C++ GraphicsContext::createCompatibleBuffer方法代码示例

void BitmapImage::drawPattern(GraphicsContext& ctxt, const FloatRect& tileRect, const AffineTransform& transform,
    const FloatPoint& phase, const FloatSize& spacing, CompositeOperator op, const FloatRect& destRect, BlendMode blendMode)
{
    if (tileRect.isEmpty())
        return;

    if (!ctxt.drawLuminanceMask()) {
        Image::drawPattern(ctxt, tileRect, transform, phase, spacing, op, destRect, blendMode);
        return;
    }
    if (!m_cachedImage) {
        std::unique_ptr<ImageBuffer> buffer = ctxt.createCompatibleBuffer(expandedIntSize(tileRect.size()));
        if (!buffer)
            return;

        ImageObserver* observer = imageObserver();
        ASSERT(observer);

        // Temporarily reset image observer, we don't want to receive any changeInRect() calls due to this relayout.
        setImageObserver(nullptr);

        draw(buffer->context(), tileRect, tileRect, op, blendMode, ImageOrientationDescription());

        setImageObserver(observer);
        buffer->convertToLuminanceMask();

        m_cachedImage = buffer->copyImage(DontCopyBackingStore, Unscaled);
        if (!m_cachedImage)
            return;
    }

    ctxt.setDrawLuminanceMask(false);
    m_cachedImage->drawPattern(ctxt, tileRect, transform, phase, spacing, op, destRect, blendMode);
}

void GradientImage::drawPattern(GraphicsContext& destContext, const FloatRect& srcRect, const AffineTransform& patternTransform,
    const FloatPoint& phase, const FloatSize& spacing, ColorSpace styleColorSpace, CompositeOperator compositeOp, const FloatRect& destRect, BlendMode blendMode)
{
    // Allow the generator to provide visually-equivalent tiling parameters for better performance.
    FloatSize adjustedSize = size();
    FloatRect adjustedSrcRect = srcRect;
    m_gradient->adjustParametersForTiledDrawing(adjustedSize, adjustedSrcRect, spacing);

    // Factor in the destination context's scale to generate at the best resolution
    AffineTransform destContextCTM = destContext.getCTM(GraphicsContext::DefinitelyIncludeDeviceScale);
    double xScale = fabs(destContextCTM.xScale());
    double yScale = fabs(destContextCTM.yScale());
    AffineTransform adjustedPatternCTM = patternTransform;
    adjustedPatternCTM.scale(1.0 / xScale, 1.0 / yScale);
    adjustedSrcRect.scale(xScale, yScale);

    unsigned generatorHash = m_gradient->hash();

    if (!m_cachedImageBuffer || m_cachedGeneratorHash != generatorHash || m_cachedAdjustedSize != adjustedSize || !destContext.isCompatibleWithBuffer(*m_cachedImageBuffer)) {
        m_cachedImageBuffer = destContext.createCompatibleBuffer(adjustedSize, m_gradient->hasAlpha());
        if (!m_cachedImageBuffer)
            return;

        // Fill with the generated image.
        m_cachedImageBuffer->context().fillRect(FloatRect(FloatPoint(), adjustedSize), *m_gradient);

        m_cachedGeneratorHash = generatorHash;
        m_cachedAdjustedSize = adjustedSize;

        if (destContext.drawLuminanceMask())
            m_cachedImageBuffer->convertToLuminanceMask();
    }

    destContext.setDrawLuminanceMask(false);

    // Tile the image buffer into the context.
    m_cachedImageBuffer->drawPattern(destContext, adjustedSrcRect, adjustedPatternCTM, phase, spacing, styleColorSpace, compositeOp, destRect, blendMode);
}

void NamedImageGeneratedImage::drawPattern(GraphicsContext& context, const FloatRect& srcRect, const AffineTransform& patternTransform, const FloatPoint& phase, const FloatSize& spacing, CompositeOperator compositeOp, const FloatRect& dstRect, BlendMode blendMode)
{
#if USE(NEW_THEME)
    std::unique_ptr<ImageBuffer> imageBuffer = context.createCompatibleBuffer(size(), true);
    if (!imageBuffer)
        return;

    GraphicsContext& graphicsContext = imageBuffer->context();
    platformTheme()->drawNamedImage(m_name, graphicsContext, FloatRect(0, 0, size().width(), size().height()));

    // Tile the image buffer into the context.
    imageBuffer->drawPattern(context, srcRect, patternTransform, phase, spacing, compositeOp, dstRect, blendMode);
#else
    UNUSED_PARAM(context);
    UNUSED_PARAM(srcRect);
    UNUSED_PARAM(patternTransform);
    UNUSED_PARAM(phase);
    UNUSED_PARAM(spacing);
    UNUSED_PARAM(dstRect);
    UNUSED_PARAM(compositeOp);
    UNUSED_PARAM(blendMode);
#endif
}