Backends: GLFW: Fixed keyboard modifiers events being reported incorrectly on Linux/X11.

backends/imgui_impl_glfw.cpp

@@ -16,7 +16,8 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-02-07: Added ImGui_ImplGlfw_InstallCallbacks()/ImGui_ImplGlfw_RestoreCallbacks() helpers to facilitate user installing callbacks after iniitializing backend.
+//  2022-03-23: Inputs: Fixed a regression in 1.87 which resulted in keyboard modifiers events being reported incorrectly on Linux/X11.
+//  2022-02-07: Added ImGui_ImplGlfw_InstallCallbacks()/ImGui_ImplGlfw_RestoreCallbacks() helpers to facilitate user installing callbacks after initializing backend.
 //  2022-01-26: Inputs: replaced short-lived io.AddKeyModsEvent() (added two weeks ago)with io.AddKeyEvent() using ImGuiKey_ModXXX flags. Sorry for the confusion.
 //  2021-01-20: Inputs: calling new io.AddKeyAnalogEvent() for gamepad support, instead of writing directly to io.NavInputs[].
 //  2022-01-17: Inputs: calling new io.AddMousePosEvent(), io.AddMouseButtonEvent(), io.AddMouseWheelEvent() API (1.87+).
@@ -244,6 +245,19 @@ static ImGuiKey ImGui_ImplGlfw_KeyToImGuiKey(int key)
     }
 }
 
+static int ImGui_ImplGlfw_KeyToModifier(int key)
+{
+    if (key == GLFW_KEY_LEFT_CONTROL || key == GLFW_KEY_RIGHT_CONTROL)
+        return GLFW_MOD_CONTROL;
+    if (key == GLFW_KEY_LEFT_SHIFT || key == GLFW_KEY_RIGHT_SHIFT)
+        return GLFW_MOD_SHIFT;
+    if (key == GLFW_KEY_LEFT_ALT || key == GLFW_KEY_RIGHT_ALT)
+        return GLFW_MOD_ALT;
+    if (key == GLFW_KEY_LEFT_SUPER || key == GLFW_KEY_RIGHT_SUPER)
+        return GLFW_MOD_SUPER;
+    return 0;
+}
+
 static void ImGui_ImplGlfw_UpdateKeyModifiers(int mods)
 {
     ImGuiIO& io = ImGui::GetIO();
@@ -312,6 +326,9 @@ void ImGui_ImplGlfw_KeyCallback(GLFWwindow* window, int keycode, int scancode, i
     if (action != GLFW_PRESS && action != GLFW_RELEASE)
         return;
 
+    // Workaround: X11 does not include current pressed/released modifier key in 'mods' flags. https://github.com/glfw/glfw/issues/1630
+    if (int keycode_to_mod = ImGui_ImplGlfw_KeyToModifier(keycode))
+        mods = (action == GLFW_PRESS) ? (mods | keycode_to_mod) : (mods & ~keycode_to_mod);
     ImGui_ImplGlfw_UpdateKeyModifiers(mods);
 
     keycode = ImGui_ImplGlfw_TranslateUntranslatedKey(keycode, scancode);

docs/CHANGELOG.txt

@@ -70,6 +70,8 @@ Other Changes:
 - Misc: Updated stb_rect_pack.h from 1.00 to 1.01 (minor). (#5075)
 - Misc: binary_to_compressed_c tool: Added -nostatic option. (#5021) [@podsvirov]
 - ImVector: Fixed erase() with empty range. (#5009) [@thedmd]
+- Backends: GLFW: Fixed a regression in 1.87 which resulted in keyboard modifiers events being
+  reported incorrectly on Linux/X11, due to a bug in GLFW. [@rokups]
 - Backends: SDL: Fixed dragging out viewport broken on some SDL setups. (#5012) [@rokups]
 - Backends: SDL: Added support for extra mouse buttons (SDL_BUTTON_X1/SDL_BUTTON_X2). (#5125) [@sgiurgiu]
 - Backends: OSX: Monitor NSKeyUp events to catch missing keyUp for key when user press Cmd + key (#5128) [@thedmd]