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      1 /*
      2  * Copyright (C) 2003, 2006, 2009 Apple Inc. All rights reserved.
      3  *               2006 Rob Buis <buis (at) kde.org>
      4  * Copyright (C) 2007-2008 Torch Mobile, Inc.
      5  * Copyright (C) 2013 Google Inc. All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     20  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     21  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     22  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     23  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     24  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef Path_h
     30 #define Path_h
     31 
     32 #include "platform/PlatformExport.h"
     33 #include "platform/geometry/RoundedRect.h"
     34 #include "platform/graphics/WindRule.h"
     35 #include "third_party/skia/include/core/SkPath.h"
     36 #include "third_party/skia/include/core/SkPathMeasure.h"
     37 #include "wtf/FastAllocBase.h"
     38 #include "wtf/Forward.h"
     39 
     40 class SkPath;
     41 
     42 namespace WebCore {
     43 
     44 class AffineTransform;
     45 class FloatPoint;
     46 class FloatRect;
     47 class FloatSize;
     48 class GraphicsContext;
     49 class StrokeData;
     50 
     51 enum PathElementType {
     52     PathElementMoveToPoint, // The points member will contain 1 value.
     53     PathElementAddLineToPoint, // The points member will contain 1 value.
     54     PathElementAddQuadCurveToPoint, // The points member will contain 2 values.
     55     PathElementAddCurveToPoint, // The points member will contain 3 values.
     56     PathElementCloseSubpath // The points member will contain no values.
     57 };
     58 
     59 // The points in the sturcture are the same as those that would be used with the
     60 // add... method. For example, a line returns the endpoint, while a cubic returns
     61 // two tangent points and the endpoint.
     62 struct PathElement {
     63     PathElementType type;
     64     FloatPoint* points;
     65 };
     66 
     67 typedef void (*PathApplierFunction)(void* info, const PathElement*);
     68 
     69 class PLATFORM_EXPORT Path {
     70     WTF_MAKE_FAST_ALLOCATED;
     71 public:
     72     Path();
     73     ~Path();
     74 
     75     Path(const Path&);
     76     Path& operator=(const Path&);
     77     bool operator==(const Path&) const;
     78 
     79     bool contains(const FloatPoint&, WindRule = RULE_NONZERO) const;
     80     bool strokeContains(const FloatPoint&, const StrokeData&) const;
     81     FloatRect boundingRect() const;
     82     FloatRect strokeBoundingRect(const StrokeData&) const;
     83 
     84     float length() const;
     85     FloatPoint pointAtLength(float length, bool& ok) const;
     86     float normalAngleAtLength(float length, bool& ok) const;
     87     bool pointAndNormalAtLength(float length, FloatPoint&, float&) const;
     88 
     89     // Helper for computing a sequence of positions and normals (normal angles) on a path.
     90     // The best possible access pattern will be one where the |length| value is
     91     // strictly increasing.
     92     // For other access patterns, performance will vary depending on curvature
     93     // and number of segments, but should never be worse than that of the
     94     // state-less method on Path.
     95     class PLATFORM_EXPORT PositionCalculator {
     96         WTF_MAKE_NONCOPYABLE(PositionCalculator);
     97     public:
     98         explicit PositionCalculator(const Path&);
     99 
    100         bool pointAndNormalAtLength(float length, FloatPoint&, float&);
    101 
    102     private:
    103         SkPath m_path;
    104         SkPathMeasure m_pathMeasure;
    105         SkScalar m_accumulatedLength;
    106     };
    107 
    108     void clear();
    109     bool isEmpty() const;
    110     // Gets the current point of the current path, which is conceptually the final point reached by the path so far.
    111     // Note the Path can be empty (isEmpty() == true) and still have a current point.
    112     bool hasCurrentPoint() const;
    113     FloatPoint currentPoint() const;
    114 
    115     WindRule windRule() const;
    116     void setWindRule(const WindRule);
    117 
    118     void moveTo(const FloatPoint&);
    119     void addLineTo(const FloatPoint&);
    120     void addQuadCurveTo(const FloatPoint& controlPoint, const FloatPoint& endPoint);
    121     void addBezierCurveTo(const FloatPoint& controlPoint1, const FloatPoint& controlPoint2, const FloatPoint& endPoint);
    122     void addArcTo(const FloatPoint&, const FloatPoint&, float radius);
    123     void closeSubpath();
    124 
    125     void addArc(const FloatPoint&, float radius, float startAngle, float endAngle, bool anticlockwise);
    126     void addRect(const FloatRect&);
    127     void addEllipse(const FloatPoint&, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise);
    128     void addEllipse(const FloatRect&);
    129 
    130     void addRoundedRect(const FloatRect&, const FloatSize& roundingRadii);
    131     void addRoundedRect(const FloatRect&, const FloatSize& topLeftRadius, const FloatSize& topRightRadius, const FloatSize& bottomLeftRadius, const FloatSize& bottomRightRadius);
    132     void addRoundedRect(const RoundedRect&);
    133 
    134     void addPath(const Path&, const AffineTransform&);
    135 
    136     void translate(const FloatSize&);
    137 
    138     const SkPath& skPath() const { return m_path; }
    139 
    140     void apply(void* info, PathApplierFunction) const;
    141     void transform(const AffineTransform&);
    142 
    143     void addPathForRoundedRect(const FloatRect&, const FloatSize& topLeftRadius, const FloatSize& topRightRadius, const FloatSize& bottomLeftRadius, const FloatSize& bottomRightRadius);
    144     void addBeziersForRoundedRect(const FloatRect&, const FloatSize& topLeftRadius, const FloatSize& topRightRadius, const FloatSize& bottomLeftRadius, const FloatSize& bottomRightRadius);
    145 
    146     // Updates the path to the union (inclusive-or) of itself with the given argument.
    147     bool unionPath(const Path& other);
    148 
    149 private:
    150     void addEllipse(const FloatPoint&, float radiusX, float radiusY, float startAngle, float endAngle, bool anticlockwise);
    151 
    152     SkPath m_path;
    153 };
    154 
    155 #if ASSERT_ENABLED
    156 PLATFORM_EXPORT bool ellipseIsRenderable(float startAngle, float endAngle);
    157 #endif
    158 
    159 }
    160 
    161 #endif
    162