root/Source/core/svg/SVGPathByteStreamBuilder.cpp

DEFINITIONS

1. m_byteStream
2. writeType
3. writeFlag
4. writeFloat
5. writeFloatPoint
6. writeSegmentType
7. moveTo
8. lineTo
9. lineToHorizontal
10. lineToVertical
11. curveToCubic
12. curveToCubicSmooth
13. curveToQuadratic
14. curveToQuadraticSmooth
15. arcTo
16. closePath

/*
 * Copyright (C) Research In Motion Limited 2010. 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 "core/svg/SVGPathByteStreamBuilder.h"

#include "core/svg/SVGPathSeg.h"
#include "wtf/OwnPtr.h"

namespace WebCore {

// Helper class that coalesces writes to a SVGPathByteStream to a local buffer.
class CoalescingBuffer {
public:
    CoalescingBuffer(SVGPathByteStream* byteStream)
        : m_currentOffset(0)
        , m_byteStream(byteStream)
    {
        ASSERT(byteStream);
    }
    ~CoalescingBuffer()
    {
        for (size_t i = 0; i < m_currentOffset; ++i)
            m_byteStream->append(m_bytes[i]);
    }

    template<typename DataType>
    void writeType(DataType value)
    {
        ByteType<DataType> data;
        data.value = value;
        size_t typeSize = sizeof(ByteType<DataType>);
        ASSERT(m_currentOffset + typeSize <= sizeof(m_bytes));
        memcpy(m_bytes + m_currentOffset, data.bytes, typeSize);
        m_currentOffset += typeSize;
    }

    void writeFlag(bool value) { writeType<bool>(value); }
    void writeFloat(float value) { writeType<float>(value); }
    void writeFloatPoint(const FloatPoint& point)
    {
        writeType<float>(point.x());
        writeType<float>(point.y());
    }
    void writeSegmentType(unsigned short value) { writeType<unsigned short>(value); }

private:
    // Adjust size to fit the largest command (in serialized/byte-stream format).
    // Currently a cubic segment.
    size_t m_currentOffset;
    unsigned char m_bytes[sizeof(unsigned short) + sizeof(FloatPoint) * 3];
    SVGPathByteStream* m_byteStream;
};

SVGPathByteStreamBuilder::SVGPathByteStreamBuilder()
    : m_byteStream(0)
{
}

void SVGPathByteStreamBuilder::moveTo(const FloatPoint& targetPoint, bool, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ?  PathSegMoveToRel : PathSegMoveToAbs);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::lineTo(const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegLineToRel : PathSegLineToAbs);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::lineToHorizontal(float x, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegLineToHorizontalRel : PathSegLineToHorizontalAbs);
    buffer.writeFloat(x);
}

void SVGPathByteStreamBuilder::lineToVertical(float y, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegLineToVerticalRel : PathSegLineToVerticalAbs);
    buffer.writeFloat(y);
}

void SVGPathByteStreamBuilder::curveToCubic(const FloatPoint& point1, const FloatPoint& point2, const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegCurveToCubicRel : PathSegCurveToCubicAbs);
    buffer.writeFloatPoint(point1);
    buffer.writeFloatPoint(point2);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::curveToCubicSmooth(const FloatPoint& point2, const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegCurveToCubicSmoothRel : PathSegCurveToCubicSmoothAbs);
    buffer.writeFloatPoint(point2);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::curveToQuadratic(const FloatPoint& point1, const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegCurveToQuadraticRel : PathSegCurveToQuadraticAbs);
    buffer.writeFloatPoint(point1);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::curveToQuadraticSmooth(const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegCurveToQuadraticSmoothRel : PathSegCurveToQuadraticSmoothAbs);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::arcTo(float r1, float r2, float angle, bool largeArcFlag, bool sweepFlag, const FloatPoint& targetPoint, PathCoordinateMode mode)
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(mode == RelativeCoordinates ? PathSegArcRel : PathSegArcAbs);
    buffer.writeFloat(r1);
    buffer.writeFloat(r2);
    buffer.writeFloat(angle);
    buffer.writeFlag(largeArcFlag);
    buffer.writeFlag(sweepFlag);
    buffer.writeFloatPoint(targetPoint);
}

void SVGPathByteStreamBuilder::closePath()
{
    CoalescingBuffer buffer(m_byteStream);
    buffer.writeSegmentType(PathSegClosePath);
}

} // namespace WebCore