4 files changed, 49 insertions, 7 deletions
diff --git a/src/widgets/graphicsview/qgraphicsscene.cpp b/src/widgets/graphicsview/qgraphicsscene.cpp
index 8765b8114d..aa42445b2a 100644
--- a/src/widgets/graphicsview/qgraphicsscene.cpp
+++ b/src/widgets/graphicsview/qgraphicsscene.cpp
@@ -1468,6 +1468,8 @@ void QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent *mou
 
         QGraphicsView *view = mouseEvent->widget() ? qobject_cast<QGraphicsView *>(mouseEvent->widget()->parentWidget()) : 0;
         bool dontClearSelection = view && view->dragMode() == QGraphicsView::ScrollHandDrag;
+        bool extendSelection = (mouseEvent->modifiers() & Qt::ControlModifier) != 0;
+        dontClearSelection |= extendSelection;
         if (!dontClearSelection) {
             // Clear the selection if the originating view isn't in scroll
             // hand drag mode. The view will clear the selection if no drag
@@ -2263,6 +2265,28 @@ void QGraphicsScene::setSelectionArea(const QPainterPath &path, const QTransform
 void QGraphicsScene::setSelectionArea(const QPainterPath &path, Qt::ItemSelectionMode mode,
                                       const QTransform &deviceTransform)
 {
+    setSelectionArea(path, Qt::ReplaceSelection, mode, deviceTransform);
+}
+
+/*!
+    \overload
+    \since 5.5
+
+    Sets the selection area to \a path using \a mode to determine if items are
+    included in the selection area.
+
+    \a deviceTransform is the transformation that applies to the view, and needs to
+    be provided if the scene contains items that ignore transformations.
+
+    \a selectionOperation determines what to do with the currently selected items.
+
+    \sa clearSelection(), selectionArea()
+*/
+void QGraphicsScene::setSelectionArea(const QPainterPath &path,
+                                      Qt::ItemSelectionOperation selectionOperation,
+                                      Qt::ItemSelectionMode mode,
+                                      const QTransform &deviceTransform)
+{
     Q_D(QGraphicsScene);
 
     // Note: with boolean path operations, we can improve performance here
@@ -2287,10 +2311,16 @@ void QGraphicsScene::setSelectionArea(const QPainterPath &path, Qt::ItemSelectio
         }
     }
 
-    // Unselect all items outside path.
-    foreach (QGraphicsItem *item, unselectItems) {
-        item->setSelected(false);
-        changed = true;
+    switch (selectionOperation) {
+    case Qt::ReplaceSelection:
+        // Deselect all items outside path.
+        foreach (QGraphicsItem *item, unselectItems) {
+            item->setSelected(false);
+            changed = true;
+        }
+        break;
+    default:
+        break;
     }
 
     // Reenable emitting selectionChanged() for individual items.
diff --git a/src/widgets/graphicsview/qgraphicsscene.h b/src/widgets/graphicsview/qgraphicsscene.h
index 6cd5da00c8..03df18fbce 100644
--- a/src/widgets/graphicsview/qgraphicsscene.h
+++ b/src/widgets/graphicsview/qgraphicsscene.h
@@ -177,6 +177,8 @@ public:
     QPainterPath selectionArea() const;
     void setSelectionArea(const QPainterPath &path, const QTransform &deviceTransform);
     void setSelectionArea(const QPainterPath &path, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape, const QTransform &deviceTransform = QTransform());
+    void setSelectionArea(const QPainterPath &path, Qt::ItemSelectionOperation selectionOperation, Qt::ItemSelectionMode mode = Qt::IntersectsItemShape, const QTransform &deviceTransform = QTransform());
+    // ### Qt6 merge the last 2 functions and add a default: Qt::ItemSelectionOperation selectionOperation = Qt::ReplaceSelection
 
     QGraphicsItemGroup *createItemGroup(const QList<QGraphicsItem *> &items);
     void destroyItemGroup(QGraphicsItemGroup *group);
diff --git a/src/widgets/graphicsview/qgraphicsview.cpp b/src/widgets/graphicsview/qgraphicsview.cpp
index 5484ecb96e..b92655013e 100644
--- a/src/widgets/graphicsview/qgraphicsview.cpp
+++ b/src/widgets/graphicsview/qgraphicsview.cpp
@@ -350,6 +350,7 @@ QGraphicsViewPrivate::QGraphicsViewPrivate()
 #ifndef QT_NO_RUBBERBAND
       rubberBanding(false),
       rubberBandSelectionMode(Qt::IntersectsItemShape),
+      rubberBandSelectionOperation(Qt::ReplaceSelection),
 #endif
       handScrollMotions(0), cacheMode(0),
 #ifndef QT_NO_CURSOR
@@ -735,6 +736,7 @@ void QGraphicsViewPrivate::updateRubberBand(const QMouseEvent *event)
     // if we didn't get the release events).
     if (!event->buttons()) {
         rubberBanding = false;
+        rubberBandSelectionOperation = Qt::ReplaceSelection;
         if (!rubberBandRect.isNull()) {
             rubberBandRect = QRect();
             emit q->rubberBandChanged(rubberBandRect, QPointF(), QPointF());
@@ -768,7 +770,7 @@ void QGraphicsViewPrivate::updateRubberBand(const QMouseEvent *event)
     selectionArea.addPolygon(q->mapToScene(rubberBandRect));
     selectionArea.closeSubpath();
     if (scene)
-        scene->setSelectionArea(selectionArea, rubberBandSelectionMode, q->viewportTransform());
+        scene->setSelectionArea(selectionArea, rubberBandSelectionOperation, rubberBandSelectionMode, q->viewportTransform());
 }
 #endif
 
@@ -3289,8 +3291,14 @@ void QGraphicsView::mousePressEvent(QMouseEvent *event)
             d->rubberBanding = true;
             d->rubberBandRect = QRect();
             if (d->scene) {
-                // Initiating a rubber band always clears the selection.
-                d->scene->clearSelection();
+                bool extendSelection = (event->modifiers() & Qt::ControlModifier) != 0;
+
+                if (extendSelection) {
+                    d->rubberBandSelectionOperation = Qt::AddToSelection;
+                } else {
+                    d->rubberBandSelectionOperation = Qt::ReplaceSelection;
+                    d->scene->clearSelection();
+                }
             }
         }
     } else
@@ -3347,6 +3355,7 @@ void QGraphicsView::mouseReleaseEvent(QMouseEvent *event)
                     d->updateAll();
             }
             d->rubberBanding = false;
+            d->rubberBandSelectionOperation = Qt::ReplaceSelection;
             if (!d->rubberBandRect.isNull()) {
                 d->rubberBandRect = QRect();
                 emit rubberBandChanged(d->rubberBandRect, QPointF(), QPointF());
diff --git a/src/widgets/graphicsview/qgraphicsview_p.h b/src/widgets/graphicsview/qgraphicsview_p.h
index ca87b932e2..546f34ba81 100644
--- a/src/widgets/graphicsview/qgraphicsview_p.h
+++ b/src/widgets/graphicsview/qgraphicsview_p.h
@@ -134,6 +134,7 @@ public:
     void updateRubberBand(const QMouseEvent *event);
     bool rubberBanding;
     Qt::ItemSelectionMode rubberBandSelectionMode;
+    Qt::ItemSelectionOperation rubberBandSelectionOperation;
 #endif
     int handScrollMotions;