Don't call qFuzzyIsNull on every single frame in QGraphicsOpacityEffect.

We only have to do it when the opacity changes (in ::setOpacity).
Also, we cannot do the cut-off when the effect has an opacity mask set.

2 files changed, 10 insertions, 3 deletions

diff --git a/src/gui/effects/qgraphicseffect.cpp b/src/gui/effects/qgraphicseffect.cpp
index 62ad44d..50644ff 100644
--- a/src/gui/effects/qgraphicseffect.cpp
+++ b/src/gui/effects/qgraphicseffect.cpp
@@ -1008,6 +1008,10 @@ void QGraphicsOpacityEffect::setOpacity(qreal opacity)
         return;
 
     d->opacity = opacity;
+    if ((d->isFullyTransparent = qFuzzyIsNull(d->opacity)))
+        d->isFullyOpaque = 0;
+    else
+        d->isFullyOpaque = qFuzzyIsNull(d->opacity - 1);
     emit opacityChanged(opacity);
 }
 
@@ -1065,11 +1069,11 @@ void QGraphicsOpacityEffect::draw(QPainter *painter, QGraphicsEffectSource *sour
     Q_D(QGraphicsOpacityEffect);
 
     // Transparent; nothing to draw.
-    if (qFuzzyIsNull(d->opacity))
+    if (d->isFullyTransparent)
         return;
 
     // Opaque; draw directly without going through a pixmap.
-    if (qFuzzyIsNull(d->opacity - 1)) {
+    if (d->isFullyOpaque && !d->hasOpacityMask) {
         source->draw(painter);
         return;
     }
diff --git a/src/gui/effects/qgraphicseffect_p.h b/src/gui/effects/qgraphicseffect_p.h
index e0a77e7..c902b67 100644
--- a/src/gui/effects/qgraphicseffect_p.h
+++ b/src/gui/effects/qgraphicseffect_p.h
@@ -164,11 +164,14 @@ class QGraphicsOpacityEffectPrivate : public QGraphicsEffectPrivate
 {
     Q_DECLARE_PUBLIC(QGraphicsOpacityEffect)
 public:
-    QGraphicsOpacityEffectPrivate() : opacity(qreal(0.7)), hasOpacityMask(0) {}
+    QGraphicsOpacityEffectPrivate()
+        : opacity(qreal(0.7)), isFullyTransparent(0), isFullyOpaque(0), hasOpacityMask(0) {}
     ~QGraphicsOpacityEffectPrivate() {}
 
     qreal opacity;
     QBrush opacityMask;
+    uint isFullyTransparent : 1;
+    uint isFullyOpaque : 1;
     uint hasOpacityMask : 1;
 };