Merge branch 'master' of scm.dev.nokia.troll.no:qt/oslo-staging-2 into master-integration

* 'master' of scm.dev.nokia.troll.no:qt/oslo-staging-2:
  Support sub pixel positioning of glyphs in raster engine
  Added basic tests for threaded QPainter drawing onto FBOs and PBOs.

16 files changed, 332 insertions, 65 deletions

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index 0b76898..94d7578 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -3098,9 +3098,17 @@ void QRasterPaintEngine::drawCachedGlyphs(int numGlyphs, const glyph_t *glyphs,
 
     int margin = cache->glyphMargin();
 
+    bool supportsSubPixelPositions = fontEngine->supportsSubPixelPositions();
+
     const uchar *bits = image.bits();
     for (int i=0; i<numGlyphs; ++i) {
-        const QTextureGlyphCache::Coord &c = cache->coords.value(glyphs[i]);
+
+        QFixed subPixelPosition;
+        if (supportsSubPixelPositions)
+            subPixelPosition = cache->subPixelPositionForX(positions[i].x);
+        QTextureGlyphCache::GlyphAndSubPixelPosition glyph(glyphs[i], subPixelPosition);
+        const QTextureGlyphCache::Coord &c = cache->coords.value(glyph);
+
         int x = qFloor(positions[i].x) + c.baseLineX - margin;
         int y = qFloor(positions[i].y) - c.baseLineY - margin;
 
diff --git a/src/gui/painting/qtextureglyphcache.cpp b/src/gui/painting/qtextureglyphcache.cpp
index 376219b..e992bb2 100644
--- a/src/gui/painting/qtextureglyphcache.cpp
+++ b/src/gui/painting/qtextureglyphcache.cpp
@@ -69,8 +69,60 @@ static inline int qt_next_power_of_two(int v)
     return v;
 }
 
+int QTextureGlyphCache::calculateSubPixelPositionCount(glyph_t glyph) const
+{
+    // Test 12 different subpixel positions since it factors into 3*4 so it gives
+    // the coverage we need.
+
+    QList<QImage> images;
+    for (int i=0; i<12; ++i) {
+        QImage img = textureMapForGlyph(glyph, QFixed::fromReal(i / 12.0));
+
+        if (images.isEmpty()) {
+            QPainterPath path;
+            QFixedPoint point;
+            m_current_fontengine->addGlyphsToPath(&glyph, &point, 1, &path, QTextItem::RenderFlags());
+
+            // Glyph is space, return 0 to indicate that we need to keep trying
+            if (path.isEmpty())
+                break;
+
+            images.append(img);
+        } else {
+            bool found = false;
+            for (int j=0; j<images.size(); ++j) {
+                if (images.at(j) == img) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found)
+                images.append(img);
+        }
+    }
+
+    return images.size();
+}
+
+QFixed QTextureGlyphCache::subPixelPositionForX(QFixed x) const
+{
+    if (m_subPixelPositionCount == 0)
+        return QFixed();
+
+    QFixed subPixelPosition;
+    if (x != 0) {
+        subPixelPosition = x - x.floor();
+        QFixed fraction = (subPixelPosition / QFixed::fromReal(1.0 / m_subPixelPositionCount)).floor();
+
+        // Compensate for precision loss in fixed point to make sure we are always drawing at a subpixel position over
+        // the lower boundary for the selected rasterization by adding 1/64.
+        subPixelPosition = fraction / QFixed(m_subPixelPositionCount) + QFixed::fromReal(0.015625);
+    }
+    return subPixelPosition;
+}
+
 void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const glyph_t *glyphs,
-                                  const QFixedPoint *)
+                                                const QFixedPoint *positions)
 {
 #ifdef CACHE_DEBUG
     printf("Populating with %d glyphs\n", numGlyphs);
@@ -81,15 +133,33 @@ void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const
     const int margin = glyphMargin();
     const int paddingDoubled = glyphPadding() * 2;
 
-    QHash<glyph_t, Coord> listItemCoordinates;
+    bool supportsSubPixelPositions = fontEngine->supportsSubPixelPositions();
+    if (m_subPixelPositionCount == 0) {
+        if (!supportsSubPixelPositions) {
+            m_subPixelPositionCount = 1;
+        } else {
+            int i = 0;
+            while (m_subPixelPositionCount == 0 && i < numGlyphs)
+                m_subPixelPositionCount = calculateSubPixelPositionCount(glyphs[i++]);
+        }
+    }
+
+    QHash<GlyphAndSubPixelPosition, Coord> listItemCoordinates;
     int rowHeight = 0;
 
     // check each glyph for its metrics and get the required rowHeight.
     for (int i=0; i < numGlyphs; ++i) {
         const glyph_t glyph = glyphs[i];
-        if (coords.contains(glyph))
+
+        QFixed subPixelPosition;
+        if (supportsSubPixelPositions) {
+            QFixed x = positions != 0 ? positions[i].x : QFixed();
+            subPixelPosition = subPixelPositionForX(x);
+        }
+
+        if (coords.contains(GlyphAndSubPixelPosition(glyph, subPixelPosition)))
             continue;
-        if (listItemCoordinates.contains(glyph))
+        if (listItemCoordinates.contains(GlyphAndSubPixelPosition(glyph, subPixelPosition)))
             continue;
         glyph_metrics_t metrics = fontEngine->boundingBox(glyph, m_transform);
 
@@ -119,7 +189,7 @@ void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const
                     metrics.x.round().truncate(),
                     -metrics.y.truncate() }; // baseline for horizontal scripts
 
-        listItemCoordinates.insert(glyph, c);
+        listItemCoordinates.insert(GlyphAndSubPixelPosition(glyph, subPixelPosition), c);
         rowHeight = qMax(rowHeight, glyph_height);
     }
     if (listItemCoordinates.isEmpty())
@@ -135,7 +205,7 @@ void QTextureGlyphCache::populate(QFontEngine *fontEngine, int numGlyphs, const
     }
 
     // now actually use the coords and paint the wanted glyps into cache.
-    QHash<glyph_t, Coord>::iterator iter = listItemCoordinates.begin();
+    QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = listItemCoordinates.begin();
     while (iter != listItemCoordinates.end()) {
         Coord c = iter.value();
 
@@ -166,7 +236,7 @@ void QTextureGlyphCache::fillInPendingGlyphs()
 
     int requiredHeight = 0;
     {
-        QHash<glyph_t, Coord>::iterator iter = m_pendingGlyphs.begin();
+        QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = m_pendingGlyphs.begin();
         while (iter != m_pendingGlyphs.end()) {
             Coord c = iter.value();
             requiredHeight = qMax(requiredHeight, c.y + c.h);
@@ -182,9 +252,10 @@ void QTextureGlyphCache::fillInPendingGlyphs()
     }
 
     {
-        QHash<glyph_t, Coord>::iterator iter = m_pendingGlyphs.begin();
+        QHash<GlyphAndSubPixelPosition, Coord>::iterator iter = m_pendingGlyphs.begin();
         while (iter != m_pendingGlyphs.end()) {
-            fillTexture(iter.value(), iter.key());
+            GlyphAndSubPixelPosition key = iter.key();
+            fillTexture(iter.value(), key.glyph, key.subPixelPosition);
 
             ++iter;
         }
@@ -193,7 +264,7 @@ void QTextureGlyphCache::fillInPendingGlyphs()
     m_pendingGlyphs.clear();
 }
 
-QImage QTextureGlyphCache::textureMapForGlyph(glyph_t g) const
+QImage QTextureGlyphCache::textureMapForGlyph(glyph_t g, QFixed subPixelPosition) const
 {
 #if defined(Q_WS_X11)
     if (m_transform.type() > QTransform::TxTranslate) {
@@ -226,7 +297,7 @@ QImage QTextureGlyphCache::textureMapForGlyph(glyph_t g) const
     } else
 #endif
     if (m_type == QFontEngineGlyphCache::Raster_RGBMask)
-        return m_current_fontengine->alphaRGBMapForGlyph(g, glyphMargin(), m_transform);
+        return m_current_fontengine->alphaRGBMapForGlyph(g, subPixelPosition, glyphMargin(), m_transform);
     else
         return m_current_fontengine->alphaMapForGlyph(g, m_transform);
 
@@ -272,9 +343,9 @@ int QImageTextureGlyphCache::glyphMargin() const
 #endif
 }
 
-void QImageTextureGlyphCache::fillTexture(const Coord &c, glyph_t g)
+void QImageTextureGlyphCache::fillTexture(const Coord &c, glyph_t g, QFixed subPixelPosition)
 {
-    QImage mask = textureMapForGlyph(g);
+    QImage mask = textureMapForGlyph(g, subPixelPosition);
 
 #ifdef CACHE_DEBUG
     printf("fillTexture of %dx%d at %d,%d in the cache of %dx%d\n", c.w, c.h, c.x, c.y, m_image.width(), m_image.height());
diff --git a/src/gui/painting/qtextureglyphcache_p.h b/src/gui/painting/qtextureglyphcache_p.h
index 0770ed4..4131003 100644
--- a/src/gui/painting/qtextureglyphcache_p.h
+++ b/src/gui/painting/qtextureglyphcache_p.h
@@ -77,11 +77,24 @@ class Q_GUI_EXPORT QTextureGlyphCache : public QFontEngineGlyphCache
 public:
     QTextureGlyphCache(QFontEngineGlyphCache::Type type, const QTransform &matrix)
         : QFontEngineGlyphCache(matrix, type), m_current_fontengine(0),
-                                               m_w(0), m_h(0), m_cx(0), m_cy(0), m_currentRowHeight(0)
+                                               m_w(0), m_h(0), m_cx(0), m_cy(0), m_currentRowHeight(0), m_subPixelPositionCount(0)
         { }
 
     virtual ~QTextureGlyphCache() { }
 
+    struct GlyphAndSubPixelPosition
+    {
+        GlyphAndSubPixelPosition(glyph_t g, QFixed spp) : glyph(g), subPixelPosition(spp) {}
+
+        bool operator==(const GlyphAndSubPixelPosition &other) const
+        {
+            return glyph == other.glyph && subPixelPosition == other.subPixelPosition;
+        }
+
+        glyph_t glyph;
+        QFixed subPixelPosition;
+    };
+
     struct Coord {
         int x;
         int y;
@@ -101,7 +114,7 @@ public:
     virtual int glyphMargin() const { return 0; }
     virtual int glyphPadding() const { return 0; }
 
-    virtual void fillTexture(const Coord &coord, glyph_t glyph) = 0;
+    virtual void fillTexture(const Coord &coord, glyph_t glyph, QFixed subPixelPosition) = 0;
 
     inline void createCache(int width, int height) {
         m_w = width;
@@ -118,22 +131,31 @@ public:
 
     inline bool isNull() const { return m_h == 0; }
 
-    QHash<glyph_t, Coord> coords;
+    QHash<GlyphAndSubPixelPosition, Coord> coords;
 
-    QImage textureMapForGlyph(glyph_t g) const;
+    QImage textureMapForGlyph(glyph_t g, QFixed subPixelPosition) const;
+
+    QFixed subPixelPositionForX(QFixed x) const;
 
 protected:
-    QFontEngine *m_current_fontengine;
+    int calculateSubPixelPositionCount(glyph_t) const;
 
-    QHash<glyph_t, Coord> m_pendingGlyphs;
+    QFontEngine *m_current_fontengine;
+    QHash<GlyphAndSubPixelPosition, Coord> m_pendingGlyphs;
 
     int m_w; // image width
     int m_h; // image height
     int m_cx; // current x
     int m_cy; // current y
     int m_currentRowHeight; // Height of last row
+    int m_subPixelPositionCount; // Number of positions within a single pixel for this cache
 };
 
+inline uint qHash(const QTextureGlyphCache::GlyphAndSubPixelPosition &g)
+{
+    return (g.glyph << 8)  | (g.subPixelPosition * 10).round().toInt();
+}
+
 
 class Q_GUI_EXPORT QImageTextureGlyphCache : public QTextureGlyphCache
 {
@@ -143,7 +165,7 @@ public:
     virtual int glyphMargin() const;
     virtual void createTextureData(int width, int height);
     virtual void resizeTextureData(int width, int height);
-    virtual void fillTexture(const Coord &c, glyph_t glyph);
+    virtual void fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition);
 
     inline const QImage &image() const { return m_image; }
 
diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 1b94915..55d2a83 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -616,7 +616,7 @@ QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, const QTransform &t)
     return i;
 }
 
-QImage QFontEngine::alphaRGBMapForGlyph(glyph_t glyph, int /* margin */, const QTransform &t)
+QImage QFontEngine::alphaRGBMapForGlyph(glyph_t glyph, QFixed /*subPixelPosition*/, int /* margin */, const QTransform &t)
 {
     QImage alphaMask = alphaMapForGlyph(glyph, t);
     QImage rgbMask(alphaMask.width(), alphaMask.height(), QImage::Format_RGB32);
diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 7a8b1e5..7b6ef0e 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -1873,10 +1873,10 @@ QImage QFontEngineFT::alphaMapForGlyph(glyph_t g)
     return img;
 }
 
-QImage QFontEngineFT::alphaRGBMapForGlyph(glyph_t g, int margin, const QTransform &t)
+QImage QFontEngineFT::alphaRGBMapForGlyph(glyph_t g, QFixed subPixelPosition, int margin, const QTransform &t)
 {
     if (t.type() > QTransform::TxTranslate)
-        return QFontEngine::alphaRGBMapForGlyph(g, margin, t);
+        return QFontEngine::alphaRGBMapForGlyph(g, subPixelPosition, margin, t);
 
     lockFace();
 
@@ -1885,7 +1885,7 @@ QImage QFontEngineFT::alphaRGBMapForGlyph(glyph_t g, int margin, const QTransfor
     Glyph *glyph = defaultGlyphSet.outline_drawing ? 0 : loadGlyph(g, glyph_format);
     if (!glyph) {
         unlockFace();
-        return QFontEngine::alphaRGBMapForGlyph(g, margin, t);
+        return QFontEngine::alphaRGBMapForGlyph(g, subPixelPosition, margin, t);
     }
 
     QImage img(glyph->width, glyph->height, QImage::Format_RGB32);
diff --git a/src/gui/text/qfontengine_ft_p.h b/src/gui/text/qfontengine_ft_p.h
index 2f05a8b..72f7d9f 100644
--- a/src/gui/text/qfontengine_ft_p.h
+++ b/src/gui/text/qfontengine_ft_p.h
@@ -241,7 +241,7 @@ private:
 
     virtual void recalcAdvances(QGlyphLayout *glyphs, QTextEngine::ShaperFlags flags) const;
     virtual QImage alphaMapForGlyph(glyph_t);
-    virtual QImage alphaRGBMapForGlyph(glyph_t, int margin, const QTransform &t);
+    virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
     virtual void removeGlyphFromCache(glyph_t glyph);
 
     virtual int glyphCount() const;
diff --git a/src/gui/text/qfontengine_mac.mm b/src/gui/text/qfontengine_mac.mm
index 2bbf9f2..1ca6ec3 100644
--- a/src/gui/text/qfontengine_mac.mm
+++ b/src/gui/text/qfontengine_mac.mm
@@ -663,7 +663,7 @@ QFont QCoreTextFontEngine::createExplicitFont() const
     return createExplicitFontWithName(familyName);
 }
 
-QImage QCoreTextFontEngine::imageForGlyph(glyph_t glyph, int margin, bool aa)
+QImage QCoreTextFontEngine::imageForGlyph(glyph_t glyph, QFixed subPixelPosition, int /*margin*/, bool aa)
 {
     const glyph_metrics_t br = boundingBox(glyph);
     QImage im(qRound(br.width)+2, qRound(br.height)+2, QImage::Format_RGB32);
@@ -700,7 +700,8 @@ QImage QCoreTextFontEngine::imageForGlyph(glyph_t glyph, int margin, bool aa)
     QCFType<CGFontRef> cgFont = CGFontCreateWithPlatformFont(&atsfont);
     CGContextSetFont(ctx, cgFont);
 
-    qreal pos_x = -br.x.toReal()+1, pos_y = im.height()+br.y.toReal();
+    qreal pos_x = -br.x.toReal() + subPixelPosition.toReal();
+    qreal pos_y = im.height()+br.y.toReal();
     CGContextSetTextPosition(ctx, pos_x, pos_y);
 
     CGSize advance;
@@ -721,7 +722,7 @@ QImage QCoreTextFontEngine::imageForGlyph(glyph_t glyph, int margin, bool aa)
 
 QImage QCoreTextFontEngine::alphaMapForGlyph(glyph_t glyph)
 {
-    QImage im = imageForGlyph(glyph, 0, false);
+    QImage im = imageForGlyph(glyph, QFixed(), 0, false);
 
     QImage indexed(im.width(), im.height(), QImage::Format_Indexed8);
     QVector<QRgb> colors(256);
@@ -742,12 +743,12 @@ QImage QCoreTextFontEngine::alphaMapForGlyph(glyph_t glyph)
     return indexed;
 }
 
-QImage QCoreTextFontEngine::alphaRGBMapForGlyph(glyph_t glyph, int margin, const QTransform &x)
+QImage QCoreTextFontEngine::alphaRGBMapForGlyph(glyph_t glyph, QFixed subPixelPosition, int margin, const QTransform &x)
 {
     if (x.type() >= QTransform::TxScale)
-        return QFontEngine::alphaRGBMapForGlyph(glyph, margin, x);
+        return QFontEngine::alphaRGBMapForGlyph(glyph, subPixelPosition, margin, x);
 
-    QImage im = imageForGlyph(glyph, margin, true);
+    QImage im = imageForGlyph(glyph, subPixelPosition, margin, true);
     qmacfontengine_gamma_correct(&im);
     return im;
 }
@@ -1706,7 +1707,7 @@ QImage QFontEngineMac::alphaMapForGlyph(glyph_t glyph)
     return indexed;
 }
 
-QImage QFontEngineMac::alphaRGBMapForGlyph(glyph_t glyph, int margin, const QTransform &t)
+QImage QFontEngineMac::alphaRGBMapForGlyph(glyph_t glyph, QFixed, int margin, const QTransform &t)
 {
     QImage im = imageForGlyph(glyph, margin, true);
 
diff --git a/src/gui/text/qfontengine_p.h b/src/gui/text/qfontengine_p.h
index 6e9bd0bc..6ebbc1f 100644
--- a/src/gui/text/qfontengine_p.h
+++ b/src/gui/text/qfontengine_p.h
@@ -155,6 +155,7 @@ public:
         SynthesizedStretch = 0x4
     };
     virtual int synthesized() const { return 0; }
+    virtual bool supportsSubPixelPositions() const { return false; }
 
     virtual QFixed emSquareSize() const { return ascent(); }
 
@@ -188,7 +189,7 @@ public:
      */
     virtual QImage alphaMapForGlyph(glyph_t);
     virtual QImage alphaMapForGlyph(glyph_t, const QTransform &t);
-    virtual QImage alphaRGBMapForGlyph(glyph_t, int margin, const QTransform &t);
+    virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
 
     virtual void removeGlyphFromCache(glyph_t);
 
@@ -448,6 +449,7 @@ public:
     virtual bool canRender(const QChar *string, int len);
 
     virtual int synthesized() const { return synthesisFlags; }
+    virtual bool supportsSubPixelPositions() const { return true; }
 
     virtual Type type() const { return QFontEngine::Mac; }
 
@@ -457,13 +459,13 @@ public:
     virtual bool getSfntTableData(uint /*tag*/, uchar * /*buffer*/, uint * /*length*/) const;
     virtual void getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_metrics_t *metrics);
     virtual QImage alphaMapForGlyph(glyph_t);
-    virtual QImage alphaRGBMapForGlyph(glyph_t, int margin, const QTransform &t);
+    virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
     virtual qreal minRightBearing() const;
     virtual qreal minLeftBearing() const;
     virtual QFont createExplicitFont() const;
 
 private:
-    QImage imageForGlyph(glyph_t glyph, int margin, bool colorful);
+    QImage imageForGlyph(glyph_t glyph, QFixed subPixelPosition, int margin, bool colorful);
     CTFontRef ctfont;
     CGFontRef cgFont;
     QCoreTextFontEngineMulti *parentEngine;
@@ -546,7 +548,7 @@ public:
     virtual Properties properties() const;
     virtual void getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_metrics_t *metrics);
     virtual QImage alphaMapForGlyph(glyph_t);
-    virtual QImage alphaRGBMapForGlyph(glyph_t, int margin, const QTransform &t);
+    virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
 
 private:
     QImage imageForGlyph(glyph_t glyph, int margin, bool colorful);
diff --git a/src/gui/text/qfontengine_win.cpp b/src/gui/text/qfontengine_win.cpp
index 4bed2b5..928bca0 100644
--- a/src/gui/text/qfontengine_win.cpp
+++ b/src/gui/text/qfontengine_win.cpp
@@ -1254,7 +1254,7 @@ QImage QFontEngineWin::alphaMapForGlyph(glyph_t glyph, const QTransform &xform)
 #define SPI_GETFONTSMOOTHINGCONTRAST           0x200C
 #define SPI_SETFONTSMOOTHINGCONTRAST           0x200D
 
-QImage QFontEngineWin::alphaRGBMapForGlyph(glyph_t glyph, int margin, const QTransform &t)
+QImage QFontEngineWin::alphaRGBMapForGlyph(glyph_t glyph, QFixed, int margin, const QTransform &t)
 {
     HFONT font = hfont;
 
diff --git a/src/gui/text/qfontengine_win_p.h b/src/gui/text/qfontengine_win_p.h
index 68b53b5..d86f42e 100644
--- a/src/gui/text/qfontengine_win_p.h
+++ b/src/gui/text/qfontengine_win_p.h
@@ -104,7 +104,7 @@ public:
 
     virtual QImage alphaMapForGlyph(glyph_t t) { return alphaMapForGlyph(t, QTransform()); }
     virtual QImage alphaMapForGlyph(glyph_t, const QTransform &xform);
-    virtual QImage alphaRGBMapForGlyph(glyph_t t, int margin, const QTransform &xform);
+    virtual QImage alphaRGBMapForGlyph(glyph_t t, QFixed subPixelPosition, int margin, const QTransform &xform);
 
 #ifndef Q_CC_MINGW
     virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = 0, qreal *rightBearing = 0);
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 6e56553..e7ee91c 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1519,8 +1519,15 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(QFontEngineGlyphCache::Type glyp
         vertexCoordinates->clear();
         textureCoordinates->clear();
 
+        bool supportsSubPixelPositions = staticTextItem->fontEngine->supportsSubPixelPositions();
         for (int i=0; i<staticTextItem->numGlyphs; ++i) {
-            const QTextureGlyphCache::Coord &c = cache->coords.value(staticTextItem->glyphs[i]);
+            QFixed subPixelPosition;
+            if (supportsSubPixelPositions)
+                subPixelPosition = cache->subPixelPositionForX(staticTextItem->glyphPositions[i].x);
+
+            QTextureGlyphCache::GlyphAndSubPixelPosition glyph(staticTextItem->glyphs[i], subPixelPosition);
+
+            const QTextureGlyphCache::Coord &c = cache->coords.value(glyph);
             int x = staticTextItem->glyphPositions[i].x.toInt() + c.baseLineX - margin;
             int y = staticTextItem->glyphPositions[i].y.toInt() - c.baseLineY - margin;
 
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
index 53a2f3a..3dc7789 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
@@ -216,7 +216,7 @@ void QGLTextureGlyphCache::resizeTextureData(int width, int height)
     pex->updateClipScissorTest();
 }
 
-void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph)
+void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition)
 {
     if (ctx == 0) {
         qWarning("QGLTextureGlyphCache::fillTexture: Called with no context");
@@ -225,7 +225,7 @@ void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph)
 
     QGLGlyphTexture *glyphTexture = m_textureResource.value(ctx);
     if (pex == 0 || ctx->d_ptr->workaround_brokenFBOReadBack) {
-        QImageTextureGlyphCache::fillTexture(c, glyph);
+        QImageTextureGlyphCache::fillTexture(c, glyph, subPixelPosition);
 
         glBindTexture(GL_TEXTURE_2D, glyphTexture->m_texture);
         const QImage &texture = image();
@@ -238,7 +238,7 @@ void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph)
         return;
     }
 
-    QImage mask = textureMapForGlyph(glyph);
+    QImage mask = textureMapForGlyph(glyph, subPixelPosition);
     const int maskWidth = mask.width();
     const int maskHeight = mask.height();
 
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
index 2ae3a64..345684d 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl_p.h
@@ -106,7 +106,7 @@ public:
 
     virtual void createTextureData(int width, int height);
     virtual void resizeTextureData(int width, int height);
-    virtual void fillTexture(const Coord &c, glyph_t glyph);
+    virtual void fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition);
     virtual int glyphPadding() const;
 
     inline GLuint texture() const {
diff --git a/tests/auto/qglthreads/tst_qglthreads.cpp b/tests/auto/qglthreads/tst_qglthreads.cpp
index 4777fb1..38b0dab 100644
--- a/tests/auto/qglthreads/tst_qglthreads.cpp
+++ b/tests/auto/qglthreads/tst_qglthreads.cpp
@@ -456,11 +456,71 @@ void tst_QGLThreads::renderInThread()
     QVERIFY(!thread.failure);
 }
 
+class Device
+{
+public:
+    virtual ~Device() {}
+    virtual QPaintDevice *realPaintDevice() = 0;
+    virtual void prepareDevice() {}
+};
+
+class GLWidgetWrapper : public Device
+{
+public:
+    GLWidgetWrapper() {
+        widget.resize(150, 150);
+        widget.show();
+        QTest::qWaitForWindowShown(&widget);
+        widget.doneCurrent();
+    }
+    QPaintDevice *realPaintDevice() { return &widget; }
+
+    ThreadSafeGLWidget widget;
+};
+
+class PixmapWrapper : public Device
+{
+public:
+    PixmapWrapper() { pixmap = new QPixmap(512, 512); }
+    ~PixmapWrapper() { delete pixmap; }
+    QPaintDevice *realPaintDevice() { return pixmap; }
+
+    QPixmap *pixmap;
+};
+
+class PixelBufferWrapper : public Device
+{
+public:
+    PixelBufferWrapper() { pbuffer = new QGLPixelBuffer(512, 512); }
+    ~PixelBufferWrapper() { delete pbuffer; }
+    QPaintDevice *realPaintDevice() { return pbuffer; }
+
+    QGLPixelBuffer *pbuffer;
+};
+
+
+class FrameBufferObjectWrapper : public Device
+{
+public:
+    FrameBufferObjectWrapper() {
+        widget.makeCurrent();
+        fbo = new QGLFramebufferObject(512, 512);
+        widget.doneCurrent();
+    }
+    ~FrameBufferObjectWrapper() { delete fbo; }
+    QPaintDevice *realPaintDevice() { return fbo; }
+    void prepareDevice() { widget.makeCurrent(); }
+
+    ThreadSafeGLWidget widget;
+    QGLFramebufferObject *fbo;
+};
+
+
 class ThreadPainter : public QObject
 {
     Q_OBJECT
 public:
-    ThreadPainter(QPaintDevice *pd) : paintDevice(pd), fail(true) {
+    ThreadPainter(Device *pd) : device(pd), fail(true) {
         pixmap = QPixmap(40, 40);
         pixmap.fill(Qt::green);
         QPainter p(&pixmap);
@@ -474,6 +534,8 @@ public slots:
         QTime time;
         time.start();
         int rotAngle = 10;
+        device->prepareDevice();
+        QPaintDevice *paintDevice = device->realPaintDevice();
         QSize s(paintDevice->width(), paintDevice->height());
         while (time.elapsed() < RUNNING_TIME) {
             QPainter p;
@@ -506,7 +568,7 @@ public slots:
 
 private:
     QPixmap pixmap;
-    QPaintDevice *paintDevice;
+    Device *device;
     bool fail;
 };
 
@@ -520,16 +582,6 @@ public:
             devices.append(new T);
             threads.append(new QThread);
             painters.append(new ThreadPainter(devices.at(i)));
-            if (devices.at(i)->devType() == QInternal::Widget) {
-                QWidget *widget = static_cast<QWidget *>(devices.at(i));
-                widget->resize(150, 150);
-                widget->show();
-                QTest::qWaitForWindowShown(widget);
-                if (widget->inherits("QGLWidget")) {
-                    QGLWidget *glWidget = static_cast<QGLWidget *>(widget);
-                    glWidget->doneCurrent();
-                }
-            }
             painters.at(i)->moveToThread(threads.at(i));
             painters.at(i)->connect(threads.at(i), SIGNAL(started()), painters.at(i), SLOT(draw()));
         }
@@ -568,7 +620,7 @@ public:
 
 private:
     QList<QThread *> threads;
-    QList<QPaintDevice *> devices;
+    QList<Device *> devices;
     QList<ThreadPainter *> painters;
     int numThreads;
 };
@@ -587,7 +639,12 @@ void tst_QGLThreads::painterOnGLWidgetInThread()
 #ifdef Q_OS_MAC
     QSKIP("OpenGL threading tests are currently disabled on Mac as they were causing reboots", SkipAll);
 #endif
-    PaintThreadManager<ThreadSafeGLWidget> painterThreads(5);
+    if (!((QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_Version_2_0) ||
+          (QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_ES_Version_2_0))) {
+        QSKIP("The OpenGL based threaded QPainter tests requires OpenGL/ES 2.0.", SkipAll);
+    }
+
+    PaintThreadManager<GLWidgetWrapper> painterThreads(5);
     painterThreads.start();
 
     while (painterThreads.areRunning()) {
@@ -601,12 +658,6 @@ void tst_QGLThreads::painterOnGLWidgetInThread()
     QVERIFY(!painterThreads.failed());
 }
 
-class Pixmap : public QPixmap
-{
-public:
-    Pixmap() : QPixmap(200, 200) {}
-};
-
 /*
    This test uses QPainter to draw onto different QPixmaps in
    different threads at the same time.
@@ -616,7 +667,74 @@ void tst_QGLThreads::painterOnPixmapInThread()
 #ifdef Q_WS_X11
     QSKIP("Drawing text in threads onto X11 drawables currently crashes on some X11 servers.", SkipAll);
 #endif
-    PaintThreadManager<Pixmap> painterThreads(5);
+    PaintThreadManager<PixmapWrapper> painterThreads(5);
+    painterThreads.start();
+
+    while (painterThreads.areRunning()) {
+        qApp->processEvents();
+#ifdef Q_WS_WIN
+        Sleep(100);
+#else
+        usleep(100 * 1000);
+#endif
+    }
+    QVERIFY(!painterThreads.failed());
+}
+
+/* This test uses QPainter to draw onto different QGLPixelBuffer
+   objects in different threads at the same time.
+*/
+void tst_QGLThreads::painterOnPboInThread()
+{
+#ifdef Q_OS_MAC
+    QSKIP("OpenGL threading tests are currently disabled on Mac as they were causing reboots", SkipAll);
+#endif
+    if (!((QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_Version_2_0) ||
+          (QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_ES_Version_2_0))) {
+        QSKIP("The OpenGL based threaded QPainter tests requires OpenGL/ES 2.0.", SkipAll);
+        return;
+    }
+
+    if (!QGLPixelBuffer::hasOpenGLPbuffers()) {
+        QSKIP("This system doesn't support pbuffers.", SkipAll);
+        return;
+    }
+
+    PaintThreadManager<PixelBufferWrapper> painterThreads(5);
+    painterThreads.start();
+
+    while (painterThreads.areRunning()) {
+        qApp->processEvents();
+#ifdef Q_WS_WIN
+        Sleep(100);
+#else
+        usleep(100 * 1000);
+#endif
+    }
+    QVERIFY(!painterThreads.failed());
+}
+
+/* This test uses QPainter to draw onto different
+   QGLFramebufferObjects (bound in a QGLWidget's context) in different
+   threads at the same time.
+*/
+void tst_QGLThreads::painterOnFboInThread()
+{
+#ifdef Q_OS_MAC
+    QSKIP("OpenGL threading tests are currently disabled on Mac as they were causing reboots", SkipAll);
+#endif
+    if (!((QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_Version_2_0) ||
+          (QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_ES_Version_2_0))) {
+        QSKIP("The OpenGL based threaded QPainter tests requires OpenGL/ES 2.0.", SkipAll);
+        return;
+    }
+
+    if (!QGLFramebufferObject::hasOpenGLFramebufferObjects()) {
+        QSKIP("This system doesn't support framebuffer objects.", SkipAll);
+        return;
+    }
+
+    PaintThreadManager<FrameBufferObjectWrapper> painterThreads(5);
     painterThreads.start();
 
     while (painterThreads.areRunning()) {
diff --git a/tests/auto/qglthreads/tst_qglthreads.h b/tests/auto/qglthreads/tst_qglthreads.h
index ae6b953..a8c2963 100644
--- a/tests/auto/qglthreads/tst_qglthreads.h
+++ b/tests/auto/qglthreads/tst_qglthreads.h
@@ -58,6 +58,8 @@ private slots:
     void renderInThread();
     void painterOnGLWidgetInThread();
     void painterOnPixmapInThread();
+    void painterOnPboInThread();
+    void painterOnFboInThread();
 };
 
 #endif // TST_QGLTHREADS_H
diff --git a/tests/auto/qpainter/tst_qpainter.cpp b/tests/auto/qpainter/tst_qpainter.cpp
index 1ba5859..06de16a 100644
--- a/tests/auto/qpainter/tst_qpainter.cpp
+++ b/tests/auto/qpainter/tst_qpainter.cpp
@@ -221,6 +221,8 @@ private slots:
     void drawRect_task215378();
     void drawRect_task247505();
 
+    void drawText_subPixelPositionsInRaster_qtbug5053();
+
     void drawImage_data();
     void drawImage();
 
@@ -4562,6 +4564,40 @@ void tst_QPainter::clipBoundingRect()
 
 }
 
+void tst_QPainter::drawText_subPixelPositionsInRaster_qtbug5053()
+{
+#if !defined(Q_WS_MAC)
+    QSKIP("Only mac supports sub pixel positions currently", SkipAll);
+#endif
+
+    QFontMetricsF fm(qApp->font());
+
+    QImage baseLine(fm.width(QChar::fromLatin1('e')), fm.height(), QImage::Format_RGB32);
+    baseLine.fill(Qt::white);
+    {
+        QPainter p(&baseLine);
+        p.drawText(0, fm.ascent(), QString::fromLatin1("e"));
+    }
+
+    bool foundDifferentRasterization = false;
+    for (int i=1; i<12; ++i) {
+        QImage comparison(baseLine.size(), QImage::Format_RGB32);
+        comparison.fill(Qt::white);
+
+        {
+            QPainter p(&comparison);
+            p.drawText(QPointF(i / 12.0, fm.ascent()), QString::fromLatin1("e"));
+        }
+
+        if (comparison != baseLine) {
+            foundDifferentRasterization = true;
+            break;
+        }
+    }
+
+    QVERIFY(foundDifferentRasterization);
+}
+
 QTEST_MAIN(tst_QPainter)
 
 #include "tst_qpainter.moc"