SVGFitToViewBox.cpp   [plain text]

/*
 * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005, 2006, 2007, 2010 Rob Buis <buis@kde.org>
 * 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 "SVGFitToViewBox.h"

#include "AffineTransform.h"
#include "Document.h"
#include "FloatRect.h"
#include "SVGDocumentExtensions.h"
#include "SVGElement.h"
#include "SVGNames.h"
#include "SVGParserUtilities.h"
#include "SVGPreserveAspectRatioValue.h"
#include <wtf/text/StringView.h>

namespace WebCore {

SVGFitToViewBox::SVGFitToViewBox(SVGElement* contextElement, SVGPropertyAccess access)
    : m_viewBox(SVGAnimatedRect::create(contextElement, access))
    , m_preserveAspectRatio(SVGAnimatedPreserveAspectRatio::create(contextElement, access))
{
    static std::once_flag onceFlag;
    std::call_once(onceFlag, [] {
        PropertyRegistry::registerProperty<SVGNames::viewBoxAttr, &SVGFitToViewBox::m_viewBox>();
        PropertyRegistry::registerProperty<SVGNames::preserveAspectRatioAttr, &SVGFitToViewBox::m_preserveAspectRatio>();
    });
}

void SVGFitToViewBox::setViewBox(const FloatRect& viewBox)
{
    m_viewBox->setBaseValInternal(viewBox);
    m_isViewBoxValid = true;
}

void SVGFitToViewBox::resetViewBox()
{
    m_viewBox->setBaseValInternal({ });
    m_isViewBoxValid = false;
}

void SVGFitToViewBox::reset()
{
    resetViewBox();
    resetPreserveAspectRatio();
}

bool SVGFitToViewBox::parseAttribute(const QualifiedName& name, const AtomString& value)
{
    if (name == SVGNames::viewBoxAttr) {
        FloatRect viewBox;
        if (!value.isNull() && parseViewBox(value, viewBox))
            setViewBox(viewBox);
        else
            resetViewBox();
        return true;
    }

    if (name == SVGNames::preserveAspectRatioAttr) {
        SVGPreserveAspectRatioValue preserveAspectRatio;
        preserveAspectRatio.parse(value);
        setPreserveAspectRatio(preserveAspectRatio);
        return true;
    }

    return false;
}

bool SVGFitToViewBox::parseViewBox(const AtomString& value, FloatRect& viewBox)
{
    auto upconvertedCharacters = StringView(value).upconvertedCharacters();
    const UChar* characters = upconvertedCharacters;
    return parseViewBox(characters, characters + value.length(), viewBox);
}

bool SVGFitToViewBox::parseViewBox(const UChar*& c, const UChar* end, FloatRect& viewBox, bool validate)
{
    String str(c, end - c);

    skipOptionalSVGSpaces(c, end);

    float x = 0.0f;
    float y = 0.0f;
    float width = 0.0f;
    float height = 0.0f;
    bool valid = parseNumber(c, end, x) && parseNumber(c, end, y) && parseNumber(c, end, width) && parseNumber(c, end, height, false);

    if (validate) {
        Document& document = m_viewBox->contextElement()->document();

        if (!valid) {
            document.accessSVGExtensions().reportWarning("Problem parsing viewBox=\"" + str + "\"");
            return false;
        }

        // Check that width is positive.
        if (width < 0.0) {
            document.accessSVGExtensions().reportError("A negative value for ViewBox width is not allowed");
            return false;
        }

        // Check that height is positive.
        if (height < 0.0) {
            document.accessSVGExtensions().reportError("A negative value for ViewBox height is not allowed");
            return false;
        }

        // Nothing should come after the last, fourth number.
        skipOptionalSVGSpaces(c, end);
        if (c < end) {
            document.accessSVGExtensions().reportWarning("Problem parsing viewBox=\"" + str + "\"");
            return false;
        }
    }

    viewBox = { x, y, width, height };
    return true;
}

AffineTransform SVGFitToViewBox::viewBoxToViewTransform(const FloatRect& viewBoxRect, const SVGPreserveAspectRatioValue& preserveAspectRatio, float viewWidth, float viewHeight)
{
    if (!viewBoxRect.width() || !viewBoxRect.height() || !viewWidth || !viewHeight)
        return AffineTransform();

    return preserveAspectRatio.getCTM(viewBoxRect.x(), viewBoxRect.y(), viewBoxRect.width(), viewBoxRect.height(), viewWidth, viewHeight);
}

}