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
|
/* Cairo - a vector graphics library with display and print output
*
* Copyright © 2008 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*
* The Original Code is the cairo graphics library.
*
* The Initial Developer of the Original Code is Red Hat, Inc.
*
* Contributor(s):
* Carl D. Worth <cworth@cworth.org>
*/
#include "cairoint.h"
#if !CAIRO_HAS_XLIB_XCB_FUNCTIONS
#include "cairo-xlib-private.h"
#include "cairo-error-private.h"
#include "cairo-list-inline.h"
/* A perceptual distance metric between two colors. No sqrt needed
* since the square of the distance is still a valid metric. */
/* XXX: This is currently using linear distance in RGB space which is
* decidedly not perceptually linear. If someone cared a lot about the
* quality, they might choose something else here. Then again, they
* might also choose not to use a PseudoColor visual... */
static inline int
_color_distance (unsigned short r1, unsigned short g1, unsigned short b1,
unsigned short r2, unsigned short g2, unsigned short b2)
{
r1 >>= 8; g1 >>= 8; b1 >>= 8;
r2 >>= 8; g2 >>= 8; b2 >>= 8;
return ((r2 - r1) * (r2 - r1) +
(g2 - g1) * (g2 - g1) +
(b2 - b1) * (b2 - b1));
}
cairo_status_t
_cairo_xlib_visual_info_create (Display *dpy,
int screen,
VisualID visualid,
cairo_xlib_visual_info_t **out)
{
cairo_xlib_visual_info_t *info;
Colormap colormap = DefaultColormap (dpy, screen);
XColor color;
int gray, red, green, blue;
int i, j, distance, min_distance = 0;
XColor colors[256];
unsigned short cube_index_to_short[CUBE_SIZE];
unsigned short ramp_index_to_short[RAMP_SIZE];
unsigned char gray_to_pseudocolor[RAMP_SIZE];
for (i = 0; i < CUBE_SIZE; i++)
cube_index_to_short[i] = (0xffff * i + ((CUBE_SIZE-1)>>1)) / (CUBE_SIZE-1);
for (i = 0; i < RAMP_SIZE; i++)
ramp_index_to_short[i] = (0xffff * i + ((RAMP_SIZE-1)>>1)) / (RAMP_SIZE-1);
info = malloc (sizeof (cairo_xlib_visual_info_t));
if (unlikely (info == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
cairo_list_init (&info->link);
info->visualid = visualid;
/* Allocate a gray ramp and a color cube.
* Give up as soon as failures start. */
for (gray = 0; gray < RAMP_SIZE; gray++) {
color.red = color.green = color.blue = ramp_index_to_short[gray];
if (! XAllocColor (dpy, colormap, &color))
goto DONE_ALLOCATE;
}
/* XXX: Could do this in a more clever order to have the best
* possible results from early failure. Could also choose a cube
* uniformly distributed in a better space than RGB. */
for (red = 0; red < CUBE_SIZE; red++) {
for (green = 0; green < CUBE_SIZE; green++) {
for (blue = 0; blue < CUBE_SIZE; blue++) {
color.red = cube_index_to_short[red];
color.green = cube_index_to_short[green];
color.blue = cube_index_to_short[blue];
color.pixel = 0;
color.flags = 0;
color.pad = 0;
if (! XAllocColor (dpy, colormap, &color))
goto DONE_ALLOCATE;
}
}
}
DONE_ALLOCATE:
for (i = 0; i < ARRAY_LENGTH (colors); i++)
colors[i].pixel = i;
XQueryColors (dpy, colormap, colors, ARRAY_LENGTH (colors));
/* Search for nearest colors within allocated colormap. */
for (gray = 0; gray < RAMP_SIZE; gray++) {
for (i = 0; i < 256; i++) {
distance = _color_distance (ramp_index_to_short[gray],
ramp_index_to_short[gray],
ramp_index_to_short[gray],
colors[i].red,
colors[i].green,
colors[i].blue);
if (i == 0 || distance < min_distance) {
gray_to_pseudocolor[gray] = colors[i].pixel;
min_distance = distance;
if (!min_distance)
break;
}
}
}
for (red = 0; red < CUBE_SIZE; red++) {
for (green = 0; green < CUBE_SIZE; green++) {
for (blue = 0; blue < CUBE_SIZE; blue++) {
for (i = 0; i < 256; i++) {
distance = _color_distance (cube_index_to_short[red],
cube_index_to_short[green],
cube_index_to_short[blue],
colors[i].red,
colors[i].green,
colors[i].blue);
if (i == 0 || distance < min_distance) {
info->cube_to_pseudocolor[red][green][blue] = colors[i].pixel;
min_distance = distance;
if (!min_distance)
break;
}
}
}
}
}
for (i = 0, j = 0; i < 256; i++) {
if (j < CUBE_SIZE - 1 && (((i<<8)+i) - (int)cube_index_to_short[j]) > ((int)cube_index_to_short[j+1] - ((i<<8)+i)))
j++;
info->field8_to_cube[i] = j;
info->dither8_to_cube[i] = ((int)i - 128) / (CUBE_SIZE - 1);
}
for (i = 0, j = 0; i < 256; i++) {
if (j < RAMP_SIZE - 1 && (((i<<8)+i) - (int)ramp_index_to_short[j]) > ((int)ramp_index_to_short[j+1] - ((i<<8)+i)))
j++;
info->gray8_to_pseudocolor[i] = gray_to_pseudocolor[j];
}
for (i = 0; i < 256; i++) {
info->colors[i].a = 0xff;
info->colors[i].r = colors[i].red >> 8;
info->colors[i].g = colors[i].green >> 8;
info->colors[i].b = colors[i].blue >> 8;
}
*out = info;
return CAIRO_STATUS_SUCCESS;
}
void
_cairo_xlib_visual_info_destroy (cairo_xlib_visual_info_t *info)
{
/* No need for XFreeColors() whilst using DefaultColormap */
_cairo_list_del (&info->link);
free (info);
}
#endif /* !CAIRO_HAS_XLIB_XCB_FUNCTIONS */
|
