sokol_app.h macos: fix for Ctrl-Tab key down event not sent (#1228)

CHANGELOG.md

@@ -1,5 +1,19 @@
 ## Updates
 
+### 20-Mar-2025
+
+- sokol_app.h macOS: A small fix for Ctrl-Tab key down. So far this wasn't forwarded
+  as an SAPP_EVENTTYPE_KEY_DOWN, presumably because Ctrl-Tab is the macOS
+  system hotkey for switching between application windows. The workaround
+  hooks into the Cocoa `performKeyEquivalent` callback to catch
+  Ctrl-Tab key-down events and forward them to sokol-app. Note that there are some
+  other special key combinations which cannot be intercepted the same way
+  (for instance Ctrl-F1 - which probably is a good thing because it enables
+  some critical accessibility features).
+
+  Relates issue: https://github.com/floooh/sokol/issues/1227
+  ...and PR: https://github.com/floooh/sokol/pull/1228
+
 ### 17-Mar-2025
 
 - sokol_fetch.h web: replace XMLHttpRequest with the more modern fetch API,

sokol_app.h

@@ -4482,6 +4482,21 @@ static void _sapp_gl_make_current(void) {
         }
     }
 }
+
+- (BOOL)performKeyEquivalent:(NSEvent*)event {
+    // fixes Ctrl-Tab keydown not triggering a keyDown event
+    //
+    // NOTE: it seems that Ctrl-F1 cannot be intercepted the same way, but since
+    // this enabled critical accessibility features that's probably a good thing.
+    switch (_sapp_translate_key(event.keyCode)) {
+        case SAPP_KEYCODE_TAB:
+            [_sapp.macos.view keyDown:event];
+            return YES;
+        default:
+            return NO;
+    }
+}
+
 - (void)keyUp:(NSEvent*)event {
     _sapp_gl_make_current();
     _sapp_macos_key_event(SAPP_EVENTTYPE_KEY_UP,