Examples: Win32+DX9/DX10/DX11/DX12, SDL2+DX11/OpenGL2/OpenGL3/SDLRenderer/Vulkan, SDL3+OpenGL/SDLGPU/SDLRenderer/Vulkan: made example DPI aware by default. (master + docking: partial support for multi-dpi by scaling fonts + viewports but not style)

We don't bother with WIN32_LEAN_AND_MEAN.

# Conflicts:
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_sdl2_directx11/main.cpp
#	examples/example_sdl2_opengl2/main.cpp
#	examples/example_sdl2_opengl3/main.cpp
#	examples/example_sdl2_vulkan/main.cpp
#	examples/example_sdl3_opengl3/main.cpp
#	examples/example_sdl3_sdlgpu3/main.cpp
#	examples/example_sdl3_vulkan/main.cpp
#	examples/example_win32_directx10/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp

examples/example_sdl3_sdlgpu3/main.cpp

@@ -34,8 +34,9 @@ int main(int, char**)
     }
 
     // Create SDL window graphics context
+    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
     SDL_WindowFlags window_flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
-    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_GPU example", 1280, 720, window_flags);
+    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_GPU example", (int)(1280 * main_scale), (int)(720 * main_scale), window_flags);
     if (window == nullptr)
     {
         printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
@@ -71,6 +72,11 @@ int main(int, char**)
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsLight();
 
+    // Setup scaling
+    ImGuiStyle& style = ImGui::GetStyle();
+    style.ScaleAllSizes(main_scale);        // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again)
+    style.FontScaleDpi = main_scale;        // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose)
+
     // Setup Platform/Renderer backends
     ImGui_ImplSDL3_InitForSDLGPU(window);
     ImGui_ImplSDLGPU3_InitInfo init_info = {};