Merge branch '4.6' of scm.dev.nokia.troll.no:qt/oslo-staging-2 into 4.6-integration

* '4.6' of scm.dev.nokia.troll.no:qt/oslo-staging-2:
  Optimize getting bearings of a glyph on Windows for true type fonts
  Fixes blending problem when paiting non-opaque items with cache enabled.
  Optimize speed of QTextLayout and QPainter::drawText
  Fix a crash in animation groups when deleting uncontrolled animations

13 files changed, 179 insertions, 64 deletions

diff --git a/src/corelib/animation/qanimationgroup.cpp b/src/corelib/animation/qanimationgroup.cpp
index a89f949..2decda3 100644
--- a/src/corelib/animation/qanimationgroup.cpp
+++ b/src/corelib/animation/qanimationgroup.cpp
@@ -244,7 +244,7 @@ QAbstractAnimation *QAnimationGroup::takeAnimation(int index)
     // in ChildRemoved event
     d->animations.removeAt(index);
     animation->setParent(0);
-    d->animationRemovedAt(index);
+    d->animationRemoved(index, animation);
     return animation;
 }
 
@@ -285,7 +285,7 @@ bool QAnimationGroup::event(QEvent *event)
 }
 
 
-void QAnimationGroupPrivate::animationRemovedAt(int index)
+void QAnimationGroupPrivate::animationRemoved(int index, QAbstractAnimation *)
 {
     Q_Q(QAnimationGroup);
     Q_UNUSED(index);
diff --git a/src/corelib/animation/qanimationgroup_p.h b/src/corelib/animation/qanimationgroup_p.h
index 394773b..45603b3 100644
--- a/src/corelib/animation/qanimationgroup_p.h
+++ b/src/corelib/animation/qanimationgroup_p.h
@@ -72,8 +72,19 @@ public:
         isGroup = true;
     }
 
-    virtual void animationInsertedAt(int index) { Q_UNUSED(index) };
-    virtual void animationRemovedAt(int index);
+    virtual void animationInsertedAt(int) { }
+    virtual void animationRemoved(int, QAbstractAnimation *);
+
+    void disconnectUncontrolledAnimation(QAbstractAnimation *anim)
+    {
+        //0 for the signal here because we might be called from the animation destructor
+        QObject::disconnect(anim, 0, q_func(), SLOT(_q_uncontrolledAnimationFinished()));
+    }
+
+    void connectUncontrolledAnimation(QAbstractAnimation *anim)
+    {
+        QObject::connect(anim, SIGNAL(finished()), q_func(), SLOT(_q_uncontrolledAnimationFinished()));
+    }
 
     QList<QAbstractAnimation *> animations;
 };
diff --git a/src/corelib/animation/qparallelanimationgroup.cpp b/src/corelib/animation/qparallelanimationgroup.cpp
index eaa0364..280afed 100644
--- a/src/corelib/animation/qparallelanimationgroup.cpp
+++ b/src/corelib/animation/qparallelanimationgroup.cpp
@@ -246,11 +246,9 @@ void QParallelAnimationGroupPrivate::_q_uncontrolledAnimationFinished()
 
 void QParallelAnimationGroupPrivate::disconnectUncontrolledAnimations()
 {
-    Q_Q(QParallelAnimationGroup);
-
     QHash<QAbstractAnimation *, int>::iterator it = uncontrolledFinishTime.begin();
     while (it != uncontrolledFinishTime.end()) {
-        QObject::disconnect(it.key(), SIGNAL(finished()), q, SLOT(_q_uncontrolledAnimationFinished()));
+        disconnectUncontrolledAnimation(it.key());
         ++it;
     }
 
@@ -259,13 +257,11 @@ void QParallelAnimationGroupPrivate::disconnectUncontrolledAnimations()
 
 void QParallelAnimationGroupPrivate::connectUncontrolledAnimations()
 {
-    Q_Q(QParallelAnimationGroup);
-
     for (int i = 0; i < animations.size(); ++i) {
         QAbstractAnimation *animation = animations.at(i);
         if (animation->duration() == -1 || animation->loopCount() < 0) {
             uncontrolledFinishTime[animation] = -1;
-            QObject::connect(animation, SIGNAL(finished()), q, SLOT(_q_uncontrolledAnimationFinished()));
+            connectUncontrolledAnimation(animation);
         }
     }
 }
@@ -305,6 +301,13 @@ bool QParallelAnimationGroupPrivate::isUncontrolledAnimationFinished(QAbstractAn
     return uncontrolledFinishTime.value(anim, -1) >= 0;
 }
 
+void QParallelAnimationGroupPrivate::animationRemoved(int index, QAbstractAnimation *anim)
+{
+    QAnimationGroupPrivate::animationRemoved(index, anim);
+    disconnectUncontrolledAnimation(anim);
+    uncontrolledFinishTime.remove(anim);
+}
+
 /*!
     \reimp
 */
diff --git a/src/corelib/animation/qparallelanimationgroup_p.h b/src/corelib/animation/qparallelanimationgroup_p.h
index a74d496..cab4fa9 100644
--- a/src/corelib/animation/qparallelanimationgroup_p.h
+++ b/src/corelib/animation/qparallelanimationgroup_p.h
@@ -80,6 +80,8 @@ public:
     void connectUncontrolledAnimations();
     void disconnectUncontrolledAnimations();
 
+    void animationRemoved(int index, QAbstractAnimation *);
+
     // private slot
     void _q_uncontrolledAnimationFinished();
 };
diff --git a/src/corelib/animation/qsequentialanimationgroup.cpp b/src/corelib/animation/qsequentialanimationgroup.cpp
index 8ab084a..7617c1f 100644
--- a/src/corelib/animation/qsequentialanimationgroup.cpp
+++ b/src/corelib/animation/qsequentialanimationgroup.cpp
@@ -479,7 +479,7 @@ void QSequentialAnimationGroupPrivate::activateCurrentAnimation(bool intermediat
 
     // connects to the finish signal of uncontrolled animations
     if (currentAnimation->totalDuration() == -1)
-        QObject::connect(currentAnimation, SIGNAL(finished()), q, SLOT(_q_uncontrolledAnimationFinished()));
+        connectUncontrolledAnimation(currentAnimation);
 
     currentAnimation->start();
     if (!intermediate && state == QSequentialAnimationGroup::Paused)
@@ -496,7 +496,7 @@ void QSequentialAnimationGroupPrivate::_q_uncontrolledAnimationFinished()
         actualDuration.append(-1);
     actualDuration[currentAnimationIndex] = currentAnimation->currentTime();
 
-    QObject::disconnect(currentAnimation, SIGNAL(finished()), q, SLOT(_q_uncontrolledAnimationFinished()));
+    disconnectUncontrolledAnimation(currentAnimation);
 
     if ((direction == QAbstractAnimation::Forward && currentAnimation == animations.last())
         || (direction == QAbstractAnimation::Backward && currentAnimationIndex == 0)) {
@@ -543,10 +543,10 @@ void QSequentialAnimationGroupPrivate::animationInsertedAt(int index)
     the group at index \a index. The animation is no more listed when this
     method is called.
 */
-void QSequentialAnimationGroupPrivate::animationRemovedAt(int index)
+void QSequentialAnimationGroupPrivate::animationRemoved(int index, QAbstractAnimation *anim)
 {
     Q_Q(QSequentialAnimationGroup);
-    QAnimationGroupPrivate::animationRemovedAt(index);
+    QAnimationGroupPrivate::animationRemoved(index, anim);
 
     Q_ASSERT(currentAnimation); // currentAnimation should always be set
 
@@ -555,7 +555,10 @@ void QSequentialAnimationGroupPrivate::animationRemovedAt(int index)
 
     const int currentIndex = animations.indexOf(currentAnimation);
     if (currentIndex == -1) {
-        //we're removing the current animation, let's update it to another one
+        //we're removing the current animation
+
+        disconnectUncontrolledAnimation(currentAnimation);
+
         if (index < animations.count())
             setCurrentAnimation(index); //let's try to take the next one
         else if (index > 0)
diff --git a/src/corelib/animation/qsequentialanimationgroup_p.h b/src/corelib/animation/qsequentialanimationgroup_p.h
index a55e136..de69916 100644
--- a/src/corelib/animation/qsequentialanimationgroup_p.h
+++ b/src/corelib/animation/qsequentialanimationgroup_p.h
@@ -85,7 +85,7 @@ public:
     void activateCurrentAnimation(bool intermediate = false);
 
     void animationInsertedAt(int index);
-    void animationRemovedAt(int index);
+    void animationRemoved(int index, QAbstractAnimation *anim);
 
     bool atEnd() const;
 
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 4ee2301..6934abc 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -4285,6 +4285,12 @@ static void _q_paintIntoCache(QPixmap *pix, QGraphicsItem *item, const QRegion &
     if (!subPix.isNull()) {
         // Blit the subpixmap into the main pixmap.
         pixmapPainter.begin(pix);
+        if (item->cacheMode() == QGraphicsItem::DeviceCoordinateCache
+            && itemToPixmap.type() > QTransform::TxTranslate) {
+            pixmapPainter.setCompositionMode(QPainter::CompositionMode_SourceAtop);
+        } else {
+            pixmapPainter.setCompositionMode(QPainter::CompositionMode_Source);
+        }
         pixmapPainter.setClipRegion(pixmapExposed);
         pixmapPainter.drawPixmap(br.topLeft(), subPix);
         pixmapPainter.end();
diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index c000457..3ec389f 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -379,6 +379,14 @@ void QFontEngine::getGlyphPositions(const QGlyphLayout &glyphs, const QTransform
     Q_ASSERT(positions.size() == glyphs_out.size());
 }
 
+void QFontEngine::getGlyphBearings(glyph_t glyph, qreal *leftBearing, qreal *rightBearing)
+{
+    glyph_metrics_t gi = boundingBox(glyph);
+    if (leftBearing != 0)
+        *leftBearing = gi.x.toReal();
+    if (rightBearing != 0)
+        *rightBearing = (gi.xoff - gi.x - gi.width).toReal();
+}
 
 glyph_metrics_t QFontEngine::tightBoundingBox(const QGlyphLayout &glyphs)
 {
@@ -1385,6 +1393,12 @@ glyph_metrics_t QFontEngineMulti::boundingBox(const QGlyphLayout &glyphs)
     return overall;
 }
 
+void QFontEngineMulti::getGlyphBearings(glyph_t glyph, qreal *leftBearing, qreal *rightBearing)
+{
+    int which = highByte(glyph);
+    engine(which)->getGlyphBearings(stripped(glyph), leftBearing, rightBearing);
+}
+
 void QFontEngineMulti::addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs,
                                         QPainterPath *path, QTextItem::RenderFlags flags)
 {
diff --git a/src/gui/text/qfontengine_p.h b/src/gui/text/qfontengine_p.h
index 71ab5a5..e645caf 100644
--- a/src/gui/text/qfontengine_p.h
+++ b/src/gui/text/qfontengine_p.h
@@ -206,6 +206,8 @@ public:
     virtual qreal minLeftBearing() const { return qreal(); }
     virtual qreal minRightBearing() const { return qreal(); }
 
+    virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = 0, qreal *rightBearing = 0);
+
     virtual const char *name() const = 0;
 
     virtual bool canRender(const QChar *string, int len) = 0;
@@ -374,6 +376,7 @@ public:
     virtual void recalcAdvances(QGlyphLayout *, QTextEngine::ShaperFlags) const;
     virtual void doKerning(QGlyphLayout *, QTextEngine::ShaperFlags) const;
     virtual void addOutlineToPath(qreal, qreal, const QGlyphLayout &, QPainterPath *, QTextItem::RenderFlags flags);
+    virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = 0, qreal *rightBearing = 0);
 
     virtual QFixed ascent() const;
     virtual QFixed descent() const;
diff --git a/src/gui/text/qfontengine_win.cpp b/src/gui/text/qfontengine_win.cpp
index 1a815d3..a133b48 100644
--- a/src/gui/text/qfontengine_win.cpp
+++ b/src/gui/text/qfontengine_win.cpp
@@ -649,6 +649,30 @@ static const ushort char_table[] = {
 
 static const int char_table_entries = sizeof(char_table)/sizeof(ushort);
 
+void QFontEngineWin::getGlyphBearings(glyph_t glyph, qreal *leftBearing, qreal *rightBearing)
+{
+    HDC hdc = shared_dc();
+    SelectObject(hdc, hfont);
+
+#ifndef Q_WS_WINCE
+    if (ttf)
+#endif
+
+    {
+        ABC abcWidths;
+        GetCharABCWidthsI(hdc, glyph, 1, 0, &abcWidths);
+        if (leftBearing)
+            *leftBearing = abcWidths.abcA;
+        if (rightBearing)
+            *rightBearing = abcWidths.abcC;
+    }
+
+#ifndef Q_WS_WINCE
+    else {
+        QFontEngine::getGlyphBearings(glyph, leftBearing, rightBearing);
+    }
+#endif
+}
 
 qreal QFontEngineWin::minLeftBearing() const
 {
diff --git a/src/gui/text/qfontengine_win_p.h b/src/gui/text/qfontengine_win_p.h
index f9d8f8b..f19e48e 100644
--- a/src/gui/text/qfontengine_win_p.h
+++ b/src/gui/text/qfontengine_win_p.h
@@ -106,6 +106,8 @@ public:
     virtual QImage alphaMapForGlyph(glyph_t, const QTransform &xform);
     virtual QImage alphaRGBMapForGlyph(glyph_t t, int margin, const QTransform &xform);
 
+    virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = 0, qreal *rightBearing = 0);
+
     int getGlyphIndexes(const QChar *ch, int numChars, QGlyphLayout *glyphs, bool mirrored) const;
     void getCMap();
 
diff --git a/src/gui/text/qfontmetrics.cpp b/src/gui/text/qfontmetrics.cpp
index 41d0af1..44a18de 100644
--- a/src/gui/text/qfontmetrics.cpp
+++ b/src/gui/text/qfontmetrics.cpp
@@ -472,8 +472,9 @@ int QFontMetrics::leftBearing(QChar ch) const
     int nglyphs = 9;
     engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
     // ### can nglyphs != 1 happen at all? Not currently I think
-    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);
-    return qRound(gi.x);
+    qreal lb;
+    engine->getGlyphBearings(glyphs.glyphs[0], &lb);
+    return qRound(lb);
 }
 
 /*!
@@ -506,8 +507,9 @@ int QFontMetrics::rightBearing(QChar ch) const
     int nglyphs = 9;
     engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
     // ### can nglyphs != 1 happen at all? Not currently I think
-    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);
-    return qRound(gi.xoff - gi.x - gi.width);
+    qreal rb;
+    engine->getGlyphBearings(glyphs.glyphs[0], 0, &rb);
+    return qRound(rb);
 }
 
 /*!
@@ -1317,8 +1319,9 @@ qreal QFontMetricsF::leftBearing(QChar ch) const
     int nglyphs = 9;
     engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
     // ### can nglyphs != 1 happen at all? Not currently I think
-    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);
-    return gi.x.toReal();
+    qreal lb;
+    engine->getGlyphBearings(glyphs.glyphs[0], &lb);
+    return lb;
 }
 
 /*!
@@ -1351,8 +1354,10 @@ qreal QFontMetricsF::rightBearing(QChar ch) const
     int nglyphs = 9;
     engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0);
     // ### can nglyphs != 1 happen at all? Not currently I think
-    glyph_metrics_t gi = engine->boundingBox(glyphs.glyphs[0]);
-    return (gi.xoff - gi.x - gi.width).toReal();
+    qreal rb;
+    engine->getGlyphBearings(glyphs.glyphs[0], 0, &rb);
+    return rb;
+
 }
 
 /*!
diff --git a/src/gui/text/qtextlayout.cpp b/src/gui/text/qtextlayout.cpp
index af91603..3c0e85e 100644
--- a/src/gui/text/qtextlayout.cpp
+++ b/src/gui/text/qtextlayout.cpp
@@ -1644,28 +1644,67 @@ namespace {
 
     struct LineBreakHelper
     {
-        LineBreakHelper() : glyphCount(0), maxGlyphs(0), manualWrap(false) {}
+        LineBreakHelper()
+            : glyphCount(0), maxGlyphs(0), currentPosition(0), fontEngine(0), logClusters(0),
+              manualWrap(false)
+        {
+        }
+
 
         QScriptLine tmpData;
         QScriptLine spaceData;
 
+        QGlyphLayout glyphs;
+
         int glyphCount;
         int maxGlyphs;
+        int currentPosition;
 
         QFixed minw;
         QFixed softHyphenWidth;
         QFixed rightBearing;
+        QFixed minimumRightBearing;
+
+        QFontEngine *fontEngine;
+        const unsigned short *logClusters;
 
         bool manualWrap;
 
         bool checkFullOtherwiseExtend(QScriptLine &line);
+
+        QFixed calculateNewWidth(const QScriptLine &line) const {
+            return line.textWidth + tmpData.textWidth + spaceData.textWidth + softHyphenWidth
+                    - qMin(rightBearing, QFixed());
+        }
+
+        inline glyph_t currentGlyph() const
+        {
+            Q_ASSERT(currentPosition > 0);
+            return glyphs.glyphs[logClusters[currentPosition - 1]];
+        }
+
+        inline void adjustRightBearing()
+        {
+            if (currentPosition <= 0)
+                return;
+
+            qreal rb;
+            fontEngine->getGlyphBearings(currentGlyph(), 0, &rb);
+            rightBearing = qMin(QFixed(), QFixed::fromReal(rb));
+        }
+
+        inline void resetRightBearing()
+        {
+            rightBearing = QFixed(1); // Any positive number is defined as invalid since only
+                                      // negative right bearings are interesting to us.
+        }
     };
 
 inline bool LineBreakHelper::checkFullOtherwiseExtend(QScriptLine &line)
 {        
     LB_DEBUG("possible break width %f, spacew=%f", tmpData.textWidth.toReal(), spaceData.textWidth.toReal());
 
-    QFixed newWidth = line.textWidth + tmpData.textWidth + spaceData.textWidth + softHyphenWidth + rightBearing;
+    QFixed newWidth = calculateNewWidth(line);
     if (line.length && !manualWrap && (newWidth > line.width || glyphCount > maxGlyphs))
         return true;
 
@@ -1741,13 +1780,12 @@ void QTextLine::layout_helper(int maxGlyphs)
     Qt::Alignment alignment = eng->option.alignment();
 
     const HB_CharAttributes *attributes = eng->attributes();
-    int pos = line.from;
+    lbh.currentPosition = line.from;
     int end = 0;
-    QGlyphLayout glyphs;
-    const unsigned short *logClusters = eng->layoutData->logClustersPtr;
+    lbh.logClusters = eng->layoutData->logClustersPtr;
 
     while (newItem < eng->layoutData->items.size()) {
-        lbh.rightBearing = 0;
+        lbh.resetRightBearing();
         lbh.softHyphenWidth = 0;
         if (newItem != item) {
             item = newItem;
@@ -1755,13 +1793,19 @@ void QTextLine::layout_helper(int maxGlyphs)
             if (!current.num_glyphs) {
                 eng->shape(item);
                 attributes = eng->attributes();
-                logClusters = eng->layoutData->logClustersPtr;
+                lbh.logClusters = eng->layoutData->logClustersPtr;
             }
-            pos = qMax(line.from, current.position);
+            lbh.currentPosition = qMax(line.from, current.position);
             end = current.position + eng->length(item);
-            glyphs = eng->shapedGlyphs(&current);
+            lbh.glyphs = eng->shapedGlyphs(&current);
         }
         const QScriptItem &current = eng->layoutData->items[item];
+        QFontEngine *fontEngine = eng->fontEngine(current);
+        if (lbh.fontEngine != fontEngine) {
+            lbh.fontEngine = fontEngine;
+            lbh.minimumRightBearing = qMin(QFixed(),
+                                           QFixed::fromReal(fontEngine->minRightBearing()));
+        }
 
         lbh.tmpData.leading = qMax(lbh.tmpData.leading + lbh.tmpData.ascent,
                                    current.leading + current.ascent) - qMax(lbh.tmpData.ascent,
@@ -1791,8 +1835,8 @@ void QTextLine::layout_helper(int maxGlyphs)
             if (!line.length && !lbh.tmpData.length)
                 line.setDefaultHeight(eng);
             if (eng->option.flags() & QTextOption::ShowLineAndParagraphSeparators) {
-                addNextCluster(pos, end, lbh.tmpData, lbh.glyphCount,
-                               current, logClusters, glyphs);
+                addNextCluster(lbh.currentPosition, end, lbh.tmpData, lbh.glyphCount,
+                               current, lbh.logClusters, lbh.glyphs);
             } else {
                 lbh.tmpData.length++;
             }
@@ -1811,10 +1855,10 @@ void QTextLine::layout_helper(int maxGlyphs)
             ++lbh.glyphCount;
             if (lbh.checkFullOtherwiseExtend(line))
                 goto found;
-        } else if (attributes[pos].whiteSpace) {
-            while (pos < end && attributes[pos].whiteSpace)
-                addNextCluster(pos, end, lbh.spaceData, lbh.glyphCount,
-                               current, logClusters, glyphs);
+        } else if (attributes[lbh.currentPosition].whiteSpace) {
+            while (lbh.currentPosition < end && attributes[lbh.currentPosition].whiteSpace)
+                addNextCluster(lbh.currentPosition, end, lbh.spaceData, lbh.glyphCount,
+                               current, lbh.logClusters, lbh.glyphs);
 
             if (!lbh.manualWrap && lbh.spaceData.textWidth > line.width) {
                 lbh.spaceData.textWidth = line.width; // ignore spaces that fall out of the line.
@@ -1823,19 +1867,19 @@ void QTextLine::layout_helper(int maxGlyphs)
         } else {
             bool sb_or_ws = false;
             do {
-                addNextCluster(pos, end, lbh.tmpData, lbh.glyphCount,
-                               current, logClusters, glyphs);
+                addNextCluster(lbh.currentPosition, end, lbh.tmpData, lbh.glyphCount,
+                               current, lbh.logClusters, lbh.glyphs);
 
-                if (attributes[pos].whiteSpace || attributes[pos-1].lineBreakType != HB_NoBreak) {
+                if (attributes[lbh.currentPosition].whiteSpace || attributes[lbh.currentPosition-1].lineBreakType != HB_NoBreak) {
                     sb_or_ws = true;
                     break;
-                } else if (breakany && attributes[pos].charStop) {
+                } else if (breakany && attributes[lbh.currentPosition].charStop) {
                     break;
                 }
-            } while (pos < end);
+            } while (lbh.currentPosition < end);
             lbh.minw = qMax(lbh.tmpData.textWidth, lbh.minw);
 
-            if (pos && attributes[pos - 1].lineBreakType == HB_SoftHyphen) {
+            if (lbh.currentPosition && attributes[lbh.currentPosition - 1].lineBreakType == HB_SoftHyphen) {
                 // if we are splitting up a word because of
                 // a soft hyphen then we ...
                 //
@@ -1853,41 +1897,39 @@ void QTextLine::layout_helper(int maxGlyphs)
                 //     and thus become invisible again.
                 //
                 if (line.length)
-                    lbh.softHyphenWidth = glyphs.advances_x[logClusters[pos - 1]];
+                    lbh.softHyphenWidth = lbh.glyphs.advances_x[lbh.logClusters[lbh.currentPosition - 1]];
                 else if (breakany)
-                    lbh.tmpData.textWidth += glyphs.advances_x[logClusters[pos - 1]];
+                    lbh.tmpData.textWidth += lbh.glyphs.advances_x[lbh.logClusters[lbh.currentPosition - 1]];
             }
 
             // The actual width of the text needs to take the right bearing into account. The
             // right bearing is left-ward, which means that if the rightmost pixel is to the right
             // of the advance of the glyph, the bearing will be negative. We flip the sign
             // for the code to be more readable. Logic borrowed from qfontmetrics.cpp.
-            if (pos) {
-                QFontEngine *fontEngine = eng->fontEngine(current);
-                glyph_t glyph = glyphs.glyphs[logClusters[pos - 1]];
-                glyph_metrics_t gi = fontEngine->boundingBox(glyph);
-                if (gi.isValid())
-                    lbh.rightBearing = qMax(QFixed(), -(gi.xoff - gi.x - gi.width));
-            }
+            // We ignore the right bearing if the minimum negative bearing is too little to
+            // expand the text beyond the edge.
+            if (sb_or_ws|breakany) {
+                if (lbh.calculateNewWidth(line) + lbh.minimumRightBearing > line.width)
+                    lbh.adjustRightBearing();
+                if (lbh.checkFullOtherwiseExtend(line)) {
+                    if (!breakany) {
+                        line.textWidth += lbh.softHyphenWidth;
+                    }
 
-            if ((sb_or_ws|breakany) && lbh.checkFullOtherwiseExtend(line)) {
-                if (!breakany) {
-                    line.textWidth += lbh.softHyphenWidth;
+                    goto found;
                 }
-
-                line.textWidth += lbh.rightBearing;
-
-                goto found;
             }
         }
-        if (pos == end)
+        if (lbh.currentPosition == end)
             newItem = item + 1;
     }
     LB_DEBUG("reached end of line");
     lbh.checkFullOtherwiseExtend(line);
-    line.textWidth += lbh.rightBearing;
-
 found:       
+    if (lbh.rightBearing > 0) // If right bearing has not yet been adjusted
+        lbh.adjustRightBearing();
+    line.textWidth -= qMin(QFixed(), lbh.rightBearing);
+
     if (line.length == 0) {
         LB_DEBUG("no break available in line, adding temp: length %d, width %f, space: length %d, width %f",
                lbh.tmpData.length, lbh.tmpData.textWidth.toReal(),