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 Shape(size_t segmentsCapacity, size_t spansCapacity);
82
83 IntRect bounds() const;
isEmpty()84 bool isEmpty() const { return m_spans.isEmpty(); }
isRect()85 bool isRect() const { return m_spans.size() <= 2 && m_segments.size() <= 2; }
86
87 typedef const Span* SpanIterator;
88 SpanIterator spansBegin() const;
89 SpanIterator spansEnd() const;
spansSize()90 size_t spansSize() const { return m_spans.size(); }
91
92 typedef const int* SegmentIterator;
93 SegmentIterator segmentsBegin(SpanIterator) const;
94 SegmentIterator segmentsEnd(SpanIterator) const;
segmentsSize()95 size_t segmentsSize() const { return m_segments.size(); }
96
97 static Shape unionShapes(const Shape& shape1, const Shape& shape2);
98 static Shape intersectShapes(const Shape& shape1, const Shape& shape2);
99 static Shape subtractShapes(const Shape& shape1, const Shape& shape2);
100
101 void translate(const IntSize&);
102 void swap(Shape&);
103
104 struct CompareContainsOperation;
105 struct CompareIntersectsOperation;
106
107 template<typename CompareOperation>
108 static bool compareShapes(const Shape& shape1, const Shape& shape2);
109 void trimCapacities();
110
111 #ifndef NDEBUG
112 void dump() const;
113 #endif
114
115 private:
116 struct UnionOperation;
117 struct IntersectOperation;
118 struct SubtractOperation;
119
120 template<typename Operation>
121 static Shape shapeOperation(const Shape& shape1, const Shape& shape2);
122
123 void appendSegment(int x);
124 void appendSpan(int y);
125 void appendSpan(int y, SegmentIterator begin, SegmentIterator end);
126 void appendSpans(const Shape&, SpanIterator begin, SpanIterator end);
127
128 bool canCoalesce(SegmentIterator begin, SegmentIterator end);
129
130 Vector<int, 32> m_segments;
131 Vector<Span, 16> m_spans;
132
133 friend bool operator==(const Shape&, const Shape&);
134 };
135
136 IntRect m_bounds;
137 Shape m_shape;
138
139 friend bool operator==(const Region&, const Region&);
140 friend bool operator==(const Shape&, const Shape&);
141 friend bool operator==(const Span&, const Span&);
142 };
143
intersect(const Region & a,const Region & b)144 static inline Region intersect(const Region& a, const Region& b)
145 {
146 Region result(a);
147 result.intersect(b);
148
149 return result;
150 }
151
subtract(const Region & a,const Region & b)152 static inline Region subtract(const Region& a, const Region& b)
153 {
154 Region result(a);
155 result.subtract(b);
156
157 return result;
158 }
159
translate(const Region & region,const IntSize & offset)160 static inline Region translate(const Region& region, const IntSize& offset)
161 {
162 Region result(region);
163 result.translate(offset);
164
165 return result;
166 }
167
168 inline bool operator==(const Region& a, const Region& b)
169 {
170 return a.m_bounds == b.m_bounds && a.m_shape == b.m_shape;
171 }
172
173 inline bool operator==(const Region::Shape& a, const Region::Shape& b)
174 {
175 return a.m_spans == b.m_spans && a.m_segments == b.m_segments;
176 }
177
178 inline bool operator==(const Region::Span& a, const Region::Span& b)
179 {
180 return a.y == b.y && a.segmentIndex == b.segmentIndex;
181 }
182
183 } // namespace WebCore
184
185 #endif // Region_h
186