C++ SVGUseElement::width方法代码示例

void RenderSVGViewportContainer::calcViewport()
{
    SVGSVGElement& svg = svgSVGElement();
    FloatRect oldViewport = m_viewport;

    SVGLengthContext lengthContext(&svg);
    m_viewport = FloatRect(svg.x().value(lengthContext), svg.y().value(lengthContext), svg.width().value(lengthContext), svg.height().value(lengthContext));

    SVGElement* correspondingElement = svg.correspondingElement();
    if (correspondingElement && svg.isInShadowTree()) {
        const HashSet<SVGElementInstance*>& instances = correspondingElement->instancesForElement();
        ASSERT(!instances.isEmpty());

        SVGUseElement* useElement = 0;
        const HashSet<SVGElementInstance*>::const_iterator end = instances.end();
        for (HashSet<SVGElementInstance*>::const_iterator it = instances.begin(); it != end; ++it) {
            const SVGElementInstance* instance = (*it);
            ASSERT(instance->correspondingElement()->hasTagName(SVGNames::svgTag) || instance->correspondingElement()->hasTagName(SVGNames::symbolTag));
            if (instance->shadowTreeElement() == &svg) {
                ASSERT(correspondingElement == instance->correspondingElement());
                useElement = instance->directUseElement();
                if (!useElement)
                    useElement = instance->correspondingUseElement();
                break;
            }
        }

        ASSERT(useElement);
        bool isSymbolElement = correspondingElement->hasTagName(SVGNames::symbolTag);

        // Spec (<use> on <symbol>): This generated 'svg' will always have explicit values for attributes width and height.
        // If attributes width and/or height are provided on the 'use' element, then these attributes
        // will be transferred to the generated 'svg'. If attributes width and/or height are not specified,
        // the generated 'svg' element will use values of 100% for these attributes.

        // Spec (<use> on <svg>): If attributes width and/or height are provided on the 'use' element, then these
        // values will override the corresponding attributes on the 'svg' in the generated tree.

        SVGLengthContext lengthContext(&svg);
        if (useElement->hasAttribute(SVGNames::widthAttr))
            m_viewport.setWidth(useElement->width().value(lengthContext));
        else if (isSymbolElement && svg.hasAttribute(SVGNames::widthAttr)) {
            SVGLength containerWidth(LengthModeWidth, "100%");
            m_viewport.setWidth(containerWidth.value(lengthContext));
        }

        if (useElement->hasAttribute(SVGNames::heightAttr))
            m_viewport.setHeight(useElement->height().value(lengthContext));
        else if (isSymbolElement && svg.hasAttribute(SVGNames::heightAttr)) {
            SVGLength containerHeight(LengthModeHeight, "100%");
            m_viewport.setHeight(containerHeight.value(lengthContext));
        }
    }

    if (oldViewport != m_viewport) {
        setNeedsBoundariesUpdate();
        setNeedsTransformUpdate();
    }
}

static void transferUseWidthAndHeightIfNeeded(
    const SVGUseElement& use,
    SVGElement& shadowElement,
    const SVGElement& originalElement) {
  DEFINE_STATIC_LOCAL(const AtomicString, hundredPercentString, ("100%"));
  // Use |originalElement| for checking the element type, because we will
  // have replaced a <symbol> with an <svg> in the instance tree.
  if (isSVGSymbolElement(originalElement)) {
    // Spec (<use> on <symbol>): This generated 'svg' will always have
    // explicit values for attributes width and height.  If attributes
    // width and/or height are provided on the 'use' element, then these
    // attributes will be transferred to the generated 'svg'. If attributes
    // width and/or height are not specified, the generated 'svg' element
    // will use values of 100% for these attributes.
    shadowElement.setAttribute(
        SVGNames::widthAttr,
        use.width()->isSpecified()
            ? AtomicString(use.width()->currentValue()->valueAsString())
            : hundredPercentString);
    shadowElement.setAttribute(
        SVGNames::heightAttr,
        use.height()->isSpecified()
            ? AtomicString(use.height()->currentValue()->valueAsString())
            : hundredPercentString);
  } else if (isSVGSVGElement(originalElement)) {
    // Spec (<use> on <svg>): If attributes width and/or height are
    // provided on the 'use' element, then these values will override the
    // corresponding attributes on the 'svg' in the generated tree.
    shadowElement.setAttribute(
        SVGNames::widthAttr,
        use.width()->isSpecified()
            ? AtomicString(use.width()->currentValue()->valueAsString())
            : originalElement.getAttribute(SVGNames::widthAttr));
    shadowElement.setAttribute(
        SVGNames::heightAttr,
        use.height()->isSpecified()
            ? AtomicString(use.height()->currentValue()->valueAsString())
            : originalElement.getAttribute(SVGNames::heightAttr));
  }
}

void transferUseWidthAndHeightIfNeeded(const SVGUseElement& use, SVGElement* shadowElement, const SVGElement& originalElement)
{
    DEFINE_STATIC_LOCAL(const AtomicString, hundredPercentString, ("100%", AtomicString::ConstructFromLiteral));
    ASSERT(shadowElement);
    if (isSVGSymbolElement(*shadowElement)) {
        // Spec (<use> on <symbol>): This generated 'svg' will always have explicit values for attributes width and height.
        // If attributes width and/or height are provided on the 'use' element, then these attributes
        // will be transferred to the generated 'svg'. If attributes width and/or height are not specified,
        // the generated 'svg' element will use values of 100% for these attributes.
        shadowElement->setAttribute(SVGNames::widthAttr, use.width()->isSpecified() ? AtomicString(use.width()->currentValue()->valueAsString()) : hundredPercentString);
        shadowElement->setAttribute(SVGNames::heightAttr, use.height()->isSpecified() ? AtomicString(use.height()->currentValue()->valueAsString()) : hundredPercentString);
    } else if (isSVGSVGElement(*shadowElement)) {
        // Spec (<use> on <svg>): If attributes width and/or height are provided on the 'use' element, then these
        // values will override the corresponding attributes on the 'svg' in the generated tree.
        if (use.width()->isSpecified())
            shadowElement->setAttribute(SVGNames::widthAttr, AtomicString(use.width()->currentValue()->valueAsString()));
        else
            shadowElement->setAttribute(SVGNames::widthAttr, originalElement.getAttribute(SVGNames::widthAttr));
        if (use.height()->isSpecified())
            shadowElement->setAttribute(SVGNames::heightAttr, AtomicString(use.height()->currentValue()->valueAsString()));
        else
            shadowElement->setAttribute(SVGNames::heightAttr, originalElement.getAttribute(SVGNames::heightAttr));
    }
}