Optimize glyph lookups with QFontEngine::glyphIndex(uint)

Change-Id: I56c7e727f3d9b08195f38939106620c744c6eaf0
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: BogDan Vatra <bogdan@kde.org>

8 files changed, 62 insertions, 264 deletions

diff --git a/src/gui/text/qdistancefield.cpp b/src/gui/text/qdistancefield.cpp
index f2b88c4692..17116ee2d0 100644
--- a/src/gui/text/qdistancefield.cpp
+++ b/src/gui/text/qdistancefield.cpp
@@ -739,20 +739,11 @@ bool qt_fontHasNarrowOutlines(QFontEngine *fontEngine)
     if (!fe)
         return false;
 
-    const QChar uc(QLatin1Char('O'));
+    QImage im;
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-    int numGlyphs = 1;
-
-    if (!fe->stringToCMap(&uc, 1, &glyphs, &numGlyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(numGlyphs == 1);
-
-    QImage im = fe->alphaMapForGlyph(glyph, QFixed(), QTransform());
+    const glyph_t glyph = fe->glyphIndex('O');
+    if (glyph != 0)
+        im = fe->alphaMapForGlyph(glyph, QFixed(), QTransform());
 
     Q_ASSERT(fe->ref.load() == 0);
     delete fe;
diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 316b491e18..87d3090a39 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -101,35 +101,13 @@ static HB_Bool hb_stringToGlyphs(HB_Font font, const HB_UChar16 *string, hb_uint
     *numGlyphs = nGlyphs;
 
     if (rightToLeft && result && !fe->symbol) {
-        uint glyph_pos = 0;
-        for (uint i = 0; i < length; ++i, ++glyph_pos) {
-            uint ucs4 = str[i].unicode();
-            if (Q_UNLIKELY(QChar::isHighSurrogate(ucs4) && i + 1 < length)) {
-                uint low = str[i + 1].unicode();
-                if (Q_LIKELY(QChar::isLowSurrogate(low))) {
-                    ucs4 = QChar::surrogateToUcs4(ucs4, low);
-                    ++i;
-                }
-            }
-
-            uint mirrored = QChar::mirroredChar(ucs4);
-            if (Q_UNLIKELY(mirrored != ucs4)) {
-                QChar chars[2];
-                uint numChars = 0;
-                if (Q_UNLIKELY(QChar::requiresSurrogates(mirrored))) {
-                    chars[numChars++] = QChar(QChar::highSurrogate(mirrored));
-                    chars[numChars++] = QChar(QChar::lowSurrogate(mirrored));
-                } else {
-                    chars[numChars++] = QChar(mirrored);
-                }
-
-                qglyphs.numGlyphs = numChars;
-                qglyphs.glyphs = glyphs + glyph_pos;
-                nGlyphs = numChars;
-                if (!fe->stringToCMap(chars, numChars, &qglyphs, &nGlyphs, QFontEngine::GlyphIndicesOnly))
-                    Q_UNREACHABLE();
-                Q_ASSERT(nGlyphs == 1);
-            }
+        QStringIterator it(str, str + length);
+        while (it.hasNext()) {
+            const uint ucs4 = it.next();
+            const uint mirrored = QChar::mirroredChar(ucs4);
+            if (Q_UNLIKELY(mirrored != ucs4))
+                *glyphs = fe->glyphIndex(mirrored);
+            ++glyphs;
         }
     }
 
@@ -417,38 +395,14 @@ glyph_metrics_t QFontEngine::boundingBox(glyph_t glyph, const QTransform &matrix
 
 QFixed QFontEngine::xHeight() const
 {
-    QChar x((ushort)'x');
-
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!stringToCMap(&x, 1, &glyphs, &nglyphs, GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
-
+    const glyph_t glyph = glyphIndex('x');
     glyph_metrics_t bb = const_cast<QFontEngine *>(this)->boundingBox(glyph);
     return bb.height;
 }
 
 QFixed QFontEngine::averageCharWidth() const
 {
-    QChar x((ushort)'x');
-
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!stringToCMap(&x, 1, &glyphs, &nglyphs, GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
-
+    const glyph_t glyph = glyphIndex('x');
     glyph_metrics_t bb = const_cast<QFontEngine *>(this)->boundingBox(glyph);
     return bb.xoff;
 }
@@ -509,18 +463,14 @@ void QFontEngine::getGlyphPositions(const QGlyphLayout &glyphs, const QTransform
             if (glyphs.justifications[i].nKashidas) {
                 QChar ch(0x640); // Kashida character
 
-                glyph_t kashidaGlyph;
+                glyph_t kashidaGlyph = glyphIndex(ch.unicode());
                 QFixed kashidaWidth;
 
                 QGlyphLayout g;
                 g.numGlyphs = 1;
                 g.glyphs = &kashidaGlyph;
                 g.advances = &kashidaWidth;
-
-                int nglyphs = 1;
-                if (!stringToCMap(&ch, 1, &g, &nglyphs, 0))
-                    Q_UNREACHABLE();
-                Q_ASSERT(nglyphs == 1);
+                recalcAdvances(&g, 0);
 
                 for (uint k = 0; k < glyphs.justifications[i].nKashidas; ++k) {
                     xpos -= kashidaWidth;
diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 04cf6bfdcb..892fc22586 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -1282,22 +1282,10 @@ qreal QFontEngineFT::minRightBearing() const
 {
     if (rbearing == SHRT_MIN) {
         lbearing = rbearing = 0;
-
-        const QChar *ch = reinterpret_cast<const QChar *>(char_table);
-
-        glyph_t glyphs[char_table_entries];
-
-        QGlyphLayout g;
-        g.glyphs = glyphs;
-        g.numGlyphs = char_table_entries;
-        int ng = char_table_entries;
-        if (!stringToCMap(ch, char_table_entries, &g, &ng, GlyphIndicesOnly))
-            Q_UNREACHABLE();
-        Q_ASSERT(ng == char_table_entries);
-
-        while (--ng) {
-            if (glyphs[ng]) {
-                glyph_metrics_t gi = const_cast<QFontEngineFT *>(this)->boundingBox(glyphs[ng]);
+        for (int i = 0; i < char_table_entries; ++i) {
+            const glyph_t glyph = glyphIndex(char_table[i]);
+            if (glyph != 0) {
+                glyph_metrics_t gi = const_cast<QFontEngineFT *>(this)->boundingBox(glyph);
                 lbearing = qMin(lbearing, gi.x);
                 rbearing = qMin(rbearing, (gi.xoff - gi.x - gi.width));
             }
diff --git a/src/gui/text/qfontmetrics.cpp b/src/gui/text/qfontmetrics.cpp
index 2f4709afe4..7868fd23d1 100644
--- a/src/gui/text/qfontmetrics.cpp
+++ b/src/gui/text/qfontmetrics.cpp
@@ -410,12 +410,7 @@ int QFontMetrics::averageCharWidth() const
 */
 bool QFontMetrics::inFont(QChar ch) const
 {
-    const int script = ch.script();
-    QFontEngine *engine = d->engineForScript(script);
-    Q_ASSERT(engine != 0);
-    if (engine->type() == QFontEngine::Box)
-        return false;
-    return engine->canRender(&ch, 1);
+    return inFontUcs4(ch.unicode());
 }
 
 /*!
@@ -458,16 +453,7 @@ int QFontMetrics::leftBearing(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     qreal lb;
     engine->getGlyphBearings(glyph, &lb);
@@ -500,16 +486,7 @@ int QFontMetrics::rightBearing(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     qreal rb;
     engine->getGlyphBearings(glyph, 0, &rb);
@@ -605,18 +582,14 @@ int QFontMetrics::width(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
     QFixed advance;
 
     QGlyphLayout glyphs;
     glyphs.numGlyphs = 1;
-    glyph_t glyph;
     glyphs.glyphs = &glyph;
     glyphs.advances = &advance;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    engine->recalcAdvances(&glyphs, 0);
 
     return qRound(advance);
 }
@@ -660,18 +633,14 @@ int QFontMetrics::charWidth(const QString &text, int pos) const
 
         d->alterCharForCapitalization(ch);
 
+        glyph_t glyph = engine->glyphIndex(ch.unicode());
         QFixed advance;
 
         QGlyphLayout glyphs;
         glyphs.numGlyphs = 1;
-        glyph_t glyph;
         glyphs.glyphs = &glyph;
         glyphs.advances = &advance;
-
-        int nglyphs = 1;
-        if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0))
-            Q_UNREACHABLE();
-        Q_ASSERT(nglyphs == 1);
+        engine->recalcAdvances(&glyphs, 0);
 
         width = qRound(advance);
     }
@@ -739,16 +708,7 @@ QRect QFontMetrics::boundingRect(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     glyph_metrics_t gm = engine->boundingBox(glyph);
     return QRect(qRound(gm.x), qRound(gm.y), qRound(gm.width), qRound(gm.height));
@@ -1315,12 +1275,7 @@ qreal QFontMetricsF::averageCharWidth() const
 */
 bool QFontMetricsF::inFont(QChar ch) const
 {
-    const int script = ch.script();
-    QFontEngine *engine = d->engineForScript(script);
-    Q_ASSERT(engine != 0);
-    if (engine->type() == QFontEngine::Box)
-        return false;
-    return engine->canRender(&ch, 1);
+    return inFontUcs4(ch.unicode());
 }
 
 /*!
@@ -1365,16 +1320,7 @@ qreal QFontMetricsF::leftBearing(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     qreal lb;
     engine->getGlyphBearings(glyph, &lb);
@@ -1407,16 +1353,7 @@ qreal QFontMetricsF::rightBearing(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     qreal rb;
     engine->getGlyphBearings(glyph, 0, &rb);
@@ -1484,18 +1421,14 @@ qreal QFontMetricsF::width(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
     QFixed advance;
 
     QGlyphLayout glyphs;
     glyphs.numGlyphs = 1;
-    glyph_t glyph;
     glyphs.glyphs = &glyph;
     glyphs.advances = &advance;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    engine->recalcAdvances(&glyphs, 0);
 
     return advance.toReal();
 }
@@ -1559,16 +1492,7 @@ QRectF QFontMetricsF::boundingRect(QChar ch) const
 
     d->alterCharForCapitalization(ch);
 
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.numGlyphs = 1;
-    glyphs.glyphs = &glyph;
-
-    int nglyphs = 1;
-    if (!engine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(nglyphs == 1);
+    glyph_t glyph = engine->glyphIndex(ch.unicode());
 
     glyph_metrics_t gm = engine->boundingBox(glyph);
     return QRectF(gm.x.toReal(), gm.y.toReal(), gm.width.toReal(), gm.height.toReal());
diff --git a/src/gui/text/qfontsubset.cpp b/src/gui/text/qfontsubset.cpp
index 2109b16bb5..4bb29da2af 100644
--- a/src/gui/text/qfontsubset.cpp
+++ b/src/gui/text/qfontsubset.cpp
@@ -201,22 +201,8 @@ static void checkRanges(QPdf::ByteStream &ts, QByteArray &ranges, int &nranges)
 QVector<int> QFontSubset::getReverseMap() const
 {
     QVector<int> reverseMap(0x10000, 0);
-
-    glyph_t glyph;
-
-    QGlyphLayout glyphs;
-    glyphs.glyphs = &glyph;
-    glyphs.numGlyphs = 1;
-
     for (uint uc = 0; uc < 0x10000; ++uc) {
-        QChar ch(uc);
-
-        int nglyphs = 1;
-        if (!fontEngine->stringToCMap(&ch, 1, &glyphs, &nglyphs, QFontEngine::GlyphIndicesOnly))
-            Q_UNREACHABLE();
-        Q_ASSERT(nglyphs == 1);
-
-        int idx = glyph_indices.indexOf(glyph);
+        int idx = glyph_indices.indexOf(fontEngine->glyphIndex(uc));
         if (idx >= 0 && !reverseMap.at(idx))
             reverseMap[idx] = uc;
     }
diff --git a/src/gui/text/qharfbuzzng.cpp b/src/gui/text/qharfbuzzng.cpp
index 31bb6f38f2..f7a1d30e6f 100644
--- a/src/gui/text/qharfbuzzng.cpp
+++ b/src/gui/text/qharfbuzzng.cpp
@@ -397,33 +397,7 @@ _hb_qt_font_get_glyph(hb_font_t * /*font*/, void *font_data,
     QFontEngine *fe = (QFontEngine *)font_data;
     Q_ASSERT(fe);
 
-    QChar chars[2];
-    int numChars = 0;
-    if (Q_UNLIKELY(QChar::requiresSurrogates(unicode))) {
-        chars[numChars++] = QChar(QChar::highSurrogate(unicode));
-        chars[numChars++] = QChar(QChar::lowSurrogate(unicode));
-    } else {
-        chars[numChars++] = QChar(unicode);
-    }
-#if 0
-    if (Q_UNLIKELY(variation_selector != 0)) {
-        if (Q_UNLIKELY(QChar::requiresSurrogates(variation_selector))) {
-            chars[numChars++] = QChar(QChar::highSurrogate(variation_selector));
-            chars[numChars++] = QChar(QChar::lowSurrogate(variation_selector));
-        } else {
-            chars[numChars++] = QChar(variation_selector);
-        }
-    }
-#endif
-
-    QGlyphLayout g;
-    g.numGlyphs = numChars;
-    g.glyphs = glyph;
-
-    int numGlyphs = numChars;
-    if (!fe->stringToCMap(chars, numChars, &g, &numGlyphs, QFontEngine::GlyphIndicesOnly))
-        Q_UNREACHABLE();
-    Q_ASSERT(numGlyphs == 1);
+    *glyph = fe->glyphIndex(unicode);
 
     return true;
 }
diff --git a/src/gui/text/qrawfont.cpp b/src/gui/text/qrawfont.cpp
index 449278df06..2ba350fb67 100644
--- a/src/gui/text/qrawfont.cpp
+++ b/src/gui/text/qrawfont.cpp
@@ -665,7 +665,7 @@ QList<QFontDatabase::WritingSystem> QRawFont::supportedWritingSystems() const
 */
 bool QRawFont::supportsCharacter(QChar character) const
 {
-    return d->isValid() && d->fontEngine->canRender(&character, 1);
+    return supportsCharacter(character.unicode());
 }
 
 /*!
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index 45894d27b6..2d7611774b 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -2011,21 +2011,16 @@ static void set(QJustificationPoint *point, int type, const QGlyphLayout &glyph,
     if (type >= Justification_Arabic_Normal) {
         QChar ch(0x640); // Kashida character
 
-        glyph_t kashidaGlyph;
-        QFixed kashidaWidth;
-
-        QGlyphLayout glyphs;
-        glyphs.numGlyphs = 1;
-        glyphs.glyphs = &kashidaGlyph;
-        glyphs.advances = &kashidaWidth;
-
-        int nglyphs = 1;
-        if (!fe->stringToCMap(&ch, 1, &glyphs, &nglyphs, 0))
-            Q_UNREACHABLE();
-        Q_ASSERT(nglyphs == 1);
-
-        if (kashidaGlyph != 0 && kashidaWidth != 0) {
-            point->kashidaWidth = kashidaWidth;
+        glyph_t kashidaGlyph = fe->glyphIndex(ch.unicode());
+        if (kashidaGlyph != 0) {
+            QGlyphLayout g;
+            g.numGlyphs = 1;
+            g.glyphs = &kashidaGlyph;
+            g.advances = &point->kashidaWidth;
+            fe->recalcAdvances(&g, 0);
+
+            if (point->kashidaWidth == 0)
+                point->type = Justification_Prohibited;
         } else {
             point->type = Justification_Prohibited;
             point->kashidaWidth = 0;
@@ -2644,40 +2639,30 @@ QString QTextEngine::elidedText(Qt::TextElideMode mode, const QFixed &width, int
     QFixed ellipsisWidth;
     QString ellipsisText;
     {
-        QChar ellipsisChar(0x2026);
-
         QFontEngine *fe = fnt.d->engineForScript(QChar::Script_Common);
+        QFontEngine *engine = fe->type() == QFontEngine::Multi ? static_cast<QFontEngineMulti *>(fe)->engine(0) : fe;
 
-        QGlyphLayoutArray<1> ellipsisGlyph;
-        {
-            QFontEngine *feForEllipsis = (fe->type() == QFontEngine::Multi)
-                ? static_cast<QFontEngineMulti *>(fe)->engine(0)
-                : fe;
+        QChar ellipsisChar(0x2026);
 
-            if (feForEllipsis->type() == QFontEngine::Mac)
-                feForEllipsis = fe;
+        glyph_t glyph = engine->glyphIndex(ellipsisChar.unicode());
 
-            int nGlyphs = 1;
-            if (!feForEllipsis->stringToCMap(&ellipsisChar, 1, &ellipsisGlyph, &nGlyphs, 0))
-                Q_UNREACHABLE();
-            Q_ASSERT(nGlyphs == 1);
-        }
+        QGlyphLayout glyphs;
+        glyphs.numGlyphs = 1;
+        glyphs.glyphs = &glyph;
+        glyphs.advances = &ellipsisWidth;
+
+        if (glyph != 0) {
+            engine->recalcAdvances(&glyphs, 0);
 
-        if (ellipsisGlyph.glyphs[0]) {
-            ellipsisWidth = ellipsisGlyph.advances[0];
             ellipsisText = ellipsisChar;
         } else {
-            QString dotDotDot(QLatin1String("..."));
-
-            QGlyphLayoutArray<3> glyphs;
-            int nGlyphs = 3;
-            if (!fe->stringToCMap(dotDotDot.constData(), 3, &glyphs, &nGlyphs, 0))
-                Q_UNREACHABLE();
-            Q_ASSERT(nGlyphs == 3);
+            glyph = engine->glyphIndex('.');
+            if (glyph != 0) {
+                engine->recalcAdvances(&glyphs, 0);
 
-            for (int i = 0; i < nGlyphs; ++i)
-                ellipsisWidth += glyphs.advances[i];
-            ellipsisText = dotDotDot;
+                ellipsisWidth *= 3;
+                ellipsisText = QStringLiteral("...");
+            }
         }
     }