3 files changed, 84 insertions, 7 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 8a7a080..65d1e0a 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -885,6 +885,38 @@ void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent, bool de
 /*!
     \internal
 
+    Returns the bounding rect of this item's children (excluding itself).
+*/
+void QGraphicsItemPrivate::childrenBoundingRectHelper(QTransform *x, QRectF *rect)
+{
+    for (int i = 0; i < children.size(); ++i) {
+        QGraphicsItem *child = children.at(i);
+        QGraphicsItemPrivate *childd = child->d_ptr;
+        bool hasX = childd->hasTransform;
+        bool hasPos = !childd->pos.isNull();
+        if (hasPos || hasX) {
+            QTransform matrix;
+            if (hasX)
+                matrix = child->transform();
+            if (hasPos) {
+                const QPointF &p = childd->pos;
+                matrix *= QTransform::fromTranslate(p.x(), p.y());
+            }
+            matrix *= *x;
+            *rect |= matrix.mapRect(child->boundingRect());
+            if (!childd->children.isEmpty())
+                childd->childrenBoundingRectHelper(&matrix, rect);
+        } else {
+            *rect |= x->mapRect(child->boundingRect());
+            if (!childd->children.isEmpty())
+                childd->childrenBoundingRectHelper(x, rect);
+        }
+    }
+}
+
+/*!
+    \internal
+
     Empty all cached pixmaps from the pixmap cache.
 */
 void QGraphicsItemCache::purge()
@@ -3019,13 +3051,8 @@ void QGraphicsItem::setZValue(qreal z)
 QRectF QGraphicsItem::childrenBoundingRect() const
 {
     QRectF childRect;
-    foreach (QGraphicsItem *child, children()) {
-        QPointF childPos = child->pos();
-        QTransform matrix = child->transform();
-        if (!childPos.isNull())
-            matrix *= QTransform::fromTranslate(childPos.x(), childPos.y());
-        childRect |= matrix.mapRect(child->boundingRect() | child->childrenBoundingRect());
-    }
+    QTransform x;
+    d_ptr->childrenBoundingRectHelper(&x, &childRect);
     return childRect;
 }
 
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index 078c543..940e566 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -178,6 +178,7 @@ public:
     void addChild(QGraphicsItem *child);
     void removeChild(QGraphicsItem *child);
     void setParentItemHelper(QGraphicsItem *parent, bool deleting);
+    void childrenBoundingRectHelper(QTransform *x, QRectF *rect);
 
     virtual void resolveFont(uint inheritedMask)
     {
diff --git a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
index 57e441b..88c64d3 100644
--- a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -172,6 +172,7 @@ private slots:
     void boundingRects2();
     void sceneBoundingRect();
     void childrenBoundingRect();
+    void childrenBoundingRectTransformed();
     void group();
     void setGroup();
     void nestedGroups();
@@ -2917,9 +2918,57 @@ void tst_QGraphicsItem::childrenBoundingRect()
     childChild->setParentItem(child);
     childChild->setPos(500, 500);
     child->rotate(90);
+
+
+    scene.addPolygon(parent->mapToScene(parent->boundingRect() | parent->childrenBoundingRect()))->setPen(QPen(Qt::red));;
+
+    QGraphicsView view(&scene);
+    view.show();
+
+    QTest::qWait(5000);
+
     QCOMPARE(parent->childrenBoundingRect(), QRectF(-500, -100, 600, 800));
 }
 
+void tst_QGraphicsItem::childrenBoundingRectTransformed()
+{
+    QGraphicsScene scene;
+
+    QGraphicsRectItem *rect = scene.addRect(QRectF(0, 0, 100, 100));
+    QGraphicsRectItem *rect2 = scene.addRect(QRectF(0, 0, 100, 100));
+    QGraphicsRectItem *rect3 = scene.addRect(QRectF(0, 0, 100, 100));
+    QGraphicsRectItem *rect4 = scene.addRect(QRectF(0, 0, 100, 100));
+    QGraphicsRectItem *rect5 = scene.addRect(QRectF(0, 0, 100, 100));
+    rect2->setParentItem(rect);
+    rect3->setParentItem(rect2);
+    rect4->setParentItem(rect3);
+    rect5->setParentItem(rect4);
+
+    rect2->setTransform(QTransform().translate(50, 50).rotate(45));
+    rect2->setPos(25, 25);
+    rect3->setTransform(QTransform().translate(50, 50).rotate(45));
+    rect3->setPos(25, 25);
+    rect4->setTransform(QTransform().translate(50, 50).rotate(45));
+    rect4->setPos(25, 25);
+    rect5->setTransform(QTransform().translate(50, 50).rotate(45));
+    rect5->setPos(25, 25);
+
+    QRectF subTreeRect = rect->childrenBoundingRect();
+    QCOMPARE(subTreeRect.left(), qreal(-206.0660171779821));
+    QCOMPARE(subTreeRect.top(), qreal(75.0));
+    QCOMPARE(subTreeRect.width(), qreal(351.7766952966369));
+    QCOMPARE(subTreeRect.height(), qreal(251.7766952966369));
+
+    rect->rotate(45);
+    rect2->rotate(-45);
+    rect3->rotate(45);
+    rect4->rotate(-45);
+    rect5->rotate(45);
+
+    subTreeRect = rect->childrenBoundingRect();
+    QCOMPARE(rect->childrenBoundingRect(), QRectF(-100, 75, 275, 250));
+}
+
 void tst_QGraphicsItem::group()
 {
     QGraphicsScene scene;