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/* See LICENSE file for copyright and license details. */
#include "arg.h"
#include "stream.h"
#include "util.h"
#include <fcntl.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
static void
usage(void)
{
eprintf("usage: %s [-i] alpha-stream\n", argv0);
}
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;
struct stream alpha;
ssize_t r;
size_t i, n;
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 = open(alpha.file, O_RDONLY);
if (alpha.fd < 0)
eprintf("open %s:", alpha.file);
einit_stream(&alpha);
if (colour.width != alpha.width || colour.height != alpha.height)
eprintf("videos do not have the same geometry\n");
if (colour.pixel_size != alpha.pixel_size)
eprintf("videos use incompatible pixel formats\n");
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);
for (;;) {
if (colour.ptr < sizeof(colour.buf) && !eread_stream(&colour, SIZE_MAX)) {
close(colour.fd);
colour.fd = -1;
break;
}
if (alpha.ptr < sizeof(alpha.buf) && !eread_stream(&alpha, SIZE_MAX)) {
close(alpha.fd);
alpha.fd = -1;
break;
}
n = colour.ptr < alpha.ptr ? colour.ptr : alpha.ptr;
n -= n % colour.pixel_size;
colour.ptr -= n;
alpha.ptr -= n;
process(&colour, &alpha, n);
for (i = 0; i < n; i += (size_t)r) {
r = write(STDOUT_FILENO, colour.buf + i, n - i);
if (r < 0)
eprintf("write <stdout>:");
}
if ((n & 3) || colour.ptr != alpha.ptr) {
memmove(colour.buf, colour.buf + n, colour.ptr);
memmove(alpha.buf, alpha.buf + n, alpha.ptr);
}
}
if (alpha.fd >= 0)
close(alpha.fd);
for (i = 0; i < colour.ptr; i += (size_t)r) {
r = write(STDOUT_FILENO, colour.buf + i, colour.ptr - i);
if (r < 0)
eprintf("write <stdout>:");
}
if (colour.fd >= 0) {
for (;;) {
colour.ptr = 0;
if (!eread_stream(&colour, SIZE_MAX)) {
close(colour.fd);
colour.fd = -1;
break;
}
for (i = 0; i < colour.ptr; i += (size_t)r) {
r = write(STDOUT_FILENO, colour.buf + i, colour.ptr - i);
if (r < 0)
eprintf("write <stdout>:");
}
}
}
return 0;
}
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