ui/cocoa: pass horizontal scroll information to the device code

Signed-off-by: Dmitry Petrov <dpetroff@gmail.com>
Message-Id: <20220108153947.171861-3-dpetroff@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/cocoa.m

@@ -970,21 +970,27 @@ - (bool) handleEventLocked:(NSEvent *)event
              */
 
             /*
-             * When deltaY is zero, it means that this scrolling event was
-             * either horizontal, or so fine that it only appears in
-             * scrollingDeltaY. So we drop the event.
+             * We shouldn't have got a scroll event when deltaY and delta Y
+             * are zero, hence no harm in dropping the event
              */
-            if ([event deltaY] != 0) {
+            if ([event deltaY] != 0 || [event deltaX] != 0) {
             /* Determine if this is a scroll up or scroll down event */
-                buttons = ([event deltaY] > 0) ?
+                if ([event deltaY] != 0) {
+                  buttons = ([event deltaY] > 0) ?
                     INPUT_BUTTON_WHEEL_UP : INPUT_BUTTON_WHEEL_DOWN;
+                } else if ([event deltaX] != 0) {
+                  buttons = ([event deltaX] > 0) ?
+                    INPUT_BUTTON_WHEEL_LEFT : INPUT_BUTTON_WHEEL_RIGHT;
+                }
+
                 qemu_input_queue_btn(dcl.con, buttons, true);
                 qemu_input_event_sync();
                 qemu_input_queue_btn(dcl.con, buttons, false);
                 qemu_input_event_sync();
             }
+
             /*
-             * Since deltaY also reports scroll wheel events we prevent mouse
+             * Since deltaX/deltaY also report scroll wheel events we prevent mouse
              * movement code from executing.
              */
             mouse_event = false;