1 files changed, 35 insertions, 9 deletions
diff --git a/src/plugins/platforms/cocoa/qnsview.mm b/src/plugins/platforms/cocoa/qnsview.mm
index 61f0012a2d..e3bee95ad9 100644
--- a/src/plugins/platforms/cocoa/qnsview.mm
+++ b/src/plugins/platforms/cocoa/qnsview.mm
@@ -147,6 +147,7 @@ Q_LOGGING_CATEGORY(lcQpaTablet, "qt.qpa.input.tablet")
         m_isMenuView = false;
         self.focusRingType = NSFocusRingTypeNone;
         self.cursor = nil;
+        m_updateRequested = false;
     }
     return self;
 }
@@ -299,6 +300,25 @@ Q_LOGGING_CATEGORY(lcQpaTablet, "qt.qpa.input.tablet")
     return m_platformWindow->isOpaque();
 }
 
+- (void)requestUpdate
+{
+    if (self.needsDisplay) {
+        // If the view already has needsDisplay set it means that there may be code waiting for
+        // a real expose event, so we can't issue setNeedsDisplay now as a way to trigger an
+        // update request. We will re-trigger requestUpdate from drawRect.
+        return;
+    }
+
+    [self setNeedsDisplay:YES];
+    m_updateRequested = true;
+}
+
+- (void)setNeedsDisplayInRect:(NSRect)rect
+{
+    [super setNeedsDisplayInRect:rect];
+    m_updateRequested = false;
+}
+
 - (void)drawRect:(NSRect)dirtyRect
 {
     Q_UNUSED(dirtyRect);
@@ -322,18 +342,24 @@ Q_LOGGING_CATEGORY(lcQpaTablet, "qt.qpa.input.tablet")
     }
 #endif
 
-    m_platformWindow->handleExposeEvent(exposedRegion);
+    QWindowPrivate *windowPrivate = qt_window_private(m_platformWindow->window());
+
+    if (m_updateRequested) {
+        Q_ASSERT(windowPrivate->updateRequestPending);
+        qCDebug(lcQpaCocoaWindow) << "Delivering update request to" << m_platformWindow->window();
+        windowPrivate->deliverUpdateRequest();
+        m_updateRequested = false;
+    } else {
+        m_platformWindow->handleExposeEvent(exposedRegion);
+    }
 
-    if (qt_window_private(m_platformWindow->window())->updateRequestPending) {
-        // A call to QWindow::requestUpdate was issued during the expose event, or we
-        // had to deliver a real expose event and still need to deliver the update.
-        // But AppKit will reset the needsDisplay state of the view after completing
+    if (windowPrivate->updateRequestPending) {
+        // A call to QWindow::requestUpdate was issued during event delivery above,
+        // but AppKit will reset the needsDisplay state of the view after completing
         // the current display cycle, so we need to defer the request to redisplay.
         // FIXME: Perhaps this should be a trigger to enable CADisplayLink?
-        qCDebug(lcQpaCocoaWindow) << "[QNSView drawRect:] issuing deferred setNeedsDisplay due to pending update request";
-        dispatch_async(dispatch_get_main_queue (), ^{
-            [self setNeedsDisplay:YES];
-        });
+        qCDebug(lcQpaCocoaWindow) << "Pending update request, triggering re-display";
+        dispatch_async(dispatch_get_main_queue (), ^{ [self requestUpdate]; });
     }
 }