Introduce a generic QFontEngine::canRender() implementation

...which uses the recently introduced glyphIndex() method;
get rid of re-implementations that did almost the same.

Change-Id: I6d32d2cee6a31f57de6aee05ed8d120d4a1f4e9c
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

src/gui/text/qfontengine.cpp

@@ -385,6 +385,17 @@ bool QFontEngine::supportsScript(QChar::Script script) const
     return hbFace->supported_scripts[script_to_hbscript(script)];
 }
 
+bool QFontEngine::canRender(const QChar *str, int len) const
+{
+    QStringIterator it(str, str + len);
+    while (it.hasNext()) {
+        if (glyphIndex(it.next()) == 0)
+            return false;
+    }
+
+    return true;
+}
+
 glyph_metrics_t QFontEngine::boundingBox(glyph_t glyph, const QTransform &matrix)
 {
     glyph_metrics_t metrics = boundingBox(glyph);
@@ -1533,7 +1544,7 @@ const char *QFontEngineBox::name() const
     return "null";
 }
 
-bool QFontEngineBox::canRender(const QChar *, int)
+bool QFontEngineBox::canRender(const QChar *, int) const
 {
     return true;
 }
@@ -1951,7 +1962,7 @@ qreal QFontEngineMulti::minRightBearing() const
     return engine(0)->minRightBearing();
 }
 
-bool QFontEngineMulti::canRender(const QChar *string, int len)
+bool QFontEngineMulti::canRender(const QChar *string, int len) const
 {
     if (engine(0)->canRender(string, len))
         return true;

src/gui/text/qfontengine_ft.cpp

@@ -1468,19 +1468,6 @@ static inline unsigned int getChar(const QChar *str, int &i, const int len)
     return ucs4;
 }
 
-bool QFontEngineFT::canRender(const QChar *string, int len)
-{
-    FT_Face face = freetype->face;
-    {
-        for ( int i = 0; i < len; i++ ) {
-            unsigned int uc = getChar(string, i, len);
-            if (!FT_Get_Char_Index(face, uc))
-                    return false;
-        }
-    }
-    return true;
-}
-
 void QFontEngineFT::addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs, QPainterPath *path, QTextItem::RenderFlags flags)
 {
     if (!glyphs.numGlyphs)

src/gui/text/qfontengine_ft_p.h

@@ -237,8 +237,6 @@ private:
 
     virtual bool supportsTransformation(const QTransform &transform) const;
 
-    virtual bool canRender(const QChar *string, int len);
-
     virtual void addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nglyphs,
                          QPainterPath *path, QTextItem::RenderFlags flags);
     virtual void addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs,

src/gui/text/qfontengine_p.h

@@ -227,19 +227,8 @@ public:
 
     virtual const char *name() const = 0;
 
-    virtual bool canRender(const QChar *string, int len) = 0;
+    inline bool canRender(uint ucs4) const { return glyphIndex(ucs4) != 0; }
-    inline bool canRender(uint ucs4) {
+    virtual bool canRender(const QChar *str, int len) const;
-        QChar utf16[2];
-        int utf16len = 1;
-        if (QChar::requiresSurrogates(ucs4)) {
-            utf16[0] = QChar::highSurrogate(ucs4);
-            utf16[1] = QChar::lowSurrogate(ucs4);
-            ++utf16len;
-        } else {
-            utf16[0] = QChar(ucs4);
-        }
-        return canRender(utf16, utf16len);
-    }
 
     virtual bool supportsTransformation(const QTransform &transform) const;
 
@@ -374,7 +363,7 @@ public:
 
     virtual const char *name() const;
 
-    virtual bool canRender(const QChar *string, int len);
+    virtual bool canRender(const QChar *string, int len) const;
 
     virtual Type type() const;
     inline int size() const { return _size; }
@@ -421,7 +410,7 @@ public:
     virtual inline Type type() const
     { return QFontEngine::Multi; }
 
-    virtual bool canRender(const QChar *string, int len);
+    virtual bool canRender(const QChar *string, int len) const;
     inline virtual const char *name() const
     { return "Multi"; }
 

src/gui/text/qfontengine_qpa.cpp

@@ -515,29 +515,6 @@ QFontEngine::Type QFontEngineQPA::type() const
     return QFontEngine::QPF2;
 }
 
-bool QFontEngineQPA::canRender(const QChar *string, int len)
-{
-    const uchar *cmap = externalCMap ? externalCMap : (fontData + cmapOffset);
-
-    if (symbol) {
-        for (int i = 0; i < len; ++i) {
-            unsigned int uc = getChar(string, i, len);
-            glyph_t g = getTrueTypeGlyphIndex(cmap, uc);
-            if(!g && uc < 0x100)
-                g = getTrueTypeGlyphIndex(cmap, uc + 0xf000);
-            if (!g)
-                return false;
-        }
-    } else {
-        for (int i = 0; i < len; ++i) {
-            unsigned int uc = getChar(string, i, len);
-            if (!getTrueTypeGlyphIndex(cmap, uc))
-                return false;
-        }
-    }
-    return true;
-}
-
 bool QFontEngineQPA::isValid() const
 {
     return fontData && dataSize && (cmapOffset || externalCMap)

src/gui/text/qfontengine_qpa_p.h

@@ -184,7 +184,6 @@ public:
 
     Type type() const;
 
-    bool canRender(const QChar *string, int len);
     inline const char *name() const { return "QPF2"; }
 
     virtual int glyphCount() const { return glyphMapEntries; }

src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm

@@ -673,7 +673,7 @@ QFontEngine::FaceId QCoreTextFontEngine::faceId() const
     return QFontEngine::FaceId();
 }
 
-bool QCoreTextFontEngine::canRender(const QChar *string, int len)
+bool QCoreTextFontEngine::canRender(const QChar *string, int len) const
 {
     QVarLengthArray<CGGlyph> cgGlyphs(len);
     return CTFontGetGlyphsForCharacters(ctfont, (const UniChar *) string, cgGlyphs.data(), len);

src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h

@@ -81,7 +81,7 @@ public:
 
     virtual const char *name() const { return "QCoreTextFontEngine"; }
 
-    virtual bool canRender(const QChar *string, int len);
+    virtual bool canRender(const QChar *string, int len) const;
 
     virtual int synthesized() const { return synthesisFlags; }
     virtual bool supportsSubPixelPositions() const { return true; }

src/plugins/platforms/windows/qwindowsfontengine.cpp

@@ -777,35 +777,6 @@ const char *QWindowsFontEngine::name() const
     return 0;
 }
 
-bool QWindowsFontEngine::canRender(const QChar *string,  int len)
-{
-    if (symbol) {
-        for (int i = 0; i < len; ++i) {
-            unsigned int uc = getChar(string, i, len);
-            if (getTrueTypeGlyphIndex(cmap, uc) == 0) {
-                if (uc < 0x100) {
-                    if (getTrueTypeGlyphIndex(cmap, uc + 0xf000) == 0)
-                        return false;
-                } else {
-                    return false;
-                }
-            }
-        }
-    } else if (ttf) {
-        for (int i = 0; i < len; ++i) {
-            unsigned int uc = getChar(string, i, len);
-            if (getTrueTypeGlyphIndex(cmap, uc) == 0)
-                return false;
-        }
-    } else {
-        while(len--) {
-            if (tm.tmFirstChar > string->unicode() || tm.tmLastChar < string->unicode())
-                return false;
-        }
-    }
-    return true;
-}
-
 QFontEngine::Type QWindowsFontEngine::type() const
 {
     return QFontEngine::Win;

src/plugins/platforms/windows/qwindowsfontengine.h

@@ -112,8 +112,6 @@ public:
 
     virtual const char *name() const;
 
-    bool canRender(const QChar *string, int len);
-
     Type type() const;
 
     virtual QImage alphaMapForGlyph(glyph_t t) { return alphaMapForGlyph(t, QTransform()); }

src/plugins/platforms/windows/qwindowsfontenginedirectwrite.cpp

@@ -647,29 +647,6 @@ const char *QWindowsFontEngineDirectWrite::name() const
     return 0;
 }
 
-bool QWindowsFontEngineDirectWrite::canRender(const QChar *string, int len)
-{
-    QVarLengthArray<UINT32> codePoints(len);
-    int actualLength = 0;
-    for (int i=0; i<len; ++i, actualLength++)
-        codePoints[actualLength] = getChar(string, i, len);
-
-    QVarLengthArray<UINT16> glyphIndices(actualLength);
-    HRESULT hr = m_directWriteFontFace->GetGlyphIndices(codePoints.data(), actualLength,
-                                                        glyphIndices.data());
-    if (FAILED(hr)) {
-        qErrnoWarning("%s: GetGlyphIndices failed", __FUNCTION__);
-        return false;
-    }
-
-    for (int i = 0; i < actualLength; ++i) {
-        if (glyphIndices.at(i) == 0)
-            return false;
-    }
-
-    return true;
-}
-
 QFontEngine::Type QWindowsFontEngineDirectWrite::type() const
 {
     return QFontEngine::DirectWrite;

src/plugins/platforms/windows/qwindowsfontenginedirectwrite.h

@@ -99,7 +99,6 @@ public:
 
     QFontEngine *cloneWithSize(qreal pixelSize) const;
 
-    bool canRender(const QChar *string, int len);
     Type type() const;
 
     const QSharedPointer<QWindowsFontEngineData> &fontEngineData() const { return m_fontEngineData; }