1 /* See LICENSE file for copyright and license details. */
2 #include <arpa/inet.h>
3
4 #include <errno.h>
5 #include <stdint.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9
10 #include <png.h>
11
12 #include "util.h"
13
14 static void
png_err(png_struct * pngs,const char * msg)15 png_err(png_struct *pngs, const char *msg)
16 {
17 (void)pngs;
18 die("libpng: %s", msg);
19 }
20
21 static void
png_setup_reader(png_struct ** s,png_info ** i,uint32_t * w,uint32_t * h)22 png_setup_reader(png_struct **s, png_info **i, uint32_t *w, uint32_t *h)
23 {
24 *s = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, png_err, NULL);
25 *i = png_create_info_struct(*s);
26
27 if (!*s || !*i) {
28 die("Failed to initialize libpng");
29 }
30
31 png_init_io(*s, stdin);
32 if (png_get_valid(*s, *i, PNG_INFO_tRNS)) {
33 png_set_tRNS_to_alpha(*s);
34 }
35 png_set_add_alpha(*s, 255*257, PNG_FILLER_AFTER);
36 png_set_expand_gray_1_2_4_to_8(*s);
37 png_set_gray_to_rgb(*s);
38 png_set_packing(*s);
39 png_read_png(*s, *i, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND, NULL);
40 *w = png_get_image_width(*s, *i);
41 *h = png_get_image_height(*s, *i);
42 }
43
44 static void
usage(void)45 usage(void)
46 {
47 die("usage: %s", argv0);
48 }
49
50 int
main(int argc,char * argv[])51 main(int argc, char *argv[])
52 {
53 png_struct *pngs;
54 png_info *pngi;
55 uint32_t width, height, rowlen, r, i;
56 uint16_t *row;
57 uint8_t **pngrows;
58
59 /* arguments */
60 argv0 = argv[0], argc--, argv++;
61
62 if (argc) {
63 usage();
64 }
65
66 /* prepare */
67 png_setup_reader(&pngs, &pngi, &width, &height);
68 row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(uint16_t));
69 rowlen = width * (sizeof("RGBA") - 1);
70 pngrows = png_get_rows(pngs, pngi);
71
72 /* write data */
73 ff_write_header(width, height);
74
75 switch(png_get_bit_depth(pngs, pngi)) {
76 case 8:
77 for (r = 0; r < height; ++r) {
78 for (i = 0; i < rowlen; i++) {
79 row[i] = htons(257 * pngrows[r][i]);
80 }
81 efwrite(row, sizeof(uint16_t), rowlen, stdout);
82 }
83 break;
84 case 16:
85 for (r = 0; r < height; ++r) {
86 efwrite(pngrows[r], sizeof(uint16_t), rowlen, stdout);
87 }
88 break;
89 default:
90 die("Invalid bit-depth");
91 }
92
93 /* clean up */
94 png_destroy_read_struct(&pngs, &pngi, NULL);
95
96 return fshut(stdout, "<stdout>");
97 }
98