Added io.AddKeyModEvent() and updated backends accordingly. (#2625, #4858)
diff --git a/backends/imgui_impl_allegro5.cpp b/backends/imgui_impl_allegro5.cpp
index 60a104e..ae50485 100644
--- a/backends/imgui_impl_allegro5.cpp
+++ b/backends/imgui_impl_allegro5.cpp
@@ -17,7 +17,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-12-08: Renderer: Fixed mishandling of the the ImDrawCmd::IdxOffset field! This is an old bug but it never had an effect until some internal rendering changes in 1.86.
 //  2021-08-17: Calling io.AddFocusEvent() on ALLEGRO_EVENT_DISPLAY_SWITCH_OUT/ALLEGRO_EVENT_DISPLAY_SWITCH_IN events.
 //  2021-06-29: Reorganized backend to pull data from a single structure to facilitate usage with multiple-contexts (all g_XXXX access changed to bd->XXXX).
@@ -565,10 +565,12 @@
     // Setup inputs
     ALLEGRO_KEYBOARD_STATE keys;
     al_get_keyboard_state(&keys);
-    io.KeyCtrl = al_key_down(&keys, ALLEGRO_KEY_LCTRL) || al_key_down(&keys, ALLEGRO_KEY_RCTRL);
-    io.KeyShift = al_key_down(&keys, ALLEGRO_KEY_LSHIFT) || al_key_down(&keys, ALLEGRO_KEY_RSHIFT);
-    io.KeyAlt = al_key_down(&keys, ALLEGRO_KEY_ALT) || al_key_down(&keys, ALLEGRO_KEY_ALTGR);
-    io.KeySuper = al_key_down(&keys, ALLEGRO_KEY_LWIN) || al_key_down(&keys, ALLEGRO_KEY_RWIN);
+    ImGuiKeyModFlags key_mods =
+        ((al_key_down(&keys, ALLEGRO_KEY_LCTRL) || al_key_down(&keys, ALLEGRO_KEY_RCTRL)) ? ImGuiKeyModFlags_Ctrl : 0) |
+        ((al_key_down(&keys, ALLEGRO_KEY_LSHIFT) || al_key_down(&keys, ALLEGRO_KEY_RSHIFT)) ? ImGuiKeyModFlags_Shift : 0) |
+        ((al_key_down(&keys, ALLEGRO_KEY_ALT) || al_key_down(&keys, ALLEGRO_KEY_ALTGR)) ? ImGuiKeyModFlags_Alt : 0) |
+        ((al_key_down(&keys, ALLEGRO_KEY_LWIN) || al_key_down(&keys, ALLEGRO_KEY_RWIN)) ? ImGuiKeyModFlags_Super : 0);
+    io.AddKeyModEvent(key_mods);
 
     ImGui_ImplAllegro5_UpdateMouseCursor();
 }
diff --git a/backends/imgui_impl_android.cpp b/backends/imgui_impl_android.cpp
index 7a09e01..1eb7a58 100644
--- a/backends/imgui_impl_android.cpp
+++ b/backends/imgui_impl_android.cpp
@@ -19,7 +19,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-03-04: Initial version.
 
 #include "imgui.h"
@@ -292,11 +292,7 @@
         io.SetKeyEventNativeData(key_event.Key, key_event.NativeKeycode, key_event.NativeScancode); // To support legacy indexing (<1.87 user code)
         key_queue.second.pop();
     }
-
-    io.KeyCtrl  = ((g_KeyModFlags & ImGuiKeyModFlags_Ctrl)  != 0);
-    io.KeyShift = ((g_KeyModFlags & ImGuiKeyModFlags_Shift) != 0);
-    io.KeyAlt   = ((g_KeyModFlags & ImGuiKeyModFlags_Alt)   != 0);
-    io.KeySuper = ((g_KeyModFlags & ImGuiKeyModFlags_Super) != 0);
+    io.AddKeyModEvent(g_KeyModFlags);
 
     // Setup display size (every frame to accommodate for window resizing)
     int32_t window_width = ANativeWindow_getWidth(g_Window);
diff --git a/backends/imgui_impl_glfw.cpp b/backends/imgui_impl_glfw.cpp
index 90295d6..d327672 100644
--- a/backends/imgui_impl_glfw.cpp
+++ b/backends/imgui_impl_glfw.cpp
@@ -16,7 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2022-01-05: Inputs: Converting GLFW untranslated keycodes back to translated keycodes (in the ImGui_ImplGlfw_KeyCallback() function) in order to match the behavior of every other backend, and facilitate the use of GLFW with lettered-shortcuts API.
 //  2021-08-17: *BREAKING CHANGE*: Now using glfwSetWindowFocusCallback() to calling io.AddFocusEvent(). If you called ImGui_ImplGlfw_InitXXX() with install_callbacks = false, you MUST install glfwSetWindowFocusCallback() and forward it to the backend via ImGui_ImplGlfw_WindowFocusCallback().
 //  2021-07-29: *BREAKING CHANGE*: Now using glfwSetCursorEnterCallback(). MousePos is correctly reported when the host platform window is hovered but not focused. If you called ImGui_ImplGlfw_InitXXX() with install_callbacks = false, you MUST install glfwSetWindowFocusCallback() callback and forward it to the backend via ImGui_ImplGlfw_CursorEnterCallback().
@@ -544,10 +544,12 @@
 {
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
     ImGuiIO& io = ImGui::GetIO();
-    io.KeyShift = ((glfwGetKey(bd->Window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SHIFT) == GLFW_PRESS));
-    io.KeyCtrl  = ((glfwGetKey(bd->Window, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_CONTROL) == GLFW_PRESS));
-    io.KeyAlt   = ((glfwGetKey(bd->Window, GLFW_KEY_LEFT_ALT) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_ALT) == GLFW_PRESS));
-    io.KeySuper = ((glfwGetKey(bd->Window, GLFW_KEY_LEFT_SUPER) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SUPER) == GLFW_PRESS));
+    ImGuiKeyModFlags key_mods =
+        (((glfwGetKey(bd->Window, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_CONTROL) == GLFW_PRESS)) ? ImGuiKeyModFlags_Ctrl : 0) |
+        (((glfwGetKey(bd->Window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SHIFT) == GLFW_PRESS)) ? ImGuiKeyModFlags_Shift : 0) |
+        (((glfwGetKey(bd->Window, GLFW_KEY_LEFT_ALT) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_ALT) == GLFW_PRESS)) ? ImGuiKeyModFlags_Alt : 0) |
+        (((glfwGetKey(bd->Window, GLFW_KEY_LEFT_SUPER) == GLFW_PRESS) || (glfwGetKey(bd->Window, GLFW_KEY_RIGHT_SUPER) == GLFW_PRESS)) ? ImGuiKeyModFlags_Super : 0);
+    io.AddKeyModEvent(key_mods);
 }
 
 void ImGui_ImplGlfw_NewFrame()
diff --git a/backends/imgui_impl_glut.cpp b/backends/imgui_impl_glut.cpp
index ba39939..68e417f 100644
--- a/backends/imgui_impl_glut.cpp
+++ b/backends/imgui_impl_glut.cpp
@@ -20,7 +20,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2019-04-03: Misc: Renamed imgui_impl_freeglut.cpp/.h to imgui_impl_glut.cpp/.h.
 //  2019-03-25: Misc: Made io.DeltaTime always above zero.
 //  2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
@@ -205,11 +205,12 @@
 static void ImGui_ImplGLUT_UpdateKeyboardMods()
 {
     ImGuiIO& io = ImGui::GetIO();
-    int mods = glutGetModifiers();
-    io.KeyCtrl = (mods & GLUT_ACTIVE_CTRL) != 0;
-    io.KeyShift = (mods & GLUT_ACTIVE_SHIFT) != 0;
-    io.KeyAlt = (mods & GLUT_ACTIVE_ALT) != 0;
-    io.KeySuper = false;
+    int glut_key_mods = glutGetModifiers();
+    ImGuiKeyModFlags key_mods =
+        ((glut_key_mods & GLUT_ACTIVE_CTRL) ? ImGuiKeyModFlags_Ctrl : 0) |
+        ((glut_key_mods & GLUT_ACTIVE_SHIFT) ? ImGuiKeyModFlags_Shift : 0) |
+        ((glut_key_mods & GLUT_ACTIVE_ALT) ? ImGuiKeyModFlags_Alt : 0);
+    io.AddKeyModEvent(key_mods);
 }
 
 static void ImGui_ImplGLUT_AddKeyEvent(ImGuiKey key, bool down, int native_keycode)
diff --git a/backends/imgui_impl_osx.mm b/backends/imgui_impl_osx.mm
index 64a45ef..64984bd 100644
--- a/backends/imgui_impl_osx.mm
+++ b/backends/imgui_impl_osx.mm
@@ -22,7 +22,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-12-13: *BREAKING CHANGE* Add NSView parameter to ImGui_ImplOSX_Init(). Generally fix keyboard support. Using kVK_* codes for keyboard keys.
 //  2021-12-13: Add game controller support.
 //  2021-09-21: Use mach_absolute_time as CFAbsoluteTimeGetCurrent can jump backwards.
@@ -496,10 +496,7 @@
 static void ImGui_ImplOSX_UpdateKeyModifiers()
 {
     ImGuiIO& io = ImGui::GetIO();
-    io.KeyCtrl  = (g_KeyModifiers & ImGuiKeyModFlags_Ctrl)  != 0;
-    io.KeyShift = (g_KeyModifiers & ImGuiKeyModFlags_Shift) != 0;
-    io.KeyAlt   = (g_KeyModifiers & ImGuiKeyModFlags_Alt)   != 0;
-    io.KeySuper = (g_KeyModifiers & ImGuiKeyModFlags_Super) != 0;
+    io.AddKeyModEvent(g_KeyModifiers);
 }
 
 void ImGui_ImplOSX_NewFrame(NSView* view)
diff --git a/backends/imgui_impl_sdl.cpp b/backends/imgui_impl_sdl.cpp
index c50caab..0d4d7ef 100644
--- a/backends/imgui_impl_sdl.cpp
+++ b/backends/imgui_impl_sdl.cpp
@@ -18,7 +18,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-08-17: Calling io.AddFocusEvent() on SDL_WINDOWEVENT_FOCUS_GAINED/SDL_WINDOWEVENT_FOCUS_LOST.
 //  2021-07-29: Inputs: MousePos is correctly reported when the host platform window is hovered but not focused (using SDL_GetMouseFocus() + SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH, requires SDL 2.0.5+)
 //  2021-06-29: *BREAKING CHANGE* Removed 'SDL_Window* window' parameter to ImGui_ImplSDL2_NewFrame() which was unnecessary.
@@ -503,13 +503,15 @@
 
 static void ImGui_ImplSDL2_UpdateKeyModifiers()
 {
-    SDL_Keymod keymod = SDL_GetModState();
-
     ImGuiIO& io = ImGui::GetIO();
-    io.KeyShift = (keymod & KMOD_SHIFT) != 0;
-    io.KeyCtrl  = (keymod & KMOD_CTRL) != 0;
-    io.KeyAlt   = (keymod & KMOD_ALT) != 0;
-    io.KeySuper = (keymod & KMOD_GUI) != 0;
+    SDL_Keymod sdl_key_mods = SDL_GetModState();
+    ImGuiKeyModFlags key_mods =
+        ((sdl_key_mods & KMOD_CTRL) ? ImGuiKeyModFlags_Ctrl : 0) |
+        ((sdl_key_mods & KMOD_SHIFT) ? ImGuiKeyModFlags_Shift : 0) |
+        ((sdl_key_mods & KMOD_ALT) ? ImGuiKeyModFlags_Alt : 0) |
+        ((sdl_key_mods & KMOD_GUI) ? ImGuiKeyModFlags_Super : 0);
+    io.AddKeyModEvent(key_mods);
+
 }
 
 void ImGui_ImplSDL2_NewFrame()
diff --git a/backends/imgui_impl_win32.cpp b/backends/imgui_impl_win32.cpp
index ebd8a31..5eb6d2b 100644
--- a/backends/imgui_impl_win32.cpp
+++ b/backends/imgui_impl_win32.cpp
@@ -33,7 +33,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-01-10: Inputs: calling new io.AddKeyEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
+//  2022-01-10: Inputs: calling new io.AddKeyEvent(), io.AddKeyModEvent() + io.SetKeyEventNativeData() API (1.87+). Support for full ImGuiKey range.
 //  2021-12-16: Inputs: Fill VK_LCONTROL/VK_RCONTROL/VK_LSHIFT/VK_RSHIFT/VK_LMENU/VK_RMENU for completeness.
 //  2021-08-17: Calling io.AddFocusEvent() on WM_SETFOCUS/WM_KILLFOCUS messages.
 //  2021-08-02: Inputs: Fixed keyboard modifiers being reported when host window doesn't have focus.
@@ -230,10 +230,12 @@
 static void ImGui_ImplWin32_UpdateKeyModifiers()
 {
     ImGuiIO& io = ImGui::GetIO();
-    io.KeyShift = IsVkDown(VK_LSHIFT) || IsVkDown(VK_RSHIFT);
-    io.KeyCtrl  = IsVkDown(VK_LCONTROL) || IsVkDown(VK_RCONTROL);
-    io.KeyAlt   = IsVkDown(VK_LMENU) || IsVkDown(VK_RMENU);
-    io.KeySuper = IsVkDown(VK_LWIN) || IsVkDown(VK_RWIN);
+    ImGuiKeyModFlags key_mods =
+        ((IsVkDown(VK_LCONTROL) || IsVkDown(VK_RCONTROL)) ? ImGuiKeyModFlags_Ctrl : 0) |
+        ((IsVkDown(VK_LSHIFT) || IsVkDown(VK_RSHIFT)) ? ImGuiKeyModFlags_Shift : 0) |
+        ((IsVkDown(VK_LMENU) || IsVkDown(VK_RMENU)) ? ImGuiKeyModFlags_Alt : 0) |
+        ((IsVkDown(VK_LWIN) || IsVkDown(VK_RWIN)) ? ImGuiKeyModFlags_Super : 0);
+    io.AddKeyModEvent(key_mods);
 }
 
 static void ImGui_ImplWin32_UpdateMousePos()
diff --git a/imgui.cpp b/imgui.cpp
index 591bca0..ee47182 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -390,6 +390,7 @@
                         - IsKeyPressed(MY_NATIVE_KEY_XXX)              -> use IsKeyPressed(ImGuiKey_XXX)
                         - IsKeyPressed(GetKeyIndex(ImGuiKey_XXX))      -> use IsKeyPressed(ImGuiKey_XXX)
                         - Backend writing to io.KeyMap[],io.KeysDown[] -> backend should call io.AddKeyEvent()
+                     - inputs: added io.AddKeyModEvent() instead of writing directly to io.KeyCtrl, io.KeyShift, io.KeyAlt, io.KeySuper.
  - 2022/01/05 (1.87) - inputs: renamed ImGuiKey_KeyPadEnter to ImGuiKey_KeypadEnter to align with new symbols. Kept redirection enum.
  - 2022/01/05 (1.87) - removed io.ImeSetInputScreenPosFn() in favor of more flexible io.SetPlatformImeDataFn(). Removed 'void* io.ImeWindowHandle' in favor of writing to 'void* ImGuiViewport::PlatformHandleRaw'.
  - 2022/01/01 (1.87) - commented out redirecting functions/enums names that were marked obsolete in 1.69, 1.70, 1.71, 1.72 (March-July 2019)
@@ -1281,6 +1282,15 @@
 #endif
 }
 
+void ImGuiIO::AddKeyModEvent(ImGuiKeyModFlags modifiers)
+{
+    KeyMods = modifiers;
+    KeyCtrl = (modifiers & ImGuiKeyModFlags_Ctrl) != 0;
+    KeyShift = (modifiers & ImGuiKeyModFlags_Shift) != 0;
+    KeyAlt = (modifiers & ImGuiKeyModFlags_Alt) != 0;
+    KeySuper = (modifiers & ImGuiKeyModFlags_Super) != 0;
+}
+
 void ImGuiIO::AddFocusEvent(bool focused)
 {
     // We intentionally overwrite this and process in NewFrame(), in order to give a chance
diff --git a/imgui.h b/imgui.h
index 77a9eb3..444d028 100644
--- a/imgui.h
+++ b/imgui.h
@@ -2007,6 +2007,7 @@
 
     // Input Functions
     IMGUI_API void  AddKeyEvent(ImGuiKey key, bool down);       // Queue a new key down/up event. Key should be "translated" (as in, generally ImGuiKey_A matches the key end-user would use to emit an 'A' character)
+    IMGUI_API void  AddKeyModEvent(ImGuiKeyModFlags modifiers); // Queue a change of Ctrl/Shift/Alt/Super modifiers
     IMGUI_API void  AddFocusEvent(bool focused);                // Queue an hosting application/platform windows gain or loss of focus
     IMGUI_API void  AddInputCharacter(unsigned int c);          // Queue new character input
     IMGUI_API void  AddInputCharacterUTF16(ImWchar16 c);        // Queue new character input from an UTF-16 character, it can be a surrogate