summaryrefslogtreecommitdiffstats
path: root/plug-ins/selection-to-path/vector.c
blob: 6c167005ebae98a1cb7582fddb372136347523f8 (plain)
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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
/* vector.c: vector/point operations.
 *
 * Copyright (C) 1992 Free Software Foundation, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <glib.h>

#include <math.h>
#include <assert.h>

#include "global.h"
#include "config.h"

#include "vector.h"


/* Given the point COORD, return the corresponding vector.  */

vector_type
make_vector (const real_coordinate_type c)
{
  vector_type v;

  v.dx = c.x;
  v.dy = c.y;

  return v;
}


/* And the converse: given a vector, return the corresponding point.  */

real_coordinate_type
vector_to_point (const vector_type v)
{
  real_coordinate_type coord;

  coord.x = v.dx;
  coord.y = v.dy;

  return coord;
}


real
magnitude (const vector_type v)
{
  return hypot (v.dx, v.dy);
}


vector_type
normalize (const vector_type v)
{
  vector_type new_v;
  real m = magnitude (v);

  assert (m > 0.0);

  new_v.dx = v.dx / m;
  new_v.dy = v.dy / m;

  return new_v;
}


vector_type
Vadd (const vector_type v1, const vector_type v2)
{
  vector_type new_v;

  new_v.dx = v1.dx + v2.dx;
  new_v.dy = v1.dy + v2.dy;

  return new_v;
}


real
Vdot (const vector_type v1, const vector_type v2)
{
  return v1.dx * v2.dx + v1.dy * v2.dy;
}


vector_type
Vmult_scalar (const vector_type v, const real r)
{
  vector_type new_v;

  new_v.dx = v.dx * r;
  new_v.dy = v.dy * r;

  return new_v;
}


/* Given the IN_VECTOR and OUT_VECTOR, return the angle between them in
   degrees, in the range zero to 180.  */

real
Vangle (const vector_type in_vector, const vector_type out_vector)
{
  vector_type v1 = normalize (in_vector);
  vector_type v2 = normalize (out_vector);

  return my_acosd (Vdot (v2, v1));
}


real_coordinate_type
Vadd_point (const real_coordinate_type c, const vector_type v)
{
  real_coordinate_type new_c;

  new_c.x = c.x + v.dx;
  new_c.y = c.y + v.dy;
  return new_c;
}


real_coordinate_type
Vsubtract_point (const real_coordinate_type c, const vector_type v)
{
  real_coordinate_type new_c;

  new_c.x = c.x - v.dx;
  new_c.y = c.y - v.dy;
  return new_c;
}


coordinate_type
Vadd_int_point (const coordinate_type c, const vector_type v)
{
  coordinate_type a;

  a.x = SROUND ((real) c.x + v.dx);
  a.y = SROUND ((real) c.y + v.dy);
  return a;
}


vector_type
Vabs (const vector_type v)
{
  vector_type new_v;

  new_v.dx = fabs (v.dx);
  new_v.dy = fabs (v.dy);
  return new_v;
}


/* Operations on points.  */

vector_type
Psubtract (const real_coordinate_type c1, const real_coordinate_type c2)
{
  vector_type v;

  v.dx = c1.x - c2.x;
  v.dy = c1.y - c2.y;

  return v;
}

/* Operations on integer points.  */

vector_type
IPsubtract (const coordinate_type coord1, const coordinate_type coord2)
{
  vector_type v;

  v.dx = coord1.x - coord2.x;
  v.dy = coord1.y - coord2.y;

  return v;
}


coordinate_type
IPsubtractP (const coordinate_type c1, const coordinate_type c2)
{
  coordinate_type c;

  c.x = c1.x - c2.x;
  c.y = c1.y - c2.y;

  return c;
}


coordinate_type
IPadd (const coordinate_type c1, const coordinate_type c2)
{
  coordinate_type c;

  c.x = c1.x + c2.x;
  c.y = c1.y + c2.y;

  return c;
}


coordinate_type
IPmult_scalar (const coordinate_type c, const int i)
{
  coordinate_type a;

  a.x = c.x * i;
  a.y = c.y * i;

  return a;
}


real_coordinate_type
IPmult_real (const coordinate_type c, const real r)
{
  real_coordinate_type a;

  a.x = c.x * r;
  a.y = c.y * r;

  return a;
}


boolean
IPequal (const coordinate_type c1, const coordinate_type c2)
{
  return c1.x == c2.x && c1.y == c2.y;
}