C++ GlyphBuffer::offsetAt方法代码示例

void Font::drawGlyphBuffer(GraphicsContext* context, const TextRun& run, const GlyphBuffer& glyphBuffer, FloatPoint& point) const
{
#if !ENABLE(SVG_FONTS)
    UNUSED_PARAM(run);
#endif

    // Draw each contiguous run of glyphs that use the same font data.
    const SimpleFontData* fontData = glyphBuffer.fontDataAt(0);
    FloatSize offset = glyphBuffer.offsetAt(0);
    FloatPoint startPoint(point.x(), point.y() - glyphBuffer.initialAdvance().height());
    float nextX = startPoint.x() + glyphBuffer.advanceAt(0).width();
    float nextY = startPoint.y() + glyphBuffer.advanceAt(0).height();
    int lastFrom = 0;
    int nextGlyph = 1;
#if ENABLE(SVG_FONTS)
    TextRun::RenderingContext* renderingContext = run.renderingContext();
#endif
    while (nextGlyph < glyphBuffer.size()) {
        const SimpleFontData* nextFontData = glyphBuffer.fontDataAt(nextGlyph);
        FloatSize nextOffset = glyphBuffer.offsetAt(nextGlyph);

        if (nextFontData != fontData || nextOffset != offset) {
#if ENABLE(SVG_FONTS)
            if (renderingContext && fontData->isSVGFont())
                renderingContext->drawSVGGlyphs(context, fontData, glyphBuffer, lastFrom, nextGlyph - lastFrom, startPoint);
            else
#endif
                drawGlyphs(context, fontData, glyphBuffer, lastFrom, nextGlyph - lastFrom, startPoint);

            lastFrom = nextGlyph;
            fontData = nextFontData;
            offset = nextOffset;
            startPoint.setX(nextX);
            startPoint.setY(nextY);
        }
        nextX += glyphBuffer.advanceAt(nextGlyph).width();
        nextY += glyphBuffer.advanceAt(nextGlyph).height();
        nextGlyph++;
    }

#if ENABLE(SVG_FONTS)
    if (renderingContext && fontData->isSVGFont())
        renderingContext->drawSVGGlyphs(context, fontData, glyphBuffer, lastFrom, nextGlyph - lastFrom, startPoint);
    else {
#endif
        drawGlyphs(context, fontData, glyphBuffer, lastFrom, nextGlyph - lastFrom, startPoint);
        point.setX(nextX);
#if ENABLE(SVG_FONTS)
    }
#endif
}

void Font::drawGlyphs(GraphicsContext* graphicsContext, const FontData* font, const GlyphBuffer& glyphBuffer, 
                      int from, int numGlyphs, const FloatPoint& point) const
{
    CGContextRef cgContext = graphicsContext->platformContext();

    uint32_t oldFontSmoothingStyle = wkSetFontSmoothingStyle(cgContext);

    const FontPlatformData& platformData = font->platformData();
    //NSFont* drawFont;
    //if ([gContext isDrawingToScreen]) {
    //    drawFont = [platformData.font screenFont];
    //    if (drawFont != platformData.font)
    //        // We are getting this in too many places (3406411); use ERROR so it only prints on debug versions for now. (We should debug this also, eventually).
    //        LOG_ERROR("Attempting to set non-screen font (%@) when drawing to screen.  Using screen font anyway, may result in incorrect metrics.",
    //            [[[platformData.font fontDescriptor] fontAttributes] objectForKey:NSFontNameAttribute]);
    //} else {
    //    drawFont = [platformData.font printerFont];
    //    if (drawFont != platformData.font)
    //        NSLog(@"Attempting to set non-printer font (%@) when printing.  Using printer font anyway, may result in incorrect metrics.",
    //            [[[platformData.font fontDescriptor] fontAttributes] objectForKey:NSFontNameAttribute]);
    //}

    CGContextSetFont(cgContext, platformData.cgFont());

    CGAffineTransform matrix = CGAffineTransformIdentity;
    matrix.b = -matrix.b;
    matrix.d = -matrix.d;

    if (platformData.syntheticOblique())
    {
        static float skew = -tanf(syntheticObliqueAngle * acosf(0) / 90);
        matrix = CGAffineTransformConcat(matrix, CGAffineTransformMake(1, 0, skew, 1, 0, 0));
    }

    // Uniscribe gives us offsets to help refine the positioning of combining glyphs.
    FloatSize translation = glyphBuffer.offsetAt(from);
    if (translation.width() || translation.height())
        CGAffineTransformTranslate(matrix, translation.width(), translation.height());
    
    CGContextSetTextMatrix(cgContext, matrix);

    //wkSetCGFontRenderingMode(cgContext, drawFont);
    CGContextSetFontSize(cgContext, platformData.size());
    CGContextSetTextPosition(cgContext, point.x(), point.y());
    CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    if (font->m_syntheticBoldOffset) {
        CGContextSetTextPosition(cgContext, point.x() + font->m_syntheticBoldOffset, point.y());
        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    }

    wkRestoreFontSmoothingStyle(cgContext, oldFontSmoothingStyle);
}

void Font::drawGlyphs(GraphicsContext* graphicsContext, const SimpleFontData* font, const GlyphBuffer& glyphBuffer,
                      int from, int numGlyphs, const FloatPoint& point) const
{
    CGContextRef cgContext = graphicsContext->platformContext();
    bool shouldUseFontSmoothing = WebCoreShouldUseFontSmoothing();

    switch(fontDescription().fontSmoothing()) {
    case Antialiased: {
        graphicsContext->setShouldAntialias(true);
        shouldUseFontSmoothing = false;
        break;
    }
    case SubpixelAntialiased: {
        graphicsContext->setShouldAntialias(true);
        shouldUseFontSmoothing = true;
        break;
    }
    case NoSmoothing: {
        graphicsContext->setShouldAntialias(false);
        shouldUseFontSmoothing = false;
        break;
    }
    case AutoSmoothing: {
        // For the AutoSmooth case, don't do anything! Keep the default settings.
        break;
    }
    default:
        ASSERT_NOT_REACHED();
    }

    if (font->platformData().useGDI() && !shouldUseFontSmoothing) {
        drawGDIGlyphs(graphicsContext, font, glyphBuffer, from, numGlyphs, point);
        return;
    }

    uint32_t oldFontSmoothingStyle = wkSetFontSmoothingStyle(cgContext, shouldUseFontSmoothing);

    const FontPlatformData& platformData = font->platformData();

    CGContextSetFont(cgContext, platformData.cgFont());

    CGAffineTransform matrix = CGAffineTransformIdentity;
    matrix.b = -matrix.b;
    matrix.d = -matrix.d;

    if (platformData.syntheticOblique()) {
        static float skew = -tanf(syntheticObliqueAngle * piFloat / 180.0f);
        matrix = CGAffineTransformConcat(matrix, CGAffineTransformMake(1, 0, skew, 1, 0, 0));
    }

    CGContextSetTextMatrix(cgContext, matrix);

    // Uniscribe gives us offsets to help refine the positioning of combining glyphs.
    FloatSize translation = glyphBuffer.offsetAt(from);

    CGContextSetFontSize(cgContext, platformData.size());
    wkSetCGContextFontRenderingStyle(cgContext, font->isSystemFont(), false, font->platformData().useGDI());

    FloatSize shadowOffset;
    float shadowBlur;
    Color shadowColor;
    ColorSpace shadowColorSpace;
    graphicsContext->getShadow(shadowOffset, shadowBlur, shadowColor, shadowColorSpace);

    bool hasSimpleShadow = graphicsContext->textDrawingMode() == TextModeFill && shadowColor.isValid() && !shadowBlur && (!graphicsContext->shadowsIgnoreTransforms() || graphicsContext->getCTM().isIdentityOrTranslationOrFlipped());
    if (hasSimpleShadow) {
        // Paint simple shadows ourselves instead of relying on CG shadows, to avoid losing subpixel antialiasing.
        graphicsContext->clearShadow();
        Color fillColor = graphicsContext->fillColor();
        Color shadowFillColor(shadowColor.red(), shadowColor.green(), shadowColor.blue(), shadowColor.alpha() * fillColor.alpha() / 255);
        graphicsContext->setFillColor(shadowFillColor, ColorSpaceDeviceRGB);
        float shadowTextX = point.x() + translation.width() + shadowOffset.width();
        // If shadows are ignoring transforms, then we haven't applied the Y coordinate flip yet, so down is negative.
        float shadowTextY = point.y() + translation.height() + shadowOffset.height() * (graphicsContext->shadowsIgnoreTransforms() ? -1 : 1);
        CGContextSetTextPosition(cgContext, shadowTextX, shadowTextY);
        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
        if (font->syntheticBoldOffset()) {
            CGContextSetTextPosition(cgContext, point.x() + translation.width() + shadowOffset.width() + font->syntheticBoldOffset(), point.y() + translation.height() + shadowOffset.height());
            CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
        }
        graphicsContext->setFillColor(fillColor, ColorSpaceDeviceRGB);
    }

    CGContextSetTextPosition(cgContext, point.x() + translation.width(), point.y() + translation.height());
    CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    if (font->syntheticBoldOffset()) {
        CGContextSetTextPosition(cgContext, point.x() + translation.width() + font->syntheticBoldOffset(), point.y() + translation.height());
        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    }

    if (hasSimpleShadow)
        graphicsContext->setShadow(shadowOffset, shadowBlur, shadowColor, ColorSpaceDeviceRGB);

    wkRestoreFontSmoothingStyle(cgContext, oldFontSmoothingStyle);
}

static void drawGDIGlyphs(GraphicsContext* graphicsContext, const SimpleFontData* font, const GlyphBuffer& glyphBuffer,
                          int from, int numGlyphs, const FloatPoint& point)
{
    Color fillColor = graphicsContext->fillColor();

    bool drawIntoBitmap = false;
    TextDrawingModeFlags drawingMode = graphicsContext->textDrawingMode();
    if (drawingMode == TextModeFill) {
        if (!fillColor.alpha())
            return;

        drawIntoBitmap = fillColor.alpha() != 255 || graphicsContext->inTransparencyLayer();
        if (!drawIntoBitmap) {
            FloatSize offset;
            float blur;
            Color color;
            ColorSpace shadowColorSpace;

            graphicsContext->getShadow(offset, blur, color, shadowColorSpace);
            drawIntoBitmap = offset.width() || offset.height() || blur;
        }
    }

    // We have to convert CG's two-dimensional floating point advances to just horizontal integer advances.
    Vector<int, 2048> gdiAdvances;
    int totalWidth = 0;
    for (int i = 0; i < numGlyphs; i++) {
        gdiAdvances.append(lroundf(glyphBuffer.advanceAt(from + i)));
        totalWidth += gdiAdvances[i];
    }

    HDC hdc = 0;
    OwnPtr<GraphicsContext::WindowsBitmap> bitmap;
    IntRect textRect;
    if (!drawIntoBitmap)
        hdc = graphicsContext->getWindowsContext(textRect, true, false);
    if (!hdc) {
        drawIntoBitmap = true;
        // We put slop into this rect, since glyphs can overflow the ascent/descent bounds and the left/right edges.
        // FIXME: Can get glyphs' optical bounds (even from CG) to get this right.
        const FontMetrics& fontMetrics = font->fontMetrics();
        int lineGap = fontMetrics.lineGap();
        textRect = IntRect(point.x() - (fontMetrics.ascent() + fontMetrics.descent()) / 2,
                           point.y() - fontMetrics.ascent() - lineGap,
                           totalWidth + fontMetrics.ascent() + fontMetrics.descent(),
                           fontMetrics.lineSpacing());
        bitmap = graphicsContext->createWindowsBitmap(textRect.size());
        memset(bitmap->buffer(), 255, bitmap->bufferLength());
        hdc = bitmap->hdc();

        XFORM xform;
        xform.eM11 = 1.0f;
        xform.eM12 = 0.0f;
        xform.eM21 = 0.0f;
        xform.eM22 = 1.0f;
        xform.eDx = -textRect.x();
        xform.eDy = -textRect.y();
        SetWorldTransform(hdc, &xform);
    }

    SelectObject(hdc, font->platformData().hfont());

    // Set the correct color.
    if (drawIntoBitmap)
        SetTextColor(hdc, RGB(0, 0, 0));
    else
        SetTextColor(hdc, RGB(fillColor.red(), fillColor.green(), fillColor.blue()));

    SetBkMode(hdc, TRANSPARENT);
    SetTextAlign(hdc, TA_LEFT | TA_BASELINE);

    // Uniscribe gives us offsets to help refine the positioning of combining glyphs.
    FloatSize translation = glyphBuffer.offsetAt(from);
    if (translation.width() || translation.height()) {
        XFORM xform;
        xform.eM11 = 1.0;
        xform.eM12 = 0;
        xform.eM21 = 0;
        xform.eM22 = 1.0;
        xform.eDx = translation.width();
        xform.eDy = translation.height();
        ModifyWorldTransform(hdc, &xform, MWT_LEFTMULTIPLY);
    }

    if (drawingMode == TextModeFill) {
        XFORM xform;
        xform.eM11 = 1.0;
        xform.eM12 = 0;
        xform.eM21 = font->platformData().syntheticOblique() ? -tanf(syntheticObliqueAngle * piFloat / 180.0f) : 0;
        xform.eM22 = 1.0;
        xform.eDx = point.x();
        xform.eDy = point.y();
        ModifyWorldTransform(hdc, &xform, MWT_LEFTMULTIPLY);
        ExtTextOut(hdc, 0, 0, ETO_GLYPH_INDEX, 0, reinterpret_cast<const WCHAR*>(glyphBuffer.glyphs(from)), numGlyphs, gdiAdvances.data());
        if (font->syntheticBoldOffset()) {
            xform.eM21 = 0;
            xform.eDx = font->syntheticBoldOffset();
            xform.eDy = 0;
            ModifyWorldTransform(hdc, &xform, MWT_LEFTMULTIPLY);
            ExtTextOut(hdc, 0, 0, ETO_GLYPH_INDEX, 0, reinterpret_cast<const WCHAR*>(glyphBuffer.glyphs(from)), numGlyphs, gdiAdvances.data());
//.........这里部分代码省略.........

void Font::drawGlyphs(GraphicsContext* graphicsContext, const SimpleFontData* font, const GlyphBuffer& glyphBuffer, 
                      int from, int numGlyphs, const FloatPoint& point) const
{
    CGContextRef cgContext = graphicsContext->platformContext();
    bool shouldUseFontSmoothing = WebCoreShouldUseFontSmoothing();

    if (font->platformData().useGDI()) {
        static bool canUsePlatformNativeGlyphs = wkCanUsePlatformNativeGlyphs();
        if (!canUsePlatformNativeGlyphs || !shouldUseFontSmoothing || (graphicsContext->textDrawingMode() & cTextStroke)) {
            drawGDIGlyphs(graphicsContext, font, glyphBuffer, from, numGlyphs, point);
            return;
        }
    }

    uint32_t oldFontSmoothingStyle = wkSetFontSmoothingStyle(cgContext, shouldUseFontSmoothing);

    const FontPlatformData& platformData = font->platformData();

    CGContextSetFont(cgContext, platformData.cgFont());

    CGAffineTransform matrix = CGAffineTransformIdentity;
    matrix.b = -matrix.b;
    matrix.d = -matrix.d;

    if (platformData.syntheticOblique()) {
        static float skew = -tanf(syntheticObliqueAngle * piFloat / 180.0f);
        matrix = CGAffineTransformConcat(matrix, CGAffineTransformMake(1, 0, skew, 1, 0, 0));
    }

    CGContextSetTextMatrix(cgContext, matrix);

    // Uniscribe gives us offsets to help refine the positioning of combining glyphs.
    FloatSize translation = glyphBuffer.offsetAt(from);

    CGContextSetFontSize(cgContext, platformData.size());
    wkSetCGContextFontRenderingStyle(cgContext, font->isSystemFont(), false, font->platformData().useGDI());

    IntSize shadowSize;
    int shadowBlur;
    Color shadowColor;
    graphicsContext->getShadow(shadowSize, shadowBlur, shadowColor);

    bool hasSimpleShadow = graphicsContext->textDrawingMode() == cTextFill && shadowColor.isValid() && !shadowBlur;
    if (hasSimpleShadow) {
        // Paint simple shadows ourselves instead of relying on CG shadows, to avoid losing subpixel antialiasing.
        graphicsContext->clearShadow();
        Color fillColor = graphicsContext->fillColor();
        Color shadowFillColor(shadowColor.red(), shadowColor.green(), shadowColor.blue(), shadowColor.alpha() * fillColor.alpha() / 255);
        graphicsContext->setFillColor(shadowFillColor);
        CGContextSetTextPosition(cgContext, point.x() + translation.width() + shadowSize.width(), point.y() + translation.height() + shadowSize.height());
        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
        if (font->m_syntheticBoldOffset) {
            CGContextSetTextPosition(cgContext, point.x() + translation.width() + shadowSize.width() + font->m_syntheticBoldOffset, point.y() + translation.height() + shadowSize.height());
            CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
        }
        graphicsContext->setFillColor(fillColor);
    }

    CGContextSetTextPosition(cgContext, point.x() + translation.width(), point.y() + translation.height());
    CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    if (font->m_syntheticBoldOffset) {
        CGContextSetTextPosition(cgContext, point.x() + translation.width() + font->m_syntheticBoldOffset, point.y() + translation.height());
        CGContextShowGlyphsWithAdvances(cgContext, glyphBuffer.glyphs(from), glyphBuffer.advances(from), numGlyphs);
    }

    if (hasSimpleShadow)
        graphicsContext->setShadow(shadowSize, shadowBlur, shadowColor);

    wkRestoreFontSmoothingStyle(cgContext, oldFontSmoothingStyle);
}