Make composition modes work better for DirectFB

It seems that I have to premultiply the colors I pass to
IDirectFBSurface->SetColor when composition mode != Source|SourceIn.

It now seems to behave the same way as the raster engine which I guess
should be considered the authority on this matter.

Reviewed-by: Noam Rosenthal <noam.rosenthal@nokia.com>

1 files changed, 39 insertions, 60 deletions

diff --git a/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp b/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
index d6e1a03..388e369 100644
--- a/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
+++ b/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
@@ -1,4 +1,4 @@
-/****************************************************************************
+ /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
@@ -68,11 +68,10 @@ public:
     };
 
     enum CompositionModeStatus {
-        PorterDuff_None = 0x00,
-        PorterDuff_SupportedBlits = 0x01,
-        PorterDuff_SupportedPrimitives = 0x02,
-        PorterDuff_SupportedOpaquePrimitives = 0x04,
-        PorterDuff_Dirty = 0x10
+        PorterDuff_None = 0x0,
+        PorterDuff_Supported = 0x1,
+        PorterDuff_PremultiplyColors = 0x2,
+        PorterDuff_AlwaysBlend = 0x4
     };
 
     enum ClipType {
@@ -97,7 +96,6 @@ public:
     inline void unlock();
     static inline void unlock(QDirectFBPaintDevice *device);
 
-    inline bool testCompositionMode(const QPen *pen, const QBrush *brush, const QColor *color = 0) const;
     inline bool isSimpleBrush(const QBrush &brush) const;
 
     void drawTiledPixmap(const QRectF &dest, const QPixmap &pixmap, const QPointF &pos);
@@ -130,6 +128,7 @@ public:
     ClipType clipType;
     QDirectFBPaintDevice *dfbDevice;
     uint compositionModeStatus;
+    bool isPremultiplied;
 
     bool inClip;
     QRect currentClip;
@@ -287,6 +286,7 @@ bool QDirectFBPaintEngine::begin(QPaintDevice *device)
         qFatal("QDirectFBPaintEngine used on an invalid device: 0x%x",
                device->devType());
     }
+    d->isPremultiplied = QDirectFBScreen::isPremultiplied(d->dfbDevice->format());
 
     d->prepare(d->dfbDevice);
     gccaps = AllFeatures;
@@ -413,7 +413,7 @@ void QDirectFBPaintEngine::drawRects(const QRect *rects, int rectCount)
         || !d->simplePen
         || d->clipType == QDirectFBPaintEnginePrivate::ComplexClip
         || !d->isSimpleBrush(brush)
-        || !d->testCompositionMode(&pen, &brush)) {
+        || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
         RASTERFALLBACK(DRAW_RECTS, rectCount, VOID_ARG(), VOID_ARG());
         d->lock();
         QRasterPaintEngine::drawRects(rects, rectCount);
@@ -443,7 +443,7 @@ void QDirectFBPaintEngine::drawRects(const QRectF *rects, int rectCount)
         || !d->simplePen
         || d->clipType == QDirectFBPaintEnginePrivate::ComplexClip
         || !d->isSimpleBrush(brush)
-        || !d->testCompositionMode(&pen, &brush)) {
+        || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
         RASTERFALLBACK(DRAW_RECTS, rectCount, VOID_ARG(), VOID_ARG());
         d->lock();
         QRasterPaintEngine::drawRects(rects, rectCount);
@@ -468,7 +468,7 @@ void QDirectFBPaintEngine::drawLines(const QLine *lines, int lineCount)
     const QPen &pen = state()->pen;
     if (!d->simplePen
         || d->clipType == QDirectFBPaintEnginePrivate::ComplexClip
-        || !d->testCompositionMode(&pen, 0)) {
+        || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
         RASTERFALLBACK(DRAW_LINES, lineCount, VOID_ARG(), VOID_ARG());
         d->lock();
         QRasterPaintEngine::drawLines(lines, lineCount);
@@ -488,7 +488,7 @@ void QDirectFBPaintEngine::drawLines(const QLineF *lines, int lineCount)
     const QPen &pen = state()->pen;
     if (!d->simplePen
         || d->clipType == QDirectFBPaintEnginePrivate::ComplexClip
-        || !d->testCompositionMode(&pen, 0)) {
+        || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
         RASTERFALLBACK(DRAW_LINES, lineCount, VOID_ARG(), VOID_ARG());
         d->lock();
         QRasterPaintEngine::drawLines(lines, lineCount);
@@ -526,7 +526,7 @@ void QDirectFBPaintEngine::drawImage(const QRectF &r, const QImage &image,
     */
 
 #if !defined QT_NO_DIRECTFB_PREALLOCATED || defined QT_DIRECTFB_IMAGECACHE
-    if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_SupportedBlits)
+    if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)
         || (d->transformationType & QDirectFBPaintEnginePrivate::Matrix_BlitsUnsupported)
         || (d->clipType == QDirectFBPaintEnginePrivate::ComplexClip)
         || (!d->supportsStretchBlit() && state()->matrix.mapRect(r).size() != sr.size())
@@ -575,7 +575,7 @@ void QDirectFBPaintEngine::drawPixmap(const QRectF &r, const QPixmap &pixmap,
         QPixmapData *data = pixmap.pixmapData();
         Q_ASSERT(data->classId() == QPixmapData::DirectFBClass);
         QDirectFBPixmapData *dfbData = static_cast<QDirectFBPixmapData*>(data);
-        if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_SupportedBlits)
+        if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)
             || (d->transformationType & QDirectFBPaintEnginePrivate::Matrix_BlitsUnsupported)
             || (d->clipType == QDirectFBPaintEnginePrivate::ComplexClip)
             || (!d->supportsStretchBlit() && state()->matrix.mapRect(r).size() != sr.size())) {
@@ -606,7 +606,7 @@ void QDirectFBPaintEngine::drawTiledPixmap(const QRectF &r,
         RASTERFALLBACK(DRAW_TILED_PIXMAP, r, pixmap.size(), offset);
         d->lock();
         QRasterPaintEngine::drawTiledPixmap(r, pixmap, offset);
-    } else if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_SupportedBlits)
+    } else if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)
                || (d->transformationType & QDirectFBPaintEnginePrivate::Matrix_BlitsUnsupported)
                || (d->clipType == QDirectFBPaintEnginePrivate::ComplexClip)
                || (!d->supportsStretchBlit() && state()->matrix.isScaling())) {
@@ -720,7 +720,7 @@ void QDirectFBPaintEngine::fillRect(const QRectF &rect, const QBrush &brush)
         switch (brush.style()) {
         case Qt::SolidPattern: {
             if (d->transformationType & QDirectFBPaintEnginePrivate::Matrix_RectsUnsupported
-                || !d->testCompositionMode(0, &brush)) {
+                || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
                 break;
             }
             const QColor color = brush.color();
@@ -732,7 +732,7 @@ void QDirectFBPaintEngine::fillRect(const QRectF &rect, const QBrush &brush)
             return; }
 
         case Qt::TexturePattern: {
-            if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_SupportedBlits)
+            if (!(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)
                 || (d->transformationType & QDirectFBPaintEnginePrivate::Matrix_BlitsUnsupported)
                 || (!d->supportsStretchBlit() && state()->matrix.isScaling())) {
                 break;
@@ -760,7 +760,7 @@ void QDirectFBPaintEngine::fillRect(const QRectF &rect, const QColor &color)
     Q_D(QDirectFBPaintEngine);
     if ((d->transformationType & QDirectFBPaintEnginePrivate::Matrix_RectsUnsupported)
         || (d->clipType == QDirectFBPaintEnginePrivate::ComplexClip)
-        || !d->testCompositionMode(0, 0, &color)) {
+        || !(d->compositionModeStatus & QDirectFBPaintEnginePrivate::PorterDuff_Supported)) {
         RASTERFALLBACK(FILL_RECT, rect, color, VOID_ARG());
         d->lock();
         QRasterPaintEngine::fillRect(rect, color);
@@ -804,7 +804,7 @@ QDirectFBPaintEnginePrivate::QDirectFBPaintEnginePrivate(QDirectFBPaintEngine *p
     : surface(0), antialiased(false), simplePen(false),
       transformationType(0), opacity(255),
       clipType(ClipUnset), dfbDevice(0),
-      compositionModeStatus(0), inClip(false), q(p)
+      compositionModeStatus(0), isPremultiplied(false), inClip(false), q(p)
 {
     fb = QDirectFBScreen::instance()->dfb();
     surfaceCache = new SurfaceCache;
@@ -820,36 +820,6 @@ bool QDirectFBPaintEnginePrivate::isSimpleBrush(const QBrush &brush) const
     return (brush.style() == Qt::NoBrush) || (brush.style() == Qt::SolidPattern && !antialiased);
 }
 
-bool QDirectFBPaintEnginePrivate::testCompositionMode(const QPen *pen, const QBrush *brush, const QColor *color) const
-{
-    Q_ASSERT(!pen || pen->style() == Qt::NoPen || pen->style() == Qt::SolidLine);
-    Q_ASSERT(!brush || brush->style() == Qt::NoBrush || brush->style() == Qt::SolidPattern);
-    switch (compositionModeStatus & (QDirectFBPaintEnginePrivate::PorterDuff_SupportedOpaquePrimitives
-                                     |QDirectFBPaintEnginePrivate::PorterDuff_SupportedPrimitives)) {
-    case QDirectFBPaintEnginePrivate::PorterDuff_SupportedPrimitives:
-        return true;
-    case QDirectFBPaintEnginePrivate::PorterDuff_SupportedOpaquePrimitives:
-        if (pen && pen->style() == Qt::SolidLine && pen->color().alpha() != 255)
-            return false;
-        if (brush) {
-            if (brush->style() == Qt::SolidPattern && brush->color().alpha() != 255) {
-                return false;
-            }
-        } else if (color && color->alpha() != 255) {
-            return false;
-        }
-        return true;
-    case QDirectFBPaintEnginePrivate::PorterDuff_None:
-        return false;
-    default:
-        // ### PorterDuff_SupportedOpaquePrimitives|PorterDuff_SupportedPrimitives can't be combined
-        break;
-    }
-    Q_ASSERT(0);
-    return false;
-}
-
-
 void QDirectFBPaintEnginePrivate::lock()
 {
     // We will potentially get a new pointer to the buffer after a
@@ -912,21 +882,23 @@ void QDirectFBPaintEnginePrivate::setCompositionMode(QPainter::CompositionMode m
 
     static const bool forceRasterFallBack = qgetenv("QT_DIRECTFB_FORCE_RASTER").toInt() > 0;
     if (forceRasterFallBack) {
-        compositionModeStatus = 0;
+        compositionModeStatus = PorterDuff_None;
         return;
     }
 
-    compositionModeStatus = PorterDuff_SupportedBlits;
+    compositionModeStatus = PorterDuff_Supported|PorterDuff_PremultiplyColors|PorterDuff_AlwaysBlend;
     switch (mode) {
     case QPainter::CompositionMode_Clear:
         surface->SetPorterDuff(surface, DSPD_CLEAR);
         break;
     case QPainter::CompositionMode_Source:
         surface->SetPorterDuff(surface, DSPD_SRC);
-        compositionModeStatus |= PorterDuff_SupportedOpaquePrimitives;
+        compositionModeStatus &= ~PorterDuff_AlwaysBlend;
+        if (!isPremultiplied)
+            compositionModeStatus &= ~PorterDuff_PremultiplyColors;
         break;
     case QPainter::CompositionMode_SourceOver:
-        compositionModeStatus |= PorterDuff_SupportedPrimitives;
+        compositionModeStatus &= ~PorterDuff_AlwaysBlend;
         surface->SetPorterDuff(surface, DSPD_SRC_OVER);
         break;
     case QPainter::CompositionMode_DestinationOver:
@@ -934,6 +906,8 @@ void QDirectFBPaintEnginePrivate::setCompositionMode(QPainter::CompositionMode m
         break;
     case QPainter::CompositionMode_SourceIn:
         surface->SetPorterDuff(surface, DSPD_SRC_IN);
+        if (!isPremultiplied)
+            compositionModeStatus &= ~PorterDuff_PremultiplyColors;
         break;
     case QPainter::CompositionMode_DestinationIn:
         surface->SetPorterDuff(surface, DSPD_DST_IN);
@@ -964,7 +938,7 @@ void QDirectFBPaintEnginePrivate::setCompositionMode(QPainter::CompositionMode m
         break;
 #endif
     default:
-        compositionModeStatus = 0;
+        compositionModeStatus = PorterDuff_None;
         break;
     }
 }
@@ -986,9 +960,6 @@ void QDirectFBPaintEnginePrivate::prepareForBlit(bool alpha)
     }
     surface->SetColor(surface, 0xff, 0xff, 0xff, opacity);
     surface->SetBlittingFlags(surface, blittingFlags);
-    if (compositionModeStatus & PorterDuff_Dirty) {
-        setCompositionMode(q->state()->composition_mode);
-    }
 }
 
 static inline uint ALPHA_MUL(uint x, uint a)
@@ -1001,12 +972,20 @@ static inline uint ALPHA_MUL(uint x, uint a)
 void QDirectFBPaintEnginePrivate::setDFBColor(const QColor &color)
 {
     Q_ASSERT(surface);
+    Q_ASSERT(compositionModeStatus & PorterDuff_Supported);
     const quint8 alpha = (opacity == 255 ?
                           color.alpha() : ALPHA_MUL(color.alpha(), opacity));
-    surface->SetColor(surface, color.red(), color.green(), color.blue(), alpha);
-    surface->SetPorterDuff(surface, DSPD_NONE);
-    surface->SetDrawingFlags(surface, alpha == 255 ? DSDRAW_NOFX : DSDRAW_BLEND);
-    compositionModeStatus |= PorterDuff_Dirty;
+    QColor col;
+    if (compositionModeStatus & PorterDuff_PremultiplyColors) {
+        col = QColor(ALPHA_MUL(color.red(), alpha),
+                     ALPHA_MUL(color.green(), alpha),
+                     ALPHA_MUL(color.blue(), alpha),
+                     alpha);
+    } else {
+        col = QColor(color.red(), color.green(), color.blue(), alpha);
+    }
+    surface->SetColor(surface, col.red(), col.green(), col.blue(), col.alpha());
+    surface->SetDrawingFlags(surface, alpha == 255 && !(compositionModeStatus & PorterDuff_AlwaysBlend) ? DSDRAW_NOFX : DSDRAW_BLEND);
 }
 
 IDirectFBSurface *QDirectFBPaintEnginePrivate::getSurface(const QImage &img, bool *release)