C++ SVGGraphicsElement::toClipPath方法代码示例

bool RenderSVGResourceClipper::pathOnlyClipping(GraphicsContext* context, const AffineTransform& animatedLocalTransform, const FloatRect& objectBoundingBox)
{
    // If the current clip-path gets clipped itself, we have to fallback to masking.
    if (!style()->svgStyle()->clipperResource().isEmpty())
        return false;
    WindRule clipRule = RULE_NONZERO;
    Path clipPath = Path();

    // If clip-path only contains one visible shape or path, we can use path-based clipping. Invisible
    // shapes don't affect the clipping and can be ignored. If clip-path contains more than one
    // visible shape, the additive clipping may not work, caused by the clipRule. EvenOdd
    // as well as NonZero can cause self-clipping of the elements.
    // See also http://www.w3.org/TR/SVG/painting.html#FillRuleProperty
    for (Node* childNode = clipPathElement().firstChild(); childNode; childNode = childNode->nextSibling()) {
        RenderObject* renderer = childNode->renderer();
        if (!renderer)
            continue;
        // Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.
        if (renderer->isSVGText())
            return false;
        if (!childNode->isSVGElement() || !toSVGElement(childNode)->isSVGGraphicsElement())
            continue;
        SVGGraphicsElement* styled = toSVGGraphicsElement(childNode);
        RenderStyle* style = renderer->style();
        if (!style || style->display() == NONE || style->visibility() != VISIBLE)
             continue;
        const SVGRenderStyle* svgStyle = style->svgStyle();
        // Current shape in clip-path gets clipped too. Fallback to masking.
        if (!svgStyle->clipperResource().isEmpty())
            return false;
        // Fallback to masking, if there is more than one clipping path.
        if (clipPath.isEmpty()) {
            styled->toClipPath(clipPath);
            clipRule = svgStyle->clipRule();
        } else
            return false;
    }
    // Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.
    if (clipPathElement().clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        clipPath.transform(transform);
    }

    // Transform path by animatedLocalTransform.
    clipPath.transform(animatedLocalTransform);

    // The SVG specification wants us to clip everything, if clip-path doesn't have a child.
    if (clipPath.isEmpty())
        clipPath.addRect(FloatRect());
    context->clipPath(clipPath, clipRule);
    return true;
}

bool RenderSVGResourceClipper::tryPathOnlyClipping(GraphicsContext* context,
    const AffineTransform& animatedLocalTransform, const FloatRect& objectBoundingBox) {
    // If the current clip-path gets clipped itself, we have to fallback to masking.
    if (!style()->svgStyle().clipperResource().isEmpty())
        return false;
    WindRule clipRule = RULE_NONZERO;
    Path clipPath = Path();

    for (SVGElement* childElement = Traversal<SVGElement>::firstChild(*element()); childElement; childElement = Traversal<SVGElement>::nextSibling(*childElement)) {
        RenderObject* renderer = childElement->renderer();
        if (!renderer)
            continue;
        // Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.
        if (renderer->isSVGText())
            return false;
        if (!childElement->isSVGGraphicsElement())
            continue;
        SVGGraphicsElement* styled = toSVGGraphicsElement(childElement);
        RenderStyle* style = renderer->style();
        if (!style || style->display() == NONE || style->visibility() != VISIBLE)
             continue;
        const SVGRenderStyle& svgStyle = style->svgStyle();
        // Current shape in clip-path gets clipped too. Fallback to masking.
        if (!svgStyle.clipperResource().isEmpty())
            return false;

        if (clipPath.isEmpty()) {
            // First clip shape.
            styled->toClipPath(clipPath);
            clipRule = svgStyle.clipRule();
            clipPath.setWindRule(clipRule);
            continue;
        }

        if (RuntimeEnabledFeatures::pathOpsSVGClippingEnabled()) {
            // Attempt to generate a combined clip path, fall back to masking if not possible.
            Path subPath;
            styled->toClipPath(subPath);
            subPath.setWindRule(svgStyle.clipRule());
            if (!clipPath.unionPath(subPath))
                return false;
        } else {
            return false;
        }
    }
    // Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.
    if (clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform transform;
        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        clipPath.transform(transform);
    }

    // Transform path by animatedLocalTransform.
    clipPath.transform(animatedLocalTransform);

    // The SVG specification wants us to clip everything, if clip-path doesn't have a child.
    if (clipPath.isEmpty())
        clipPath.addRect(FloatRect());
    context->clipPath(clipPath, clipRule);
    return true;
}