Revert 4bf7f90a27377f439e86d6175e5e3cdebd131be0 and implement differently.

Setting painter clip can reduce performance in some cases, so items
must access system clip.

2 files changed, 18 insertions, 5 deletions

diff --git a/src/declarative/graphicsitems/qmlgraphicspainteditem.cpp b/src/declarative/graphicsitems/qmlgraphicspainteditem.cpp
index 2c849c8..b1b1210 100644
--- a/src/declarative/graphicsitems/qmlgraphicspainteditem.cpp
+++ b/src/declarative/graphicsitems/qmlgraphicspainteditem.cpp
@@ -49,6 +49,7 @@
 #include <QApplication>
 #include <QGraphicsSceneMouseEvent>
 #include <QPainter>
+#include <QPaintEngine>
 
 QT_BEGIN_NAMESPACE
 
@@ -209,9 +210,24 @@ void QmlGraphicsPaintedItem::paint(QPainter *p, const QStyleOptionGraphicsItem *
 
     ++inpaint;
 
-    const QRect clip = p->clipRegion().boundingRect();
+    const QTransform &x = p->deviceTransform();
+    QTransform xinv = x.inverted();
+    QRegion effectiveClip;
+    QRegion sysClip = p->paintEngine()->systemClip();
+    if (xinv.type() <= QTransform::TxScale && sysClip.numRects() < 5) {
+        // simple transform, region gets no more complicated...
+        effectiveClip = xinv.map(sysClip);
+    } else {
+        // do not make complicated regions...
+        effectiveClip = xinv.mapRect(sysClip.boundingRect());
+    }
+
+    QRegion topaint = p->clipRegion();
+    if (topaint.isEmpty())
+        topaint = effectiveClip;
+    else
+        topaint &= effectiveClip;
 
-    QRegion topaint(clip);
     topaint &= content;
     QRegion uncached(content);
     p->setRenderHints(QPainter::SmoothPixmapTransform, d->smooth);
diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 87585a2..90c0ff2 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -3275,13 +3275,10 @@ void QGraphicsView::paintEvent(QPaintEvent *event)
 
     // Determine the exposed region
     d->exposedRegion = event->region();
-    if (d->exposedRegion.isEmpty())
-        d->exposedRegion = viewport()->rect();
     QRectF exposedSceneRect = mapToScene(d->exposedRegion.boundingRect()).boundingRect();
 
     // Set up the painter
     QPainter painter(viewport());
-    painter.setClipRect(event->rect(), Qt::IntersectClip);
 #ifndef QT_NO_RUBBERBAND
     if (d->rubberBanding && !d->rubberBandRect.isEmpty())
         painter.save();