LinearGradientAttributes SVGLinearGradientElement::collectGradientProperties() const
{
    LinearGradientAttributes attributes;
    HashSet<const SVGGradientElement*> processedGradients;

    bool isLinear = true;
    const SVGGradientElement* current = this;

    while (current) {
        if (!attributes.hasSpreadMethod() && current->hasAttribute(SVGNames::spreadMethodAttr))
            attributes.setSpreadMethod((GradientSpreadMethod) current->spreadMethod());

        if (!attributes.hasBoundingBoxMode() && current->hasAttribute(SVGNames::gradientUnitsAttr))
            attributes.setBoundingBoxMode(current->gradientUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX);

        if (!attributes.hasGradientTransform() && current->hasAttribute(SVGNames::gradientTransformAttr))
            attributes.setGradientTransform(current->gradientTransform()->consolidate().matrix());

        if (!attributes.hasStops()) {
            const Vector<SVGGradientStop>& stops(current->buildStops());
            if (!stops.isEmpty())
                attributes.setStops(stops);
        }

        if (isLinear) {
            const SVGLinearGradientElement* linear = static_cast<const SVGLinearGradientElement*>(current);

            if (!attributes.hasX1() && current->hasAttribute(SVGNames::x1Attr))
                attributes.setX1(linear->x1());

            if (!attributes.hasY1() && current->hasAttribute(SVGNames::y1Attr))
                attributes.setY1(linear->y1());

            if (!attributes.hasX2() && current->hasAttribute(SVGNames::x2Attr))
                attributes.setX2(linear->x2());

            if (!attributes.hasY2() && current->hasAttribute(SVGNames::y2Attr))
                attributes.setY2(linear->y2());
        }

        processedGradients.add(current);

        // Respect xlink:href, take attributes from referenced element
        Node* refNode = ownerDocument()->getElementById(SVGURIReference::getTarget(current->href()));
        if (refNode && (refNode->hasTagName(SVGNames::linearGradientTag) || refNode->hasTagName(SVGNames::radialGradientTag))) {
            current = static_cast<const SVGGradientElement*>(const_cast<const Node*>(refNode));

            // Cycle detection
            if (processedGradients.contains(current))
                return LinearGradientAttributes();

            isLinear = current->gradientType() == LinearGradientPaintServer;
        } else
            current = 0;
    }

    return attributes;
}
static void setGradientAttributes(SVGGradientElement& element, LinearGradientAttributes& attributes, bool isLinear = true)
{
    if (!attributes.hasSpreadMethod() && element.hasAttribute(SVGNames::spreadMethodAttr))
        attributes.setSpreadMethod(element.spreadMethod());

    if (!attributes.hasGradientUnits() && element.hasAttribute(SVGNames::gradientUnitsAttr))
        attributes.setGradientUnits(element.gradientUnits());

    if (!attributes.hasGradientTransform() && element.hasAttribute(SVGNames::gradientTransformAttr)) {
        AffineTransform transform;
        element.gradientTransform().concatenate(transform);
        attributes.setGradientTransform(transform);
    }

    if (!attributes.hasStops()) {
        const Vector<Gradient::ColorStop>& stops(element.buildStops());
        if (!stops.isEmpty())
            attributes.setStops(stops);
    }

    if (isLinear) {
        SVGLinearGradientElement& linear = downcast<SVGLinearGradientElement>(element);

        if (!attributes.hasX1() && element.hasAttribute(SVGNames::x1Attr))
            attributes.setX1(linear.x1());

        if (!attributes.hasY1() && element.hasAttribute(SVGNames::y1Attr))
            attributes.setY1(linear.y1());

        if (!attributes.hasX2() && element.hasAttribute(SVGNames::x2Attr))
            attributes.setX2(linear.x2());

        if (!attributes.hasY2() && element.hasAttribute(SVGNames::y2Attr))
            attributes.setY2(linear.y2());
    }
}
static void setGradientAttributes(SVGGradientElement* element, LinearGradientAttributes& attributes, bool isLinear = true)
{
    if (!attributes.hasSpreadMethod() && element->spreadMethod()->isSpecified())
        attributes.setSpreadMethod(element->spreadMethod()->currentValue()->enumValue());

    if (!attributes.hasGradientUnits() && element->gradientUnits()->isSpecified())
        attributes.setGradientUnits(element->gradientUnits()->currentValue()->enumValue());

    if (!attributes.hasGradientTransform() && element->gradientTransform()->isSpecified()) {
        AffineTransform transform;
        element->gradientTransform()->currentValue()->concatenate(transform);
        attributes.setGradientTransform(transform);
    }

    if (!attributes.hasStops()) {
        const Vector<Gradient::ColorStop>& stops(element->buildStops());
        if (!stops.isEmpty())
            attributes.setStops(stops);
    }

    if (isLinear) {
        SVGLinearGradientElement* linear = toSVGLinearGradientElement(element);

        if (!attributes.hasX1() && linear->x1()->isSpecified())
            attributes.setX1(linear->x1()->currentValue());

        if (!attributes.hasY1() && linear->y1()->isSpecified())
            attributes.setY1(linear->y1()->currentValue());

        if (!attributes.hasX2() && linear->x2()->isSpecified())
            attributes.setX2(linear->x2()->currentValue());

        if (!attributes.hasY2() && linear->y2()->isSpecified())
            attributes.setY2(linear->y2()->currentValue());
    }
}