SVGRadialGradientElement.cpp   [plain text]

/*
 * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
 * Copyright (C) 2018 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "SVGRadialGradientElement.h"

#include "FloatConversion.h"
#include "FloatPoint.h"
#include "RadialGradientAttributes.h"
#include "RenderSVGResourceRadialGradient.h"
#include "SVGNames.h"
#include "SVGStopElement.h"
#include "SVGUnitTypes.h"
#include <wtf/IsoMallocInlines.h>
#include <wtf/NeverDestroyed.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(SVGRadialGradientElement);

inline SVGRadialGradientElement::SVGRadialGradientElement(const QualifiedName& tagName, Document& document)
    : SVGGradientElement(tagName, document)
{
    // Spec: If the cx/cy/r/fr attribute is not specified, the effect is as if a value of "50%" were specified.
    ASSERT(hasTagName(SVGNames::radialGradientTag));
    registerAttributes();
}

Ref<SVGRadialGradientElement> SVGRadialGradientElement::create(const QualifiedName& tagName, Document& document)
{
    return adoptRef(*new SVGRadialGradientElement(tagName, document));
}

void SVGRadialGradientElement::registerAttributes()
{
    auto& registry = attributeRegistry();
    if (!registry.isEmpty())
        return;
    registry.registerAttribute<SVGNames::cxAttr, &SVGRadialGradientElement::m_cx>();
    registry.registerAttribute<SVGNames::cyAttr, &SVGRadialGradientElement::m_cy>();
    registry.registerAttribute<SVGNames::rAttr, &SVGRadialGradientElement::m_r>();
    registry.registerAttribute<SVGNames::fxAttr, &SVGRadialGradientElement::m_fx>();
    registry.registerAttribute<SVGNames::fyAttr, &SVGRadialGradientElement::m_fy>();
    registry.registerAttribute<SVGNames::frAttr, &SVGRadialGradientElement::m_fr>();
}

void SVGRadialGradientElement::parseAttribute(const QualifiedName& name, const AtomicString& value)
{
    SVGParsingError parseError = NoError;

    if (name == SVGNames::cxAttr)
        m_cx.setValue(SVGLengthValue::construct(LengthModeWidth, value, parseError));
    else if (name == SVGNames::cyAttr)
        m_cy.setValue(SVGLengthValue::construct(LengthModeHeight, value, parseError));
    else if (name == SVGNames::rAttr)
        m_r.setValue(SVGLengthValue::construct(LengthModeOther, value, parseError, ForbidNegativeLengths));
    else if (name == SVGNames::fxAttr)
        m_fx.setValue(SVGLengthValue::construct(LengthModeWidth, value, parseError));
    else if (name == SVGNames::fyAttr)
        m_fy.setValue(SVGLengthValue::construct(LengthModeHeight, value, parseError));
    else if (name == SVGNames::frAttr)
        m_fr.setValue(SVGLengthValue::construct(LengthModeOther, value, parseError, ForbidNegativeLengths));

    reportAttributeParsingError(parseError, name, value);

    SVGGradientElement::parseAttribute(name, value);
}

void SVGRadialGradientElement::svgAttributeChanged(const QualifiedName& attrName)
{
    if (isKnownAttribute(attrName)) {
        InstanceInvalidationGuard guard(*this);
        updateRelativeLengthsInformation();
        if (RenderObject* object = renderer())
            object->setNeedsLayout();
        return;
    }

    SVGGradientElement::svgAttributeChanged(attrName);
}

RenderPtr<RenderElement> SVGRadialGradientElement::createElementRenderer(RenderStyle&& style, const RenderTreePosition&)
{
    return createRenderer<RenderSVGResourceRadialGradient>(*this, WTFMove(style));
}

static void setGradientAttributes(SVGGradientElement& element, RadialGradientAttributes& attributes, bool isRadial = 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 (isRadial) {
        SVGRadialGradientElement& radial = downcast<SVGRadialGradientElement>(element);

        if (!attributes.hasCx() && element.hasAttribute(SVGNames::cxAttr))
            attributes.setCx(radial.cx());

        if (!attributes.hasCy() && element.hasAttribute(SVGNames::cyAttr))
            attributes.setCy(radial.cy());

        if (!attributes.hasR() && element.hasAttribute(SVGNames::rAttr))
            attributes.setR(radial.r());

        if (!attributes.hasFx() && element.hasAttribute(SVGNames::fxAttr))
            attributes.setFx(radial.fx());

        if (!attributes.hasFy() && element.hasAttribute(SVGNames::fyAttr))
            attributes.setFy(radial.fy());

        if (!attributes.hasFr() && element.hasAttribute(SVGNames::frAttr))
            attributes.setFr(radial.fr());
    }
}

bool SVGRadialGradientElement::collectGradientAttributes(RadialGradientAttributes& attributes)
{
    if (!renderer())
        return false;

    HashSet<SVGGradientElement*> processedGradients;
    SVGGradientElement* current = this;

    setGradientAttributes(*current, attributes);
    processedGradients.add(current);

    while (true) {
        // Respect xlink:href, take attributes from referenced element
        auto target = SVGURIReference::targetElementFromIRIString(current->href(), treeScope());
        if (is<SVGGradientElement>(target.element)) {
            current = downcast<SVGGradientElement>(target.element.get());

            // Cycle detection
            if (processedGradients.contains(current))
                break;

            if (!current->renderer())
                return false;

            setGradientAttributes(*current, attributes, current->hasTagName(SVGNames::radialGradientTag));
            processedGradients.add(current);
        } else
            break;
    }

    // Handle default values for fx/fy
    if (!attributes.hasFx())
        attributes.setFx(attributes.cx());

    if (!attributes.hasFy())
        attributes.setFy(attributes.cy());

    return true;
}

bool SVGRadialGradientElement::selfHasRelativeLengths() const
{
    return cx().isRelative()
        || cy().isRelative()
        || r().isRelative()
        || fx().isRelative()
        || fy().isRelative()
        || fr().isRelative();
}

}