1 /*
2 * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
3 * Copyright (C) 2005 Nokia. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include "config.h"
28 #include "FloatPoint.h"
29
30 #include "AffineTransform.h"
31 #include "TransformationMatrix.h"
32 #include "FloatConversion.h"
33 #include "IntPoint.h"
34 #include <limits>
35 #include <math.h>
36
37 namespace WebCore {
38
FloatPoint(const IntPoint & p)39 FloatPoint::FloatPoint(const IntPoint& p) : m_x(p.x()), m_y(p.y())
40 {
41 }
42
normalize()43 void FloatPoint::normalize()
44 {
45 float tempLength = length();
46
47 if (tempLength) {
48 m_x /= tempLength;
49 m_y /= tempLength;
50 }
51 }
52
length() const53 float FloatPoint::length() const
54 {
55 return sqrtf(lengthSquared());
56 }
57
matrixTransform(const AffineTransform & transform) const58 FloatPoint FloatPoint::matrixTransform(const AffineTransform& transform) const
59 {
60 double newX, newY;
61 transform.map(static_cast<double>(m_x), static_cast<double>(m_y), newX, newY);
62 return narrowPrecision(newX, newY);
63 }
64
matrixTransform(const TransformationMatrix & transform) const65 FloatPoint FloatPoint::matrixTransform(const TransformationMatrix& transform) const
66 {
67 double newX, newY;
68 transform.map(static_cast<double>(m_x), static_cast<double>(m_y), newX, newY);
69 return narrowPrecision(newX, newY);
70 }
71
narrowPrecision(double x,double y)72 FloatPoint FloatPoint::narrowPrecision(double x, double y)
73 {
74 return FloatPoint(narrowPrecisionToFloat(x), narrowPrecisionToFloat(y));
75 }
76
findSlope(const FloatPoint & p1,const FloatPoint & p2,float & c)77 float findSlope(const FloatPoint& p1, const FloatPoint& p2, float& c)
78 {
79 if (p2.x() == p1.x())
80 return std::numeric_limits<float>::infinity();
81
82 // y = mx + c
83 float slope = (p2.y() - p1.y()) / (p2.x() - p1.x());
84 c = p1.y() - slope * p1.x();
85 return slope;
86 }
87
findIntersection(const FloatPoint & p1,const FloatPoint & p2,const FloatPoint & d1,const FloatPoint & d2,FloatPoint & intersection)88 bool findIntersection(const FloatPoint& p1, const FloatPoint& p2, const FloatPoint& d1, const FloatPoint& d2, FloatPoint& intersection)
89 {
90 float pOffset = 0;
91 float pSlope = findSlope(p1, p2, pOffset);
92
93 float dOffset = 0;
94 float dSlope = findSlope(d1, d2, dOffset);
95
96 if (dSlope == pSlope)
97 return false;
98
99 if (pSlope == std::numeric_limits<float>::infinity()) {
100 intersection.setX(p1.x());
101 intersection.setY(dSlope * intersection.x() + dOffset);
102 return true;
103 }
104 if (dSlope == std::numeric_limits<float>::infinity()) {
105 intersection.setX(d1.x());
106 intersection.setY(pSlope * intersection.x() + pOffset);
107 return true;
108 }
109
110 // Find x at intersection, where ys overlap; x = (c' - c) / (m - m')
111 intersection.setX((dOffset - pOffset) / (pSlope - dSlope));
112 intersection.setY(pSlope * intersection.x() + pOffset);
113 return true;
114 }
115
116 }
117