Optimized graphics effects to not needlessly invalidate cache.

When the effect rect changes we only need to invalidate the cache if the
mode is ExpandToEffectRectPadMode.

Reviewed-by: Gunnar Sletta

2 files changed, 9 insertions, 2 deletions

diff --git a/src/gui/effects/qgraphicseffect.cpp b/src/gui/effects/qgraphicseffect.cpp
index 3a6bab5..c8e39da 100644
--- a/src/gui/effects/qgraphicseffect.cpp
+++ b/src/gui/effects/qgraphicseffect.cpp
@@ -279,6 +279,13 @@ QPixmap QGraphicsEffectSource::pixmap(Qt::CoordinateSystem system, QPoint *offse
     return pm;
 }
 
+void QGraphicsEffectSourcePrivate::invalidateCache(bool effectRectChanged) const
+{
+    if (effectRectChanged && m_cachedMode != QGraphicsEffectSource::ExpandToEffectRectPadMode)
+        return;
+    QPixmapCache::remove(m_cacheKey);
+}
+
 /*!
     Constructs a new QGraphicsEffect instance having the
     specified \a parent.
@@ -418,7 +425,7 @@ void QGraphicsEffect::updateBoundingRect()
     Q_D(QGraphicsEffect);
     if (d->source) {
         d->source->d_func()->effectBoundingRectChanged();
-        d->source->d_func()->invalidateCache();
+        d->source->d_func()->invalidateCache(true);
     }
 }
 
diff --git a/src/gui/effects/qgraphicseffect_p.h b/src/gui/effects/qgraphicseffect_p.h
index 1ed7103..0ff5794 100644
--- a/src/gui/effects/qgraphicseffect_p.h
+++ b/src/gui/effects/qgraphicseffect_p.h
@@ -85,7 +85,7 @@ public:
     virtual QPixmap pixmap(Qt::CoordinateSystem system, QPoint *offset = 0,
                            QGraphicsEffectSource::PixmapPadMode mode = QGraphicsEffectSource::ExpandToTransparentBorderPadMode) const = 0;
     virtual void effectBoundingRectChanged() = 0;
-    void invalidateCache() const { QPixmapCache::remove(m_cacheKey); }
+    void invalidateCache(bool effectRectChanged = false) const;
 
     friend class QGraphicsScenePrivate;
     friend class QGraphicsItem;