C++ SVGUseElement::y方法代码示例

bool RenderSVGTransformableContainer::calculateLocalTransform()
{
    SVGGraphicsElement& element = graphicsElement();

    // If we're either the renderer for a <use> element, or for any <g> element inside the shadow
    // tree, that was created during the use/symbol/svg expansion in SVGUseElement. These containers
    // need to respect the translations induced by their corresponding use elements x/y attributes.
    SVGUseElement* useElement = nullptr;
    if (is<SVGUseElement>(element))
        useElement = &downcast<SVGUseElement>(element);
    else if (element.isInShadowTree() && is<SVGGElement>(element)) {
        SVGElement* correspondingElement = element.correspondingElement();
        if (is<SVGUseElement>(correspondingElement))
            useElement = downcast<SVGUseElement>(correspondingElement);
    }

    if (useElement) {
        SVGLengthContext lengthContext(useElement);
        FloatSize translation(useElement->x().value(lengthContext), useElement->y().value(lengthContext));
        if (translation != m_lastTranslation)
            m_needsTransformUpdate = true;
        m_lastTranslation = translation;
    }

    m_didTransformToRootUpdate = m_needsTransformUpdate || SVGRenderSupport::transformToRootChanged(parent());
    if (!m_needsTransformUpdate)
        return false;

    m_localTransform = element.animatedLocalTransform();
    m_localTransform.translate(m_lastTranslation.width(), m_lastTranslation.height());
    m_needsTransformUpdate = false;
    return true;
}

static void updateContainerOffset(SVGElementInstance* targetInstance)
{
    // Depth-first used to write the method in early exit style, no particular other reason.
    for (SVGElementInstance* instance = targetInstance->firstChild(); instance; instance = instance->nextSibling())
        updateContainerOffset(instance);

    SVGElement* correspondingElement = targetInstance->correspondingElement();
    ASSERT(correspondingElement);

    if (!correspondingElement->hasTagName(SVGNames::useTag))
        return;

    SVGElement* shadowTreeElement = targetInstance->shadowTreeElement();
    ASSERT(shadowTreeElement);
    ASSERT(shadowTreeElement->hasTagName(SVGNames::gTag));

    if (!static_cast<SVGGElement*>(shadowTreeElement)->isShadowTreeContainerElement())
        return;

    // Spec: An additional transformation translate(x,y) is appended to the end
    // (i.e., right-side) of the transform attribute on the generated 'g', where x
    // and y represent the values of the x and y attributes on the 'use' element. 
    SVGUseElement* useElement = static_cast<SVGUseElement*>(correspondingElement);
    SVGShadowTreeContainerElement* containerElement = static_cast<SVGShadowTreeContainerElement*>(shadowTreeElement);
    containerElement->setContainerOffset(useElement->x(), useElement->y());
}

bool LayoutSVGTransformableContainer::calculateLocalTransform()
{
    SVGGraphicsElement* element = toSVGGraphicsElement(this->element());
    ASSERT(element);

    // If we're either the layoutObject for a <use> element, or for any <g> element inside the shadow
    // tree, that was created during the use/symbol/svg expansion in SVGUseElement. These containers
    // need to respect the translations induced by their corresponding use elements x/y attributes.
    SVGUseElement* useElement = nullptr;
    if (isSVGUseElement(*element)) {
        useElement = toSVGUseElement(element);
    } else if (isSVGGElement(*element) && toSVGGElement(element)->inUseShadowTree()) {
        SVGElement* correspondingElement = element->correspondingElement();
        if (isSVGUseElement(correspondingElement))
            useElement = toSVGUseElement(correspondingElement);
    }

    if (useElement) {
        SVGLengthContext lengthContext(useElement);
        FloatSize translation(
            useElement->x()->currentValue()->value(lengthContext),
            useElement->y()->currentValue()->value(lengthContext));
        if (translation != m_additionalTranslation)
            m_needsTransformUpdate = true;
        m_additionalTranslation = translation;
    }

    m_didTransformToRootUpdate = m_needsTransformUpdate || SVGLayoutSupport::transformToRootChanged(parent());
    if (!m_needsTransformUpdate)
        return false;

    m_localTransform = element->calculateAnimatedLocalTransform();
    m_localTransform.translate(m_additionalTranslation.width(), m_additionalTranslation.height());
    m_needsTransformUpdate = false;
    return true;
}

void SVGUseElement::expandUseElementsInShadowTree(Node* element)
{
    // Why expand the <use> elements in the shadow tree here, and not just
    // do this directly in buildShadowTree, if we encounter a <use> element?
    //
    // Short answer: Because we may miss to expand some elements. Ie. if a <symbol>
    // contains <use> tags, we'd miss them. So once we're done with settin' up the
    // actual shadow tree (after the special case modification for svg/symbol) we have
    // to walk it completely and expand all <use> elements.
    if (element->hasTagName(SVGNames::useTag)) {
        SVGUseElement* use = static_cast<SVGUseElement*>(element);

        String id = SVGURIReference::getTarget(use->href());
        Element* targetElement = document()->getElementById(id); 
        SVGElement* target = 0;
        if (targetElement && targetElement->isSVGElement())
            target = static_cast<SVGElement*>(targetElement);

        // Don't ASSERT(target) here, it may be "pending", too.
        if (target) {
            // Setup sub-shadow tree root node
            RefPtr<SVGElement> cloneParent = new SVGGElement(SVGNames::gTag, document());

            // Spec: In the generated content, the 'use' will be replaced by 'g', where all attributes from the
            // 'use' element except for x, y, width, height and xlink:href are transferred to the generated 'g' element.
            transferUseAttributesToReplacedElement(use, cloneParent.get());

            // Spec: An additional transformation translate(x,y) is appended to the end
            // (i.e., right-side) of the transform attribute on the generated 'g', where x
            // and y represent the values of the x and y attributes on the 'use' element.
            if (use->x().value() != 0.0 || use->y().value() != 0.0) {
                if (!cloneParent->hasAttribute(SVGNames::transformAttr)) {
                    String transformString = String::format("translate(%f, %f)", use->x().value(), use->y().value());
                    cloneParent->setAttribute(SVGNames::transformAttr, transformString);
                } else {
                    String transformString = String::format(" translate(%f, %f)", use->x().value(), use->y().value());
                    const AtomicString& transformAttribute = cloneParent->getAttribute(SVGNames::transformAttr);
                    cloneParent->setAttribute(SVGNames::transformAttr, transformAttribute + transformString); 
                }
            }

            ExceptionCode ec = 0;
 
            // For instance <use> on <foreignObject> (direct case).
            if (isDisallowedElement(target)) {
                // We still have to setup the <use> replacment (<g>). Otherwhise
                // associateInstancesWithShadowTreeElements() makes wrong assumptions.
                // Replace <use> with referenced content.
                ASSERT(use->parentNode()); 
                use->parentNode()->replaceChild(cloneParent.release(), use, ec);
                ASSERT(ec == 0);
                return;
            }

            RefPtr<Node> newChild = target->cloneNode(true);

            // We don't walk the target tree element-by-element, and clone each element,
            // but instead use cloneNode(deep=true). This is an optimization for the common
            // case where <use> doesn't contain disallowed elements (ie. <foreignObject>).
            // Though if there are disallowed elements in the subtree, we have to remove them.
            // For instance: <use> on <g> containing <foreignObject> (indirect case).
            if (subtreeContainsDisallowedElement(newChild.get()))
                removeDisallowedElementsFromSubtree(newChild.get());

            SVGElement* newChildPtr = 0;
            if (newChild->isSVGElement())
                newChildPtr = static_cast<SVGElement*>(newChild.get());
            ASSERT(newChildPtr);

            cloneParent->appendChild(newChild.release(), ec);
            ASSERT(ec == 0);

            // Replace <use> with referenced content.
            ASSERT(use->parentNode()); 
            use->parentNode()->replaceChild(cloneParent.release(), use, ec);
            ASSERT(ec == 0);

            // Handle use referencing <svg> special case
            if (target->hasTagName(SVGNames::svgTag))
                alterShadowTreeForSVGTag(newChildPtr);

            // Immediately stop here, and restart expanding.
            expandUseElementsInShadowTree(m_shadowTreeRootElement.get());
            return;
        }
    }

    for (RefPtr<Node> child = element->firstChild(); child; child = child->nextSibling())
        expandUseElementsInShadowTree(child.get());
}