float SVGTextLayoutEngineSpacing::calculateSVGKerning(bool isVerticalText, const SVGTextMetrics::Glyph& currentGlyph)
{
#if ENABLE(SVG_FONTS)
    if (!m_font.isSVGFont()) {
        m_lastGlyph.isValid = false;
        return 0;
    }

    SVGFontElement* svgFont = m_font.svgFont();
    ASSERT(svgFont);

    float kerning = 0;
    if (m_lastGlyph.isValid) {
        if (isVerticalText)
            kerning = svgFont->verticalKerningForPairOfStringsAndGlyphs(m_lastGlyph.unicodeString, m_lastGlyph.name, currentGlyph.unicodeString, currentGlyph.name);
        else
            kerning = svgFont->horizontalKerningForPairOfStringsAndGlyphs(m_lastGlyph.unicodeString, m_lastGlyph.name, currentGlyph.unicodeString, currentGlyph.name);
    }

    m_lastGlyph = currentGlyph;
    m_lastGlyph.isValid = true;
    kerning *= m_font.size() / m_font.primaryFont()->unitsPerEm();
    return kerning;
#else
    UNUSED_PARAM(isVerticalText);
    UNUSED_PARAM(currentGlyph);
    return false;
#endif
}
bool SVGTextRunRenderingContext::applySVGKerning(const SimpleFontData* fontData, WidthIterator& iterator, GlyphBuffer* glyphBuffer, int from) const
{
    ASSERT(glyphBuffer);
    ASSERT(glyphBuffer->size() > 1);
    SVGFontElement* fontElement = 0;
    SVGFontFaceElement* fontFaceElement = 0;

    svgFontAndFontFaceElementForFontData(fontData, fontFaceElement, fontElement);
    if (!fontElement || !fontFaceElement)
        return false;

    if (fontElement->horizontalKerningMapIsEmpty())
        return true;

    float scale = scaleEmToUnits(fontData->platformData().size(), fontFaceElement->unitsPerEm());

    String lastGlyphName;
    String lastUnicodeString;
    int characterOffset = iterator.m_currentCharacter;
    String text = iterator.run().string();
    const int glyphCount = glyphBuffer->size() - from;
    GlyphBufferAdvance* advances = glyphBuffer->advances(from);

    for (int i = 0; i < glyphCount; ++i) {
        Glyph glyph = glyphBuffer->glyphAt(from + i);
        if (!glyph)
            continue;
        float kerning = 0;
        SVGGlyph svgGlyph = fontElement->svgGlyphForGlyph(glyph);
        String unicodeString = text.substring(characterOffset, svgGlyph.unicodeStringLength);
        if (i >= 1) {
            // FIXME: Support vertical text.
            kerning = fontElement->horizontalKerningForPairOfStringsAndGlyphs(lastUnicodeString, lastGlyphName, unicodeString, svgGlyph.glyphName);
            advances[i - 1].setWidth(advances[i - 1].width() - kerning * scale);
        }
        lastGlyphName = svgGlyph.glyphName;
        lastUnicodeString = unicodeString;
        characterOffset += svgGlyph.unicodeStringLength;
    }

    return true;
}
float SVGTextLayoutEngineSpacing::calculateSVGKerning(bool isVerticalText, const SVGTextMetrics::Glyph& currentGlyph)
{
#if ENABLE(SVG_FONTS)
    const SimpleFontData* fontData = m_font.primaryFont();
    if (!fontData->isSVGFont()) {
        m_lastGlyph.isValid = false;
        return 0;
    }

    ASSERT(fontData->isCustomFont());
    ASSERT(fontData->isSVGFont());

    const SVGFontData* svgFontData = static_cast<const SVGFontData*>(fontData->fontData());
    SVGFontFaceElement* svgFontFace = svgFontData->svgFontFaceElement();
    ASSERT(svgFontFace);

    SVGFontElement* svgFont = svgFontFace->associatedFontElement();
    if (!svgFont) {
        m_lastGlyph.isValid = false;
        return 0;
    }

    float kerning = 0;
    if (m_lastGlyph.isValid) {
        if (isVerticalText)
            kerning = svgFont->verticalKerningForPairOfStringsAndGlyphs(m_lastGlyph.unicodeString, m_lastGlyph.name, currentGlyph.unicodeString, currentGlyph.name);
        else
            kerning = svgFont->horizontalKerningForPairOfStringsAndGlyphs(m_lastGlyph.unicodeString, m_lastGlyph.name, currentGlyph.unicodeString, currentGlyph.name);
    }

    m_lastGlyph = currentGlyph;
    m_lastGlyph.isValid = true;
    kerning *= m_font.size() / m_font.fontMetrics().unitsPerEm();
    return kerning;
#else
    UNUSED_PARAM(isVerticalText);
    UNUSED_PARAM(currentGlyph);
    return false;
#endif
}