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	jpg2ff.c - farbfeld - suckless image format with conversion tools
	git clone git://git.suckless.org/farbfeld
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	jpg2ff.c (1925B)
	---
	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 <jpeglib.h>
	11
	12 #include "util.h"
	13
	14 static void
	15 jpeg_error(j_common_ptr js)
	16 {
	17 fprintf(stderr, "%s: libjpeg: ", argv0);
	18 (*js->err->output_message)(js);
	19 exit(1);
	20 }
	21
	22 static void
	23 jpeg_setup_reader(struct jpeg_decompress_struct *s, struct jpeg_error_mg…
	24 uint32_t w, uint32_t h)
	25 {
	26 jpeg_create_decompress(s);
	27 e->error_exit = jpeg_error;
	28 s->err = jpeg_std_error(e);
	29
	30 jpeg_stdio_src(s, stdin);
	31 jpeg_read_header(s, 1);
	32 *w = s->image_width;
	33 *h = s->image_height;
	34 s->output_components = 3; /* color components per pixel */
	35 s->out_color_space = JCS_RGB; /* input color space */
	36
	37 jpeg_start_decompress(s);
	38 }
	39
	40 static void
	41 usage(void)
	42 {
	43 die("usage: %s", argv0);
	44 }
	45
	46 int
	47 main(int argc, char *argv[])
	48 {
	49 struct jpeg_decompress_struct js;
	50 struct jpeg_error_mgr jerr;
	51 uint32_t width, height;
	52 uint16_t *row;
	53 uint8_t *rowin;
	54 size_t rowlen, i;
	55
	56 /* arguments */
	57 argv0 = argv[0], argc--, argv++;
	58
	59 if (argc) {
	60 usage();
	61 }
	62
	63 /* prepare */
	64 jpeg_setup_reader(&js, &jerr, &width, &height);
	65 row = ereallocarray(NULL, width, (sizeof("RGBA") - 1) * sizeof(u…
	66 rowlen = width * (sizeof("RGBA") - 1);
	67 rowin = ereallocarray(NULL, width, (sizeof("RGB") - 1) * sizeof(…
	68
	69 /* write data */
	70 ff_write_header(width, height);
	71
	72 while (js.output_scanline < js.output_height) {
	73 jpeg_read_scanlines(&js, &rowin, 1);
	74
	75 for (i = 0; i < width; ++i) {
	76 row[4 * i + 0] = htons(rowin[3 * i + 0] * 257);
	77 row[4 * i + 1] = htons(rowin[3 * i + 1] * 257);
	78 row[4 * i + 2] = htons(rowin[3 * i + 2] * 257);
	79 row[4 * i + 3] = htons(65535);
	80 }
	81
	82 efwrite(row, sizeof(uint16_t), rowlen, stdout);
	83 }
	84
	85 /* clean up */
	86 jpeg_finish_decompress(&js);
	87 jpeg_destroy_decompress(&js);
	88
	89 return fshut(stdout, "<stdout>");
	90 }