Make sure QGraphicsSceneHoverLeave event has non-null widget pointer.

When constructing QGraphicsSceneHoverLeave event out of QEvent::Leave
we should set the widget pointer to the graphicsview's viewport, th
same as we do for other graphicsscene events like QGraphicsSceneMouseEvent.

Reviewed-by: Yoann Lopes
Reviewed-by: Bjørn Erik Nilsen

4 files changed, 12 insertions, 8 deletions

diff --git a/src/corelib/kernel/qcoreevent.h b/src/corelib/kernel/qcoreevent.h
index 9d3513a..4c91aaf 100644
--- a/src/corelib/kernel/qcoreevent.h
+++ b/src/corelib/kernel/qcoreevent.h
@@ -328,6 +328,7 @@ private:
     friend class QETWidget;
     friend class QGraphicsView;
     friend class QGraphicsViewPrivate;
+    friend class QGraphicsScene;
     friend class QGraphicsScenePrivate;
 #ifndef QT_NO_GESTURES
     friend class QGestureManager;
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 5b1da9e..981fbbc 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -3461,7 +3461,8 @@ bool QGraphicsScene::event(QEvent *event)
         break;
     }
     case QEvent::Leave:
-        d->leaveScene();
+        // hackieshly unpacking the viewport pointer from the leave event.
+        d->leaveScene(reinterpret_cast<QWidget *>(event->d));
         break;
     case QEvent::GraphicsSceneHelp:
         helpEvent(static_cast<QGraphicsSceneHelpEvent *>(event));
@@ -3933,20 +3934,19 @@ bool QGraphicsScenePrivate::dispatchHoverEvent(QGraphicsSceneHoverEvent *hoverEv
     Handles all actions necessary to clean up the scene when the mouse leaves
     the view.
 */
-void QGraphicsScenePrivate::leaveScene()
+void QGraphicsScenePrivate::leaveScene(QWidget *viewport)
 {
-    Q_Q(QGraphicsScene);
 #ifndef QT_NO_TOOLTIP
     QToolTip::hideText();
 #endif
+    QGraphicsView *view = qobject_cast<QGraphicsView *>(viewport->parent());
     // Send HoverLeave events to all existing hover items, topmost first.
-    QGraphicsView *senderWidget = qobject_cast<QGraphicsView *>(q->sender());
     QGraphicsSceneHoverEvent hoverEvent;
-    hoverEvent.setWidget(senderWidget);
+    hoverEvent.setWidget(viewport);
 
-    if (senderWidget) {
+    if (view) {
         QPoint cursorPos = QCursor::pos();
-        hoverEvent.setScenePos(senderWidget->mapToScene(senderWidget->mapFromGlobal(cursorPos)));
+        hoverEvent.setScenePos(view->mapToScene(viewport->mapFromGlobal(cursorPos)));
         hoverEvent.setLastScenePos(hoverEvent.scenePos());
         hoverEvent.setScreenPos(cursorPos);
         hoverEvent.setLastScreenPos(hoverEvent.screenPos());
diff --git a/src/gui/graphicsview/qgraphicsscene_p.h b/src/gui/graphicsview/qgraphicsscene_p.h
index f28dfe9..2818fb2 100644
--- a/src/gui/graphicsview/qgraphicsscene_p.h
+++ b/src/gui/graphicsview/qgraphicsscene_p.h
@@ -201,7 +201,7 @@ public:
 
     bool dispatchHoverEvent(QGraphicsSceneHoverEvent *hoverEvent);
     bool itemAcceptsHoverEvents_helper(const QGraphicsItem *item) const;
-    void leaveScene();
+    void leaveScene(QWidget *viewport);
 
     void cloneDragDropEvent(QGraphicsSceneDragDropEvent *dest,
                            QGraphicsSceneDragDropEvent *source);
diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 2db29b9..0d39bb5 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -2790,6 +2790,9 @@ bool QGraphicsView::viewportEvent(QEvent *event)
                 d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
         }
         d->useLastMouseEvent = false;
+        // a hack to pass a viewport pointer to the scene inside the leave event
+        Q_ASSERT(event->d == 0);
+        event->d = reinterpret_cast<QEventPrivate *>(viewport());
         QApplication::sendEvent(d->scene, event);
         break;
 #ifndef QT_NO_TOOLTIP