5 files changed, 70 insertions, 25 deletions
diff --git a/src/plugins/platforms/cocoa/qcocoabackingstore.h b/src/plugins/platforms/cocoa/qcocoabackingstore.h
index 6f24598250..470da63e3d 100644
--- a/src/plugins/platforms/cocoa/qcocoabackingstore.h
+++ b/src/plugins/platforms/cocoa/qcocoabackingstore.h
@@ -76,8 +76,10 @@ public:
     void endPaint() override;
 
     void flush(QWindow *, const QRegion &, const QPoint &) override;
+#ifndef QT_NO_OPENGL
     void composeAndFlush(QWindow *window, const QRegion &region, const QPoint &offset,
         QPlatformTextureList *textures, bool translucentBackground) override;
+#endif
 
     QPlatformGraphicsBuffer *graphicsBuffer() const override;
 
diff --git a/src/plugins/platforms/cocoa/qcocoabackingstore.mm b/src/plugins/platforms/cocoa/qcocoabackingstore.mm
index d42a723b47..e786ecb5a5 100644
--- a/src/plugins/platforms/cocoa/qcocoabackingstore.mm
+++ b/src/plugins/platforms/cocoa/qcocoabackingstore.mm
@@ -523,6 +523,7 @@ void QCALayerBackingStore::flush(QWindow *flushedWindow, const QRegion &region,
     // the window server.
 }
 
+#ifndef QT_NO_OPENGL
 void QCALayerBackingStore::composeAndFlush(QWindow *window, const QRegion &region, const QPoint &offset,
                                     QPlatformTextureList *textures, bool translucentBackground)
 {
@@ -531,6 +532,7 @@ void QCALayerBackingStore::composeAndFlush(QWindow *window, const QRegion &regio
 
     QPlatformBackingStore::composeAndFlush(window, region, offset, textures, translucentBackground);
 }
+#endif
 
 QPlatformGraphicsBuffer *QCALayerBackingStore::graphicsBuffer() const
 {
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index 298d11fe08..0d7eab9a94 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -1208,23 +1208,34 @@ void QCocoaWindow::windowDidChangeScreen()
     if (!window())
         return;
 
-    const bool wasRunningDisplayLink = static_cast<QCocoaScreen *>(screen())->isRunningDisplayLink();
-
-    if (QCocoaScreen *newScreen = QCocoaIntegration::instance()->screenForNSScreen(m_view.window.screen)) {
-        if (newScreen == screen()) {
-            // Screen properties have changed. Will be handled by
-            // NSApplicationDidChangeScreenParametersNotification
-            // in QCocoaIntegration::updateScreens().
-            return;
-        }
-
-        qCDebug(lcQpaWindow) << window() << "moved to" << newScreen;
-        QWindowSystemInterface::handleWindowScreenChanged<QWindowSystemInterface::SynchronousDelivery>(window(), newScreen->screen());
-
-        if (hasPendingUpdateRequest() && wasRunningDisplayLink)
-            requestUpdate(); // Restart display-link on new screen
-    } else {
-        qCWarning(lcQpaWindow) << "Failed to get QCocoaScreen for" << m_view.window.screen;
+    // Note: When a window is resized to 0x0 Cocoa will report the window's screen as nil
+    auto *currentScreen = QCocoaIntegration::instance()->screenForNSScreen(m_view.window.screen);
+    auto *previousScreen = static_cast<QCocoaScreen*>(screen());
+
+    Q_ASSERT_X(!m_view.window.screen || currentScreen,
+        "QCocoaWindow", "Failed to get QCocoaScreen for NSScreen");
+
+    // Note: The previous screen may be the same as the current screen, either because
+    // the screen was just reconfigured, which still results in AppKit sending an
+    // NSWindowDidChangeScreenNotification, because the previous screen was removed,
+    // and we ended up calling QWindow::setScreen to move the window, which doesn't
+    // actually move the window to the new screen, or because we've delivered the
+    // screen change to the top level window, which will make all the child windows
+    // of that window report the new screen when requested via QWindow::screen().
+    // We still need to deliver the screen change in all these cases, as the
+    // device-pixel ratio may have changed, and needs to be delivered to all
+    // windows, both top level and child windows.
+
+    qCDebug(lcQpaWindow) << "Screen changed for" << window() << "from" << previousScreen << "to" << currentScreen;
+    QWindowSystemInterface::handleWindowScreenChanged<QWindowSystemInterface::SynchronousDelivery>(
+        window(), currentScreen ? currentScreen->screen() : nullptr);
+
+    if (currentScreen && hasPendingUpdateRequest()) {
+        // Restart display-link on new screen. We need to do this unconditionally,
+        // since we can't rely on the previousScreen reflecting whether or not the
+        // window actually moved from one screen to another, or just stayed on the
+        // same screen.
+        currentScreen->requestUpdate();
     }
 }
 
diff --git a/src/plugins/platforms/cocoa/qnsview_mouse.mm b/src/plugins/platforms/cocoa/qnsview_mouse.mm
index 6e3cff2b48..d4419b42a4 100644
--- a/src/plugins/platforms/cocoa/qnsview_mouse.mm
+++ b/src/plugins/platforms/cocoa/qnsview_mouse.mm
@@ -147,9 +147,34 @@
 
     ulong timestamp = [theEvent timestamp] * 1000;
 
-    auto eventType = cocoaEvent2QtMouseEvent(theEvent);
-    qCInfo(lcQpaMouse) << "Frame-strut" << eventType << "at" << qtWindowPoint << "with" << m_frameStrutButtons << "in" << self.window;
-    QWindowSystemInterface::handleFrameStrutMouseEvent(m_platformWindow->window(), timestamp, qtWindowPoint, qtScreenPoint, m_frameStrutButtons);
+    const auto button = cocoaButton2QtButton(theEvent);
+    auto eventType = [&]() {
+        switch (theEvent.type) {
+        case NSEventTypeLeftMouseDown:
+        case NSEventTypeRightMouseDown:
+        case NSEventTypeOtherMouseDown:
+            return QEvent::NonClientAreaMouseButtonPress;
+
+        case NSEventTypeLeftMouseUp:
+        case NSEventTypeRightMouseUp:
+        case NSEventTypeOtherMouseUp:
+            return QEvent::NonClientAreaMouseButtonRelease;
+
+        case NSEventTypeLeftMouseDragged:
+        case NSEventTypeRightMouseDragged:
+        case NSEventTypeOtherMouseDragged:
+            return QEvent::NonClientAreaMouseMove;
+
+        default:
+            break;
+        }
+
+        return QEvent::None;
+    }();
+
+    qCInfo(lcQpaMouse) << eventType << "at" << qtWindowPoint << "with" << m_frameStrutButtons << "in" << self.window;
+    QWindowSystemInterface::handleFrameStrutMouseEvent(m_platformWindow->window(),
+        timestamp, qtWindowPoint, qtScreenPoint, m_frameStrutButtons, button, eventType);
 }
 @end
 
@@ -472,12 +497,15 @@
     // uses the legacy cursorRect API, so the cursor is reset to the arrow
     // cursor. See rdar://34183708
 
-    if (self.cursor && self.cursor != NSCursor.currentCursor) {
-        qCInfo(lcQpaMouse) << "Updating cursor for" << self << "to" << self.cursor;
+    auto previousCursor = NSCursor.currentCursor;
+
+    if (self.cursor)
         [self.cursor set];
-    } else {
+    else
         [super cursorUpdate:theEvent];
-    }
+
+    if (NSCursor.currentCursor != previousCursor)
+        qCInfo(lcQpaMouse) << "Cursor update for" << self << "resulted in new cursor" << NSCursor.currentCursor;
 }
 
 - (void)mouseMovedImpl:(NSEvent *)theEvent
diff --git a/src/plugins/platforms/cocoa/qnswindowdelegate.mm b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
index 087cb3651f..9502a315d8 100644
--- a/src/plugins/platforms/cocoa/qnswindowdelegate.mm
+++ b/src/plugins/platforms/cocoa/qnswindowdelegate.mm
@@ -51,7 +51,9 @@ static QRegExp whitespaceRegex = QRegExp(QStringLiteral("\\s*"));
 
 static QCocoaWindow *toPlatformWindow(NSWindow *window)
 {
-    return qnsview_cast(window.contentView).platformWindow;
+    if ([window conformsToProtocol:@protocol(QNSWindowProtocol)])
+        return static_cast<QCocoaNSWindow *>(window).platformWindow;
+    return nullptr;
 }
 
 @implementation QNSWindowDelegate