Backends: GLFW+Emscripten: Added support for GLFW3 contrib port. (#7647)

backends/imgui_impl_glfw.cpp

@@ -21,6 +21,7 @@
 // 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.
+//  2024-07-08: Emscripten: Added support for GLFW3 contrib port (GLFW 3.4.0 features + bug fixes): to enable, replace -sUSE_GLFW=3 with --use-port=contrib.glfw3 (requires emscripten 3.1.59+) (https://github.com/pongasoft/emscripten-glfw)
 //  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.
@@ -102,6 +103,11 @@
 #ifdef __EMSCRIPTEN__
 #include <emscripten.h>
 #include <emscripten/html5.h>
+#ifdef EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3
+#include <GLFW/emscripten_glfw3.h>
+#else
+#define EMSCRIPTEN_USE_EMBEDDED_GLFW3
+#endif
 #endif
 
 // We gather version tests as define in order to easily see which features are version-dependent.
@@ -133,7 +139,7 @@ struct ImGui_ImplGlfw_Data
     ImVec2                  LastValidMousePos;
     bool                    InstalledCallbacks;
     bool                    CallbacksChainForAllWindows;
-#ifdef __EMSCRIPTEN__
+#if EMSCRIPTEN_USE_EMBEDDED_GLFW3
     const char*             CanvasSelector;
 #endif
 
@@ -337,7 +343,7 @@ void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yo
     if (bd->PrevUserCallbackScroll != nullptr && ImGui_ImplGlfw_ShouldChainCallback(window))
         bd->PrevUserCallbackScroll(window, xoffset, yoffset);
 
-#ifdef __EMSCRIPTEN__
+#ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
     // Ignore GLFW events: will be processed in ImGui_ImplEmscripten_WheelCallback().
     return;
 #endif
@@ -348,7 +354,7 @@ void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yo
 
 static int ImGui_ImplGlfw_TranslateUntranslatedKey(int key, int scancode)
 {
-#if GLFW_HAS_GETKEYNAME && !defined(__EMSCRIPTEN__)
+#if GLFW_HAS_GETKEYNAME && !defined(EMSCRIPTEN_USE_EMBEDDED_GLFW3)
     // GLFW 3.1+ attempts to "untranslate" keys, which goes the opposite of what every other framework does, making using lettered shortcuts difficult.
     // (It had reasons to do so: namely GLFW is/was more likely to be used for WASD-type game controls rather than lettered shortcuts, but IHMO the 3.1 change could have been done differently)
     // See https://github.com/glfw/glfw/issues/1502 for details.
@@ -359,7 +365,7 @@ static int ImGui_ImplGlfw_TranslateUntranslatedKey(int key, int scancode)
     GLFWerrorfun prev_error_callback = glfwSetErrorCallback(nullptr);
     const char* key_name = glfwGetKeyName(key, scancode);
     glfwSetErrorCallback(prev_error_callback);
-#if GLFW_HAS_GETERROR && !defined(__EMSCRIPTEN__) // Eat errors (see #5908)
+#if GLFW_HAS_GETERROR && !defined(EMSCRIPTEN_USE_EMBEDDED_GLFW3) // Eat errors (see #5908)
     (void)glfwGetError(nullptr);
 #endif
     if (key_name && key_name[0] != 0 && key_name[1] == 0)
@@ -456,7 +462,7 @@ 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.
 }
 
-#ifdef __EMSCRIPTEN__
+#ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
 static EM_BOOL ImGui_ImplEmscripten_WheelCallback(int, const EmscriptenWheelEvent* ev, void*)
 {
     // Mimic Emscripten_HandleWheel() in SDL.
@@ -658,7 +664,7 @@ void ImGui_ImplGlfw_Shutdown()
 
     if (bd->InstalledCallbacks)
         ImGui_ImplGlfw_RestoreCallbacks(bd->Window);
-#ifdef __EMSCRIPTEN__
+#ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
     if (bd->CanvasSelector)
         emscripten_set_wheel_callback(bd->CanvasSelector, nullptr, false, nullptr);
 #endif
@@ -687,7 +693,7 @@ static void ImGui_ImplGlfw_UpdateMouseData()
     // (those braces are here to reduce diff with multi-viewports support in 'docking' branch)
     {
         GLFWwindow* window = bd->Window;
-#ifdef __EMSCRIPTEN__
+#ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
         const bool is_window_focused = true;
 #else
         const bool is_window_focused = glfwGetWindowAttrib(window, GLFW_FOCUSED) != 0;
@@ -745,7 +751,7 @@ static void ImGui_ImplGlfw_UpdateGamepads()
         return;
 
     io.BackendFlags &= ~ImGuiBackendFlags_HasGamepad;
-#if GLFW_HAS_GAMEPAD_API && !defined(__EMSCRIPTEN__)
+#if GLFW_HAS_GAMEPAD_API && !defined(EMSCRIPTEN_USE_EMBEDDED_GLFW3)
     GLFWgamepadstate gamepad;
     if (!glfwGetGamepadState(GLFW_JOYSTICK_1, &gamepad))
         return;
@@ -819,7 +825,7 @@ void ImGui_ImplGlfw_NewFrame()
     ImGui_ImplGlfw_UpdateGamepads();
 }
 
-#ifdef __EMSCRIPTEN__
+#ifdef EMSCRIPTEN_USE_EMBEDDED_GLFW3
 static EM_BOOL ImGui_ImplGlfw_OnCanvasSizeChange(int event_type, const EmscriptenUiEvent* event, void* user_data)
 {
     ImGui_ImplGlfw_Data* bd = (ImGui_ImplGlfw_Data*)user_data;
@@ -858,7 +864,18 @@ void ImGui_ImplGlfw_InstallEmscriptenCallbacks(GLFWwindow*, const char* canvas_s
     // FIXME: May break chaining in case user registered their own Emscripten callback?
     emscripten_set_wheel_callback(bd->CanvasSelector, nullptr, false, ImGui_ImplEmscripten_WheelCallback);
 }
-#endif
+#elif defined(EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3)
+// When using --use-port=contrib.glfw3 for the GLFW implementation, you can override the behavior of this call
+// by invoking emscripten_glfw_make_canvas_resizable afterward.
+// See https://github.com/pongasoft/emscripten-glfw/blob/master/docs/Usage.md#how-to-make-the-canvas-resizable-by-the-user for an explanation
+void ImGui_ImplGlfw_InstallEmscriptenCallbacks(GLFWwindow* window, const char* canvas_selector)
+{
+  GLFWwindow* w = (GLFWwindow*)(EM_ASM_INT({ return Module.glfwGetWindow(UTF8ToString($0)); }, canvas_selector));
+  IM_ASSERT(window == w); // Sanity check
+  IM_UNUSED(w);
+  emscripten_glfw_make_canvas_resizable(window, "window", nullptr);
+}
+#endif // #ifdef EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3
 
 //-----------------------------------------------------------------------------
 

examples/example_glfw_wgpu/CMakeLists.txt

@@ -27,6 +27,12 @@ set(IMGUI_DIR ../../)
 
 # Libraries
 if(EMSCRIPTEN)
+  if(EMSCRIPTEN_VERSION VERSION_GREATER_EQUAL "3.1.57")
+    set(IMGUI_EMSCRIPTEN_GLFW3 "--use-port=contrib.glfw3" CACHE STRING "Choose between --use-port=contrib.glfw3 and -sUSE_GLFW=3 for GLFW implementation (default to --use-port=contrib.glfw3)")
+  else()
+    # cannot use contrib.glfw3 prior to 3.1.57
+    set(IMGUI_EMSCRIPTEN_GLFW3 "-sUSE_GLFW=3" CACHE STRING "Use -sUSE_GLFW=3 for GLFW implementation" FORCE)
+  endif()
   set(LIBRARIES glfw)
   add_compile_options(-sDISABLE_EXCEPTION_CATCHING=1 -DIMGUI_DISABLE_FILE_FUNCTIONS=1)
 else()
@@ -82,9 +88,16 @@ target_link_libraries(example_glfw_wgpu PUBLIC ${LIBRARIES})
 
 # Emscripten settings
 if(EMSCRIPTEN)
+  if("${IMGUI_EMSCRIPTEN_GLFW3}" STREQUAL "--use-port=contrib.glfw3")
+    target_compile_options(example_glfw_wgpu PUBLIC
+        "${IMGUI_EMSCRIPTEN_GLFW3}"
+        "-DEMSCRIPTEN_USE_PORT_CONTRIB_GLFW3" # unnecessary beyond emscripten 3.1.59
+    )
+  endif()
+  message(STATUS "Using ${IMGUI_EMSCRIPTEN_GLFW3} GLFW implementation")
   target_link_options(example_glfw_wgpu PRIVATE
     "-sUSE_WEBGPU=1"
-    "-sUSE_GLFW=3"
+    "${IMGUI_EMSCRIPTEN_GLFW3}"
     "-sWASM=1"
     "-sALLOW_MEMORY_GROWTH=1"
     "-sNO_EXIT_RUNTIME=0"