Fixes: Make raster engine perform better on 0-opacity drawing

RevBy:    sroedal
Task:     came in from brisbane

2 files changed, 19 insertions, 7 deletions

diff --git a/src/gui/painting/qdrawhelper_p.h b/src/gui/painting/qdrawhelper_p.h
index de97683..586ffe3 100644
--- a/src/gui/painting/qdrawhelper_p.h
+++ b/src/gui/painting/qdrawhelper_p.h
@@ -110,6 +110,7 @@ struct QSpanData;
 class QGradient;
 class QRasterBuffer;
 class QClipData;
+class QRasterPaintEngineState;
 
 typedef QT_FT_SpanFunc ProcessSpans;
 typedef void (*BitmapBlitFunc)(QRasterBuffer *rasterBuffer,
@@ -293,7 +294,7 @@ struct QSpanData
     };
 
     void init(QRasterBuffer *rb, const QRasterPaintEngine *pe);
-    void setup(const QBrush &brush, int alpha);
+    void setup(const QBrush &brush, int alpha, const QRasterPaintEngineState *s);
     void setupMatrix(const QTransform &matrix, int bilinear);
     void initTexture(const QImage *image, int alpha, QTextureData::Type = QTextureData::Plain, const QRect &sourceRect = QRect());
     void adjustSpanMethods();
diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index ba79b5b..92a196c 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -483,12 +483,12 @@ bool QRasterPaintEngine::begin(QPaintDevice *device)
     d->rasterizer->setClipRect(d->deviceRect);
 
     s->penData.init(d->rasterBuffer, this);
-    s->penData.setup(s->pen.brush(), s->intOpacity);
+    s->penData.setup(s->pen.brush(), s->intOpacity, s);
     s->stroker = &d->basicStroker;
     d->basicStroker.setClipRect(d->deviceRect);
 
     s->brushData.init(d->rasterBuffer, this);
-    s->brushData.setup(s->brush, s->intOpacity);
+    s->brushData.setup(s->brush, s->intOpacity, s);
 
     d->rasterBuffer->compositionMode = QPainter::CompositionMode_SourceOver;
 
@@ -769,7 +769,7 @@ void QRasterPaintEngine::updatePen(const QPen &pen)
     s->strokeFlags = 0;
 
     s->penData.clip = d->clip();
-    s->penData.setup(pen_style == Qt::NoPen ? QBrush() : pen.brush(), s->intOpacity);
+    s->penData.setup(pen_style == Qt::NoPen ? QBrush() : pen.brush(), s->intOpacity, s);
 
     if (s->strokeFlags & QRasterPaintEngine::DirtyTransform
         || pen.brush().transform().type() >= QTransform::TxNone) {
@@ -869,7 +869,7 @@ void QRasterPaintEngine::updateBrush(const QBrush &brush)
     QRasterPaintEngineState *s = state();
     // must set clip prior to setup, as setup uses it...
     s->brushData.clip = d->clip();
-    s->brushData.setup(brush, s->intOpacity);
+    s->brushData.setup(brush, s->intOpacity, s);
     if (s->fillFlags & DirtyTransform
         || brush.transform().type() >= QTransform::TxNone)
         d_func()->updateMatrixData(&s->brushData, brush, d->brushMatrix());
@@ -1024,6 +1024,10 @@ void QRasterPaintEnginePrivate::drawImage(const QPointF &pt,
 {
     if (!clip.isValid())
         return;
+
+    if (alpha ==0)
+        return;
+
     Q_ASSERT(img.depth() >= 8);
 
     int srcBPL = img.bytesPerLine();
@@ -1867,9 +1871,12 @@ void QRasterPaintEngine::fillRect(const QRectF &r, const QColor &color)
     QRasterPaintEngineState *s = state();
 
     d->solid_color_filler.solid.color = PREMUL(ARGB_COMBINE_ALPHA(color.rgba(), s->intOpacity));
+    if ((d->solid_color_filler.solid.color & 0xff000000) == 0
+        && s->composition_mode == QPainter::CompositionMode_SourceOver) {
+        return;
+    }
     d->solid_color_filler.clip = d->clip();
     d->solid_color_filler.adjustSpanMethods();
-
     fillRect(r, &d->solid_color_filler);
 }
 
@@ -4906,7 +4913,7 @@ void QSpanData::init(QRasterBuffer *rb, const QRasterPaintEngine *pe)
 
 extern QImage qt_imageForBrush(int brushStyle, bool invert);
 
-void QSpanData::setup(const QBrush &brush, int alpha)
+void QSpanData::setup(const QBrush &brush, int alpha, const QRasterPaintEngineState *s)
 {
     Qt::BrushStyle brushStyle = qbrush_style(brush);
     switch (brushStyle) {
@@ -4914,6 +4921,10 @@ void QSpanData::setup(const QBrush &brush, int alpha)
         type = Solid;
         QColor c = qbrush_color(brush);
         solid.color = PREMUL(ARGB_COMBINE_ALPHA(c.rgba(), alpha));
+        if ((solid.color & 0xff000000) == 0
+            && s->composition_mode == QPainter::CompositionMode_SourceOver) {
+            type = None;
+        }
         break;
     }