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/* See LICENSE file for copyright and license details. */
#include "stream.h"
#include "util.h"
#include <fcntl.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
USAGE("[-i] alpha-stream")
static void
process_xyza(struct stream *colour, struct stream *alpha, size_t n)
{
size_t i;
double a;
for (i = 0; i < n; i += colour->pixel_size) {
a = ((double *)(alpha->buf + i))[1];
a *= ((double *)(alpha->buf + i))[3];
((double *)(colour->buf + i))[3] *= a;
}
}
static void
process_xyza_i(struct stream *colour, struct stream *alpha, size_t n)
{
size_t i;
double a;
for (i = 0; i < n; i += colour->pixel_size) {
a = 1 - ((double *)(alpha->buf + i))[1];
a *= ((double *)(alpha->buf + i))[3];
((double *)(colour->buf + i))[3] *= a;
}
}
int
main(int argc, char *argv[])
{
int invert = 0;
struct stream colour, alpha;
void (*process)(struct stream *colour, struct stream *alpha, size_t n) = NULL;
ARGBEGIN {
case 'i':
invert = 1;
break;
default:
usage();
} ARGEND;
if (argc != 1)
usage();
colour.file = "<stdin>";
colour.fd = STDIN_FILENO;
einit_stream(&colour);
alpha.file = argv[0];
alpha.fd = eopen(alpha.file, O_RDONLY);
einit_stream(&alpha);
if (!strcmp(colour.pixfmt, "xyza"))
process = invert ? process_xyza_i : process_xyza;
else
eprintf("pixel format %s is not supported, try xyza\n", colour.pixfmt);
process_two_streams(&colour, &alpha, STDOUT_FILENO, "<stdout>", process);
return 0;
}
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