Backends: GLFW: Fixed mods state on Linux with Alt-GR text input (e.g…

…. German keyboard layout), (ocornut#6034)

Amend 0755767, 1ad8ad6
Ref maybe glfw/glfw#1630

backends/imgui_impl_glfw.cpp

@@ -16,6 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2023-01-04: Inputs: Fixed mods state on Linux when using Alt-GR text input (e.g. German keyboard layout), could lead to broken text input. Revert a 2022/01/17 change were we resumed using mods provided by GLFW, turns out they were faulty.
 //  2022-11-22: Perform a dummy glfwGetError() read to cancel missing names with glfwGetKeyName(). (#5908)
 //  2022-10-18: Perform a dummy glfwGetError() read to cancel missing mouse cursors errors. Using GLFW_VERSION_COMBINED directly. (#5785)
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -251,26 +252,16 @@ 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)
+// X11 does not include current pressed/released modifier key in 'mods' flags submitted by GLFW
+// See https://github.com/ocornut/imgui/issues/6034 and https://github.com/glfw/glfw/issues/1630
+static void ImGui_ImplGlfw_UpdateKeyModifiers()
 {
     ImGuiIO& io = ImGui::GetIO();
-    io.AddKeyEvent(ImGuiMod_Ctrl, (mods & GLFW_MOD_CONTROL) != 0);
-    io.AddKeyEvent(ImGuiMod_Shift, (mods & GLFW_MOD_SHIFT) != 0);
-    io.AddKeyEvent(ImGuiMod_Alt, (mods & GLFW_MOD_ALT) != 0);
-    io.AddKeyEvent(ImGuiMod_Super, (mods & GLFW_MOD_SUPER) != 0);
+    ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    io.AddKeyEvent(ImGuiMod_Ctrl,  (glfwGetKey(bd->Window, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_CONTROL) == GLFW_PRESS));
+    io.AddKeyEvent(ImGuiMod_Shift, (glfwGetKey(bd->Window, GLFW_KEY_LEFT_SHIFT)   == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SHIFT)   == GLFW_PRESS));
+    io.AddKeyEvent(ImGuiMod_Alt,   (glfwGetKey(bd->Window, GLFW_KEY_LEFT_ALT)     == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_ALT)     == GLFW_PRESS));
+    io.AddKeyEvent(ImGuiMod_Super, (glfwGetKey(bd->Window, GLFW_KEY_LEFT_SUPER)   == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SUPER)   == GLFW_PRESS));
 }
 
 void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
@@ -279,7 +270,7 @@ void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int acti
     if (bd->PrevUserCallbackMousebutton != nullptr && window == bd->Window)
         bd->PrevUserCallbackMousebutton(window, button, action, mods);
 
-    ImGui_ImplGlfw_UpdateKeyModifiers(mods);
+    ImGui_ImplGlfw_UpdateKeyModifiers();
 
     ImGuiIO& io = ImGui::GetIO();
     if (button >= 0 && button < ImGuiMouseButton_COUNT)
@@ -338,10 +329,7 @@ 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);
+    ImGui_ImplGlfw_UpdateKeyModifiers();
 
     keycode = ImGui_ImplGlfw_TranslateUntranslatedKey(keycode, scancode);
 

docs/CHANGELOG.txt

@@ -78,6 +78,9 @@ Other changes:
   with IMGUI_DISABLE_DEBUG_TOOLS is used. (#5901) [@Teselka]
 - Misc: fixed compile-time detection of SSE features on MSVC 32-bits builds. (#5943) [@TheMostDiligent]
 - Examples: DirectX10, DirectX11: try WARP software driver if hardware driver is not available. (#5924, #5562)
+- Backends: GLFW: Fixed mods state on Linux when using Alt-GR text input (e.g. German keyboard layout), which
+  could lead to broken text input. Revert a 2022/01/17 change were we resumed using mods provided by GLFW,
+  turns out they are faulty in this specific situation. (#6034)
 - Backends: Allegro5: restoring using al_draw_indexed_prim() when Allegro version is >= 5.2.5. (#5937) [@Espyo]
 - Backends: Vulkan: Fixed sampler passed to ImGui_ImplVulkan_AddTexture() not being honored as we were using
   an immutable sampler. (#5502, #6001, #914) [@martin-ejdestig, @rytisss]