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
|
/* Shared code for cairo based loaders like svgload and pdfload.
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/vips.h>
#include <vips/internal.h>
/* Convert from ARGB to RGBA and undo premultiplication.
*
* See also openslide's argb2rgba().
*/
void
vips__cairo2rgba( guint32 * restrict buf, int n )
{
int i;
for( i = 0; i < n; i++ ) {
guint32 * restrict p = buf + i;
guint32 x = *p;
guint8 a = x >> 24;
VipsPel * restrict out = (VipsPel *) p;
if( a == 255 )
*p = GUINT32_TO_BE( (x << 8) | 255 );
else if( a == 0 )
*p = GUINT32_TO_BE( x << 8 );
else {
/* Undo premultiplication.
*/
out[0] = 255 * ((x >> 16) & 255) / a;
out[1] = 255 * ((x >> 8) & 255) / a;
out[2] = 255 * (x & 255) / a;
out[3] = a;
}
}
}
|
