third_party/WebKit/Source/platform/graphics/Path.h

/*
 * Copyright (C) 2003, 2006, 2009 Apple Inc. All rights reserved.
 *               2006 Rob Buis <buis@kde.org>
 * Copyright (C) 2007-2008 Torch Mobile, Inc.
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * 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 Path_h
#define Path_h

#include "platform/PlatformExport.h"
#include "platform/geometry/FloatRoundedRect.h"
#include "platform/graphics/GraphicsTypes.h"
#include "third_party/skia/include/core/SkPath.h"
#include "third_party/skia/include/core/SkPathMeasure.h"
#include "wtf/Allocator.h"
#include "wtf/Forward.h"

namespace blink {

class AffineTransform;
class FloatPoint;
class FloatRect;
class FloatSize;
class StrokeData;

enum PathElementType {
  PathElementMoveToPoint,          // The points member will contain 1 value.
  PathElementAddLineToPoint,       // The points member will contain 1 value.
  PathElementAddQuadCurveToPoint,  // The points member will contain 2 values.
  PathElementAddCurveToPoint,      // The points member will contain 3 values.
  PathElementCloseSubpath          // The points member will contain no values.
};

// The points in the structure are the same as those that would be used with the
// add... method. For example, a line returns the endpoint, while a cubic
// returns two tangent points and the endpoint.
struct PathElement {
  PathElementType type;
  FloatPoint* points;
};

typedef void (*PathApplierFunction)(void* info, const PathElement*);

class PLATFORM_EXPORT Path {
  USING_FAST_MALLOC(Path);

 public:
  Path();
  ~Path();

  Path(const Path&);
  Path(const SkPath&);
  Path& operator=(const Path&);
  Path& operator=(const SkPath&);
  bool operator==(const Path&) const;

  bool contains(const FloatPoint&) const;
  bool contains(const FloatPoint&, WindRule) const;
  bool strokeContains(const FloatPoint&, const StrokeData&) const;

  enum class BoundsType {
    Conservative,  // Fast version, includes control points.
    Exact,         // Tight, slower version.
  };
  FloatRect boundingRect(BoundsType = BoundsType::Conservative) const;
  FloatRect strokeBoundingRect(const StrokeData&,
                               BoundsType = BoundsType::Conservative) const;

  float length() const;
  FloatPoint pointAtLength(float length) const;
  void pointAndNormalAtLength(float length, FloatPoint&, float&) const;

  // Helper for computing a sequence of positions and normals (normal angles) on
  // a path. The best possible access pattern will be one where the |length|
  // value is strictly increasing. For other access patterns, performance will
  // vary depending on curvature and number of segments, but should never be
  // worse than that of the state-less method on Path.
  class PLATFORM_EXPORT PositionCalculator {
    WTF_MAKE_NONCOPYABLE(PositionCalculator);
    USING_FAST_MALLOC(PositionCalculator);

   public:
    explicit PositionCalculator(const Path&);

    void pointAndNormalAtLength(float length, FloatPoint&, float&);

   private:
    SkPath m_path;
    SkPathMeasure m_pathMeasure;
    SkScalar m_accumulatedLength;
  };

  void clear();
  bool isEmpty() const;
  bool isClosed() const;

  // Specify whether this path is volatile. Temporary paths that are discarded
  // or modified after use should be marked as volatile. This is a hint to the
  // device to not cache this path.
  void setIsVolatile(bool);

  // Gets the current point of the current path, which is conceptually the final
  // point reached by the path so far. Note the Path can be empty
  // (isEmpty() == true) and still have a current point.
  bool hasCurrentPoint() const;
  FloatPoint currentPoint() const;

  void setWindRule(const WindRule);

  void moveTo(const FloatPoint&);
  void addLineTo(const FloatPoint&);
  void addQuadCurveTo(const FloatPoint& controlPoint,
                      const FloatPoint& endPoint);
  void addBezierCurveTo(const FloatPoint& controlPoint1,
                        const FloatPoint& controlPoint2,
                        const FloatPoint& endPoint);
  void addArcTo(const FloatPoint&, const FloatPoint&, float radius);
  void addArcTo(const FloatPoint&,
                const FloatSize& r,
                float xRotate,
                bool largeArc,
                bool sweep);
  void closeSubpath();

  void addArc(const FloatPoint&,
              float radius,
              float startAngle,
              float endAngle,
              bool anticlockwise);
  void addRect(const FloatRect&);
  void addEllipse(const FloatPoint&,
                  float radiusX,
                  float radiusY,
                  float rotation,
                  float startAngle,
                  float endAngle,
                  bool anticlockwise);
  void addEllipse(const FloatRect&);

  void addRoundedRect(const FloatRect&, const FloatSize& roundingRadii);
  void addRoundedRect(const FloatRect&,
                      const FloatSize& topLeftRadius,
                      const FloatSize& topRightRadius,
                      const FloatSize& bottomLeftRadius,
                      const FloatSize& bottomRightRadius);
  void addRoundedRect(const FloatRoundedRect&);

  void addPath(const Path&, const AffineTransform&);

  void translate(const FloatSize&);

  const SkPath& getSkPath() const { return m_path; }

  void apply(void* info, PathApplierFunction) const;
  void transform(const AffineTransform&);

  void addPathForRoundedRect(const FloatRect&,
                             const FloatSize& topLeftRadius,
                             const FloatSize& topRightRadius,
                             const FloatSize& bottomLeftRadius,
                             const FloatSize& bottomRightRadius);

  bool subtractPath(const Path&);

  // Updates the path to the union (inclusive-or) of itself with the given
  // argument.
  bool unionPath(const Path& other);

  bool intersectPath(const Path& other);

 private:
  void addEllipse(const FloatPoint&,
                  float radiusX,
                  float radiusY,
                  float startAngle,
                  float endAngle,
                  bool anticlockwise);
  SkPath strokePath(const StrokeData&) const;

  SkPath m_path;
};

#if ENABLE(ASSERT)
PLATFORM_EXPORT bool ellipseIsRenderable(float startAngle, float endAngle);
#endif

}  // namespace blink

#endif