Speedup QGraphicsScenePrivate::processDirtyItemsRecursive

Avoid QTransform copy in common case.

2 files changed, 20 insertions, 13 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index ce74b4f..b7fb122 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -55,6 +55,7 @@
 
 #include "qgraphicsitem.h"
 #include "qpixmapcache.h"
+#include "qgraphicsview_p.h"
 
 #include <QtCore/qpoint.h>
 
@@ -365,6 +366,14 @@ public:
                || (childrenCombineOpacity() && isFullyTransparent());
     }
 
+    inline bool updateHelper(QGraphicsViewPrivate *view, const QRectF &rect, const QTransform &xform) const
+    {
+        Q_ASSERT(view);
+        if (hasBoundingRegionGranularity)
+            return view->updateRegion(xform.map(QRegion(rect.toRect())));
+        return view->updateRect(xform.mapRect(rect).toRect());
+    }
+
     inline QTransform transformToParent() const;
 
     QPainterPath cachedClipPath;
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 7dbe6d9..3f4bdde 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -5395,21 +5395,19 @@ void QGraphicsScenePrivate::processDirtyItemsRecursive(QGraphicsItem *item, bool
                 if (dirtyRect.isEmpty())
                     continue; // Discard updates outside the bounding rect.
 
-                QTransform deviceTransform = item->d_ptr->sceneTransform;
-                if (view->isTransformed()) {
-                    if (!untransformableItem)
-                        deviceTransform *= view->viewportTransform();
-                    else
-                        deviceTransform = item->deviceTransform(view->viewportTransform());
-                }
-
-                if (item->d_ptr->hasBoundingRegionGranularity) {
-                    if (!viewPrivate->updateRegion(deviceTransform.map(QRegion(dirtyRect.toRect()))))
-                        paintedViewBoundingRect = QRect();
+                bool valid = false;
+                if (untransformableItem) {
+                    valid = item->d_ptr->updateHelper(viewPrivate, dirtyRect,
+                                                      item->deviceTransform(view->viewportTransform()));
+                } else if (!view->isTransformed()) {
+                    valid = item->d_ptr->updateHelper(viewPrivate, dirtyRect, item->d_ptr->sceneTransform);
                 } else {
-                    if (!viewPrivate->updateRect(deviceTransform.mapRect(dirtyRect).toRect()))
-                        paintedViewBoundingRect = QRect();
+                    QTransform deviceTransform = item->d_ptr->sceneTransform;
+                    deviceTransform *= view->viewportTransform();
+                    valid = !item->d_ptr->updateHelper(viewPrivate, dirtyRect, deviceTransform);
                 }
+                if (!valid)
+                    paintedViewBoundingRect = QRect();
             }
         }
     }