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
|
/**
* scrotty — Screenshot program for Linux's TTY
*
* Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
*
* 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 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 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 <http://www.gnu.org/licenses/>.
*/
#include "common.h"
#include "png.h"
#include "kern.h"
/*
* Rationale:
*
* Users want their files in PNG (most often), not PNM.
* Calling an external program for conversion poses
* potential security risks, and is significantly slower.
*/
/**
* Create an PNG file.
*
* @param fbfd The file descriptor connected to framebuffer device.
* @param width The width of the image.
* @param height The height of the image.
* @param imgfd The file descriptor connected to conversion process's stdin.
* @param data Additional data for `convert_fb_to_pnm`
* and `convert_fb_to_png`.
* @return Zero on success, -1 on error.
*/
int
save_png (int fbfd, long width, long height, int imgfd, void *restrict data)
{
char buf[8 << 10];
FILE *file = NULL;
ssize_t got, off;
size_t adjustment;
png_byte *restrict pixbuf = NULL;
png_struct *pngbuf = NULL;
png_info *pnginfo = NULL;
long width3, state = 0;
int rc, saved_errno;
/* Get a FILE * for the output, libpng wants a FILE *, not a file descriptor. */
file = fdopen (imgfd, "w");
if (file == NULL)
goto fail;
/* Allocte structures for the PNG. */
width3 = width * 3;
pixbuf = malloc ((size_t)width3 * sizeof (png_byte));
if (pixbuf == NULL)
goto fail;
pngbuf = png_create_write_struct (png_get_libpng_ver (NULL), NULL, NULL, NULL);
if (pngbuf == NULL)
goto fail;
pnginfo = png_create_info_struct (pngbuf);
if (pnginfo == NULL)
goto fail;
/* Initialise PNG write, and write head. */
if (setjmp (png_jmpbuf(pngbuf))) /* Failing libpng calls jump here. */
goto fail;
png_init_io (pngbuf, file);
png_set_IHDR (pngbuf, pnginfo, (png_uint_32)width, (png_uint_32)height,
8 /* bit depth */, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_write_info (pngbuf, pnginfo);
/* TODO (maybe) The image shall be packed. That is, if 24 bits per pixel is
* unnecessary, less shall be used. 6 bits is often sufficient. */
/* Convert raw framebuffer data into a PNG image (body). */
for (off = 0;;)
{
/* Read data from the framebuffer, we may have up to 3 bytes buffered. */
got = read (fbfd, buf + off, sizeof (buf) - (size_t)off * sizeof (char));
if (got < 0)
goto fail;
if (got == 0)
break;
got += off;
/* Convert read pixels. */
if (convert_fb_to_png (pngbuf, pixbuf, buf, (size_t)got,
width3, &adjustment, &state, data) < 0)
goto fail;
/* If we read a whole number of pixels, reset the buffer, otherwise,
move the unconverted bytes to the beginning of the buffer. */
if (adjustment)
{
off -= (ssize_t)adjustment;
memcpy (buf, buf + off, (size_t)(got - off) * sizeof (char));
off = got - off;
}
else
off = 0;
}
/* Done! */
png_write_end (pngbuf, pnginfo);
rc = 0;
goto cleanup;
fail:
saved_errno = errno;
rc = -1;
goto cleanup;
cleanup:
png_destroy_write_struct (&pngbuf, (pnginfo ? &pnginfo : NULL));
if (file != NULL)
{
fflush (file);
fclose (file);
}
free (pixbuf);
errno = saved_errno;
return rc;
}
|
