Backends: GLFW+Emscripten: (Breaking) Renamed ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback() to ImGui_ImplGlfw_InstallEmscriptenCallbacks(), added GLFWwindow* parameter. (#7647, #7600)

+ Fixed Emscripten warning when using mouse wheel on some setups.

Author: ypujante

backends/imgui_impl_glfw.cpp

@@ -20,6 +20,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2024-07-08: *BREAKING* Renamed ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback to ImGui_ImplGlfw_InstallEmscriptenCallbacks(), added GLFWWindow* parameter.
 //  2024-07-02: Emscripten: Added io.PlatformOpenInShellFn() handler for Emscripten versions.
 //  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.
@@ -611,12 +612,6 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     // Chain GLFW callbacks: our callbacks will call the user's previously installed callbacks, if any.
     if (install_callbacks)
         ImGui_ImplGlfw_InstallCallbacks(window);
-    // Register Emscripten Wheel callback to workaround issue in Emscripten GLFW Emulation (#6096)
-    // We intentionally do not check 'if (install_callbacks)' here, as some users may set it to false and call GLFW callback themselves.
-    // FIXME: May break chaining in case user registered their own Emscripten callback?
-#ifdef __EMSCRIPTEN__
-    emscripten_set_wheel_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, nullptr, false, ImGui_ImplEmscripten_WheelCallback);
-#endif
 
     // Set platform dependent data in viewport
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();
@@ -664,7 +659,8 @@ void ImGui_ImplGlfw_Shutdown()
     if (bd->InstalledCallbacks)
         ImGui_ImplGlfw_RestoreCallbacks(bd->Window);
 #ifdef __EMSCRIPTEN__
-    emscripten_set_wheel_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, nullptr, false, nullptr);
+    if (bd->CanvasSelector)
+        emscripten_set_wheel_callback(bd->CanvasSelector, nullptr, false, nullptr);
 #endif
 
     for (ImGuiMouseCursor cursor_n = 0; cursor_n < ImGuiMouseCursor_COUNT; cursor_n++)
@@ -844,7 +840,7 @@ static EM_BOOL ImGui_ImplEmscripten_FullscreenChangeCallback(int event_type, con
 
 // 'canvas_selector' is a CSS selector. The event listener is applied to the first element that matches the query.
 // STRING MUST PERSIST FOR THE APPLICATION DURATION. PLEASE USE A STRING LITERAL OR ENSURE POINTER WILL STAY VALID.
-void ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_selector)
+void ImGui_ImplGlfw_InstallEmscriptenCallbacks(GLFWwindow*, const char* canvas_selector)
 {
     IM_ASSERT(canvas_selector != nullptr);
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
@@ -856,6 +852,11 @@ void ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_sel
 
     // Change the size of the GLFW window according to the size of the canvas
     ImGui_ImplGlfw_OnCanvasSizeChange(EMSCRIPTEN_EVENT_RESIZE, {}, bd);
+
+    // Register Emscripten Wheel callback to workaround issue in Emscripten GLFW Emulation (#6096)
+    // We intentionally do not check 'if (install_callbacks)' here, as some users may set it to false and call GLFW callback themselves.
+    // FIXME: May break chaining in case user registered their own Emscripten callback?
+    emscripten_set_wheel_callback(bd->CanvasSelector, nullptr, false, ImGui_ImplEmscripten_WheelCallback);
 }
 #endif
 

backends/imgui_impl_glfw.h

@@ -30,9 +30,10 @@ 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();
 
-// Emscripten related initialization phase methods
+// Emscripten related initialization phase methods (call after ImGui_ImplGlfw_InitForOpenGL)
 #ifdef __EMSCRIPTEN__
-IMGUI_IMPL_API void     ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_selector);
+IMGUI_IMPL_API void     ImGui_ImplGlfw_InstallEmscriptenCallbacks(GLFWwindow* window, const char* canvas_selector);
+//static inline void    ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback(const char* canvas_selector) { ImGui_ImplGlfw_InstallEmscriptenCallbacks(nullptr, canvas_selector); } } // Renamed in 1.91.0
 #endif
 
 // GLFW callbacks install

docs/CHANGELOG.txt

@@ -49,6 +49,8 @@ Breaking changes:
 - Commented out obsolete ImGuiModFlags (renamed to ImGuiKeyChord in 1.89). (#4921, #456)
 - Commented out obsolete ImGuiModFlags_XXX values (renamed to ImGuiMod_XXX in 1.89). (#4921, #456)
     - ImGuiModFlags_Ctrl -> ImGuiMod_Ctrl, ImGuiModFlags_Shift -> ImGuiMod_Shift etc.
+- Backends: GLFW+Emscripten: Renamed ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback() to
+  ImGui_ImplGlfw_InstallEmscriptenCallbacks(), with additional GLFWWindow* parameter. (#7647) [@ypujante]
 
 Other changes:
 
@@ -66,6 +68,8 @@ Other changes:
 - Backends: SDL2,SDL3,OSX: Update for io.SetPlatformImeDataFn() -> io.PlatformSetImeDataFn() rename.
 - Backends: GLFW,SDL2: Added io.PlatformOpenInShellFn handler for web/Emscripten versions. (#7660)
   [@ypujante, @ocornut]
+- Backends: GLFW+Emscripten: Fixed Emscripten warning when using mouse wheel on some setups
+  "Unable to preventDefault inside passive event listener". (#7647, #7600) [@ypujante]
 
 
 -----------------------------------------------------------------------

examples/example_glfw_opengl3/main.cpp

@@ -85,7 +85,7 @@ int main(int, char**)
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
 #ifdef __EMSCRIPTEN__
-    ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback("#canvas");
+    ImGui_ImplGlfw_InstallEmscriptenCallbacks(window, "#canvas");
 #endif
     ImGui_ImplOpenGL3_Init(glsl_version);
 

examples/example_glfw_wgpu/main.cpp

@@ -101,7 +101,7 @@ int main(int, char**)
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOther(window, true);
 #ifdef __EMSCRIPTEN__
-    ImGui_ImplGlfw_InstallEmscriptenCanvasResizeCallback("#canvas");
+    ImGui_ImplGlfw_InstallEmscriptenCallbacks(window, "#canvas");
 #endif
     ImGui_ImplWGPU_InitInfo init_info;
     init_info.Device = wgpu_device;