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

2 files changed, 7 insertions, 0 deletions

diff --git a/src/gui/effects/qgraphicseffect.cpp b/src/gui/effects/qgraphicseffect.cpp
index 90145feeb7..ad23df304a 100644
--- a/src/gui/effects/qgraphicseffect.cpp
+++ b/src/gui/effects/qgraphicseffect.cpp
@@ -374,6 +374,11 @@ QGraphicsEffectSourcePrivate::~QGraphicsEffectSourcePrivate()
     invalidateCache();
 }
 
+void QGraphicsEffectSourcePrivate::setCachedOffset(const QPoint &offset)
+{
+    m_cachedOffset = offset;
+}
+
 void QGraphicsEffectSourcePrivate::invalidateCache(InvalidateReason reason) const
 {
     if (m_cachedMode != QGraphicsEffect::PadToEffectiveBoundingRect
diff --git a/src/gui/effects/qgraphicseffect_p.h b/src/gui/effects/qgraphicseffect_p.h
index 91ad74a713..e34dbf96d3 100644
--- a/src/gui/effects/qgraphicseffect_p.h
+++ b/src/gui/effects/qgraphicseffect_p.h
@@ -129,8 +129,10 @@ public:
                            QGraphicsEffect::PixmapPadMode mode = QGraphicsEffect::PadToTransparentBorder) const = 0;
     virtual void effectBoundingRectChanged() = 0;
 
+    void setCachedOffset(const QPoint &offset);
     void invalidateCache(InvalidateReason reason = SourceChanged) const;
     Qt::CoordinateSystem currentCachedSystem() const { return m_cachedSystem; }
+    QGraphicsEffect::PixmapPadMode currentCachedMode() const { return m_cachedMode; }
 
     friend class QGraphicsScenePrivate;
     friend class QGraphicsItem;