Provide hook that's called when items' stacking order is changed.

This is required by the QtDeclarative module. As an isolated change,
this is just a noop. It takes effect when somebody reimpements the
private virtual function.

Reviewed-by: Alan Alpert

2 files changed, 17 insertions, 0 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index e69a295..e014763 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -4345,6 +4345,12 @@ void QGraphicsItem::stackBefore(const QGraphicsItem *sibling)
                 ++index;
         }
         d_ptr->siblingIndex = siblingIndex;
+        for (int i = 0; i < siblings->size(); ++i) {
+            int &index = siblings->at(i)->d_ptr->siblingIndex;
+            if (i != siblingIndex && index >= siblingIndex && index <= myIndex)
+                siblings->at(i)->d_ptr->siblingOrderChange();
+        }
+        d_ptr->siblingOrderChange();
     }
 }
 
@@ -5342,6 +5348,16 @@ void QGraphicsItemPrivate::subFocusItemChange()
 /*!
     \internal
 
+    Subclasses can reimplement this function to be notified when its
+    siblingIndex order is changed.
+*/
+void QGraphicsItemPrivate::siblingOrderChange()
+{
+}
+
+/*!
+    \internal
+
     Tells us if it is a proxy widget
 */
 bool QGraphicsItemPrivate::isProxyWidget() const
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index 92d45f6..977fa96 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -431,6 +431,7 @@ public:
     static inline bool insertionOrder(QGraphicsItem *a, QGraphicsItem *b);
     void ensureSequentialSiblingIndex();
     inline void sendScenePosChange();
+    virtual void siblingOrderChange();
 
     QPainterPath cachedClipPath;
     QRectF childrenBoundingRect;