Merge pull request matplotlib#23636 from greglucas/macosx-flush-events

FIX: macosx flush_events should process all events

Author: QuLogic

src/_macosx.m

@@ -391,9 +391,20 @@ static CGFloat _get_device_scale(CGContextRef cr)
 static PyObject*
 FigureCanvas_flush_events(FigureCanvas* self)
 {
-    // We need to allow the runloop to run very briefly
-    // to allow the view to be displayed when used in a fast updating animation
-    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.0]];
+    // We run the app, matching any events that are waiting in the queue
+    // to process, breaking out of the loop when no events remain and
+    // displaying the canvas if needed.
+    NSEvent *event;
+    while (true) {
+        event = [NSApp nextEventMatchingMask: NSEventMaskAny
+                                   untilDate: [NSDate distantPast]
+                                      inMode: NSDefaultRunLoopMode
+                                     dequeue: YES];
+        if (!event) {
+            break;
+        }
+        [NSApp sendEvent:event];
+    }
     [self->view displayIfNeeded];
     Py_RETURN_NONE;
 }