1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/*
* Copyright (c) 2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Format.h>
#include <AK/Optional.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <LibGfx/Forward.h>
#include <LibGfx/Point.h>
#include <LibGfx/Rect.h>
#include <stdlib.h>
namespace Gfx {
template<typename T>
class Line {
public:
Line() = default;
Line(Point<T> a, Point<T> b)
: m_a(a)
, m_b(b)
{
}
template<typename U>
Line(U a, U b)
: m_a(a)
, m_b(b)
{
}
template<typename U>
explicit Line(Line<U> const& other)
: m_a(other.a())
, m_b(other.b())
{
}
bool intersects(Line const& other) const
{
return intersected(other).has_value();
}
Optional<Point<T>> intersected(Line const& other) const
{
auto cross_product = [](Point<T> const& p1, Point<T> const& p2) {
return p1.x() * p2.y() - p1.y() * p2.x();
};
auto r = m_b - m_a;
auto s = other.m_b - other.m_a;
auto delta_a = other.m_a - m_a;
auto num = cross_product(delta_a, r);
auto denom = cross_product(r, s);
if (denom == 0) {
if (num == 0) {
// Lines are collinear, check if line ends are touching
if (m_a == other.m_a || m_a == other.m_b)
return m_a;
if (m_b == other.m_a || m_b == other.m_b)
return m_b;
// Check if they're overlapping
if (!(m_b.x() - m_a.x() < 0 && m_b.x() - other.m_a.x() < 0 && other.m_b.x() - m_a.x() && other.m_b.x() - other.m_a.x())) {
// Overlapping
// TODO find center point?
}
if (!(m_b.y() - m_a.y() < 0 && m_b.y() - other.m_a.y() < 0 && other.m_b.y() - m_a.y() && other.m_b.y() - other.m_a.y())) {
// Overlapping
// TODO find center point?
}
return {};
} else {
// Lines are parallel and not intersecting
return {};
}
}
auto u = static_cast<float>(num) / static_cast<float>(denom);
if (u < 0.0f || u > 1.0f) {
// Lines are not parallel and don't intersect
return {};
}
auto t = static_cast<float>(cross_product(delta_a, s)) / static_cast<float>(denom);
if (t < 0.0f || t > 1.0f) {
// Lines are not parallel and don't intersect
return {};
}
// TODO: round if we're dealing with int
return Point<T> { m_a.x() + static_cast<T>(t * r.x()), m_a.y() + static_cast<T>(t * r.y()) };
}
float length() const
{
return m_a.distance_from(m_b);
}
Point<T> closest_to(Point<T> const& point) const
{
if (m_a == m_b)
return m_a;
auto delta_a = point.x() - m_a.x();
auto delta_b = point.y() - m_a.y();
auto delta_c = m_b.x() - m_a.x();
auto delta_d = m_b.y() - m_a.y();
auto len_sq = delta_c * delta_c + delta_d * delta_d;
float param = -1.0;
if (len_sq != 0)
param = static_cast<float>(delta_a * delta_c + delta_b * delta_d) / static_cast<float>(len_sq);
if (param < 0)
return m_a;
if (param > 1)
return m_b;
// TODO: round if we're dealing with int
return { static_cast<T>(m_a.x() + param * delta_c), static_cast<T>(m_a.y() + param * delta_d) };
}
Line<T> shortest_line_to(Point<T> const& point) const
{
return { closest_to(point), point };
}
float distance_to(Point<T> const& point) const
{
return shortest_line_to(point).length();
}
Point<T> const& a() const { return m_a; }
Point<T> const& b() const { return m_b; }
void set_a(Point<T> const& a) { m_a = a; }
void set_b(Point<T> const& b) { m_b = b; }
String to_string() const;
private:
Point<T> m_a;
Point<T> m_b;
};
template<>
inline String IntLine::to_string() const
{
return String::formatted("[{},{} -> {},{}]", m_a.x(), m_a.y(), m_b.x(), m_b.y());
}
template<>
inline String FloatLine::to_string() const
{
return String::formatted("[{},{} -> {},{}]", m_a.x(), m_a.y(), m_b.x(), m_b.y());
}
}
namespace AK {
template<typename T>
struct Formatter<Gfx::Line<T>> : Formatter<FormatString> {
ErrorOr<void> format(FormatBuilder& builder, Gfx::Line<T> const& value)
{
return Formatter<FormatString>::format(builder, "[{},{} -> {},{}]"sv, value.a().x(), value.a().y(), value.b().x(), value.b().y());
}
};
}
|
