Added caching of graphics effect source pixmaps to speed up effects.

If an effect is applied repeatedly on the same source, just with
varying parameters, we can save a lot by caching the source pixmaps.

Reviewed-by: Bjørn Erik Nilsen

3 files changed, 35 insertions, 8 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 45627f6..5153783 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -2482,12 +2482,14 @@ void QGraphicsItem::setOpacity(qreal opacity)
     itemChange(ItemOpacityHasChanged, newOpacityVariant);
 
     // Update.
-    if (d_ptr->scene)
+    if (d_ptr->scene) {
+        d_ptr->invalidateGraphicsEffectsRecursively();
         d_ptr->scene->d_func()->markDirty(this, QRectF(),
                                           /*invalidateChildren=*/true,
                                           /*maybeDirtyClipPath=*/false,
                                           /*force=*/false,
                                           /*ignoreOpacity=*/true);
+    }
 
     if (d_ptr->isObject)
         emit static_cast<QGraphicsObject *>(this)->opacityChanged();
@@ -4949,6 +4951,22 @@ int QGraphicsItemPrivate::depth() const
 /*!
     \internal
 */
+void QGraphicsItemPrivate::invalidateGraphicsEffectsRecursively()
+{
+    QGraphicsItemPrivate *itemPrivate = this;
+    do {
+        if (itemPrivate->graphicsEffect) {
+            itemPrivate->notifyInvalidated = 1;
+
+            if (!itemPrivate->updateDueToGraphicsEffect)
+                static_cast<QGraphicsItemEffectSourcePrivate *>(itemPrivate->graphicsEffect->d_func()->source->d_func())->invalidateCache();
+        }
+    } while ((itemPrivate = itemPrivate->parent ? itemPrivate->parent->d_ptr.data() : 0));
+}
+
+/*!
+    \internal
+*/
 void QGraphicsItemPrivate::invalidateDepthRecursively()
 {
     if (itemDepth == -1)
@@ -5280,11 +5298,7 @@ void QGraphicsItem::update(const QRectF &rect)
         return;
 
     // Make sure we notify effects about invalidated source.
-    QGraphicsItem *item = this;
-    do {
-        if (item->d_ptr->graphicsEffect)
-            item->d_ptr->notifyInvalidated = 1;
-    } while ((item = item->d_ptr->parent));
+    d_ptr->invalidateGraphicsEffectsRecursively();
 
     if (CacheMode(d_ptr->cacheMode) != NoCache) {
         // Invalidate cache.
@@ -10721,6 +10735,7 @@ QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QP
     }
 
     pixmapPainter.end();
+
     return pixmap;
 }
 
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index 6550362..8fd1a75 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -177,6 +177,7 @@ public:
         wantsActive(0),
         holesInSiblingIndex(0),
         sequentialOrdering(1),
+        updateDueToGraphicsEffect(0),
         globalStackingOrder(-1),
         q_ptr(0)
     {
@@ -221,6 +222,7 @@ public:
     bool discardUpdateRequest(bool ignoreClipping = false, bool ignoreVisibleBit = false,
                               bool ignoreDirtyBit = false, bool ignoreOpacity = false) const;
     int depth() const;
+    void invalidateGraphicsEffectsRecursively();
     void invalidateDepthRecursively();
     void resolveDepth();
     void addChild(QGraphicsItem *child);
@@ -502,6 +504,7 @@ public:
     quint32 wantsActive : 1;
     quint32 holesInSiblingIndex : 1;
     quint32 sequentialOrdering : 1;
+    quint32 updateDueToGraphicsEffect : 1;
 
     // Optional stacking order
     int globalStackingOrder;
@@ -589,8 +592,11 @@ public:
     inline const QWidget *widget() const
     { return 0; }
 
-    inline void update()
-    { item->update(); }
+    inline void update() {
+        item->d_ptr->updateDueToGraphicsEffect = true;
+        item->update();
+        item->d_ptr->updateDueToGraphicsEffect = false;
+    }
 
     inline void effectBoundingRectChanged()
     { item->prepareGeometryChange(); }
@@ -619,6 +625,7 @@ public:
 
     QGraphicsItem *item;
     QGraphicsItemPaintInfo *info;
+    QTransform lastEffectTransform;
 };
 
 
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index a624b10..fc8ce8a 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -4569,6 +4569,11 @@ void QGraphicsScenePrivate::drawSubtreeRecursive(QGraphicsItem *item, QPainter *
         else
             painter->setWorldTransform(*transformPtr);
         painter->setOpacity(opacity);
+
+        if (sourced->lastEffectTransform != painter->worldTransform()) {
+            sourced->lastEffectTransform = painter->worldTransform();
+            sourced->invalidateCache();
+        }
         item->d_ptr->graphicsEffect->draw(painter, source);
         painter->setWorldTransform(restoreTransform);
         sourced->info = 0;