Backends: GLFW: added ImGui_ImplGlfw_SetCallbacksChainForAllWindows(). (#6142)

backends/imgui_impl_glfw.cpp

@@ -108,6 +108,7 @@ struct ImGui_ImplGlfw_Data
     GLFWcursor*             MouseCursors[ImGuiMouseCursor_COUNT];
     ImVec2                  LastValidMousePos;
     bool                    InstalledCallbacks;
+    bool                    CallbacksChainForAllWindows;
 
     // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
     GLFWwindowfocusfun      PrevUserCallbackWindowFocus;
@@ -270,10 +271,16 @@ static void ImGui_ImplGlfw_UpdateKeyModifiers()
     io.AddKeyEvent(ImGuiMod_Super, (glfwGetKey(bd->Window, GLFW_KEY_LEFT_SUPER)   == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SUPER)   == GLFW_PRESS));
 }
 
+static bool ImGui_ImplGlfw_ShouldChainCallback(GLFWwindow* window)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    return bd->CallbacksChainForAllWindows ? true : (window == bd->Window);
+}
+
 void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackMousebutton != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackMousebutton != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackMousebutton(window, button, action, mods);
 
     ImGui_ImplGlfw_UpdateKeyModifiers();
@@ -286,7 +293,7 @@ void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int acti
 void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackScroll != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackScroll != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackScroll(window, xoffset, yoffset);
 
 #ifdef __EMSCRIPTEN__
@@ -334,7 +341,7 @@ static int ImGui_ImplGlfw_TranslateUntranslatedKey(int key, int scancode)
 void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, int action, int mods)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackKey != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackKey != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackKey(window, keycode, scancode, action, mods);
 
     if (action != GLFW_PRESS && action != GLFW_RELEASE)
@@ -353,7 +360,7 @@ void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, i
 void ImGui_ImplGlfw_WindowFocusCallback(GLFWwindow* window, int focused)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackWindowFocus != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackWindowFocus != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackWindowFocus(window, focused);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -363,7 +370,7 @@ void ImGui_ImplGlfw_WindowFocusCallback(GLFWwindow* window, int focused)
 void ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackCursorPos != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackCursorPos != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackCursorPos(window, x, y);
     if (glfwGetInputMode(window, GLFW_CURSOR) == GLFW_CURSOR_DISABLED)
         return;
@@ -378,7 +385,7 @@ void ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y)
 void ImGui_ImplGlfw_CursorEnterCallback(GLFWwindow* window, int entered)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackCursorEnter != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackCursorEnter != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackCursorEnter(window, entered);
     if (glfwGetInputMode(window, GLFW_CURSOR) == GLFW_CURSOR_DISABLED)
         return;
@@ -400,7 +407,7 @@ void ImGui_ImplGlfw_CursorEnterCallback(GLFWwindow* window, int entered)
 void ImGui_ImplGlfw_CharCallback(GLFWwindow* window, unsigned int c)
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
-    if (bd->PrevUserCallbackChar != nullptr && window == bd->Window)
+    if (bd->PrevUserCallbackChar != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackChar(window, c);
 
     ImGuiIO& io = ImGui::GetIO();
@@ -472,6 +479,16 @@ void ImGui_ImplGlfw_RestoreCallbacks(GLFWwindow* window)
     bd->PrevUserCallbackMonitor = nullptr;
 }
 
+// Set to 'true' to enable chaining installed callbacks for all windows (including secondary viewports created by backends or by user.
+// This is 'false' by default meaning we only chain callbacks for the main viewport.
+// We cannot set this to 'true' by default because user callbacks code may be not testing the 'window' parameter of their callback.
+// If you set this to 'true' your user callback code will need to make sure you are testing the 'window' parameter.
+void ImGui_ImplGlfw_SetCallbacksChainForAllWindows(bool chain_for_all_windows)
+{
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    bd->CallbacksChainForAllWindows = chain_for_all_windows;
+}
+
 static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, GlfwClientApi client_api)
 {
     ImGuiIO& io = ImGui::GetIO();

backends/imgui_impl_glfw.h

@@ -25,13 +25,17 @@ IMGUI_IMPL_API bool     ImGui_ImplGlfw_InitForOther(GLFWwindow* window, bool ins
 IMGUI_IMPL_API void     ImGui_ImplGlfw_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplGlfw_NewFrame();
 
-// GLFW callbacks (installer)
+// GLFW callbacks install
 // - When calling Init with 'install_callbacks=true': ImGui_ImplGlfw_InstallCallbacks() is called. GLFW callbacks will be installed for you. They will chain-call user's previously installed callbacks, if any.
 // - When calling Init with 'install_callbacks=false': GLFW callbacks won't be installed. You will need to call individual function yourself from your own GLFW callbacks.
 IMGUI_IMPL_API void     ImGui_ImplGlfw_InstallCallbacks(GLFWwindow* window);
 IMGUI_IMPL_API void     ImGui_ImplGlfw_RestoreCallbacks(GLFWwindow* window);
 
-// GLFW callbacks (individual callbacks to call if you didn't install callbacks)
+// GFLW callbacks options:
+// - Set 'chain_for_all_windows=true' to enable chaining callbacks for all windows (including secondary viewports created by backends or by user)
+IMGUI_IMPL_API void     ImGui_ImplGlfw_SetCallbacksChainForAllWindows(bool chain_for_all_windows);
+
+// GLFW callbacks (individual callbacks to call yourself if you didn't install callbacks)
 IMGUI_IMPL_API void     ImGui_ImplGlfw_WindowFocusCallback(GLFWwindow* window, int focused);        // Since 1.84
 IMGUI_IMPL_API void     ImGui_ImplGlfw_CursorEnterCallback(GLFWwindow* window, int entered);        // Since 1.84
 IMGUI_IMPL_API void     ImGui_ImplGlfw_CursorPosCallback(GLFWwindow* window, double x, double y);   // Since 1.87

docs/CHANGELOG.txt

@@ -90,6 +90,9 @@ All changes:
   is surprisingly costly on Mac with latest SDL (may be fixed in next SDL version). (#6113)
 - Backends: GLFW: Registering custom low-level mouse wheel handler to get more accurate
   scrolling impulses on Emscripten. (#4019, #6096) [@ocornut, @wolfpld, @tolopolarity]
+- Backends: GLFW: Added ImGui_ImplGlfw_SetCallbacksChainForAllWindows() to instruct backend
+  to chain callbacks even for secondary viewports/windows. User callbacks may need to test
+  the 'window' parameter. (#6142)
 - Backends: WebGPU: Fix building for latest WebGPU specs (remove implicit layout generation).
   (#6117, #4116, #3632) [@tonygrue, @bfierz]
 - Examples: refactord all examples to use a "MainLoopStep()" function. This is in order