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
37namespace WebCore {
38
39FloatPoint::FloatPoint(const IntPoint& p) : m_x(p.x()), m_y(p.y())
40{
41}
42
43void FloatPoint::normalize()
44{
45    float tempLength = length();
46
47    if (tempLength) {
48        m_x /= tempLength;
49        m_y /= tempLength;
50    }
51}
52
53float FloatPoint::length() const
54{
55    return sqrtf(lengthSquared());
56}
57
58FloatPoint 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
65FloatPoint 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
72FloatPoint FloatPoint::narrowPrecision(double x, double y)
73{
74    return FloatPoint(narrowPrecisionToFloat(x), narrowPrecisionToFloat(y));
75}
76
77float 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
88bool 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