1 /*
2 * Copyright (C) 2010, 2011 Apple Inc. 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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #ifndef Region_h
27 #define Region_h
28
29 #include "platform/PlatformExport.h"
30 #include "platform/geometry/IntRect.h"
31 #include "wtf/Vector.h"
32
33 namespace WebCore {
34
35 class PLATFORM_EXPORT Region {
36 public:
37 Region();
38 Region(const IntRect&);
39
bounds()40 IntRect bounds() const { return m_bounds; }
isEmpty()41 bool isEmpty() const { return m_bounds.isEmpty(); }
isRect()42 bool isRect() const { return m_shape.isRect(); }
43
44 Vector<IntRect> rects() const;
45
46 void unite(const Region&);
47 void intersect(const Region&);
48 void subtract(const Region&);
49
50 void translate(const IntSize&);
51
52 // Returns true if the query region is a subset of this region.
53 bool contains(const Region&) const;
54
55 bool contains(const IntPoint&) const;
56
57 // Returns true if the query region intersects any part of this region.
58 bool intersects(const Region&) const;
59
60 unsigned totalArea() const;
61
62 #ifndef NDEBUG
63 void dump() const;
64 #endif
65
66 private:
67 struct Span {
SpanSpan68 Span(int y, size_t segmentIndex)
69 : y(y), segmentIndex(segmentIndex)
70 {
71 }
72
73 int y;
74 size_t segmentIndex;
75 };
76
77 class Shape {
78 public:
79 Shape();
80 Shape(const IntRect&);
81
82 IntRect bounds() const;
isEmpty()83 bool isEmpty() const { return m_spans.isEmpty(); }
isRect()84 bool isRect() const { return m_spans.size() <= 2 && m_segments.size() <= 2; }
85
86 typedef const Span* SpanIterator;
87 SpanIterator spansBegin() const;
88 SpanIterator spansEnd() const;
89
90 typedef const int* SegmentIterator;
91 SegmentIterator segmentsBegin(SpanIterator) const;
92 SegmentIterator segmentsEnd(SpanIterator) const;
93
94 static Shape unionShapes(const Shape& shape1, const Shape& shape2);
95 static Shape intersectShapes(const Shape& shape1, const Shape& shape2);
96 static Shape subtractShapes(const Shape& shape1, const Shape& shape2);
97
98 void translate(const IntSize&);
99 void swap(Shape&);
100
101 struct CompareContainsOperation;
102 struct CompareIntersectsOperation;
103
104 template<typename CompareOperation>
105 static bool compareShapes(const Shape& shape1, const Shape& shape2);
106
107 #ifndef NDEBUG
108 void dump() const;
109 #endif
110
111 private:
112 struct UnionOperation;
113 struct IntersectOperation;
114 struct SubtractOperation;
115
116 template<typename Operation>
117 static Shape shapeOperation(const Shape& shape1, const Shape& shape2);
118
119 void appendSegment(int x);
120 void appendSpan(int y);
121 void appendSpan(int y, SegmentIterator begin, SegmentIterator end);
122 void appendSpans(const Shape&, SpanIterator begin, SpanIterator end);
123
124 bool canCoalesce(SegmentIterator begin, SegmentIterator end);
125
126 Vector<int, 32> m_segments;
127 Vector<Span, 16> m_spans;
128
129 friend bool operator==(const Shape&, const Shape&);
130 };
131
132 IntRect m_bounds;
133 Shape m_shape;
134
135 friend bool operator==(const Region&, const Region&);
136 friend bool operator==(const Shape&, const Shape&);
137 friend bool operator==(const Span&, const Span&);
138 };
139
intersect(const Region & a,const Region & b)140 static inline Region intersect(const Region& a, const Region& b)
141 {
142 Region result(a);
143 result.intersect(b);
144
145 return result;
146 }
147
subtract(const Region & a,const Region & b)148 static inline Region subtract(const Region& a, const Region& b)
149 {
150 Region result(a);
151 result.subtract(b);
152
153 return result;
154 }
155
translate(const Region & region,const IntSize & offset)156 static inline Region translate(const Region& region, const IntSize& offset)
157 {
158 Region result(region);
159 result.translate(offset);
160
161 return result;
162 }
163
164 inline bool operator==(const Region& a, const Region& b)
165 {
166 return a.m_bounds == b.m_bounds && a.m_shape == b.m_shape;
167 }
168
169 inline bool operator==(const Region::Shape& a, const Region::Shape& b)
170 {
171 return a.m_spans == b.m_spans && a.m_segments == b.m_segments;
172 }
173
174 inline bool operator==(const Region::Span& a, const Region::Span& b)
175 {
176 return a.y == b.y && a.segmentIndex == b.segmentIndex;
177 }
178
179 } // namespace WebCore
180
181 #endif // Region_h
182