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

SVGResource* SVGClipPathElement::canvasResource()
{
    if (!m_clipper)
        m_clipper = SVGResourceClipper::create();
    else
        m_clipper->resetClipData();

    bool bbox = clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;

    RenderStyle* clipPathStyle = styleForRenderer(parent()->renderer()); // FIXME: Manual style resolution is a hack
    for (Node* n = firstChild(); n; n = n->nextSibling()) {
        if (n->isSVGElement() && static_cast<SVGElement*>(n)->isStyledTransformable()) {
            SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(n);
            RenderStyle* pathStyle = document()->styleSelector()->styleForElement(styled, clipPathStyle);
            if (pathStyle->display() != NONE) {
                Path pathData = styled->toClipPath();
                // FIXME: How do we know the element has done a layout?
                pathData.transform(styled->animatedLocalTransform());
                if (!pathData.isEmpty())
                    m_clipper->addClipData(pathData, pathStyle->svgStyle()->clipRule(), bbox);
            }
            pathStyle->deref(document()->renderArena());
        }
    }
    if (m_clipper->clipData().isEmpty()) {
        Path pathData;
        pathData.addRect(FloatRect());
        m_clipper->addClipData(pathData, RULE_EVENODD, bbox);
    }
    clipPathStyle->deref(document()->renderArena());
    return m_clipper.get();
}

FloatRect RenderSVGResourceClipper::resourceBoundingBox(const FloatRect& objectBoundingBox) const
{
    FloatRect clipRect;
    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyledTransformable())
            continue;
        SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(childNode);
        RenderStyle* style = styled->renderer() ? styled->renderer()->style() : 0;
        if (!style || style->display() == NONE || styled->toClipPath().isEmpty())
            continue;
        clipRect.unite(styled->renderer()->objectBoundingBox());
    }

    if (clipRect.isEmpty())
        return FloatRect();

    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        AffineTransform obbTransform;
        obbTransform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        obbTransform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
        return obbTransform.mapRect(clipRect);
    }

    return clipRect;
}

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 = node()->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)->isStyledTransformable())
            continue;
        SVGStyledTransformableElement* styled = toSVGStyledTransformableElement(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 (static_cast<SVGClipPathElement*>(node())->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::applyResource(RenderObject* object, GraphicsContext* context)
{
    ASSERT(object);
    ASSERT(context);

    m_clipper.add(object);

    context->beginPath();

    AffineTransform obbTransform;
    FloatRect objectBoundingBox = object->objectBoundingBox();
    bool bbox = static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    if (bbox) {
        obbTransform.translate(objectBoundingBox.x(), objectBoundingBox.y());
        obbTransform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());
    }

    bool hasClipPath = false;
    WindRule clipRule = RULE_EVENODD;
    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {
        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyledTransformable())
            continue;
        SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(childNode);
        RenderStyle* style = styled->renderer() ? styled->renderer()->style() : 0;
        if (!style || style->display() == NONE)
            continue;
        Path pathData = styled->toClipPath();
        if (pathData.isEmpty())
            continue;
        if (bbox)
            pathData.transform(obbTransform);
        hasClipPath = true;
        context->addPath(pathData);
        clipRule = style->svgStyle()->clipRule();
    }

    if (!hasClipPath) {
        Path clipPath;
        clipPath.addRect(FloatRect());
        context->addPath(clipPath);
    }

    // FIXME!
    // We don't currently allow for heterogenous clip rules.
    // we would have to detect such, draw to a mask, and then clip
    // to that mask
    context->clipPath(clipRule);

    return true;
}