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/* See LICENSE file for copyright and license details. */
#include <arpa/inet.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <png.h>
#include "util.h"
static void
png_err(png_struct *pngs, const char *msg)
{
(void)pngs;
fprintf(stderr, "%s: libpng: %s\n", argv0, msg);
exit(1);
}
static void
png_setup_reader(png_struct **s, png_info **i, uint32_t *w, uint32_t *h)
{
*s = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, png_err, NULL);
*i = png_create_info_struct(*s);
if (!*s || !*i) {
fprintf(stderr, "%s: failed to initialize libpng\n", argv0);
exit(1);
}
png_init_io(*s, stdin);
if (png_get_valid(*s, *i, PNG_INFO_tRNS)) {
png_set_tRNS_to_alpha(*s);
}
png_set_add_alpha(*s, 255*257, PNG_FILLER_AFTER);
png_set_expand_gray_1_2_4_to_8(*s);
png_set_gray_to_rgb(*s);
png_set_packing(*s);
png_read_png(*s, *i, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND, NULL);
*w = png_get_image_width(*s, *i);
*h = png_get_image_height(*s, *i);
}
static void
usage(void)
{
fprintf(stderr, "usage: %s\n", argv0);
exit(1);
}
int
main(int argc, char *argv[])
{
png_struct *pngs;
png_info *pngi;
uint32_t width, height, rowlen, r, i;
uint16_t *row;
uint8_t **pngrows;
/* arguments */
argv0 = argv[0], argc--, argv++;
if (argc) {
usage();
}
/* prepare */
png_setup_reader(&pngs, &pngi, &width, &height);
row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(uint16_t));
rowlen = width * (sizeof("RGBA") - 1);
pngrows = png_get_rows(pngs, pngi);
/* write data */
ff_write_header(width, height);
switch(png_get_bit_depth(pngs, pngi)) {
case 8:
for (r = 0; r < height; ++r) {
for (i = 0; i < rowlen; i++) {
row[i] = htons(257 * pngrows[r][i]);
}
if (fwrite(row, sizeof(uint16_t), rowlen,
stdout) != rowlen) {
fprintf(stderr, "%s: fwrite: %s\n", argv0,
strerror(errno));
return 1;
}
}
break;
case 16:
for (r = 0; r < height; ++r) {
if (fwrite(pngrows[r], sizeof(uint16_t), rowlen,
stdout) != rowlen) {
fprintf(stderr, "%s: fwrite: %s\n", argv0,
strerror(errno));
return 1;
}
}
break;
default:
fprintf(stderr, "%s: invalid bit-depth\n", argv0);
return 1;
}
/* clean up */
png_destroy_read_struct(&pngs, &pngi, NULL);
return fshut(stdout, "<stdout>");
}
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