From 189f9873ae3f23377708fbf9880398fd6a078715 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Arne=20Vestb=C3=B8?= <tor.arne.vestbo@qt.io>
Date: Mon, 13 Nov 2023 16:49:25 +0100
Subject: [PATCH] macOS: Take window mask into account when computing
 QCocoaScreen::topLevelAt

Although not explicitly documented, this is the behavior in practice
on XCB and Windows, and we rely on this behavior in our implementation
of QApplication::widgetAt(), where we punch a temporary hole in the
widget using a mask if it has Qt::WA_TransparentForMouseEvents set.

Pick-to: 6.5 6.6
Fixes: QTBUG-41696
Task-number: QTBUG-119092
Change-Id: Ie7abc31b6930ee6b56fcdf391befc625c1ddf502
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
---
 src/plugins/platforms/cocoa/qcocoascreen.mm   |  7 +++-
 .../qguiapplication/tst_qguiapplication.cpp   | 33 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/src/plugins/platforms/cocoa/qcocoascreen.mm b/src/plugins/platforms/cocoa/qcocoascreen.mm
index 7f1995761a7..966b412de33 100644
--- a/src/plugins/platforms/cocoa/qcocoascreen.mm
+++ b/src/plugins/platforms/cocoa/qcocoascreen.mm
@@ -542,7 +542,12 @@ QWindow *QCocoaScreen::topLevelAt(const QPoint &point) const
             if (!w->isVisible())
                 return;
 
-            if (!QHighDpi::toNativePixels(w->geometry(), w).contains(point))
+            auto nativeGeometry = QHighDpi::toNativePixels(w->geometry(), w);
+            if (!nativeGeometry.contains(point))
+                return;
+
+            QRegion mask = QHighDpi::toNativeLocalPosition(w->mask(), w);
+            if (!mask.isEmpty() && !mask.contains(point - nativeGeometry.topLeft()))
                 return;
 
             window = w;
diff --git a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
index 2a2dbd0e48e..e4f1158d27d 100644
--- a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
+++ b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
@@ -61,6 +61,8 @@ private slots:
 
     void staticFunctions();
 
+    void topLevelAt();
+
     void settableStyleHints_data();
     void settableStyleHints(); // Needs to run last as it changes style hints.
 };
@@ -1325,6 +1327,37 @@ void tst_QGuiApplication::staticFunctions()
     QPixmap::defaultDepth();
 }
 
+void tst_QGuiApplication::topLevelAt()
+{
+    int argc = 1;
+    char *argv[] = { const_cast<char*>("tst_qguiapplication") };
+    QGuiApplication app(argc, argv);
+
+    QWindow bottom;
+    bottom.setObjectName("Bottom");
+    bottom.setFlag(Qt::FramelessWindowHint);
+    bottom.setGeometry(200, 200, 200, 200);
+    bottom.showNormal();
+    QVERIFY(QTest::qWaitForWindowExposed(&bottom));
+    QTRY_COMPARE(app.topLevelAt(QPoint(300, 300)), &bottom);
+
+    QWindow top;
+    top.setObjectName("Top");
+    top.setFlag(Qt::FramelessWindowHint);
+    top.setGeometry(200, 200, 200, 200);
+    top.showNormal();
+    QVERIFY(QTest::qWaitForWindowExposed(&top));
+    top.raise();
+    QTRY_COMPARE(app.topLevelAt(QPoint(300, 300)), &top);
+
+    if (!QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::WindowMasks))
+        QSKIP("QWindow::setMask() is not supported.");
+
+    top.setMask(QRect(0, 0, 50, 50));
+    QTRY_COMPARE(app.topLevelAt(QPoint(300, 300)), &bottom);
+    QTRY_COMPARE(app.topLevelAt(QPoint(225, 225)), &top);
+}
+
 void tst_QGuiApplication::settableStyleHints_data()
 {
     QTest::addColumn<bool>("appInstance");