QGraphicsView: Clear the rubber band when dragMode changes

Without this change, and ongoing rubber-band selection will not be
cleared when the dragmode property changes (e.g. because of a key press)
which leaves a rubber-band displayed on the view.

Move the rubber-band-clearing code from mouseReleaseEvent into a private
helper that is then called from setDragMode.

Change-Id: I32c15f7fe4ef2b8002ef5dd58e22f4bb30dd2409
Fixes: QTBUG-65186
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

2 files changed, 27 insertions, 14 deletions

diff --git a/src/widgets/graphicsview/qgraphicsview.cpp b/src/widgets/graphicsview/qgraphicsview.cpp
index 7ac9aebfe6..a75f1ab24b 100644
--- a/src/widgets/graphicsview/qgraphicsview.cpp
+++ b/src/widgets/graphicsview/qgraphicsview.cpp
@@ -786,6 +786,27 @@ void QGraphicsViewPrivate::updateRubberBand(const QMouseEvent *event)
     if (scene)
         scene->setSelectionArea(selectionArea, rubberBandSelectionOperation, rubberBandSelectionMode, q->viewportTransform());
 }
+
+void QGraphicsViewPrivate::clearRubberBand()
+{
+    Q_Q(QGraphicsView);
+    if (dragMode != QGraphicsView::RubberBandDrag || !sceneInteractionAllowed || !rubberBanding)
+        return;
+
+    if (viewportUpdateMode != QGraphicsView::NoViewportUpdate) {
+        if (viewportUpdateMode != QGraphicsView::FullViewportUpdate)
+            q->viewport()->update(rubberBandRegion(q->viewport(), rubberBandRect));
+        else
+            updateAll();
+    }
+
+    rubberBanding = false;
+    rubberBandSelectionOperation = Qt::ReplaceSelection;
+    if (!rubberBandRect.isNull()) {
+        rubberBandRect = QRect();
+        emit q->rubberBandChanged(rubberBandRect, QPointF(), QPointF());
+    }
+}
 #endif
 
 /*!
@@ -1489,6 +1510,10 @@ void QGraphicsView::setDragMode(DragMode mode)
     if (d->dragMode == mode)
         return;
 
+#if QT_CONFIG(rubberband)
+    d->clearRubberBand();
+#endif
+
 #ifndef QT_NO_CURSOR
     if (d->dragMode == ScrollHandDrag)
         viewport()->unsetCursor();
@@ -3358,20 +3383,7 @@ void QGraphicsView::mouseReleaseEvent(QMouseEvent *event)
 
 #if QT_CONFIG(rubberband)
     if (d->dragMode == QGraphicsView::RubberBandDrag && d->sceneInteractionAllowed && !event->buttons()) {
-        if (d->rubberBanding) {
-            if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate){
-                if (d->viewportUpdateMode != FullViewportUpdate)
-                    viewport()->update(d->rubberBandRegion(viewport(), d->rubberBandRect));
-                else
-                    d->updateAll();
-            }
-            d->rubberBanding = false;
-            d->rubberBandSelectionOperation = Qt::ReplaceSelection;
-            if (!d->rubberBandRect.isNull()) {
-                d->rubberBandRect = QRect();
-                emit rubberBandChanged(d->rubberBandRect, QPointF(), QPointF());
-            }
-        }
+        d->clearRubberBand();
     } else
 #endif
     if (d->dragMode == QGraphicsView::ScrollHandDrag && event->button() == Qt::LeftButton) {
diff --git a/src/widgets/graphicsview/qgraphicsview_p.h b/src/widgets/graphicsview/qgraphicsview_p.h
index 01af61d6ba..e877e6e887 100644
--- a/src/widgets/graphicsview/qgraphicsview_p.h
+++ b/src/widgets/graphicsview/qgraphicsview_p.h
@@ -140,6 +140,7 @@ public:
     QRect rubberBandRect;
     QRegion rubberBandRegion(const QWidget *widget, const QRect &rect) const;
     void updateRubberBand(const QMouseEvent *event);
+    void clearRubberBand();
     bool rubberBanding;
     Qt::ItemSelectionMode rubberBandSelectionMode;
     Qt::ItemSelectionOperation rubberBandSelectionOperation;