3 files changed, 51 insertions, 14 deletions

diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp
index 5fa9a92..1951ab2 100644
--- a/src/gui/kernel/qwidget.cpp
+++ b/src/gui/kernel/qwidget.cpp
@@ -1825,18 +1825,6 @@ void QWidgetPrivate::setDirtyOpaqueRegion()
         pd->setDirtyOpaqueRegion();
 }
 
-QRegion QWidgetPrivate::getOpaqueRegion() const
-{
-    Q_Q(const QWidget);
-
-    QRegion r = isOpaque ? q->rect() : getOpaqueChildren();
-    if (extra && extra->hasMask)
-        r &= extra->mask;
-    if (r.isEmpty())
-        return r;
-    return r & clipRect();
-}
-
 const QRegion &QWidgetPrivate::getOpaqueChildren() const
 {
     if (!dirtyOpaqueChildren)
@@ -1851,9 +1839,17 @@ const QRegion &QWidgetPrivate::getOpaqueChildren() const
             continue;
 
         const QPoint offset = child->geometry().topLeft();
-        that->opaqueChildren += child->d_func()->getOpaqueRegion().translated(offset);
+        QWidgetPrivate *childd = child->d_func();
+        QRegion r = childd->isOpaque ? child->rect() : childd->getOpaqueChildren();
+        if (childd->extra && childd->extra->hasMask)
+            r &= childd->extra->mask;
+        if (r.isEmpty())
+            continue;
+        r.translate(offset);
+        that->opaqueChildren += r;
     }
 
+    that->opaqueChildren &= q_func()->rect();
     that->dirtyOpaqueChildren = false;
 
     return that->opaqueChildren;
diff --git a/src/gui/kernel/qwidget_p.h b/src/gui/kernel/qwidget_p.h
index 159a3f2..5cea641 100644
--- a/src/gui/kernel/qwidget_p.h
+++ b/src/gui/kernel/qwidget_p.h
@@ -386,7 +386,6 @@ public:
     bool paintOnScreen() const;
     void invalidateGraphicsEffectsRecursively();
 
-    QRegion getOpaqueRegion() const;
     const QRegion &getOpaqueChildren() const;
     void setDirtyOpaqueRegion();
 
diff --git a/tests/auto/qwidget/tst_qwidget.cpp b/tests/auto/qwidget/tst_qwidget.cpp
index 050d1c5..9c421d1 100644
--- a/tests/auto/qwidget/tst_qwidget.cpp
+++ b/tests/auto/qwidget/tst_qwidget.cpp
@@ -332,6 +332,7 @@ private slots:
     void doubleRepaint();
 #ifndef Q_WS_MAC
     void resizeInPaintEvent();
+    void opaqueChildren();
 #endif
 
     void setMaskInResizeEvent();
@@ -8272,6 +8273,47 @@ void tst_QWidget::resizeInPaintEvent()
     // Make sure the resize triggers another update.
     QTRY_COMPARE(widget.numPaintEvents, 1);
 }
+
+void tst_QWidget::opaqueChildren()
+{
+    QWidget widget;
+    widget.resize(200, 200);
+
+    QWidget child(&widget);
+    child.setGeometry(-700, -700, 200, 200);
+
+    QWidget grandChild(&child);
+    grandChild.resize(200, 200);
+
+    QWidget greatGrandChild(&grandChild);
+    greatGrandChild.setGeometry(50, 50, 200, 200);
+    greatGrandChild.setPalette(Qt::red);
+    greatGrandChild.setAutoFillBackground(true); // Opaque child widget.
+
+    widget.show();
+#ifdef Q_WS_X11
+    qt_x11_wait_for_window_manager(&widget);
+#endif
+    QTest::qWait(100);
+
+    // Child, grandChild and greatGrandChild are outside the ancestor clip.
+    QRegion expectedOpaqueRegion(50, 50, 150, 150);
+    QCOMPARE(qt_widget_private(&grandChild)->getOpaqueChildren(), expectedOpaqueRegion);
+
+    // Now they are all inside the ancestor clip.
+    child.setGeometry(50, 50, 150, 150);
+    QCOMPARE(qt_widget_private(&grandChild)->getOpaqueChildren(), expectedOpaqueRegion);
+
+    // Set mask on greatGrandChild.
+    const QRegion mask(10, 10, 50, 50);
+    greatGrandChild.setMask(mask);
+    expectedOpaqueRegion &= mask.translated(50, 50);
+    QCOMPARE(qt_widget_private(&grandChild)->getOpaqueChildren(), expectedOpaqueRegion);
+
+    // Make greatGrandChild "transparent".
+    greatGrandChild.setAutoFillBackground(false);
+    QCOMPARE(qt_widget_private(&grandChild)->getOpaqueChildren(), QRegion());
+}
 #endif