FloatRect RenderSVGResourceMasker::resourceBoundingBox(RenderObject* object)
{
    // Save the reference to the calling object for relayouting it on changing resource properties.
    if (!m_masker.contains(object))
        m_masker.set(object, new MaskerData);

    // Resource was not layouted yet. Give back clipping rect of the mask.
    SVGMaskElement* maskElement = static_cast<SVGMaskElement*>(node());
    FloatRect objectBoundingBox = object->objectBoundingBox();
    FloatRect maskBoundaries = maskElement->maskBoundingBox(objectBoundingBox);
    if (selfNeedsLayout())
        return maskBoundaries;

    if (m_maskBoundaries.isEmpty())
        calculateMaskContentRepaintRect();

    if (!maskElement)
        return FloatRect();

    FloatRect maskRect = m_maskBoundaries;
    if (maskElement->maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        maskRect =  transform.mapRect(maskRect);
    }

    maskRect.intersect(maskBoundaries);
    return maskRect;
}
FloatRect RenderSVGResourceMasker::resourceBoundingBox(RenderObject* object)
{
    SVGMaskElement* maskElement = static_cast<SVGMaskElement*>(node());
    ASSERT(maskElement);

    FloatRect objectBoundingBox = object->objectBoundingBox();
    FloatRect maskBoundaries = maskElement->maskBoundingBox(objectBoundingBox);

    // Resource was not layouted yet. Give back clipping rect of the mask.
    if (selfNeedsLayout())
        return maskBoundaries;

    if (m_maskContentBoundaries.isEmpty())
        calculateMaskContentRepaintRect();

    FloatRect maskRect = m_maskContentBoundaries;
    if (maskElement->maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        maskRect = transform.mapRect(maskRect);
    }

    maskRect.intersect(maskBoundaries);
    return maskRect;
}
FloatRect RenderSVGResourceMasker::resourceBoundingBox(const FloatRect& objectBoundingBox)
{
    if (m_maskBoundaries.isEmpty())
        calculateMaskContentRepaintRect();

    SVGMaskElement* maskElement = static_cast<SVGMaskElement*>(node());
    if (!maskElement)
        return FloatRect();

    FloatRect maskRect = m_maskBoundaries;
    if (maskElement->maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        maskRect =  transform.mapRect(maskRect);
    }

    maskRect.intersect(maskElement->maskBoundingBox(objectBoundingBox));
    return maskRect;
}
FloatRect RenderSVGResourceMasker::resourceBoundingBox(const RenderObject& object)
{
    FloatRect objectBoundingBox = object.objectBoundingBox();
    FloatRect maskBoundaries = SVGLengthContext::resolveRectangle<SVGMaskElement>(&maskElement(), maskElement().maskUnits(), objectBoundingBox);

    // Resource was not layouted yet. Give back clipping rect of the mask.
    if (selfNeedsLayout())
        return maskBoundaries;

    if (m_maskContentBoundaries.isEmpty())
        calculateMaskContentRepaintRect();

    FloatRect maskRect = m_maskContentBoundaries;
    if (maskElement().maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        maskRect = transform.mapRect(maskRect);
    }

    maskRect.intersect(maskBoundaries);
    return maskRect;
}
void RenderSVGResourceMasker::createMaskImage(MaskerData* maskerData, const SVGMaskElement* maskElement, RenderObject* object)
{
    FloatRect objectBoundingBox = object->objectBoundingBox();

    // Mask rect clipped with clippingBoundingBox and filterBoundingBox as long as they are present.
    maskerData->maskRect = object->repaintRectInLocalCoordinates();
    if (maskerData->maskRect.isEmpty()) {
        maskerData->emptyMask = true;
        return;
    }
    
    if (m_maskBoundaries.isEmpty())
        calculateMaskContentRepaintRect();

    FloatRect repaintRect = m_maskBoundaries;
    AffineTransform contextTransform;
    // We need to scale repaintRect for objectBoundingBox to get the drawing area.
    if (maskElement->maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        contextTransform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        FloatPoint contextAdjustment = repaintRect.location();
        repaintRect = contextTransform.mapRect(repaintRect);
        repaintRect.move(objectBoundingBox.x(), objectBoundingBox.y());
        contextTransform.translate(-contextAdjustment.x(), -contextAdjustment.y());
    }
    repaintRect.intersect(maskerData->maskRect);
    maskerData->maskRect = repaintRect;
    IntRect maskImageRect = enclosingIntRect(maskerData->maskRect);

    maskImageRect.setLocation(IntPoint());

    // Don't create ImageBuffers with image size of 0
    if (maskImageRect.isEmpty()) {
        maskerData->emptyMask = true;
        return;
    }

    // FIXME: This changes color space to linearRGB, the default color space
    // for masking operations in SVG. We need a switch for the other color-space
    // attribute values sRGB, inherit and auto.
    maskerData->maskImage = ImageBuffer::create(maskImageRect.size(), LinearRGB);
    if (!maskerData->maskImage)
        return;

    GraphicsContext* maskImageContext = maskerData->maskImage->context();
    ASSERT(maskImageContext);

    maskImageContext->save();

    if (maskElement->maskContentUnits() == SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE)
        maskImageContext->translate(-maskerData->maskRect.x(), -maskerData->maskRect.y());
    maskImageContext->concatCTM(contextTransform);

    // draw the content into the ImageBuffer
    for (Node* node = maskElement->firstChild(); node; node = node->nextSibling()) {
        RenderObject* renderer = node->renderer();
        if (!node->isSVGElement() || !static_cast<SVGElement*>(node)->isStyled() || !renderer)
            continue;
        RenderStyle* style = renderer->style();
        if (!style || style->display() == NONE || style->visibility() != VISIBLE)
            continue;
        renderSubtreeToImage(maskerData->maskImage.get(), renderer);
    }

    maskImageContext->restore();

    // create the luminance mask
    RefPtr<ImageData> imageData(maskerData->maskImage->getUnmultipliedImageData(maskImageRect));
    CanvasPixelArray* srcPixelArray(imageData->data());

    for (unsigned pixelOffset = 0; pixelOffset < srcPixelArray->length(); pixelOffset += 4) {
        unsigned char a = srcPixelArray->get(pixelOffset + 3);
        if (!a)
            continue;
        unsigned char r = srcPixelArray->get(pixelOffset);
        unsigned char g = srcPixelArray->get(pixelOffset + 1);
        unsigned char b = srcPixelArray->get(pixelOffset + 2);

        double luma = (r * 0.2125 + g * 0.7154 + b * 0.0721) * ((double)a / 255.0);
        srcPixelArray->set(pixelOffset + 3, luma);
    }

    maskerData->maskImage->putUnmultipliedImageData(imageData.get(), maskImageRect, IntPoint());
}