third_party/WebKit/Source/core/layout/svg/LayoutSVGPath.cpp

/*
 * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005, 2008 Rob Buis <buis@kde.org>
 * Copyright (C) 2005, 2007 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2009 Google, Inc.
 * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
 * Copyright (C) 2009 Jeff Schiller <codedread@gmail.com>
 * Copyright (C) 2011 Renata Hodovan <reni@webkit.org>
 * Copyright (C) 2011 University of Szeged
 *
 * 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/layout/svg/LayoutSVGPath.h"

#include "core/layout/svg/LayoutSVGResourceMarker.h"
#include "core/layout/svg/SVGResources.h"
#include "core/layout/svg/SVGResourcesCache.h"
#include "core/svg/SVGGeometryElement.h"
#include "wtf/MathExtras.h"

namespace blink {

LayoutSVGPath::LayoutSVGPath(SVGGeometryElement* node) : LayoutSVGShape(node) {}

LayoutSVGPath::~LayoutSVGPath() {}

void LayoutSVGPath::updateShapeFromElement() {
  LayoutSVGShape::updateShapeFromElement();
  processMarkerPositions();

  m_strokeBoundingBox = calculateUpdatedStrokeBoundingBox();
  if (element())
    element()->setNeedsResizeObserverUpdate();
}

FloatRect LayoutSVGPath::hitTestStrokeBoundingBox() const {
  const SVGComputedStyle& svgStyle = style()->svgStyle();
  if (svgStyle.hasStroke())
    return m_strokeBoundingBox;

  // Implementation of
  // http://dev.w3.org/fxtf/css-masking-1/#compute-stroke-bounding-box
  // except that we ignore whether the stroke is none.

  FloatRect box = m_fillBoundingBox;

  const float strokeWidth = this->strokeWidth();
  if (strokeWidth <= 0)
    return box;

  float delta = strokeWidth / 2;

  if (svgStyle.hasMiterJoinStyle()) {
    const float miter = svgStyle.strokeMiterLimit();
    if (miter < M_SQRT2 && svgStyle.hasSquareCapStyle())
      delta *= M_SQRT2;
    else
      delta *= miter;
  } else if (svgStyle.hasSquareCapStyle()) {
    delta *= M_SQRT2;
  }

  box.inflate(delta);
  return box;
}

FloatRect LayoutSVGPath::calculateUpdatedStrokeBoundingBox() const {
  FloatRect strokeBoundingBox = m_strokeBoundingBox;
  if (!m_markerPositions.isEmpty())
    strokeBoundingBox.unite(markerRect(strokeWidth()));
  return strokeBoundingBox;
}

FloatRect LayoutSVGPath::markerRect(float strokeWidth) const {
  ASSERT(!m_markerPositions.isEmpty());

  SVGResources* resources =
      SVGResourcesCache::cachedResourcesForLayoutObject(this);
  ASSERT(resources);

  LayoutSVGResourceMarker* markerStart = resources->markerStart();
  LayoutSVGResourceMarker* markerMid = resources->markerMid();
  LayoutSVGResourceMarker* markerEnd = resources->markerEnd();
  ASSERT(markerStart || markerMid || markerEnd);

  FloatRect boundaries;
  unsigned size = m_markerPositions.size();
  for (unsigned i = 0; i < size; ++i) {
    if (LayoutSVGResourceMarker* marker = SVGMarkerData::markerForType(
            m_markerPositions[i].type, markerStart, markerMid, markerEnd))
      boundaries.unite(marker->markerBoundaries(marker->markerTransformation(
          m_markerPositions[i].origin, m_markerPositions[i].angle,
          strokeWidth)));
  }
  return boundaries;
}

bool LayoutSVGPath::shouldGenerateMarkerPositions() const {
  if (!style()->svgStyle().hasMarkers())
    return false;

  if (!SVGResources::supportsMarkers(*toSVGGraphicsElement(element())))
    return false;

  SVGResources* resources =
      SVGResourcesCache::cachedResourcesForLayoutObject(this);
  if (!resources)
    return false;

  return resources->markerStart() || resources->markerMid() ||
         resources->markerEnd();
}

void LayoutSVGPath::processMarkerPositions() {
  m_markerPositions.clear();

  if (!shouldGenerateMarkerPositions())
    return;

  SVGResources* resources =
      SVGResourcesCache::cachedResourcesForLayoutObject(this);
  ASSERT(resources);

  LayoutSVGResourceMarker* markerStart = resources->markerStart();

  SVGMarkerData markerData(
      m_markerPositions,
      markerStart ? markerStart->orientType() == SVGMarkerOrientAutoStartReverse
                  : false);
  path().apply(&markerData, SVGMarkerData::updateFromPathElement);
  markerData.pathIsDone();
}

}  // namespace blink