ui/cocoa: add option to swap Option and Command

On Mac OS X the Option key maps to Alt and Command to Super/Meta. This change
swaps them around so that Alt is the key closer to the space bar and Meta/Super
is between Control and Alt, like on non-Mac keyboards.

It is a cocoa display option, disabled by default.

Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Gustavo Noronha Silva <gustavo@noronha.dev.br>
Message-Id: <20210713213200.2547-3-gustavo@noronha.dev.br>
Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Message-Id: <20220306121119.45631-3-akihiko.odaki@gmail.com>
Reviewed-by: Will Cohen <wwcohen@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

qapi/ui.json

@@ -1275,12 +1275,17 @@
 #             a global grab on key events. (default: off)
 #             See https://support.apple.com/en-in/guide/mac-help/mh32356/mac
 #
+# @swap-opt-cmd: Swap the Option and Command keys so that their key codes match
+#                their position on non-Mac keyboards and you can use Meta/Super
+#                and Alt where you expect them. (default: off)
+#
 # Since: 7.0
 ##
 { 'struct': 'DisplayCocoa',
   'data': {
       '*left-command-key': 'bool',
-      '*full-grab': 'bool'
+      '*full-grab': 'bool',
+      '*swap-opt-cmd': 'bool'
   } }
 
 ##

qemu-options.hx

@@ -1917,7 +1917,7 @@ DEF("display", HAS_ARG, QEMU_OPTION_display,
     "-display curses[,charset=<encoding>]\n"
 #endif
 #if defined(CONFIG_COCOA)
-    "-display cocoa[,full_grab=on|off]\n"
+    "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n"
 #endif
 #if defined(CONFIG_OPENGL)
     "-display egl-headless[,rendernode=<file>]\n"

ui/cocoa.m

@@ -96,6 +96,7 @@ static void cocoa_switch(DisplayChangeListener *dcl,
 static int last_buttons;
 static int cursor_hide = 1;
 static int left_command_key_enabled = 1;
+static bool swap_opt_cmd;
 
 static int gArgc;
 static char **gArgv;
@@ -854,12 +855,22 @@ - (bool) handleEventLocked:(NSEvent *)event
         qkbd_state_key_event(kbd, Q_KEY_CODE_CTRL_R, false);
     }
     if (!(modifiers & NSEventModifierFlagOption)) {
-        qkbd_state_key_event(kbd, Q_KEY_CODE_ALT, false);
-        qkbd_state_key_event(kbd, Q_KEY_CODE_ALT_R, false);
+        if (swap_opt_cmd) {
+            qkbd_state_key_event(kbd, Q_KEY_CODE_META_L, false);
+            qkbd_state_key_event(kbd, Q_KEY_CODE_META_R, false);
+        } else {
+            qkbd_state_key_event(kbd, Q_KEY_CODE_ALT, false);
+            qkbd_state_key_event(kbd, Q_KEY_CODE_ALT_R, false);
+        }
     }
     if (!(modifiers & NSEventModifierFlagCommand)) {
-        qkbd_state_key_event(kbd, Q_KEY_CODE_META_L, false);
-        qkbd_state_key_event(kbd, Q_KEY_CODE_META_R, false);
+        if (swap_opt_cmd) {
+            qkbd_state_key_event(kbd, Q_KEY_CODE_ALT, false);
+            qkbd_state_key_event(kbd, Q_KEY_CODE_ALT_R, false);
+        } else {
+            qkbd_state_key_event(kbd, Q_KEY_CODE_META_L, false);
+            qkbd_state_key_event(kbd, Q_KEY_CODE_META_R, false);
+        }
     }
 
     switch ([event type]) {
@@ -891,29 +902,44 @@ - (bool) handleEventLocked:(NSEvent *)event
 
                 case kVK_Option:
                     if (!!(modifiers & NSEventModifierFlagOption)) {
-                        [self toggleKey:Q_KEY_CODE_ALT];
+                        if (swap_opt_cmd) {
+                            [self toggleKey:Q_KEY_CODE_META_L];
+                        } else {
+                            [self toggleKey:Q_KEY_CODE_ALT];
+                        }
                     }
                     break;
 
                 case kVK_RightOption:
                     if (!!(modifiers & NSEventModifierFlagOption)) {
-                        [self toggleKey:Q_KEY_CODE_ALT_R];
+                        if (swap_opt_cmd) {
+                            [self toggleKey:Q_KEY_CODE_META_R];
+                        } else {
+                            [self toggleKey:Q_KEY_CODE_ALT_R];
+                        }
                     }
                     break;
 
                 /* Don't pass command key changes to guest unless mouse is grabbed */
                 case kVK_Command:
                     if (isMouseGrabbed &&
-                        !!(modifiers & NSEventModifierFlagCommand) &&
-                        left_command_key_enabled) {
-                        [self toggleKey:Q_KEY_CODE_META_L];
+                        !!(modifiers & NSEventModifierFlagCommand)) {
+                        if (swap_opt_cmd) {
+                            [self toggleKey:Q_KEY_CODE_ALT];
+                        } else {
+                            [self toggleKey:Q_KEY_CODE_META_L];
+                        }
                     }
                     break;
 
                 case kVK_RightCommand:
                     if (isMouseGrabbed &&
                         !!(modifiers & NSEventModifierFlagCommand)) {
-                        [self toggleKey:Q_KEY_CODE_META_R];
+                        if (swap_opt_cmd) {
+                            [self toggleKey:Q_KEY_CODE_ALT_R];
+                        } else {
+                            [self toggleKey:Q_KEY_CODE_META_R];
+                        }
                     }
                     break;
             }
@@ -2068,6 +2094,9 @@ static void cocoa_display_init(DisplayState *ds, DisplayOptions *opts)
     if (opts->has_show_cursor && opts->show_cursor) {
         cursor_hide = 0;
     }
+    if (opts->u.cocoa.has_swap_opt_cmd) {
+        swap_opt_cmd = opts->u.cocoa.swap_opt_cmd;
+    }
 
     if (opts->u.cocoa.has_left_command_key && !opts->u.cocoa.left_command_key) {
         left_command_key_enabled = 0;