1/*
2 * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above
9 *    copyright notice, this list of conditions and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above
12 *    copyright notice, this list of conditions and the following
13 *    disclaimer in the documentation and/or other materials
14 *    provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
20 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
21 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
27 * OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#ifndef FloatPolygon_h
31#define FloatPolygon_h
32
33#include "FloatPoint.h"
34#include "FloatRect.h"
35#include "PODIntervalTree.h"
36#include "ValueToString.h"
37#include "WindRule.h"
38#include <memory>
39#include <wtf/Vector.h>
40
41namespace WebCore {
42
43class FloatPolygonEdge;
44
45class FloatPolygon {
46public:
47    FloatPolygon(std::unique_ptr<Vector<FloatPoint>> vertices, WindRule fillRule);
48
49    const FloatPoint& vertexAt(unsigned index) const { return (*m_vertices)[index]; }
50    unsigned numberOfVertices() const { return m_vertices->size(); }
51
52    WindRule fillRule() const { return m_fillRule; }
53
54    const FloatPolygonEdge& edgeAt(unsigned index) const { return m_edges[index]; }
55    unsigned numberOfEdges() const { return m_edges.size(); }
56
57    FloatRect boundingBox() const { return m_boundingBox; }
58    bool overlappingEdges(float minY, float maxY, Vector<const FloatPolygonEdge*>& result) const;
59    bool contains(const FloatPoint&) const;
60    bool isEmpty() const { return m_empty; }
61
62private:
63    typedef PODInterval<float, FloatPolygonEdge*> EdgeInterval;
64    typedef PODIntervalTree<float, FloatPolygonEdge*> EdgeIntervalTree;
65
66    bool containsNonZero(const FloatPoint&) const;
67    bool containsEvenOdd(const FloatPoint&) const;
68
69    std::unique_ptr<Vector<FloatPoint>> m_vertices;
70    WindRule m_fillRule;
71    FloatRect m_boundingBox;
72    bool m_empty;
73    Vector<FloatPolygonEdge> m_edges;
74    EdgeIntervalTree m_edgeTree; // Each EdgeIntervalTree node stores minY, maxY, and a ("UserData") pointer to a FloatPolygonEdge.
75
76};
77
78class VertexPair {
79public:
80    virtual ~VertexPair() { }
81
82    virtual const FloatPoint& vertex1() const = 0;
83    virtual const FloatPoint& vertex2() const = 0;
84
85    float minX() const { return std::min(vertex1().x(), vertex2().x()); }
86    float minY() const { return std::min(vertex1().y(), vertex2().y()); }
87    float maxX() const { return std::max(vertex1().x(), vertex2().x()); }
88    float maxY() const { return std::max(vertex1().y(), vertex2().y()); }
89
90    bool overlapsRect(const FloatRect&) const;
91    bool intersection(const VertexPair&, FloatPoint&) const;
92};
93
94class FloatPolygonEdge : public VertexPair {
95    friend class FloatPolygon;
96public:
97    virtual const FloatPoint& vertex1() const override
98    {
99        ASSERT(m_polygon);
100        return m_polygon->vertexAt(m_vertexIndex1);
101    }
102
103    virtual const FloatPoint& vertex2() const override
104    {
105        ASSERT(m_polygon);
106        return m_polygon->vertexAt(m_vertexIndex2);
107    }
108
109    const FloatPolygonEdge& previousEdge() const
110    {
111        ASSERT(m_polygon && m_polygon->numberOfEdges() > 1);
112        return m_polygon->edgeAt((m_edgeIndex + m_polygon->numberOfEdges() - 1) % m_polygon->numberOfEdges());
113    }
114
115    const FloatPolygonEdge& nextEdge() const
116    {
117        ASSERT(m_polygon && m_polygon->numberOfEdges() > 1);
118        return m_polygon->edgeAt((m_edgeIndex + 1) % m_polygon->numberOfEdges());
119    }
120
121    const FloatPolygon* polygon() const { return m_polygon; }
122    unsigned vertexIndex1() const { return m_vertexIndex1; }
123    unsigned vertexIndex2() const { return m_vertexIndex2; }
124    unsigned edgeIndex() const { return m_edgeIndex; }
125
126private:
127    // Edge vertex index1 is less than index2, except the last edge, where index2 is 0. When a polygon edge
128    // is defined by 3 or more colinear vertices, index2 can be the the index of the last colinear vertex.
129    unsigned m_vertexIndex1;
130    unsigned m_vertexIndex2;
131    unsigned m_edgeIndex;
132    const FloatPolygon* m_polygon;
133};
134
135// This structure is used by PODIntervalTree for debugging.
136#ifndef NDEBUG
137template<> struct ValueToString<FloatPolygonEdge*> {
138    static String string(const FloatPolygonEdge* edge) { return String::format("%p (%f,%f %f,%f)", edge, edge->vertex1().x(), edge->vertex1().y(), edge->vertex2().x(), edge->vertex2().y()); }
139};
140#endif
141
142} // namespace WebCore
143
144#endif // FloatPolygon_h
145