1/*
2 * Copyright (C) 2008 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 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef FloatQuad_h
30#define FloatQuad_h
31
32#include "FloatPoint.h"
33#include "FloatRect.h"
34#include "IntRect.h"
35
36namespace WebCore {
37
38// A FloatQuad is a collection of 4 points, often representing the result of
39// mapping a rectangle through transforms. When initialized from a rect, the
40// points are in clockwise order from top left.
41class FloatQuad {
42public:
43    FloatQuad()
44    {
45    }
46
47    FloatQuad(const FloatPoint& p1, const FloatPoint& p2, const FloatPoint& p3, const FloatPoint& p4)
48        : m_p1(p1)
49        , m_p2(p2)
50        , m_p3(p3)
51        , m_p4(p4)
52    {
53    }
54
55    FloatQuad(const FloatRect& inRect)
56        : m_p1(inRect.location())
57        , m_p2(inRect.maxX(), inRect.y())
58        , m_p3(inRect.maxX(), inRect.maxY())
59        , m_p4(inRect.x(), inRect.maxY())
60    {
61    }
62
63    FloatPoint p1() const { return m_p1; }
64    FloatPoint p2() const { return m_p2; }
65    FloatPoint p3() const { return m_p3; }
66    FloatPoint p4() const { return m_p4; }
67
68    void setP1(const FloatPoint& p) { m_p1 = p; }
69    void setP2(const FloatPoint& p) { m_p2 = p; }
70    void setP3(const FloatPoint& p) { m_p3 = p; }
71    void setP4(const FloatPoint& p) { m_p4 = p; }
72
73    // isEmpty tests that the bounding box is empty. This will not identify
74    // "slanted" empty quads.
75    bool isEmpty() const { return boundingBox().isEmpty(); }
76
77    // Tests whether this quad can be losslessly represented by a FloatRect,
78    // that is, if two edges are parallel to the x-axis and the other two
79    // are parallel to the y-axis. If this method returns true, the
80    // corresponding FloatRect can be retrieved with boundingBox().
81    bool isRectilinear() const;
82
83    // Tests whether the given point is inside, or on an edge or corner of this quad.
84    bool containsPoint(const FloatPoint&) const;
85
86    // Tests whether the four corners of other are inside, or coincident with the sides of this quad.
87    // Note that this only works for convex quads, but that includes all quads that originate
88    // from transformed rects.
89    bool containsQuad(const FloatQuad&) const;
90
91    // Tests whether any part of the rectangle intersects with this quad.
92    // This only works for convex quads.
93    bool intersectsRect(const FloatRect&) const;
94
95    // Test whether any part of the circle/ellipse intersects with this quad.
96    // Note that these two functions only work for convex quads.
97    bool intersectsCircle(const FloatPoint& center, float radius) const;
98    bool intersectsEllipse(const FloatPoint& center, const FloatSize& radii) const;
99
100    // The center of the quad. If the quad is the result of a affine-transformed rectangle this is the same as the original center transformed.
101    FloatPoint center() const
102    {
103        return FloatPoint((m_p1.x() + m_p2.x() + m_p3.x() + m_p4.x()) / 4.0,
104                          (m_p1.y() + m_p2.y() + m_p3.y() + m_p4.y()) / 4.0);
105    }
106
107    FloatRect boundingBox() const;
108    IntRect enclosingBoundingBox() const
109    {
110        return enclosingIntRect(boundingBox());
111    }
112
113    void move(const FloatSize& offset)
114    {
115        m_p1 += offset;
116        m_p2 += offset;
117        m_p3 += offset;
118        m_p4 += offset;
119    }
120
121    void move(float dx, float dy)
122    {
123        m_p1.move(dx, dy);
124        m_p2.move(dx, dy);
125        m_p3.move(dx, dy);
126        m_p4.move(dx, dy);
127    }
128
129    void scale(float dx, float dy)
130    {
131        m_p1.scale(dx, dy);
132        m_p2.scale(dx, dy);
133        m_p3.scale(dx, dy);
134        m_p4.scale(dx, dy);
135    }
136
137    // Tests whether points are in clock-wise, or counter clock-wise order.
138    // Note that output is undefined when all points are colinear.
139    bool isCounterclockwise() const;
140
141private:
142    FloatPoint m_p1;
143    FloatPoint m_p2;
144    FloatPoint m_p3;
145    FloatPoint m_p4;
146};
147
148inline FloatQuad& operator+=(FloatQuad& a, const FloatSize& b)
149{
150    a.move(b);
151    return a;
152}
153
154inline FloatQuad& operator-=(FloatQuad& a, const FloatSize& b)
155{
156    a.move(-b.width(), -b.height());
157    return a;
158}
159
160inline bool operator==(const FloatQuad& a, const FloatQuad& b)
161{
162    return a.p1() == b.p1() &&
163           a.p2() == b.p2() &&
164           a.p3() == b.p3() &&
165           a.p4() == b.p4();
166}
167
168inline bool operator!=(const FloatQuad& a, const FloatQuad& b)
169{
170    return a.p1() != b.p1() ||
171           a.p2() != b.p2() ||
172           a.p3() != b.p3() ||
173           a.p4() != b.p4();
174}
175
176}   // namespace WebCore
177
178
179#endif // FloatQuad_h
180
181