macOS: Update window geometries after screen properties change

Task-number: QTBUG-69794
Task-number: QTBUG-68140
Change-Id: I4d33bc2136478d779cc4ae8170c3421d9a7557cc
Reviewed-by: Erik Verbruggen <erik.verbruggen@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoascreen.mm b/src/plugins/platforms/cocoa/qcocoascreen.mm
index a17a02b629..3e8261dfc2 100644
--- a/src/plugins/platforms/cocoa/qcocoascreen.mm
+++ b/src/plugins/platforms/cocoa/qcocoascreen.mm
@@ -138,6 +138,20 @@ void QCocoaScreen::updateGeometry()
     QWindowSystemInterface::handleScreenGeometryChange(screen(), geometry(), availableGeometry());
     QWindowSystemInterface::handleScreenLogicalDotsPerInchChange(screen(), m_logicalDpi.first, m_logicalDpi.second);
     QWindowSystemInterface::handleScreenRefreshRateChange(screen(), m_refreshRate);
+
+    // When a screen changes its geometry, AppKit will send us a NSWindowDidMoveNotification
+    // for each window, resulting in calls to handleGeometryChange(), but this happens before
+    // the NSApplicationDidChangeScreenParametersNotification, so when we map the new geometry
+    // (which is correct at that point) to the screen using QCocoaScreen::mapFromNative(), we
+    // end up using the stale screen geometry, and the new window geometry we report is wrong.
+    // To make sure we finally report the correct window geometry, we need to do another pass
+    // of geometry reporting, now that the screen properties have been updates. FIXME: Ideally
+    // this would be solved by not caching the screen properties in QCocoaScreen, but that
+    // requires more research.
+    for (QWindow *window : windows()) {
+        if (QCocoaWindow *cocoaWindow = static_cast<QCocoaWindow*>(window->handle()))
+            cocoaWindow->handleGeometryChange();
+    }
 }
 
 qreal QCocoaScreen::devicePixelRatio() const