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1 /*
2  * Copyright (C) 2003, 2006, 2009 Apple Inc. All rights reserved.
3  *               2006 Rob Buis <buis@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 
skPath()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