SVGPaintServerGradient.h

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/*
 * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#ifndef SVGPaintServerGradient_h
#define SVGPaintServerGradient_h

#if ENABLE(SVG)

#include "AffineTransform.h"
#include "SVGPaintServer.h"

#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>

#if PLATFORM(QT)
#include <qglobal.h>
QT_BEGIN_NAMESPACE
class QGradient;
QT_END_NAMESPACE
#endif

namespace WebCore {

    class ImageBuffer;
    class SVGGradientElement;

    // FIXME: Remove the spread method enum in SVGGradientElement
    enum SVGGradientSpreadMethod {
        SPREADMETHOD_PAD = 1,
        SPREADMETHOD_REFLECT = 2,
        SPREADMETHOD_REPEAT = 3
    };

    typedef std::pair<float, QColor> SVGGradientStop;


    class SVGPaintServerGradient : public SVGPaintServer {
    public:
        virtual ~SVGPaintServerGradient();

        const Vector<SVGGradientStop>& gradientStops() const;
        void setGradientStops(const Vector<SVGGradientStop>&);

        SVGGradientSpreadMethod spreadMethod() const;
        void setGradientSpreadMethod(const SVGGradientSpreadMethod&);

        // Gradient start and end points are percentages when used in boundingBox mode.
        // For instance start point with value (0,0) is top-left and end point with
        // value (100, 100) is bottom-right. BoundingBox mode is enabled by default.
        bool boundingBoxMode() const;
        void setBoundingBoxMode(bool mode = true);

        AffineTransform gradientTransform() const;
        void setGradientTransform(const AffineTransform&);

        /*virtual TextStream& externalRepresentation(TextStream&) const;*/

        virtual bool setup(QPainter* painter, QPainterPath* path, const RenderObject*, SVGPaintTargetType, bool isPaintingText) const;
#if PLATFORM(CG)
        virtual void teardown(GraphicsContext*&, const RenderObject*, SVGPaintTargetType, bool isPaintingText) const;
        virtual void renderPath(GraphicsContext*&, const RenderObject*, SVGPaintTargetType) const;

        virtual void invalidate();

        // Helpers
        void updateQuartzGradientStopsCache(const Vector<SVGGradientStop>&);
        void updateQuartzGradientCache(const SVGPaintServerGradient*);
        void handleBoundingBoxModeAndGradientTransformation(GraphicsContext*, const FloatRect& targetRect) const;
#endif

#if PLATFORM(QT)
    protected:
        void fillColorArray(QGradient&, const Vector<SVGGradientStop>&, float opacity) const;
        virtual QGradient setupGradient(QPainter* painter, QPainterPath* painterPath, const RenderObject*) const = 0;
#endif

    protected:
        SVGPaintServerGradient(const SVGGradientElement* owner);
        
    private:
        Vector<SVGGradientStop> m_stops;
        SVGGradientSpreadMethod m_spreadMethod;
        bool m_boundingBoxMode;
        AffineTransform m_gradientTransform;
        const SVGGradientElement* m_ownerElement;

#if PLATFORM(CG)
    public:
        typedef struct {
            CGFloat colorArray[4];
            CGFloat offset;
            CGFloat previousDeltaInverse;
        } QuartzGradientStop;
        
        struct SharedStopCache : public RefCounted<SharedStopCache> {
        public:
            static PassRefPtr<SharedStopCache> create() { return adoptRef(new SharedStopCache); }
            
            Vector<QuartzGradientStop> m_stops;
        
        private:
            SharedStopCache() { }
        };

        RefPtr<SharedStopCache> m_stopsCache;

        CGShadingRef m_shadingCache;
        mutable GraphicsContext* m_savedContext;
        mutable ImageBuffer* m_imageBuffer;
#endif
    };

    inline SVGGradientStop makeGradientStop(float offset, const QColor& color)
    {
        return std::make_pair(offset, color);
    }

} // namespace WebCore

#endif

#endif // SVGPaintServerGradient_h