Correction for effectiveBoundingRect() calculation for QGraphicsItem

QGraphicsItemPrivate::effectiveBoundingRect() should use ItemClipsChildrenToShape
flag from the parent while looping to check for clipping and not use
its own AncestorClipsChildren flag.
By using AncestorClipsChildren, you're checking if one of your ancestors
clips you, but you really want to know if your direct parent clips you.

Merge-request: 1419
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 73e8eed..ff21296 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -2845,16 +2845,23 @@ QRectF QGraphicsItemPrivate::effectiveBoundingRect(const QRectF &rect) const
     If the item has an effect, the effective rect can be larger than the item's
     bouding rect, depending on the effect.
 
+    \a topMostEffectItem is the top most parent of which a possible QGraphicsEffect
+    should be taken into account (\a topMostEffectItem is inclusive). Any effects
+    of any ancestors of \a topMostEffectItem are not taken into consideration.
+
     \sa boundingRect()
 */
 QRectF QGraphicsItemPrivate::effectiveBoundingRect(QGraphicsItem *topMostEffectItem) const
 {
 #ifndef QT_NO_GRAPHICSEFFECT
     Q_Q(const QGraphicsItem);
+    // Take into account the items own effect
     QRectF brect = effectiveBoundingRect(q_ptr->boundingRect());
-    if (ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren || topMostEffectItem == q)
+
+    if (topMostEffectItem == q)
         return brect;
 
+    // Take into account any effects applied to the parents
     const QGraphicsItem *effectParent = parent;
     while (effectParent) {
         QGraphicsEffect *effect = effectParent->d_ptr->graphicsEffect;
@@ -2863,10 +2870,10 @@ QRectF QGraphicsItemPrivate::effectiveBoundingRect(QGraphicsItem *topMostEffectI
             const QRectF effectRectInParentSpace = effectParent->d_ptr->effectiveBoundingRect(brectInParentSpace);
             brect = effectParent->mapRectToItem(q, effectRectInParentSpace);
         }
-        if (effectParent->d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren
-            || topMostEffectItem == effectParent) {
+        if (effectParent && (effectParent->d_ptr->flags & QGraphicsItem::ItemClipsChildrenToShape))
+            return brect.intersected(q->mapRectFromItem(effectParent, effectParent->boundingRect()));
+        else if (topMostEffectItem == effectParent)
             return brect;
-        }
         effectParent = effectParent->d_ptr->parent;
     }