label_name_eol + 1;
                 }
             }
@@ -4057,7 +4005,7 @@ float ImGui::GetColumnNormFromOffset(const ImGuiOldColumns* columns, float offse
     return offset / (columns->OffMaxX - columns->OffMinX);
 }
 
-static const float COLUMNS_HIT_RECT_HALF_THICKNESS = 4.0f;
+static const float COLUMNS_HIT_RECT_HALF_WIDTH = 4.0f;
 
 static float GetDraggedColumnOffset(ImGuiOldColumns* columns, int column_index)
 {
@@ -4068,7 +4016,7 @@ static float GetDraggedColumnOffset(ImGuiOldColumns* columns, int column_index)
     IM_ASSERT(column_index > 0); // We are not supposed to drag column 0.
     IM_ASSERT(g.ActiveId == columns->ID + ImGuiID(column_index));
 
-    float x = g.IO.MousePos.x - g.ActiveIdClickOffset.x + ImTrunc(COLUMNS_HIT_RECT_HALF_THICKNESS * g.CurrentDpiScale) - window->Pos.x;
+    float x = g.IO.MousePos.x - g.ActiveIdClickOffset.x + COLUMNS_HIT_RECT_HALF_WIDTH - window->Pos.x;
     x = ImMax(x, ImGui::GetColumnOffset(column_index - 1) + g.Style.ColumnsMinSpacing);
     if ((columns->Flags & ImGuiOldColumnFlags_NoPreserveWidths))
         x = ImMin(x, ImGui::GetColumnOffset(column_index + 1) - g.Style.ColumnsMinSpacing);
@@ -4383,7 +4331,7 @@ void ImGui::EndColumns()
             ImGuiOldColumnData* column = &columns->Columns[n];
             float x = window->Pos.x + GetColumnOffset(n);
             const ImGuiID column_id = columns->ID + ImGuiID(n);
-            const float column_hit_hw = ImTrunc(COLUMNS_HIT_RECT_HALF_THICKNESS * g.CurrentDpiScale);
+            const float column_hit_hw = COLUMNS_HIT_RECT_HALF_WIDTH;
             const ImRect column_hit_rect(ImVec2(x - column_hit_hw, y1), ImVec2(x + column_hit_hw, y2));
             if (!ItemAdd(column_hit_rect, column_id, NULL, ImGuiItemFlags_NoNav))
                 continue;

imgui_widgets.cpp

@@ -1,4 +1,4 @@
-// dear imgui, v1.90.8
+// dear imgui, v1.90.5
 // (widgets code)
 
 /*
@@ -75,7 +75,6 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wenum-enum-conversion"           // warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_')
 #pragma clang diagnostic ignored "-Wdeprecated-enum-enum-conversion"// warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_') is deprecated
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
-#pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"                // warning: format not a string literal, format string not checked
@@ -488,7 +487,7 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
 
     // Default only reacts to left mouse button
     if ((flags & ImGuiButtonFlags_MouseButtonMask_) == 0)
-        flags |= ImGuiButtonFlags_MouseButtonLeft;
+        flags |= ImGuiButtonFlags_MouseButtonDefault_;
 
     // Default behavior requires click + release inside bounding box
     if ((flags & ImGuiButtonFlags_PressedOnMask_) == 0)
@@ -503,13 +502,13 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
         item_flags |= ImGuiItemFlags_ButtonRepeat;
 
     ImGuiWindow* backup_hovered_window = g.HoveredWindow;
-    const bool flatten_hovered_children = (flags & ImGuiButtonFlags_FlattenChildren) && g.HoveredWindow && g.HoveredWindow->RootWindow == window;
+    const bool flatten_hovered_children = (flags & ImGuiButtonFlags_FlattenChildren) && g.HoveredWindow && g.HoveredWindow->RootWindowDockTree == window->RootWindowDockTree;
     if (flatten_hovered_children)
         g.HoveredWindow = window;
 
 #ifdef IMGUI_ENABLE_TEST_ENGINE
     // Alternate registration spot, for when caller didn't use ItemAdd()
-    if (g.LastItemData.ID != id)
+    if (id != 0 && g.LastItemData.ID != id)
         IMGUI_TEST_ENGINE_ITEM_ADD(id, bb, NULL);
 #endif
 
@@ -537,8 +536,6 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     const ImGuiID test_owner_id = (flags & ImGuiButtonFlags_NoTestKeyOwner) ? ImGuiKeyOwner_Any : id;
     if (hovered)
     {
-        IM_ASSERT(id != 0); // Lazily check inside rare path.
-
         // Poll mouse buttons
         // - 'mouse_button_clicked' is generally carried into ActiveIdMouseButton when setting ActiveId.
         // - Technically we only need some values in one code path, but since this is gated by hovered test this is fine.
@@ -547,7 +544,7 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
         for (int button = 0; button < 3; button++)
             if (flags & (ImGuiButtonFlags_MouseButtonLeft << button)) // Handle ImGuiButtonFlags_MouseButtonRight and ImGuiButtonFlags_MouseButtonMiddle here.
             {
-                if (IsMouseClicked(button, ImGuiInputFlags_None, test_owner_id) && mouse_button_clicked == -1) { mouse_button_clicked = button; }
+                if (IsMouseClicked(button, test_owner_id) && mouse_button_clicked == -1) { mouse_button_clicked = button; }
                 if (IsMouseReleased(button, test_owner_id) && mouse_button_released == -1) { mouse_button_released = button; }
             }
 
@@ -595,7 +592,7 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
             // 'Repeat' mode acts when held regardless of _PressedOn flags (see table above).
             // Relies on repeat logic of IsMouseClicked() but we may as well do it ourselves if we end up exposing finer RepeatDelay/RepeatRate settings.
             if (g.ActiveId == id && (item_flags & ImGuiItemFlags_ButtonRepeat))
-                if (g.IO.MouseDownDuration[g.ActiveIdMouseButton] > 0.0f && IsMouseClicked(g.ActiveIdMouseButton, ImGuiInputFlags_Repeat, test_owner_id))
+                if (g.IO.MouseDownDuration[g.ActiveIdMouseButton] > 0.0f && IsMouseClicked(g.ActiveIdMouseButton, test_owner_id, ImGuiInputFlags_Repeat))
                     pressed = true;
         }
 
@@ -849,7 +846,8 @@ bool ImGui::CloseButton(ImGuiID id, const ImVec2& pos)
     return pressed;
 }
 
-bool ImGui::CollapseButton(ImGuiID id, const ImVec2& pos)
+// The Collapse button also functions as a Dock Menu button.
+bool ImGui::CollapseButton(ImGuiID id, const ImVec2& pos, ImGuiDockNode* dock_node)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
@@ -862,15 +860,20 @@ bool ImGui::CollapseButton(ImGuiID id, const ImVec2& pos)
         return pressed;
 
     // Render
+    //bool is_dock_menu = (window->DockNodeAsHost && !window->Collapsed);
     ImU32 bg_col = GetColorU32((held && hovered) ? ImGuiCol_ButtonActive : hovered ? ImGuiCol_ButtonHovered : ImGuiCol_Button);
     ImU32 text_col = GetColorU32(ImGuiCol_Text);
     if (hovered || held)
         window->DrawList->AddCircleFilled(bb.GetCenter() + ImVec2(0.0f, -0.5f), g.FontSize * 0.5f + 1.0f, bg_col);
-    RenderArrow(window->DrawList, bb.Min, text_col, window->Collapsed ? ImGuiDir_Right : ImGuiDir_Down, 1.0f);
+
+    if (dock_node)
+        RenderArrowDockMenu(window->DrawList, bb.Min, g.FontSize, text_col);
+    else
+        RenderArrow(window->DrawList, bb.Min, text_col, window->Collapsed ? ImGuiDir_Right : ImGuiDir_Down, 1.0f);
 
     // Switch to moving the window after mouse is moved beyond the initial drag threshold
     if (IsItemActive() && IsMouseDragging(0))
-        StartMouseMovingWindow(window);
+        StartMouseMovingWindowOrNode(window, dock_node, true); // Undock from window/collapse menu button
 
     return pressed;
 }
@@ -916,10 +919,10 @@ void ImGui::Scrollbar(ImGuiAxis axis)
         if (!window->ScrollbarX)
             rounding_corners |= ImDrawFlags_RoundCornersBottomRight;
     }
-    float size_visible = window->InnerRect.Max[axis] - window->InnerRect.Min[axis];
+    float size_avail = window->InnerRect.Max[axis] - window->InnerRect.Min[axis];
     float size_contents = window->ContentSize[axis] + window->WindowPadding[axis] * 2.0f;
     ImS64 scroll = (ImS64)window->Scroll[axis];
-    ScrollbarEx(bb, id, axis, &scroll, (ImS64)size_visible, (ImS64)size_contents, rounding_corners);
+    ScrollbarEx(bb, id, axis, &scroll, (ImS64)size_avail, (ImS64)size_contents, rounding_corners);
     window->Scroll[axis] = (float)scroll;
 }
 
@@ -929,7 +932,7 @@ void ImGui::Scrollbar(ImGuiAxis axis)
 // - We store values as normalized ratio and in a form that allows the window content to change while we are holding on a scrollbar
 // - We handle both horizontal and vertical scrollbars, which makes the terminology not ideal.
 // Still, the code should probably be made simpler..
-bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS64* p_scroll_v, ImS64 size_visible_v, ImS64 size_contents_v, ImDrawFlags flags)
+bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS64* p_scroll_v, ImS64 size_avail_v, ImS64 size_contents_v, ImDrawFlags flags)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
@@ -959,9 +962,9 @@ bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS6
 
     // Calculate the height of our grabbable box. It generally represent the amount visible (vs the total scrollable amount)
     // But we maintain a minimum size in pixel to allow for the user to still aim inside.
-    IM_ASSERT(ImMax(size_contents_v, size_visible_v) > 0.0f); // Adding this assert to check if the ImMax(XXX,1.0f) is still needed. PLEASE CONTACT ME if this triggers.
-    const ImS64 win_size_v = ImMax(ImMax(size_contents_v, size_visible_v), (ImS64)1);
-    const float grab_h_pixels = ImClamp(scrollbar_size_v * ((float)size_visible_v / (float)win_size_v), style.GrabMinSize, scrollbar_size_v);
+    IM_ASSERT(ImMax(size_contents_v, size_avail_v) > 0.0f); // Adding this assert to check if the ImMax(XXX,1.0f) is still needed. PLEASE CONTACT ME if this triggers.
+    const ImS64 win_size_v = ImMax(ImMax(size_contents_v, size_avail_v), (ImS64)1);
+    const float grab_h_pixels = ImClamp(scrollbar_size_v * ((float)size_avail_v / (float)win_size_v), style.GrabMinSize, scrollbar_size_v);
     const float grab_h_norm = grab_h_pixels / scrollbar_size_v;
 
     // Handle input right away. None of the code of Begin() is relying on scrolling position before calling Scrollbar().
@@ -970,7 +973,7 @@ bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS6
     ItemAdd(bb_frame, id, NULL, ImGuiItemFlags_NoNav);
     ButtonBehavior(bb, id, &hovered, &held, ImGuiButtonFlags_NoNavFocus);
 
-    const ImS64 scroll_max = ImMax((ImS64)1, size_contents_v - size_visible_v);
+    const ImS64 scroll_max = ImMax((ImS64)1, size_contents_v - size_avail_v);
     float scroll_ratio = ImSaturate((float)*p_scroll_v / (float)scroll_max);
     float grab_v_norm = scroll_ratio * (scrollbar_size_v - grab_h_pixels) / scrollbar_size_v; // Grab position in normalized space
     if (held && allow_interaction && grab_h_norm < 1.0f)
@@ -981,39 +984,29 @@ bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS6
         // Click position in scrollbar normalized space (0.0f->1.0f)
         const float clicked_v_norm = ImSaturate((mouse_pos_v - scrollbar_pos_v) / scrollbar_size_v);
 
-        const int held_dir = (clicked_v_norm < grab_v_norm) ? -1 : (clicked_v_norm > grab_v_norm + grab_h_norm) ? +1 : 0;
+        bool seek_absolute = false;
         if (g.ActiveIdIsJustActivated)
         {
             // On initial click calculate the distance between mouse and the center of the grab
-            g.ScrollbarSeekMode = (short)held_dir;
-            g.ScrollbarClickDeltaToGrabCenter = (g.ScrollbarSeekMode == 0.0f) ? clicked_v_norm - grab_v_norm - grab_h_norm * 0.5f : 0.0f;
+            seek_absolute = (clicked_v_norm < grab_v_norm || clicked_v_norm > grab_v_norm + grab_h_norm);
+            if (seek_absolute)
+                g.ScrollbarClickDeltaToGrabCenter = 0.0f;
+            else
+                g.ScrollbarClickDeltaToGrabCenter = clicked_v_norm - grab_v_norm - grab_h_norm * 0.5f;
         }
 
         // Apply scroll (p_scroll_v will generally point on one member of window->Scroll)
         // It is ok to modify Scroll here because we are being called in Begin() after the calculation of ContentSize and before setting up our starting position
-        if (g.ScrollbarSeekMode == 0)
-        {
-            // Absolute seeking
-            const float scroll_v_norm = ImSaturate((clicked_v_norm - g.ScrollbarClickDeltaToGrabCenter - grab_h_norm * 0.5f) / (1.0f - grab_h_norm));
-            *p_scroll_v = (ImS64)(scroll_v_norm * scroll_max);
-        }
-        else
-        {
-            // Page by page
-            if (IsMouseClicked(ImGuiMouseButton_Left, ImGuiInputFlags_Repeat) && held_dir == g.ScrollbarSeekMode)
-            {
-                float page_dir = (g.ScrollbarSeekMode > 0.0f) ? +1.0f : -1.0f;
-                *p_scroll_v = ImClamp(*p_scroll_v + (ImS64)(page_dir * size_visible_v), (ImS64)0, scroll_max);
-            }
-        }
+        const float scroll_v_norm = ImSaturate((clicked_v_norm - g.ScrollbarClickDeltaToGrabCenter - grab_h_norm * 0.5f) / (1.0f - grab_h_norm));
+        *p_scroll_v = (ImS64)(scroll_v_norm * scroll_max);
 
         // Update values for rendering
         scroll_ratio = ImSaturate((float)*p_scroll_v / (float)scroll_max);
         grab_v_norm = scroll_ratio * (scrollbar_size_v - grab_h_pixels) / scrollbar_size_v;
 
-        // Update distance to grab now that we have seek'ed and saturated
-        //if (seek_absolute)
-        //    g.ScrollbarClickDeltaToGrabCenter = clicked_v_norm - grab_v_norm - grab_h_norm * 0.5f;
+        // Update distance to grab now that we have seeked and saturated
+        if (seek_absolute)
+            g.ScrollbarClickDeltaToGrabCenter = clicked_v_norm - grab_v_norm - grab_h_norm * 0.5f;
     }
 
     // Render
@@ -1301,47 +1294,27 @@ void ImGui::ProgressBar(float fraction, const ImVec2& size_arg, const char* over
     if (!ItemAdd(bb, 0))
         return;
 
-    // Fraction < 0.0f will display an indeterminate progress bar animation
-    // The value must be animated along with time, so e.g. passing '-1.0f * ImGui::GetTime()' as fraction works.
-    const bool is_indeterminate = (fraction < 0.0f);
-    if (!is_indeterminate)
-        fraction = ImSaturate(fraction);
-
     // Out of courtesy we accept a NaN fraction without crashing
-    float fill_n0 = 0.0f;
-    float fill_n1 = (fraction == fraction) ? fraction : 0.0f;
-
-    if (is_indeterminate)
-    {
-        const float fill_width_n = 0.2f;
-        fill_n0 = ImFmod(-fraction, 1.0f) * (1.0f + fill_width_n) - fill_width_n;
-        fill_n1 = ImSaturate(fill_n0 + fill_width_n);
-        fill_n0 = ImSaturate(fill_n0);
-    }
+    fraction = ImSaturate(fraction);
+    const float fraction_not_nan = (fraction == fraction) ? fraction : 0.0f;
 
     // Render
     RenderFrame(bb.Min, bb.Max, GetColorU32(ImGuiCol_FrameBg), true, style.FrameRounding);
     bb.Expand(ImVec2(-style.FrameBorderSize, -style.FrameBorderSize));
-    RenderRectFilledRangeH(window->DrawList, bb, GetColorU32(ImGuiCol_PlotHistogram), fill_n0, fill_n1, style.FrameRounding);
+    const ImVec2 fill_br = ImVec2(ImLerp(bb.Min.x, bb.Max.x, fraction_not_nan), bb.Max.y);
+    RenderRectFilledRangeH(window->DrawList, bb, GetColorU32(ImGuiCol_PlotHistogram), 0.0f, fraction_not_nan, style.FrameRounding);
 
     // Default displaying the fraction as percentage string, but user can override it
-    // Don't display text for indeterminate bars by default
     char overlay_buf[32];
-    if (!is_indeterminate || overlay != NULL)
+    if (!overlay)
     {
-        if (!overlay)
-        {
-            ImFormatString(overlay_buf, IM_ARRAYSIZE(overlay_buf), "%.0f%%", fraction * 100 + 0.01f);
-            overlay = overlay_buf;
-        }
-
-        ImVec2 overlay_size = CalcTextSize(overlay, NULL);
-        if (overlay_size.x > 0.0f)
-        {
-            float text_x = is_indeterminate ? (bb.Min.x + bb.Max.x - overlay_size.x) * 0.5f : ImLerp(bb.Min.x, bb.Max.x, fill_n1) + style.ItemSpacing.x;
-            RenderTextClipped(ImVec2(ImClamp(text_x, bb.Min.x, bb.Max.x - overlay_size.x - style.ItemInnerSpacing.x), bb.Min.y), bb.Max, overlay, NULL, &overlay_size, ImVec2(0.0f, 0.5f), &bb);
-        }
+        ImFormatString(overlay_buf, IM_ARRAYSIZE(overlay_buf), "%.0f%%", fraction * 100 + 0.01f);
+        overlay = overlay_buf;
     }
+
+    ImVec2 overlay_size = CalcTextSize(overlay, NULL);
+    if (overlay_size.x > 0.0f)
+        RenderTextClipped(ImVec2(ImClamp(fill_br.x + style.ItemSpacing.x, bb.Min.x, bb.Max.x - overlay_size.x - style.ItemInnerSpacing.x), bb.Min.y), bb.Max, overlay, NULL, &overlay_size, ImVec2(0.0f, 0.5f), &bb);
 }
 
 void ImGui::Bullet()
@@ -1525,7 +1498,7 @@ void ImGui::SeparatorTextEx(ImGuiID id, const char* label, const char* label_end
     const float separator_thickness = style.SeparatorTextBorderSize;
     const ImVec2 min_size(label_size.x + extra_w + padding.x * 2.0f, ImMax(label_size.y + padding.y * 2.0f, separator_thickness));
     const ImRect bb(pos, ImVec2(window->WorkRect.Max.x, pos.y + min_size.y));
-    const float text_baseline_y = ImTrunc((bb.GetHeight() - label_size.y) * style.SeparatorTextAlign.y + 0.99999f); //ImMax(padding.y, ImFloor((style.SeparatorTextSize - label_size.y) * 0.5f));
+    const float text_baseline_y = ImTrunc((bb.GetHeight() - label_size.y) * style.SeparatorTextAlign.y + 0.99999f); //ImMax(padding.y, ImTrunc((style.SeparatorTextSize - label_size.y) * 0.5f));
     ItemSize(min_size, text_baseline_y);
     if (!ItemAdd(bb, id))
         return;
@@ -1952,30 +1925,28 @@ bool ImGui::Combo(const char* label, int* current_item, const char* (*getter)(vo
         return false;
 
     // Display items
+    // FIXME-OPT: Use clipper (but we need to disable it on the appearing frame to make sure our call to SetItemDefaultFocus() is processed)
     bool value_changed = false;
-    ImGuiListClipper clipper;
-    clipper.Begin(items_count);
-    clipper.IncludeItemByIndex(*current_item);
-    while (clipper.Step())
-        for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
-        {
-            const char* item_text = getter(user_data, i);
-            if (item_text == NULL)
-                item_text = "*Unknown item*";
+    for (int i = 0; i < items_count; i++)
+    {
+        const char* item_text = getter(user_data, i);
+        if (item_text == NULL)
+            item_text = "*Unknown item*";
 
-            PushID(i);
-            const bool item_selected = (i == *current_item);
-            if (Selectable(item_text, item_selected) && *current_item != i)
-            {
-                value_changed = true;
-                *current_item = i;
-            }
-            if (item_selected)
-                SetItemDefaultFocus();
-            PopID();
+        PushID(i);
+        const bool item_selected = (i == *current_item);
+        if (Selectable(item_text, item_selected) && *current_item != i)
+        {
+            value_changed = true;
+            *current_item = i;
         }
+        if (item_selected)
+            SetItemDefaultFocus();
+        PopID();
+    }
 
     EndCombo();
+
     if (value_changed)
         MarkItemEdited(g.LastItemData.ID);
 
@@ -2141,24 +2112,17 @@ void ImGui::DataTypeApplyOp(ImGuiDataType data_type, int op, void* output, const
 
 // User can input math operators (e.g. +100) to edit a numerical values.
 // NB: This is _not_ a full expression evaluator. We should probably add one and replace this dumb mess..
-bool ImGui::DataTypeApplyFromText(const char* buf, ImGuiDataType data_type, void* p_data, const char* format, void* p_data_when_empty)
+bool ImGui::DataTypeApplyFromText(const char* buf, ImGuiDataType data_type, void* p_data, const char* format)
 {
-    // Copy the value in an opaque buffer so we can compare at the end of the function if it changed at all.
-    const ImGuiDataTypeInfo* type_info = DataTypeGetInfo(data_type);
-    ImGuiDataTypeStorage data_backup;
-    memcpy(&data_backup, p_data, type_info->Size);
-
     while (ImCharIsBlankA(*buf))
         buf++;
     if (!buf[0])
-    {
-        if (p_data_when_empty != NULL)
-        {
-            memcpy(p_data, p_data_when_empty, type_info->Size);
-            return memcmp(&data_backup, p_data, type_info->Size) != 0;
-        }
         return false;
-    }
+
+    // Copy the value in an opaque buffer so we can compare at the end of the function if it changed at all.
+    const ImGuiDataTypeInfo* type_info = DataTypeGetInfo(data_type);
+    ImGuiDataTypeTempStorage data_backup;
+    memcpy(&data_backup, p_data, type_info->Size);
 
     // Sanitize format
     // - For float/double we have to ignore format with precision (e.g. "%.2f") because sscanf doesn't take them in, so force them into %f and %lf
@@ -2328,7 +2292,7 @@ bool ImGui::DragBehaviorT(ImGuiDataType data_type, TYPE* v, float v_speed, const
         const int decimal_precision = is_floating_point ? ImParseFormatPrecision(format, 3) : 0;
         const bool tweak_slow = IsKeyDown((g.NavInputSource == ImGuiInputSource_Gamepad) ? ImGuiKey_NavGamepadTweakSlow : ImGuiKey_NavKeyboardTweakSlow);
         const bool tweak_fast = IsKeyDown((g.NavInputSource == ImGuiInputSource_Gamepad) ? ImGuiKey_NavGamepadTweakFast : ImGuiKey_NavKeyboardTweakFast);
-        const float tweak_factor = tweak_slow ? 1.0f / 10.0f : tweak_fast ? 10.0f : 1.0f;
+        const float tweak_factor = tweak_slow ? 1.0f / 1.0f : tweak_fast ? 10.0f : 1.0f;
         adjust_delta = GetNavTweakPressedAmount(axis) * tweak_factor;
         v_speed = ImMax(v_speed, GetMinimumStepAtDecimalPrecision(decimal_precision));
     }
@@ -2487,7 +2451,7 @@ bool ImGui::DragScalar(const char* label, ImGuiDataType data_type, void* p_data,
     if (!temp_input_is_active)
     {
         // Tabbing or CTRL-clicking on Drag turns it into an InputText
-        const bool clicked = hovered && IsMouseClicked(0, ImGuiInputFlags_None, id);
+        const bool clicked = hovered && IsMouseClicked(0, id);
         const bool double_clicked = (hovered && g.IO.MouseClickedCount[0] == 2 && TestKeyOwner(ImGuiKey_MouseLeft, id));
         const bool make_active = (clicked || double_clicked || g.NavActivateId == id);
         if (make_active && (clicked || double_clicked))
@@ -3078,7 +3042,7 @@ bool ImGui::SliderScalar(const char* label, ImGuiDataType data_type, void* p_dat
     if (!temp_input_is_active)
     {
         // Tabbing or CTRL-clicking on Slider turns it into an input box
-        const bool clicked = hovered && IsMouseClicked(0, ImGuiInputFlags_None, id);
+        const bool clicked = hovered && IsMouseClicked(0, id);
         const bool make_active = (clicked || g.NavActivateId == id);
         if (make_active && clicked)
             SetKeyOwner(ImGuiKey_MouseLeft, id);
@@ -3240,7 +3204,7 @@ bool ImGui::VSliderScalar(const char* label, const ImVec2& size, ImGuiDataType d
         format = DataTypeGetInfo(data_type)->PrintFmt;
 
     const bool hovered = ItemHoverable(frame_bb, id, g.LastItemData.InFlags);
-    const bool clicked = hovered && IsMouseClicked(0, ImGuiInputFlags_None, id);
+    const bool clicked = hovered && IsMouseClicked(0, id);
     if (clicked || g.NavActivateId == id)
     {
         if (clicked)
@@ -3478,11 +3442,11 @@ bool ImGui::TempInputScalar(const ImRect& bb, ImGuiID id, const char* label, ImG
     {
         // Backup old value
         size_t data_type_size = type_info->Size;
-        ImGuiDataTypeStorage data_backup;
+        ImGuiDataTypeTempStorage data_backup;
         memcpy(&data_backup, p_data, data_type_size);
 
         // Apply new value (or operations) then clamp
-        DataTypeApplyFromText(data_buf, data_type, p_data, format, NULL);
+        DataTypeApplyFromText(data_buf, data_type, p_data, format);
         if (p_clamp_min || p_clamp_max)
         {
             if (p_clamp_min && p_clamp_max && DataTypeCompare(data_type, p_clamp_min, p_clamp_max) > 0)
@@ -3498,13 +3462,6 @@ bool ImGui::TempInputScalar(const ImRect& bb, ImGuiID id, const char* label, ImG
     return value_changed;
 }
 
-void ImGui::SetNextItemRefVal(ImGuiDataType data_type, void* p_data)
-{
-    ImGuiContext& g = *GImGui;
-    g.NextItemData.Flags |= ImGuiNextItemDataFlags_HasRefVal;
-    memcpy(&g.NextItemData.RefVal, p_data, DataTypeGetInfo(data_type)->Size);
-}
-
 // Note: p_data, p_step, p_step_fast are _pointers_ to a memory address holding the data. For an Input widget, p_step and p_step_fast are optional.
 // Read code of e.g. InputFloat(), InputInt() etc. or examples in 'Demo->Widgets->Data Types' to understand how to use this function directly.
 bool ImGui::InputScalar(const char* label, ImGuiDataType data_type, void* p_data, const void* p_step, const void* p_step_fast, const char* format, ImGuiInputTextFlags flags)
@@ -3519,13 +3476,8 @@ bool ImGui::InputScalar(const char* label, ImGuiDataType data_type, void* p_data
     if (format == NULL)
         format = DataTypeGetInfo(data_type)->PrintFmt;
 
-    void* p_data_default = (g.NextItemData.Flags & ImGuiNextItemDataFlags_HasRefVal) ? &g.NextItemData.RefVal : &g.DataTypeZeroValue;
-
     char buf[64];
-    if ((flags & ImGuiInputTextFlags_DisplayEmptyRefVal) && DataTypeCompare(data_type, p_data, p_data_default) == 0)
-        buf[0] = 0;
-    else
-        DataTypeFormatString(buf, IM_ARRAYSIZE(buf), data_type, p_data, format);
+    DataTypeFormatString(buf, IM_ARRAYSIZE(buf), data_type, p_data, format);
 
     flags |= ImGuiInputTextFlags_AutoSelectAll | (ImGuiInputTextFlags)ImGuiInputTextFlags_NoMarkEdited; // We call MarkItemEdited() ourselves by comparing the actual data rather than the string.
     flags |= (ImGuiInputTextFlags)ImGuiInputTextFlags_LocalizeDecimalPoint;
@@ -3534,7 +3486,7 @@ bool ImGui::InputScalar(const char* label, ImGuiDataType data_type, void* p_data
     if (p_step == NULL)
     {
         if (InputText(label, buf, IM_ARRAYSIZE(buf), flags))
-            value_changed = DataTypeApplyFromText(buf, data_type, p_data, format, (flags & ImGuiInputTextFlags_ParseEmptyRefVal) ? p_data_default : NULL);
+            value_changed = DataTypeApplyFromText(buf, data_type, p_data, format);
     }
     else
     {
@@ -3544,7 +3496,7 @@ bool ImGui::InputScalar(const char* label, ImGuiDataType data_type, void* p_data
         PushID(label);
         SetNextItemWidth(ImMax(1.0f, CalcItemWidth() - (button_size + style.ItemInnerSpacing.x) * 2));
         if (InputText("", buf, IM_ARRAYSIZE(buf), flags)) // PushId(label) + "" gives us the expected ID from outside point of view
-            value_changed = DataTypeApplyFromText(buf, data_type, p_data, format, (flags & ImGuiInputTextFlags_ParseEmptyRefVal) ? p_data_default : NULL);
+            value_changed = DataTypeApplyFromText(buf, data_type, p_data, format);
         IMGUI_TEST_ENGINE_ITEM_INFO(g.LastItemData.ID, label, g.LastItemData.StatusFlags | ImGuiItemStatusFlags_Inputable);
 
         // Step buttons
@@ -4340,7 +4292,6 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
             SetKeyOwner(ImGuiKey_PageUp, id);
             SetKeyOwner(ImGuiKey_PageDown, id);
         }
-        // FIXME: May be a problem to always steal Alt on OSX, would ideally still allow an uninterrupted Alt down-up to toggle menu
         if (is_osx)
             SetKeyOwner(ImGuiMod_Alt, id);
     }
@@ -4473,7 +4424,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         // (For Tab and Enter: Win32/SFML/Allegro are sending both keys and chars, GLFW and SDL are only sending keys. For Space they all send all threes)
         if ((flags & ImGuiInputTextFlags_AllowTabInput) && !is_readonly)
         {
-            if (Shortcut(ImGuiKey_Tab, ImGuiInputFlags_Repeat, id))
+            if (Shortcut(ImGuiKey_Tab, id, ImGuiInputFlags_Repeat))
             {
                 unsigned int c = '\t'; // Insert TAB
                 if (InputTextFilterCharacter(&g, &c, flags, callback, callback_user_data))
@@ -4481,7 +4432,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
             }
             // FIXME: Implement Shift+Tab
             /*
-            if (Shortcut(ImGuiKey_Tab | ImGuiMod_Shift, ImGuiInputFlags_Repeat, id))
+            if (Shortcut(ImGuiKey_Tab | ImGuiMod_Shift, id, ImGuiInputFlags_Repeat))
             {
             }
             */
@@ -4489,7 +4440,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
 
         // Process regular text input (before we check for Return because using some IME will effectively send a Return?)
         // We ignore CTRL inputs, but need to allow ALT+CTRL as some keyboards (e.g. German) use AltGR (which _is_ Alt+Ctrl) to input certain characters.
-        const bool ignore_char_inputs = (io.KeyCtrl && !io.KeyAlt) || (is_osx && io.KeyCtrl);
+        const bool ignore_char_inputs = (io.KeyCtrl && !io.KeyAlt) || (is_osx && io.KeySuper);
         if (io.InputQueueCharacters.Size > 0)
         {
             if (!ignore_char_inputs && !is_readonly && !input_requested_by_nav)
@@ -4519,26 +4470,25 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
 
         const int k_mask = (io.KeyShift ? STB_TEXTEDIT_K_SHIFT : 0);
         const bool is_wordmove_key_down = is_osx ? io.KeyAlt : io.KeyCtrl;                     // OS X style: Text editing cursor movement using Alt instead of Ctrl
-        const bool is_startend_key_down = is_osx && io.KeyCtrl && !io.KeySuper && !io.KeyAlt;  // OS X style: Line/Text Start and End using Cmd+Arrows instead of Home/End
+        const bool is_startend_key_down = is_osx && io.KeySuper && !io.KeyCtrl && !io.KeyAlt;  // OS X style: Line/Text Start and End using Cmd+Arrows instead of Home/End
 
         // Using Shortcut() with ImGuiInputFlags_RouteFocused (default policy) to allow routing operations for other code (e.g. calling window trying to use CTRL+A and CTRL+B: formet would be handled by InputText)
         // Otherwise we could simply assume that we own the keys as we are active.
         const ImGuiInputFlags f_repeat = ImGuiInputFlags_Repeat;
-        const bool is_cut   = (Shortcut(ImGuiMod_Ctrl | ImGuiKey_X, f_repeat, id) || Shortcut(ImGuiMod_Shift | ImGuiKey_Delete, f_repeat, id)) && !is_readonly && !is_password && (!is_multiline || state->HasSelection());
-        const bool is_copy  = (Shortcut(ImGuiMod_Ctrl | ImGuiKey_C, 0,        id) || Shortcut(ImGuiMod_Ctrl  | ImGuiKey_Insert, 0,        id)) && !is_password && (!is_multiline || state->HasSelection());
-        const bool is_paste = (Shortcut(ImGuiMod_Ctrl | ImGuiKey_V, f_repeat, id) || Shortcut(ImGuiMod_Shift | ImGuiKey_Insert, f_repeat, id)) && !is_readonly;
-        const bool is_undo  = (Shortcut(ImGuiMod_Ctrl | ImGuiKey_Z, f_repeat, id)) && !is_readonly && is_undoable;
-        const bool is_redo =  (Shortcut(ImGuiMod_Ctrl | ImGuiKey_Y, f_repeat, id) || (is_osx && Shortcut(ImGuiMod_Ctrl | ImGuiMod_Shift | ImGuiKey_Z, f_repeat, id))) && !is_readonly && is_undoable;
-        const bool is_select_all = Shortcut(ImGuiMod_Ctrl | ImGuiKey_A, 0, id);
+        const bool is_cut   = (Shortcut(ImGuiMod_Shortcut | ImGuiKey_X, id, f_repeat) || Shortcut(ImGuiMod_Shift | ImGuiKey_Delete, id, f_repeat)) && !is_readonly && !is_password && (!is_multiline || state->HasSelection());
+        const bool is_copy  = (Shortcut(ImGuiMod_Shortcut | ImGuiKey_C, id) || Shortcut(ImGuiMod_Ctrl | ImGuiKey_Insert, id))  && !is_password && (!is_multiline || state->HasSelection());
+        const bool is_paste = (Shortcut(ImGuiMod_Shortcut | ImGuiKey_V, id, f_repeat) || Shortcut(ImGuiMod_Shift | ImGuiKey_Insert, id, f_repeat)) && !is_readonly;
+        const bool is_undo  = (Shortcut(ImGuiMod_Shortcut | ImGuiKey_Z, id, f_repeat)) && !is_readonly && is_undoable;
+        const bool is_redo =  (Shortcut(ImGuiMod_Shortcut | ImGuiKey_Y, id, f_repeat) || (is_osx && Shortcut(ImGuiMod_Shortcut | ImGuiMod_Shift | ImGuiKey_Z, id, f_repeat))) && !is_readonly && is_undoable;
+        const bool is_select_all = Shortcut(ImGuiMod_Shortcut | ImGuiKey_A, id);
 
         // We allow validate/cancel with Nav source (gamepad) to makes it easier to undo an accidental NavInput press with no keyboard wired, but otherwise it isn't very useful.
         const bool nav_gamepad_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) != 0 && (io.BackendFlags & ImGuiBackendFlags_HasGamepad) != 0;
         const bool is_enter_pressed = IsKeyPressed(ImGuiKey_Enter, true) || IsKeyPressed(ImGuiKey_KeypadEnter, true);
         const bool is_gamepad_validate = nav_gamepad_active && (IsKeyPressed(ImGuiKey_NavGamepadActivate, false) || IsKeyPressed(ImGuiKey_NavGamepadInput, false));
-        const bool is_cancel = Shortcut(ImGuiKey_Escape, f_repeat, id) || (nav_gamepad_active && Shortcut(ImGuiKey_NavGamepadCancel, f_repeat, id));
+        const bool is_cancel = Shortcut(ImGuiKey_Escape, id, f_repeat) || (nav_gamepad_active && Shortcut(ImGuiKey_NavGamepadCancel, id, f_repeat));
 
         // FIXME: Should use more Shortcut() and reduce IsKeyPressed()+SetKeyOwner(), but requires modifiers combination to be taken account of.
-        // FIXME-OSX: Missing support for Alt(option)+Right/Left = go to end of line, or next line if already in end of line.
         if (IsKeyPressed(ImGuiKey_LeftArrow))                        { state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_LINESTART : is_wordmove_key_down ? STB_TEXTEDIT_K_WORDLEFT : STB_TEXTEDIT_K_LEFT) | k_mask); }
         else if (IsKeyPressed(ImGuiKey_RightArrow))                  { state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_LINEEND : is_wordmove_key_down ? STB_TEXTEDIT_K_WORDRIGHT : STB_TEXTEDIT_K_RIGHT) | k_mask); }
         else if (IsKeyPressed(ImGuiKey_UpArrow) && is_multiline)     { if (io.KeyCtrl) SetScrollY(draw_window, ImMax(draw_window->Scroll.y - g.FontSize, 0.0f)); else state->OnKeyPressed((is_startend_key_down ? STB_TEXTEDIT_K_TEXTSTART : STB_TEXTEDIT_K_UP) | k_mask); }
@@ -4563,7 +4513,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
             {
                 if (is_wordmove_key_down)
                     state->OnKeyPressed(STB_TEXTEDIT_K_WORDLEFT | STB_TEXTEDIT_K_SHIFT);
-                else if (is_osx && io.KeyCtrl && !io.KeyAlt && !io.KeySuper)
+                else if (is_osx && io.KeySuper && !io.KeyAlt && !io.KeyCtrl)
                     state->OnKeyPressed(STB_TEXTEDIT_K_LINESTART | STB_TEXTEDIT_K_SHIFT);
             }
             state->OnKeyPressed(STB_TEXTEDIT_K_BACKSPACE | k_mask);
@@ -4733,7 +4683,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
                 // The reason we specify the usage semantic (Completion/History) is that Completion needs to disable keyboard TABBING at the moment.
                 ImGuiInputTextFlags event_flag = 0;
                 ImGuiKey event_key = ImGuiKey_None;
-                if ((flags & ImGuiInputTextFlags_CallbackCompletion) != 0 && Shortcut(ImGuiKey_Tab, 0, id))
+                if ((flags & ImGuiInputTextFlags_CallbackCompletion) != 0 && Shortcut(ImGuiKey_Tab, id))
                 {
                     event_flag = ImGuiInputTextFlags_CallbackCompletion;
                     event_key = ImGuiKey_Tab;
@@ -5049,6 +4999,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
                 g.PlatformImeData.WantVisible = true;
                 g.PlatformImeData.InputPos = ImVec2(cursor_screen_pos.x - 1.0f, cursor_screen_pos.y - g.FontSize);
                 g.PlatformImeData.InputLineHeight = g.FontSize;
+                g.PlatformImeViewport = window->Viewport->ID;
             }
         }
     }
@@ -6238,17 +6189,13 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
         label_end = FindRenderedTextEnd(label);
     const ImVec2 label_size = CalcTextSize(label, label_end, false);
 
-    const float text_offset_x = g.FontSize + (display_frame ? padding.x * 3 : padding.x * 2);   // Collapsing arrow width + Spacing
-    const float text_offset_y = ImMax(padding.y, window->DC.CurrLineTextBaseOffset);            // Latch before ItemSize changes it
-    const float text_width = g.FontSize + label_size.x + padding.x * 2;                         // Include collapsing arrow
-
     // We vertically grow up to current line height up the typical widget height.
     const float frame_height = ImMax(ImMin(window->DC.CurrLineSize.y, g.FontSize + style.FramePadding.y * 2), label_size.y + padding.y * 2);
     const bool span_all_columns = (flags & ImGuiTreeNodeFlags_SpanAllColumns) != 0 && (g.CurrentTable != NULL);
     ImRect frame_bb;
     frame_bb.Min.x = span_all_columns ? window->ParentWorkRect.Min.x : (flags & ImGuiTreeNodeFlags_SpanFullWidth) ? window->WorkRect.Min.x : window->DC.CursorPos.x;
     frame_bb.Min.y = window->DC.CursorPos.y;
-    frame_bb.Max.x = span_all_columns ? window->ParentWorkRect.Max.x : (flags & ImGuiTreeNodeFlags_SpanTextWidth) ? window->DC.CursorPos.x + text_width + padding.x : window->WorkRect.Max.x;
+    frame_bb.Max.x = span_all_columns ? window->ParentWorkRect.Max.x : window->WorkRect.Max.x;
     frame_bb.Max.y = window->DC.CursorPos.y + frame_height;
     if (display_frame)
     {
@@ -6258,13 +6205,16 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
         frame_bb.Max.x += IM_TRUNC(window->WindowPadding.x * 0.5f);
     }
 
+    const float text_offset_x = g.FontSize + (display_frame ? padding.x * 3 : padding.x * 2);           // Collapsing arrow width + Spacing
+    const float text_offset_y = ImMax(padding.y, window->DC.CurrLineTextBaseOffset);                    // Latch before ItemSize changes it
+    const float text_width = g.FontSize + (label_size.x > 0.0f ? label_size.x + padding.x * 2 : 0.0f);  // Include collapsing
     ImVec2 text_pos(window->DC.CursorPos.x + text_offset_x, window->DC.CursorPos.y + text_offset_y);
     ItemSize(ImVec2(text_width, frame_height), padding.y);
 
     // For regular tree nodes, we arbitrary allow to click past 2 worth of ItemSpacing
     ImRect interact_bb = frame_bb;
-    if ((flags & (ImGuiTreeNodeFlags_Framed | ImGuiTreeNodeFlags_SpanAvailWidth | ImGuiTreeNodeFlags_SpanFullWidth | ImGuiTreeNodeFlags_SpanTextWidth | ImGuiTreeNodeFlags_SpanAllColumns)) == 0)
-        interact_bb.Max.x = frame_bb.Min.x + text_width + (label_size.x > 0.0f ? style.ItemSpacing.x * 2.0f : 0.0f);
+    if (!display_frame && (flags & (ImGuiTreeNodeFlags_SpanAvailWidth | ImGuiTreeNodeFlags_SpanFullWidth | ImGuiTreeNodeFlags_SpanAllColumns)) == 0)
+        interact_bb.Max.x = frame_bb.Min.x + text_width + style.ItemSpacing.x * 2.0f;
 
     // Modify ClipRect for the ItemAdd(), faster than doing a PushColumnsBackground/PushTableBackgroundChannel for every Selectable..
     const float backup_clip_rect_min_x = window->ClipRect.Min.x;
@@ -6516,7 +6466,7 @@ void ImGui::SetNextItemOpen(bool is_open, ImGuiCond cond)
         return;
     g.NextItemData.Flags |= ImGuiNextItemDataFlags_HasOpen;
     g.NextItemData.OpenVal = is_open;
-    g.NextItemData.OpenCond = (ImU8)(cond ? cond : ImGuiCond_Always);
+    g.NextItemData.OpenCond = cond ? cond : ImGuiCond_Always;
 }
 
 // CollapsingHeader returns true when opened but do not indent nor push into the ID stack (because of the ImGuiTreeNodeFlags_NoTreePushOnOpen flag).
@@ -6800,7 +6750,7 @@ ImGuiTypingSelectRequest* ImGui::GetTypingSelectRequest(ImGuiTypingSelectFlags f
     g.IO.InputQueueCharacters.resize(0);
 
     // Handle backspace
-    if ((flags & ImGuiTypingSelectFlags_AllowBackspace) && IsKeyPressed(ImGuiKey_Backspace, ImGuiInputFlags_Repeat))
+    if ((flags & ImGuiTypingSelectFlags_AllowBackspace) && IsKeyPressed(ImGuiKey_Backspace, 0, ImGuiInputFlags_Repeat))
     {
         char* p = (char*)(void*)ImTextFindPreviousUtf8Codepoint(data->SearchBuffer, data->SearchBuffer + buffer_len);
         *p = 0;
@@ -7032,7 +6982,6 @@ bool ImGui::ListBox(const char* label, int* current_item, const char* (*getter)(
     bool value_changed = false;
     ImGuiListClipper clipper;
     clipper.Begin(items_count, GetTextLineHeightWithSpacing()); // We know exactly our line height here so we pass it as a minor optimization, but generally you don't need to.
-    clipper.IncludeItemByIndex(*current_item);
     while (clipper.Step())
         for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
         {
@@ -7406,10 +7355,10 @@ bool ImGui::BeginViewportSideBar(const char* name, ImGuiViewport* viewport_p, Im
     IM_ASSERT(dir != ImGuiDir_None);
 
     ImGuiWindow* bar_window = FindWindowByName(name);
+    ImGuiViewportP* viewport = (ImGuiViewportP*)(void*)(viewport_p ? viewport_p : GetMainViewport());
     if (bar_window == NULL || bar_window->BeginCount == 0)
     {
         // Calculate and set window size/position
-        ImGuiViewportP* viewport = (ImGuiViewportP*)(void*)(viewport_p ? viewport_p : GetMainViewport());
         ImRect avail_rect = viewport->GetBuildWorkRect();
         ImGuiAxis axis = (dir == ImGuiDir_Up || dir == ImGuiDir_Down) ? ImGuiAxis_Y : ImGuiAxis_X;
         ImVec2 pos = avail_rect.Min;
@@ -7427,7 +7376,8 @@ bool ImGui::BeginViewportSideBar(const char* name, ImGuiViewport* viewport_p, Im
             viewport->BuildWorkOffsetMax[axis] -= axis_size;
     }
 
-    window_flags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove;
+    window_flags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoDocking;
+    SetNextWindowViewport(viewport->ID); // Enforce viewport so we don't create our own viewport when ImGuiConfigFlags_ViewportsNoMerge is set.
     PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
     PushStyleVar(ImGuiStyleVar_WindowMinSize, ImVec2(0, 0)); // Lift normal size constraint
     bool is_open = Begin(name, NULL, window_flags);
@@ -7441,6 +7391,9 @@ bool ImGui::BeginMainMenuBar()
     ImGuiContext& g = *GImGui;
     ImGuiViewportP* viewport = (ImGuiViewportP*)(void*)GetMainViewport();
 
+    // Notify of viewport change so GetFrameHeight() can be accurate in case of DPI change
+    SetCurrentViewport(NULL, viewport);
+
     // For the main menu bar, which cannot be moved, we honor g.Style.DisplaySafeAreaPadding to ensure text can be visible on a TV set.
     // FIXME: This could be generalized as an opt-in way to clamp window->DC.CursorStartPos to avoid SafeArea?
     // FIXME: Consider removing support for safe area down the line... it's messy. Nowadays consoles have support for TV calibration in OS settings.
@@ -7491,7 +7444,7 @@ static bool IsRootOfOpenMenuSet()
     const ImGuiPopupData* upper_popup = &g.OpenPopupStack[g.BeginPopupStack.Size];
     if (window->DC.NavLayerCurrent != upper_popup->ParentNavLayer)
         return false;
-    return upper_popup->Window && (upper_popup->Window->Flags & ImGuiWindowFlags_ChildMenu) && ImGui::IsWindowChildOf(upper_popup->Window, window, true);
+    return upper_popup->Window && (upper_popup->Window->Flags & ImGuiWindowFlags_ChildMenu) && ImGui::IsWindowChildOf(upper_popup->Window, window, true, false);
 }
 
 bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
@@ -7551,7 +7504,7 @@ bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
         // Menu inside an horizontal menu bar
         // Selectable extend their highlight by half ItemSpacing in each direction.
         // For ChildMenu, the popup position will be overwritten by the call to FindBestWindowPosForPopup() in Begin()
-        popup_pos = ImVec2(pos.x - 1.0f - IM_TRUNC(style.ItemSpacing.x * 0.5f), pos.y - style.FramePadding.y + window->MenuBarHeight);
+        popup_pos = ImVec2(pos.x - 1.0f - IM_TRUNC(style.ItemSpacing.x * 0.5f), pos.y - style.FramePadding.y + window->MenuBarHeight());
         window->DC.CursorPos.x += IM_TRUNC(style.ItemSpacing.x * 0.5f);
         PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(style.ItemSpacing.x * 2.0f, style.ItemSpacing.y));
         float w = label_size.x;
@@ -7830,8 +7783,10 @@ bool ImGui::MenuItem(const char* label, const char* shortcut, bool* p_selected,
 // - TabBarCalcMaxTabWidth() [Internal]
 // - TabBarFindTabById() [Internal]
 // - TabBarFindTabByOrder() [Internal]
+// - TabBarFindMostRecentlySelectedTabForActiveWindow() [Internal]
 // - TabBarGetCurrentTab() [Internal]
 // - TabBarGetTabName() [Internal]
+// - TabBarAddTab() [Internal]
 // - TabBarRemoveTab() [Internal]
 // - TabBarCloseTab() [Internal]
 // - TabBarScrollClamp() [Internal]
@@ -7950,7 +7905,8 @@ bool    ImGui::BeginTabBarEx(ImGuiTabBar* tab_bar, const ImRect& tab_bar_bb, ImG
 
     // Ensure correct ordering when toggling ImGuiTabBarFlags_Reorderable flag, or when a new tab was added while being not reorderable
     if ((flags & ImGuiTabBarFlags_Reorderable) != (tab_bar->Flags & ImGuiTabBarFlags_Reorderable) || (tab_bar->TabsAddedNew && !(flags & ImGuiTabBarFlags_Reorderable)))
-        ImQsort(tab_bar->Tabs.Data, tab_bar->Tabs.Size, sizeof(ImGuiTabItem), TabItemComparerByBeginOrder);
+        if ((flags & ImGuiTabBarFlags_DockNode) == 0) // FIXME: TabBar with DockNode can now be hybrid
+            ImQsort(tab_bar->Tabs.Data, tab_bar->Tabs.Size, sizeof(ImGuiTabItem), TabItemComparerByBeginOrder);
     tab_bar->TabsAddedNew = false;
 
     // Flags
@@ -8232,6 +8188,10 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
     tab_bar->VisibleTabId = tab_bar->SelectedTabId;
     tab_bar->VisibleTabWasSubmitted = false;
 
+    // CTRL+TAB can override visible tab temporarily
+    if (g.NavWindowingTarget != NULL && g.NavWindowingTarget->DockNode && g.NavWindowingTarget->DockNode->TabBar == tab_bar)
+        tab_bar->VisibleTabId = scroll_to_tab_id = g.NavWindowingTarget->TabId;
+
     // Apply request requests
     if (scroll_to_tab_id != 0)
         TabBarScrollToTab(tab_bar, scroll_to_tab_id, sections);
@@ -8277,11 +8237,11 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
 // Dockable windows uses Name/ID in the global namespace. Non-dockable items use the ID stack.
 static ImU32   ImGui::TabBarCalcTabID(ImGuiTabBar* tab_bar, const char* label, ImGuiWindow* docked_window)
 {
-    IM_ASSERT(docked_window == NULL); // master branch only
-    IM_UNUSED(docked_window);
-    if (tab_bar->Flags & ImGuiTabBarFlags_DockNode)
+    if (docked_window != NULL)
     {
-        ImGuiID id = ImHashStr(label);
+        IM_UNUSED(tab_bar);
+        IM_ASSERT(tab_bar->Flags & ImGuiTabBarFlags_DockNode);
+        ImGuiID id = docked_window->TabId;
         KeepAliveID(id);
         return id;
     }
@@ -8315,21 +8275,58 @@ ImGuiTabItem* ImGui::TabBarFindTabByOrder(ImGuiTabBar* tab_bar, int order)
     return &tab_bar->Tabs[order];
 }
 
+// FIXME: See references to #2304 in TODO.txt
+ImGuiTabItem* ImGui::TabBarFindMostRecentlySelectedTabForActiveWindow(ImGuiTabBar* tab_bar)
+{
+    ImGuiTabItem* most_recently_selected_tab = NULL;
+    for (int tab_n = 0; tab_n < tab_bar->Tabs.Size; tab_n++)
+    {
+        ImGuiTabItem* tab = &tab_bar->Tabs[tab_n];
+        if (most_recently_selected_tab == NULL || most_recently_selected_tab->LastFrameSelected < tab->LastFrameSelected)
+            if (tab->Window && tab->Window->WasActive)
+                most_recently_selected_tab = tab;
+    }
+    return most_recently_selected_tab;
+}
+
 ImGuiTabItem* ImGui::TabBarGetCurrentTab(ImGuiTabBar* tab_bar)
 {
-    if (tab_bar->LastTabItemIdx < 0 || tab_bar->LastTabItemIdx >= tab_bar->Tabs.Size)
+    if (tab_bar->LastTabItemIdx <= 0 || tab_bar->LastTabItemIdx >= tab_bar->Tabs.Size)
         return NULL;
     return &tab_bar->Tabs[tab_bar->LastTabItemIdx];
 }
 
 const char* ImGui::TabBarGetTabName(ImGuiTabBar* tab_bar, ImGuiTabItem* tab)
 {
+    if (tab->Window)
+        return tab->Window->Name;
     if (tab->NameOffset == -1)
         return "N/A";
     IM_ASSERT(tab->NameOffset < tab_bar->TabsNames.Buf.Size);
     return tab_bar->TabsNames.Buf.Data + tab->NameOffset;
 }
 
+// The purpose of this call is to register tab in advance so we can control their order at the time they appear.
+// Otherwise calling this is unnecessary as tabs are appending as needed by the BeginTabItem() function.
+void ImGui::TabBarAddTab(ImGuiTabBar* tab_bar, ImGuiTabItemFlags tab_flags, ImGuiWindow* window)
+{
+    ImGuiContext& g = *GImGui;
+    IM_ASSERT(TabBarFindTabByID(tab_bar, window->TabId) == NULL);
+    IM_ASSERT(g.CurrentTabBar != tab_bar);  // Can't work while the tab bar is active as our tab doesn't have an X offset yet, in theory we could/should test something like (tab_bar->CurrFrameVisible < g.FrameCount) but we'd need to solve why triggers the commented early-out assert in BeginTabBarEx() (probably dock node going from implicit to explicit in same frame)
+
+    if (!window->HasCloseButton)
+        tab_flags |= ImGuiTabItemFlags_NoCloseButton;       // Set _NoCloseButton immediately because it will be used for first-frame width calculation.
+
+    ImGuiTabItem new_tab;
+    new_tab.ID = window->TabId;
+    new_tab.Flags = tab_flags;
+    new_tab.LastFrameVisible = tab_bar->CurrFrameVisible;   // Required so BeginTabBar() doesn't ditch the tab
+    if (new_tab.LastFrameVisible == -1)
+        new_tab.LastFrameVisible = g.FrameCount - 1;
+    new_tab.Window = window;                                // Required so tab bar layout can compute the tab width before tab submission
+    tab_bar->Tabs.push_back(new_tab);
+}
+
 // The *TabId fields are already set by the docking system _before_ the actual TabItem was created, so we clear them regardless.
 void ImGui::TabBarRemoveTab(ImGuiTabBar* tab_bar, ImGuiID tab_id)
 {
@@ -8610,7 +8607,7 @@ bool    ImGui::BeginTabItem(const char* label, bool* p_open, ImGuiTabItemFlags f
         IM_ASSERT_USER_ERROR(tab_bar, "Needs to be called between BeginTabBar() and EndTabBar()!");
         return false;
     }
-    IM_ASSERT(!(flags & ImGuiTabItemFlags_Button)); // BeginTabItem() Can't be used with button flags, use TabItemButton() instead!
+    IM_ASSERT((flags & ImGuiTabItemFlags_Button) == 0);             // BeginTabItem() Can't be used with button flags, use TabItemButton() instead!
 
     bool ret = TabItemEx(tab_bar, label, p_open, flags, NULL);
     if (ret && !(flags & ImGuiTabItemFlags_NoPushId))
@@ -8720,11 +8717,14 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     const bool is_tab_button = (flags & ImGuiTabItemFlags_Button) != 0;
     tab->LastFrameVisible = g.FrameCount;
     tab->Flags = flags;
+    tab->Window = docked_window;
 
     // Append name _WITH_ the zero-terminator
+    // (regular tabs are permitted in a DockNode tab bar, but window tabs not permitted in a non-DockNode tab bar)
     if (docked_window != NULL)
     {
-        IM_ASSERT(docked_window == NULL); // master branch only
+        IM_ASSERT(tab_bar->Flags & ImGuiTabBarFlags_DockNode);
+        tab->NameOffset = -1;
     }
     else
     {
@@ -8749,7 +8749,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
         tab_bar->VisibleTabWasSubmitted = true;
 
     // On the very first frame of a tab bar we let first tab contents be visible to minimize appearing glitches
-    if (!tab_contents_visible && tab_bar->SelectedTabId == 0 && tab_bar_appearing)
+    if (!tab_contents_visible && tab_bar->SelectedTabId == 0 && tab_bar_appearing && docked_window == NULL)
         if (tab_bar->Tabs.Size == 1 && !(tab_bar->Flags & ImGuiTabBarFlags_AutoSelectNewTabs))
             tab_contents_visible = true;
 
@@ -8797,30 +8797,82 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     }
 
     // Click to Select a tab
-    // Allow the close button to overlap
     ImGuiButtonFlags button_flags = ((is_tab_button ? ImGuiButtonFlags_PressedOnClickRelease : ImGuiButtonFlags_PressedOnClick) | ImGuiButtonFlags_AllowOverlap);
-    if (g.DragDropActive)
+    if (g.DragDropActive && !g.DragDropPayload.IsDataType(IMGUI_PAYLOAD_TYPE_WINDOW)) // FIXME: May be an opt-in property of the payload to disable this
         button_flags |= ImGuiButtonFlags_PressedOnDragDropHold;
     bool hovered, held;
     bool pressed = ButtonBehavior(bb, id, &hovered, &held, button_flags);
     if (pressed && !is_tab_button)
         TabBarQueueFocus(tab_bar, tab);
 
-    // Drag and drop: re-order tabs
-    if (held && !tab_appearing && IsMouseDragging(0))
+    // Transfer active id window so the active id is not owned by the dock host (as StartMouseMovingWindow()
+    // will only do it on the drag). This allows FocusWindow() to be more conservative in how it clears active id.
+    if (held && docked_window && g.ActiveId == id && g.ActiveIdIsJustActivated)
+        g.ActiveIdWindow = docked_window;
+
+    // Drag and drop a single floating window node moves it
+    ImGuiDockNode* node = docked_window ? docked_window->DockNode : NULL;
+    const bool single_floating_window_node = node && node->IsFloatingNode() && (node->Windows.Size == 1);
+    if (held && single_floating_window_node && IsMouseDragging(0, 0.0f))
     {
-        if (!g.DragDropActive && (tab_bar->Flags & ImGuiTabBarFlags_Reorderable))
+        // Move
+        StartMouseMovingWindow(docked_window);
+    }
+    else if (held && !tab_appearing && IsMouseDragging(0))
+    {
+        // Drag and drop: re-order tabs
+        int drag_dir = 0;
+        float drag_distance_from_edge_x = 0.0f;
+        if (!g.DragDropActive && ((tab_bar->Flags & ImGuiTabBarFlags_Reorderable) || (docked_window != NULL)))
         {
             // While moving a tab it will jump on the other side of the mouse, so we also test for MouseDelta.x
             if (g.IO.MouseDelta.x < 0.0f && g.IO.MousePos.x < bb.Min.x)
             {
+                drag_dir = -1;
+                drag_distance_from_edge_x = bb.Min.x - g.IO.MousePos.x;
                 TabBarQueueReorderFromMousePos(tab_bar, tab, g.IO.MousePos);
             }
             else if (g.IO.MouseDelta.x > 0.0f && g.IO.MousePos.x > bb.Max.x)
             {
+                drag_dir = +1;
+                drag_distance_from_edge_x = g.IO.MousePos.x - bb.Max.x;
                 TabBarQueueReorderFromMousePos(tab_bar, tab, g.IO.MousePos);
             }
         }
+
+        // Extract a Dockable window out of it's tab bar
+        const bool can_undock = docked_window != NULL && !(docked_window->Flags & ImGuiWindowFlags_NoMove) && !(node->MergedFlags & ImGuiDockNodeFlags_NoUndocking);
+        if (can_undock)
+        {
+            // We use a variable threshold to distinguish dragging tabs within a tab bar and extracting them out of the tab bar
+            bool undocking_tab = (g.DragDropActive && g.DragDropPayload.SourceId == id);
+            if (!undocking_tab) //&& (!g.IO.ConfigDockingWithShift || g.IO.KeyShift)
+            {
+                float threshold_base = g.FontSize;
+                float threshold_x = (threshold_base * 2.2f);
+                float threshold_y = (threshold_base * 1.5f) + ImClamp((ImFabs(g.IO.MouseDragMaxDistanceAbs[0].x) - threshold_base * 2.0f) * 0.20f, 0.0f, threshold_base * 4.0f);
+                //GetForegroundDrawList()->AddRect(ImVec2(bb.Min.x - threshold_x, bb.Min.y - threshold_y), ImVec2(bb.Max.x + threshold_x, bb.Max.y + threshold_y), IM_COL32_WHITE); // [DEBUG]
+
+                float distance_from_edge_y = ImMax(bb.Min.y - g.IO.MousePos.y, g.IO.MousePos.y - bb.Max.y);
+                if (distance_from_edge_y >= threshold_y)
+                    undocking_tab = true;
+                if (drag_distance_from_edge_x > threshold_x)
+                    if ((drag_dir < 0 && TabBarGetTabOrder(tab_bar, tab) == 0) || (drag_dir > 0 && TabBarGetTabOrder(tab_bar, tab) == tab_bar->Tabs.Size - 1))
+                        undocking_tab = true;
+            }
+
+            if (undocking_tab)
+            {
+                // Undock
+                // FIXME: refactor to share more code with e.g. StartMouseMovingWindow
+                DockContextQueueUndockWindow(&g, docked_window);
+                g.MovingWindow = docked_window;
+                SetActiveID(g.MovingWindow->MoveId, g.MovingWindow);
+                g.ActiveIdClickOffset -= g.MovingWindow->Pos - bb.Min;
+                g.ActiveIdNoClearOnFocusLoss = true;
+                SetActiveIdUsingAllKeyboardKeys();
+            }
+        }
     }
 
 #if 0
@@ -8848,7 +8900,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
         flags |= ImGuiTabItemFlags_NoCloseWithMiddleMouseButton;
 
     // Render tab label, process close button
-    const ImGuiID close_button_id = p_open ? GetIDWithSeed("#CLOSE", NULL, id) : 0;
+    const ImGuiID close_button_id = p_open ? GetIDWithSeed("#CLOSE", NULL, docked_window ? docked_window->ID : id) : 0;
     bool just_closed;
     bool text_clipped;
     TabItemLabelAndCloseButton(display_draw_list, bb, tab_just_unsaved ? (flags & ~ImGuiTabItemFlags_UnsavedDocument) : flags, tab_bar->FramePadding, label, id, close_button_id, tab_contents_visible, &just_closed, &text_clipped);
@@ -8858,6 +8910,11 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
         TabBarCloseTab(tab_bar, tab);
     }
 
+    // Forward Hovered state so IsItemHovered() after Begin() can work (even though we are technically hovering our parent)
+    // That state is copied to window->DockTabItemStatusFlags by our caller.
+    if (docked_window && (hovered || g.HoveredId == close_button_id))
+        g.LastItemData.StatusFlags |= ImGuiItemStatusFlags_HoveredWindow;
+
     // Restore main window position so user can draw there
     if (want_clip_rect)
         PopClipRect();
@@ -8892,6 +8949,16 @@ void    ImGui::SetTabItemClosed(const char* label)
         if (ImGuiTabItem* tab = TabBarFindTabByID(tab_bar, tab_id))
             tab->WantClose = true; // Will be processed by next call to TabBarLayout()
     }
+    else if (ImGuiWindow* window = FindWindowByName(label))
+    {
+        if (window->DockIsActive)
+            if (ImGuiDockNode* node = window->DockNode)
+            {
+                ImGuiID tab_id = TabBarCalcTabID(node->TabBar, label, window);
+                TabBarRemoveTab(node->TabBar, tab_id);
+                window->DockTabWantClose = true;
+            }
+    }
 }
 
 ImVec2 ImGui::TabItemCalcSize(const char* label, bool has_close_button_or_unsaved_marker)
@@ -8906,10 +8973,9 @@ ImVec2 ImGui::TabItemCalcSize(const char* label, bool has_close_button_or_unsave
     return ImVec2(ImMin(size.x, TabBarCalcMaxTabWidth()), size.y);
 }
 
-ImVec2 ImGui::TabItemCalcSize(ImGuiWindow*)
+ImVec2 ImGui::TabItemCalcSize(ImGuiWindow* window)
 {
-    IM_ASSERT(0); // This function exists to facilitate merge with 'docking' branch.
-    return ImVec2(0.0f, 0.0f);
+    return TabItemCalcSize(window->Name, window->HasCloseButton || (window->Flags & ImGuiWindowFlags_UnsavedDocument));
 }
 
 void ImGui::TabItemBackground(ImDrawList* draw_list, const ImRect& bb, ImGuiTabItemFlags flags, ImU32 col)

imstb_textedit.h

@@ -41,7 +41,7 @@
 //   1.13 (2019-02-07) fix bug in undo size management
 //   1.12 (2018-01-29) user can change STB_TEXTEDIT_KEYTYPE, fix redo to avoid crash
 //   1.11 (2017-03-03) fix HOME on last line, dragging off single-line textfield
-//   1.10 (2016-10-25) suppress warnings about casting away const with -Wcast-qual
+//   1.10 (2016-10-25) supress warnings about casting away const with -Wcast-qual
 //   1.9  (2016-08-27) customizable move-by-word
 //   1.8  (2016-04-02) better keyboard handling when mouse button is down
 //   1.7  (2015-09-13) change y range handling in case baseline is non-0

imstb_truetype.h

@@ -656,7 +656,7 @@ STBTT_DEF void stbtt_PackSetOversampling(stbtt_pack_context *spc, unsigned int h
 STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip);
 // If skip != 0, this tells stb_truetype to skip any codepoints for which
 // there is no corresponding glyph. If skip=0, which is the default, then
-// codepoints without a glyph received the font's "missing character" glyph,
+// codepoints without a glyph recived the font's "missing character" glyph,
 // typically an empty box by convention.
 
 STBTT_DEF void stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph,  // same data as above

misc/debuggers/imgui.natvis

@@ -55,4 +55,8 @@ More information at: https://docs.microsoft.com/en-us/visualstudio/debugger/crea
   <DisplayString>{{Name {Name,s} Active {(Active||WasActive)?1:0,d} Child {(Flags &amp; 0x01000000)?1:0,d} Popup {(Flags &amp; 0x04000000)?1:0,d} Hidden {(Hidden)?1:0,d}}</DisplayString>
 </Type>
 
+<Type Name="ImGuiDockNode">
+  <DisplayString>{{ID {ID,x} Pos=({Pos.x,g} {Pos.y,g}) Size=({Size.x,g} {Size.y,g}) Parent {(ParentNode==0)?0:ParentNode->ID,x} Childs {(ChildNodes[0] != 0)+(ChildNodes[1] != 0)} Windows {Windows.Size}  }</DisplayString>
+</Type>
+
 </AutoVisualizer>

misc/freetype/imgui_freetype.cpp

@@ -11,7 +11,7 @@
 //  2023/01/04: fixed a packing issue which in some occurrences would prevent large amount of glyphs from being packed correctly.
 //  2021/08/23: fixed crash when FT_Render_Glyph() fails to render a glyph and returns NULL.
 //  2021/03/05: added ImGuiFreeTypeBuilderFlags_Bitmap to load bitmap glyphs.
-//  2021/03/02: set 'atlas->TexPixelsUseColors = true' to help some backends with deciding of a preferred texture format.
+//  2021/03/02: set 'atlas->TexPixelsUseColors = true' to help some backends with deciding of a prefered texture format.
 //  2021/01/28: added support for color-layered glyphs via ImGuiFreeTypeBuilderFlags_LoadColor (require Freetype 2.10+).
 //  2021/01/26: simplified integration by using '#define IMGUI_ENABLE_FREETYPE'. renamed ImGuiFreeType::XXX flags to ImGuiFreeTypeBuilderFlags_XXX for consistency with other API. removed ImGuiFreeType::BuildFontAtlas().
 //  2020/06/04: fix for rare case where FT_Get_Char_Index() succeed but FT_Load_Glyph() fails.