From ac2ad79812e8f17ed4d76b8645c3f10e385018c8 Mon Sep 17 00:00:00 2001
From: Yan Pujante <yan@pongasoft.com>
Date: Sat, 7 Sep 2024 10:22:45 -0700
Subject: [PATCH] Backends: GLFW+Emscripten: use OSX behaviors automatically
 when using contrib glfw port. (#7965, #7915)

---
 backends/imgui_impl_glfw.cpp              | 22 +++++++++++++++++++++-
 docs/CHANGELOG.txt                        |  2 ++
 examples/example_glfw_wgpu/CMakeLists.txt |  1 -
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
index 06b5142a1..9c6722f78 100644
--- a/backends/imgui_impl_glfw.cpp
+++ b/backends/imgui_impl_glfw.cpp
@@ -18,6 +18,11 @@
 // - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
 // - Introduction, links and more at the top of imgui.cpp
 
+// About Emscripten support:
+// - Emscripten provides its own GLFW (3.2.1) implementation (syntax: "-sUSE_GLFW=3"), but Joystick is broken and several features are not supported (multiple windows, clipboard, timer, etc.)
+// - A third-party Emscripten GLFW (3.4.0) implementation (syntax: "--use-port=contrib.glfw3") fixes the Joystick issue and implements all relevant features for the browser.
+// See https://github.com/pongasoft/emscripten-glfw/blob/master/docs/Comparison.md for details.
+
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
@@ -560,7 +565,7 @@ void ImGui_ImplGlfw_SetCallbacksChainForAllWindows(bool chain_for_all_windows)
 }
 
 #ifdef __EMSCRIPTEN__
-#if EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3 >= 3'4'0'20240817
+#if EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3 >= 34020240817
 void ImGui_ImplGlfw_EmscriptenOpenURL(const char* url) { if (url) emscripten::glfw3::OpenURL(url); }
 #else
 EM_JS(void, ImGui_ImplGlfw_EmscriptenOpenURL, (const char* url), { url = url ? UTF8ToString(url) : null; if (url) window.open(url, '_blank'); });
@@ -639,6 +644,21 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     ::SetWindowLongPtrW((HWND)main_viewport->PlatformHandleRaw, GWLP_WNDPROC, (LONG_PTR)ImGui_ImplGlfw_WndProc);
 #endif
 
+    // Emscripten: the same application can run on various platforms, so we detect the Apple platform at runtime
+    // to override io.ConfigMacOSXBehaviors from its default (which is always false in Emscripten).
+#if EMSCRIPTEN_USE_PORT_CONTRIB_GLFW3 >= 34020240817
+    if (emscripten::glfw3::IsRuntimePlatformApple())
+    {
+        ImGui::GetIO().ConfigMacOSXBehaviors = true;
+
+        // Due to how the browser (poorly) handles the Meta Key, this line essentially disables repeats when used.
+        // This means that Meta + V only registers a single key-press, even if the keys are held.
+        // This is a compromise for dealing with this issue in ImGui since ImGui implements key repeat itself.
+        // See https://github.com/pongasoft/emscripten-glfw/blob/v3.4.0.20240817/docs/Usage.md#the-problem-of-the-super-key
+        emscripten::glfw3::SetSuperPlusKeyTimeouts(10, 10);
+    }
+#endif
+
     bd->ClientApi = client_api;
     return true;
 }
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 28b3cae26..2189f2584 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -71,6 +71,8 @@ Other changes:
 - Fonts: fixed ellipsis "..." rendering width miscalculation bug introduced in 1.91.0. (#7976) [@DDeimos]
 - TextLinkOpenURL(): modified tooltip to display a verb "Open 'xxxx'". (#7885, #7660)
 - Backends: SDL2: use SDL_Vulkan_GetDrawableSize() when available. (#7967, #3190) [@scribam]
+- Backends: GLFW+Emscripten: use OSX behaviors automatically when using contrib glfw port. (#7965, #7915)
+  [@ypujante]
 
 -----------------------------------------------------------------------
  VERSION 1.91.1 (Released 2024-09-04)
diff --git a/examples/example_glfw_wgpu/CMakeLists.txt b/examples/example_glfw_wgpu/CMakeLists.txt
index 77b492fdc..6be95af44 100644
--- a/examples/example_glfw_wgpu/CMakeLists.txt
+++ b/examples/example_glfw_wgpu/CMakeLists.txt
@@ -91,7 +91,6 @@ 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")