Viewports: Backported 'void* ImGuiViewport::PlatformHandle' from docking branch for use by backends.

backends/imgui_impl_glfw.cpp

@@ -145,7 +145,7 @@ struct ImGui_ImplGlfw_Data
     GLFWcharfun             PrevUserCallbackChar;
     GLFWmonitorfun          PrevUserCallbackMonitor;
 #ifdef _WIN32
-    WNDPROC                 GlfwWndProc;
+    WNDPROC                 PrevWndProc;
 #endif
 
     ImGui_ImplGlfw_Data()   { memset((void*)this, 0, sizeof(*this)); }
@@ -497,7 +497,7 @@ static LRESULT CALLBACK ImGui_ImplGlfw_WndProc(HWND hWnd, UINT msg, WPARAM wPara
         ImGui::GetIO().AddMouseSourceEvent(GetMouseSourceFromMessageExtraInfo());
         break;
     }
-    return ::CallWindowProcW(bd->GlfwWndProc, hWnd, msg, wParam, lParam);
+    return ::CallWindowProcW(bd->PrevWndProc, hWnd, msg, wParam, lParam);
 }
 #endif
 
@@ -612,6 +612,7 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 
     // 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__)
@@ -622,8 +623,8 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
 
     // 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
 
@@ -661,11 +662,11 @@ 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;

backends/imgui_impl_osx.mm

@@ -402,6 +402,8 @@ bool ImGui_ImplOSX_Init(NSView* view)
     //io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
 
     bd->Observer = [ImGuiObserver new];
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (__bridge_retained void*)bd->Window;
 
     // Load cursors. Some of them are undocumented.
     bd->MouseCursorHidden = false;

backends/imgui_impl_sdl2.cpp

@@ -397,7 +397,7 @@ 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();
@@ -448,6 +448,7 @@ 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 +482,13 @@ static bool ImGui_ImplSDL2_Init(SDL_Window* window, SDL_Renderer* renderer)
     SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0");
 #endif
 
+    (void)sdl_gl_context; // Unused in 'master' branch.
     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 +496,7 @@ bool ImGui_ImplSDL2_InitForVulkan(SDL_Window* window)
 #if !SDL_HAS_VULKAN
     IM_ASSERT(0 && "Unsupported");
 #endif
-    return ImGui_ImplSDL2_Init(window, nullptr);
+    return ImGui_ImplSDL2_Init(window, nullptr, nullptr);
 }
 
 bool ImGui_ImplSDL2_InitForD3D(SDL_Window* window)
@@ -503,22 +504,22 @@ 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();

backends/imgui_impl_sdl3.cpp

@@ -365,7 +365,7 @@ 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);

backends/imgui_impl_win32.cpp

@@ -169,7 +169,8 @@ static bool ImGui_ImplWin32_InitEx(void* hwnd, bool platform_has_own_dc)
     ImGui_ImplWin32_UpdateKeyboardCodePage();
 
     // Set platform dependent data in viewport
-    ImGui::GetMainViewport()->PlatformHandleRaw = (void*)hwnd;
+    ImGuiViewport* main_viewport = ImGui::GetMainViewport();
+    main_viewport->PlatformHandle = main_viewport->PlatformHandleRaw = (void*)bd->hWnd;
     IM_UNUSED(platform_has_own_dc); // Used in 'docking' branch
 
     // Dynamically load XInput library

docs/CHANGELOG.txt

@@ -81,6 +81,8 @@ Other changes:
   frame instead of last drag source frame, which makes a difference if not resubmitting
   payload every frame. (#143)
 - Debug Tools: Metrics/Debugger: Browsing a Storage perform hover lookup on identifier.
+- Viewports: Backported 'void* ImGuiViewport::PlatformHandle' from docking branch for
+  use by backends.
 - Backends: SDL3: Update for API removal of keysym field in SDL_KeyboardEvent. (#7728)
 - Backends: Vulkan: Remove Volk/ from volk.h #include directives. (#7722, #6582, #4854)
   [@martin-ejdestig]

imgui.h

@@ -2202,7 +2202,7 @@ 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()/io.ClearInputMouse() 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)
 
     //------------------------------------------------------------------
@@ -3240,6 +3240,7 @@ struct ImGuiViewport
     ImVec2              WorkSize;               // Work Area: Size of the viewport minus task bars, menu bars, status bars (<= Size)
 
     // Platform/Backend Dependent Data
+    void*               PlatformHandle;         // void* to hold higher-level, platform window handle (e.g. 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)
 
     ImGuiViewport()     { memset(this, 0, sizeof(*this)); }