Wrong opacity set on the painter in QGraphicsEffect::draw.

We have to initialize the painter with the 'effected' item's
opacity before calling QGraphicsEffect::draw; otherwise we'll
use the previous rendered item's opacity (which is wrong).

Reviewed-by: Michael Brasser

2 files changed, 25 insertions, 1 deletions

diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 0fd1647..fbd78d9 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -4460,6 +4460,7 @@ void QGraphicsScenePrivate::drawSubtreeRecursive(QGraphicsItem *item, QPainter *
             painter->setWorldTransform(*transformPtr * *effectTransform);
         else
             painter->setWorldTransform(*transformPtr);
+        painter->setOpacity(opacity);
         item->d_ptr->graphicsEffect->draw(painter, source);
         painter->setWorldTransform(restoreTransform);
         sourced->info = 0;
diff --git a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
index 785b3ff..b36cf73 100644
--- a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -62,6 +62,7 @@ private slots:
     void boundingRectFor();
     void boundingRect();
     void draw();
+    void opacity();
 };
 
 void tst_QGraphicsEffect::initTestCase()
@@ -100,7 +101,7 @@ class CustomEffect : public QGraphicsEffect
 public:
     CustomEffect()
         : QGraphicsEffect(), numRepaints(0), m_margin(10),
-          doNothingInDraw(false), m_painter(0), m_styleOption(0), m_source(0)
+          doNothingInDraw(false), m_painter(0), m_styleOption(0), m_source(0), m_opacity(1.0)
     {}
 
     QRectF boundingRectFor(const QRectF &rect) const
@@ -113,6 +114,7 @@ public:
         m_painter = 0;
         m_styleOption = 0;
         m_source = 0;
+        m_opacity = 1.0;
     }
 
     void setMargin(int margin)
@@ -132,6 +134,7 @@ public:
         m_source = source;
         m_painter = painter;
         m_styleOption = source->styleOption();
+        m_opacity = painter->opacity();
         source->draw(painter);
     }
 
@@ -145,6 +148,7 @@ public:
     QPainter *m_painter;
     const QStyleOption *m_styleOption;
     QGraphicsEffectSource *m_source;
+    qreal m_opacity;
 };
 
 void tst_QGraphicsEffect::setEnabled()
@@ -342,6 +346,25 @@ void tst_QGraphicsEffect::draw()
     delete effect;
 }
 
+void tst_QGraphicsEffect::opacity()
+{
+    // Make sure the painter's opacity is correct in QGraphicsEffect::draw.
+    QGraphicsScene scene;
+    CustomItem *item = new CustomItem(0, 0, 100, 100);
+    item->setOpacity(0.5);
+    CustomEffect *effect = new CustomEffect;
+    item->setGraphicsEffect(effect);
+    scene.addItem(item);
+
+    QGraphicsView view(&scene);
+    view.show();
+#ifdef Q_WS_X11
+    qt_x11_wait_for_window_manager(&view);
+#endif
+    QTest::qWait(100);
+    QCOMPARE(effect->m_opacity, qreal(0.5));
+}
+
 QTEST_MAIN(tst_QGraphicsEffect)
 #include "tst_qgraphicseffect.moc"