Compatibility fix for QGraphicsScene::changed signal.

Makes tst_QGraphicsScene::changedSignal and
tst_QGraphicsItem::setMatrix happy.

2 files changed, 22 insertions, 3 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 807ee06..a2d885b 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -5979,10 +5979,21 @@ void QGraphicsItem::prepareGeometryChange()
     if (d_ptr->scene) {
         d_ptr->geometryChanged = 1;
         d_ptr->paintedViewBoundingRectsNeedRepaint = 1;
-        d_ptr->scene->d_func()->markDirty(this, QRectF(),
-                                          /*invalidateChildren=*/true,
-                                          /*maybeDirtyClipPath=*/!d_ptr->inSetPosHelper);
+
         QGraphicsScenePrivate *scenePrivate = d_ptr->scene->d_func();
+        scenePrivate->markDirty(this, QRectF(),
+                                /*invalidateChildren=*/true,
+                                /*maybeDirtyClipPath=*/!d_ptr->inSetPosHelper);
+
+        // For compatibility reasons, we have to update the item's old geometry
+        // if someone is connected to the changed signal or the scene has no views.
+        // Note that this has to be done *after* markDirty to ensure that
+        // _q_processDirtyItems is called before _q_emitUpdated.
+        if ((scenePrivate->connectedSignals & scenePrivate->changedSignalMask)
+            || scenePrivate->views.isEmpty()) {
+            d_ptr->scene->update(sceneTransform().mapRect(boundingRect()));
+        }
+
         scenePrivate->removeFromIndex(this);
     }
 
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 4578bd4..c7a41d6 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -682,6 +682,7 @@ void QGraphicsScenePrivate::_q_processDirtyItems()
     if (updateAll)
         return;
 
+    const bool wasPendingSceneUpdate = calledEmitUpdated;
     const QRectF oldGrowingItemsBoundingRect = growingItemsBoundingRect;
     processDirtyItemsRecursive(0);
     if (!hasSceneRect && oldGrowingItemsBoundingRect != growingItemsBoundingRect)
@@ -689,6 +690,13 @@ void QGraphicsScenePrivate::_q_processDirtyItems()
 
     for (int i = 0; i < views.size(); ++i)
         views.at(i)->d_func()->processPendingUpdates();
+
+    if (!wasPendingSceneUpdate && calledEmitUpdated) {
+        // We did a compatibility QGraphicsScene::update in processDirtyItemsRecursive
+        // and we cannot wait for the control to reach the eventloop before the
+        // changed signal is emitted, so we emit it now.
+        _q_emitUpdated();
+    }
 }
 
 /*!