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

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann
 * <zimmermann@kde.org>
 * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
 * 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 "core/svg/SVGPathQuery.h"

#include "core/svg/SVGPathByteStreamSource.h"
#include "core/svg/SVGPathConsumer.h"
#include "core/svg/SVGPathData.h"
#include "core/svg/SVGPathParser.h"
#include "platform/graphics/PathTraversalState.h"

namespace blink {

namespace {

class SVGPathTraversalState final : public SVGPathConsumer {
 public:
  SVGPathTraversalState(PathTraversalState::PathTraversalAction traversalAction,
                        float desiredLength = 0)
      : m_traversalState(traversalAction), m_segmentIndex(0) {
    m_traversalState.m_desiredLength = desiredLength;
  }

  unsigned segmentIndex() const { return m_segmentIndex; }
  float totalLength() const { return m_traversalState.m_totalLength; }
  FloatPoint computedPoint() const { return m_traversalState.m_current; }

  bool processSegment(bool hasMoreData) {
    m_traversalState.processSegment();
    if (m_traversalState.m_success)
      return true;
    if (hasMoreData)
      m_segmentIndex++;
    return false;
  }

 private:
  void emitSegment(const PathSegmentData&) override;

  PathTraversalState m_traversalState;
  unsigned m_segmentIndex;
};

void SVGPathTraversalState::emitSegment(const PathSegmentData& segment) {
  switch (segment.command) {
    case PathSegMoveToAbs:
      m_traversalState.m_totalLength +=
          m_traversalState.moveTo(segment.targetPoint);
      break;
    case PathSegLineToAbs:
      m_traversalState.m_totalLength +=
          m_traversalState.lineTo(segment.targetPoint);
      break;
    case PathSegClosePath:
      m_traversalState.m_totalLength += m_traversalState.closeSubpath();
      break;
    case PathSegCurveToCubicAbs:
      m_traversalState.m_totalLength += m_traversalState.cubicBezierTo(
          segment.point1, segment.point2, segment.targetPoint);
      break;
    default:
      ASSERT_NOT_REACHED();
  }
}

void executeQuery(const SVGPathByteStream& pathByteStream,
                  SVGPathTraversalState& traversalState) {
  SVGPathByteStreamSource source(pathByteStream);
  SVGPathNormalizer normalizer(&traversalState);

  bool hasMoreData = source.hasMoreData();
  while (hasMoreData) {
    PathSegmentData segment = source.parseSegment();
    ASSERT(segment.command != PathSegUnknown);

    normalizer.emitSegment(segment);

    hasMoreData = source.hasMoreData();
    if (traversalState.processSegment(hasMoreData))
      break;
  }
}

}  // namespace

SVGPathQuery::SVGPathQuery(const SVGPathByteStream& pathByteStream)
    : m_pathByteStream(pathByteStream) {}

unsigned SVGPathQuery::getPathSegIndexAtLength(float length) const {
  SVGPathTraversalState traversalState(
      PathTraversalState::TraversalSegmentAtLength, length);
  executeQuery(m_pathByteStream, traversalState);
  return traversalState.segmentIndex();
}

float SVGPathQuery::getTotalLength() const {
  SVGPathTraversalState traversalState(
      PathTraversalState::TraversalTotalLength);
  executeQuery(m_pathByteStream, traversalState);
  return traversalState.totalLength();
}

FloatPoint SVGPathQuery::getPointAtLength(float length) const {
  SVGPathTraversalState traversalState(
      PathTraversalState::TraversalPointAtLength, length);
  executeQuery(m_pathByteStream, traversalState);
  return traversalState.computedPoint();
}

}  // namespace blink