third_party/WebKit/Source/core/svg/SVGPathByteStreamBuilder.cpp

   1 /*
   2  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public License
  15  * along with this library; see the file COPYING.LIB.  If not, write to
  16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  */
  19
  20 #include "config.h"
  21 #include "core/svg/SVGPathByteStreamBuilder.h"
  22
  23 #include "core/svg/SVGPathByteStream.h"
  24 #include "core/svg/SVGPathSeg.h"
  25 #include "platform/geometry/FloatPoint.h"
  26
  27 namespace blink {
  28
  29 // Helper class that coalesces writes to a SVGPathByteStream to a local buffer.
  30 class CoalescingBuffer {
  31 public:
  32     CoalescingBuffer(SVGPathByteStream& byteStream)
  33         : m_currentOffset(0)
  34         , m_byteStream(byteStream)
  35     {
  36     }
  37     ~CoalescingBuffer()
  38     {
  39         for (size_t i = 0; i < m_currentOffset; ++i)
  40             m_byteStream.append(m_bytes[i]);
  41     }
  42
  43     template<typename DataType>
  44     void writeType(DataType value)
  45     {
  46         ByteType<DataType> data;
  47         data.value = value;
  48         size_t typeSize = sizeof(ByteType<DataType>);
  49         ASSERT(m_currentOffset + typeSize <= sizeof(m_bytes));
  50         memcpy(m_bytes + m_currentOffset, data.bytes, typeSize);
  51         m_currentOffset += typeSize;
  52     }
  53
  54     void writeFlag(bool value) { writeType<bool>(value); }
  55     void writeFloat(float value) { writeType<float>(value); }
  56     void writeFloatPoint(const FloatPoint& point)
  57     {
  58         writeType<float>(point.x());
  59         writeType<float>(point.y());
  60     }
  61     void writeSegmentType(unsigned short value) { writeType<unsigned short>(value); }
  62
  63 private:
  64     // Adjust size to fit the largest command (in serialized/byte-stream format).
  65     // Currently a cubic segment.
  66     size_t m_currentOffset;
  67     unsigned char m_bytes[sizeof(unsigned short) + sizeof(FloatPoint) * 3];
  68     SVGPathByteStream& m_byteStream;
  69 };
  70
  71 SVGPathByteStreamBuilder::SVGPathByteStreamBuilder(SVGPathByteStream& byteStream)
  72     : m_byteStream(byteStream)
  73 {
  74 }
  75
  76 void SVGPathByteStreamBuilder::emitSegment(const PathSegmentData& segment)
  77 {
  78     CoalescingBuffer buffer(m_byteStream);
  79     buffer.writeSegmentType(segment.command);
  80
  81     switch (segment.command) {
  82     case PathSegMoveToRel:
  83     case PathSegMoveToAbs:
  84     case PathSegLineToRel:
  85     case PathSegLineToAbs:
  86     case PathSegCurveToQuadraticSmoothRel:
  87     case PathSegCurveToQuadraticSmoothAbs:
  88         buffer.writeFloatPoint(segment.targetPoint);
  89         break;
  90     case PathSegLineToHorizontalRel:
  91     case PathSegLineToHorizontalAbs:
  92         buffer.writeFloat(segment.targetPoint.x());
  93         break;
  94     case PathSegLineToVerticalRel:
  95     case PathSegLineToVerticalAbs:
  96         buffer.writeFloat(segment.targetPoint.y());
  97         break;
  98     case PathSegClosePath:
  99         break;
 100     case PathSegCurveToCubicRel:
 101     case PathSegCurveToCubicAbs:
 102         buffer.writeFloatPoint(segment.point1);
 103         buffer.writeFloatPoint(segment.point2);
 104         buffer.writeFloatPoint(segment.targetPoint);
 105         break;
 106     case PathSegCurveToCubicSmoothRel:
 107     case PathSegCurveToCubicSmoothAbs:
 108         buffer.writeFloatPoint(segment.point2);
 109         buffer.writeFloatPoint(segment.targetPoint);
 110         break;
 111     case PathSegCurveToQuadraticRel:
 112     case PathSegCurveToQuadraticAbs:
 113         buffer.writeFloatPoint(segment.point1);
 114         buffer.writeFloatPoint(segment.targetPoint);
 115         break;
 116     case PathSegArcRel:
 117     case PathSegArcAbs:
 118         buffer.writeFloatPoint(segment.point1);
 119         buffer.writeFloat(segment.point2.x());
 120         buffer.writeFlag(segment.arcLarge);
 121         buffer.writeFlag(segment.arcSweep);
 122         buffer.writeFloatPoint(segment.targetPoint);
 123         break;
 124     default:
 125         ASSERT_NOT_REACHED();
 126     }
 127 }
 128
 129 } // namespace blink