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/* See LICENSE file for copyright and license details. */
#include "stream.h"
#include "util.h"
#include <string.h>
USAGE("[-i] alpha-stream")
#define PROCESS(TYPE, INV)\
do {\
size_t i;\
TYPE a;\
for (i = 0; i < n; i += colour->pixel_size) {\
a = INV ((TYPE *)(alpha->buf + i))[1];\
a *= ((TYPE *)(alpha->buf + i))[3];\
((TYPE *)(colour->buf + i))[3] *= a;\
}\
} while (0)
static void process_xyza (struct stream *colour, struct stream *alpha, size_t n) {PROCESS(double,);}
static void process_xyza_i (struct stream *colour, struct stream *alpha, size_t n) {PROCESS(double, 1 -);}
static void process_xyzaf (struct stream *colour, struct stream *alpha, size_t n) {PROCESS(float,);}
static void process_xyzaf_i(struct stream *colour, struct stream *alpha, size_t n) {PROCESS(float, 1 -);}
int
main(int argc, char *argv[])
{
int invert = 0;
struct stream colour, alpha;
void (*process)(struct stream *colour, struct stream *alpha, size_t n);
ARGBEGIN {
case 'i':
invert = 1;
break;
default:
usage();
} ARGEND;
if (argc != 1)
usage();
eopen_stream(&colour, NULL);
eopen_stream(&alpha, argv[0]);
if (!strcmp(colour.pixfmt, "xyza"))
process = invert ? process_xyza_i : process_xyza;
else if (!strcmp(colour.pixfmt, "xyza f"))
process = invert ? process_xyzaf_i : process_xyzaf;
else
eprintf("pixel format %s is not supported, try xyza\n", colour.pixfmt);
fprint_stream_head(stdout, &colour);
efflush(stdout, "<stdout>");
process_two_streams(&colour, &alpha, STDOUT_FILENO, "<stdout>", process);
return 0;
}
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