Improved performance of translating device coordinate graphics effects.

Don't invalidate the cache if we're only translating and the effect rect
is fully contained within the device rect of the painter.

Task-number: QTBUG-6901
Reviewed-by: Bjørn Erik Nilsen

1 files changed, 46 insertions, 0 deletions

diff --git a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
index 95de70e..51e2a57 100644
--- a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -70,6 +70,7 @@ private slots:
     void grayscale();
     void colorize();
     void drawPixmapItem();
+    void deviceCoordinateTranslateCaching();
 };
 
 void tst_QGraphicsEffect::initTestCase()
@@ -514,6 +515,51 @@ void tst_QGraphicsEffect::drawPixmapItem()
     QTRY_VERIFY(effect->repaints >= 2);
 }
 
+class DeviceEffect : public QGraphicsEffect
+{
+public:
+    QRectF boundingRectFor(const QRectF &rect) const
+    { return rect; }
+
+    void draw(QPainter *painter)
+    {
+        QPoint offset;
+        QPixmap pixmap = sourcePixmap(Qt::DeviceCoordinates, &offset, QGraphicsEffect::NoPad);
+
+        if (pixmap.isNull())
+            return;
+
+        painter->save();
+        painter->setWorldTransform(QTransform());
+        painter->drawPixmap(offset, pixmap);
+        painter->restore();
+    }
+};
+
+void tst_QGraphicsEffect::deviceCoordinateTranslateCaching()
+{
+    QGraphicsScene scene;
+    CustomItem *item = new CustomItem(0, 0, 10, 10);
+    scene.addItem(item);
+    scene.setSceneRect(0, 0, 50, 0);
+
+    item->setGraphicsEffect(new DeviceEffect);
+    item->setPen(Qt::NoPen);
+    item->setBrush(Qt::red);
+
+    QGraphicsView view(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+    QTRY_VERIFY(item->numRepaints >= 1);
+    int numRepaints = item->numRepaints;
+
+    item->translate(10, 0);
+    QTest::qWait(50);
+
+    QVERIFY(item->numRepaints == numRepaints);
+}
+
 QTEST_MAIN(tst_QGraphicsEffect)
 #include "tst_qgraphicseffect.moc"