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/* See LICENSE file for copyright and license details. */
#include <arpa/inet.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <png.h>
int
main(int argc, char *argv[])
{
png_structp png_struct_p;
png_infop png_info_p;
png_bytepp png_row_p;
int depth, color, interlace;
uint32_t width, height, png_row_len, tmp32, r, i;
uint16_t tmp16;
if (argc > 1) {
fprintf(stderr, "usage:%s\n", argv[0]);
return 1;
}
/* load png */
png_struct_p = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
NULL, NULL);
png_info_p = png_create_info_struct(png_struct_p);
if (!png_struct_p || !png_info_p || setjmp(png_jmpbuf(png_struct_p))) {
fprintf(stderr, "failed to initialize libpng\n");
return 1;
}
png_init_io(png_struct_p, stdin);
png_set_add_alpha(png_struct_p, 255, PNG_FILLER_AFTER);
png_set_gray_to_rgb(png_struct_p);
png_read_png(png_struct_p, png_info_p, PNG_TRANSFORM_STRIP_16 |
PNG_TRANSFORM_PACKING | PNG_TRANSFORM_EXPAND, NULL);
png_get_IHDR(png_struct_p, png_info_p, &width, &height, &depth,
&color, &interlace, NULL, NULL);
png_row_len = png_get_rowbytes(png_struct_p, png_info_p);
png_row_p = png_get_rows(png_struct_p, png_info_p);
/* write header */
fprintf(stdout, "farbfeld");
tmp32 = htonl(width);
fwrite(&tmp32, sizeof(uint32_t), 1, stdout);
tmp32 = htonl(height);
fwrite(&tmp32, sizeof(uint32_t), 1, stdout);
/* write data */
/* TODO: allow 16 bit PNGs to be converted losslessly */
for (r = 0; r < height; ++r) {
for (i = 0; i < png_row_len; i++) {
/* ((2^16-1) / 255) == 257 */
tmp16 = htons(257 * png_row_p[r][i]);
fwrite(&tmp16, sizeof(uint16_t), 1, stdout);
}
}
/* cleanup */
png_destroy_read_struct(&png_struct_p, &png_info_p, NULL);
return 0;
}
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