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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("[-w] saturation-stream")
static void
process_xyza(struct stream *colour, struct stream *satur, size_t n)
{
size_t i;
double s, *x, y, *z, X, Z;
X = D65_XYY_X / D65_XYY_Y;
Z = 1 / D65_XYY_Y - 1 - X;
for (i = 0; i < n; i += colour->pixel_size) {
s = ((double *)(satur->buf + i))[1];
s *= ((double *)(satur->buf + i))[3];
x = ((double *)(colour->buf + i)) + 0;
y = ((double *)(colour->buf + i))[1];
z = ((double *)(colour->buf + i)) + 2;
*x = ((*x / X - y) * s + y) * X;
*z = ((*z / Z - y) * s + y) * Z;
/*
* Explaination:
* Y is the luma and ((X / Xn - Y / Yn), (Z / Zn - Y / Yn))
* is the chroma (according to CIELAB), where (Xn, Yn, Zn)
* is the white point.
*/
}
}
static void
process_xyza_w(struct stream *colour, struct stream *satur, size_t n)
{
size_t i;
double s, *x, y, *z, X, Z;
for (i = 0; i < n; i += colour->pixel_size) {
X = ((double *)(satur->buf + i))[0];
Z = ((double *)(satur->buf + i))[2];
s = ((double *)(satur->buf + i))[1];
s *= ((double *)(satur->buf + i))[3];
x = ((double *)(colour->buf + i)) + 0;
y = ((double *)(colour->buf + i))[1];
z = ((double *)(colour->buf + i)) + 2;
*x = ((*x / X - y) * s + y) * X;
*z = ((*z / Z - y) * s + y) * Z;
}
}
int
main(int argc, char *argv[])
{
struct stream colour, satur;
int whitepoint = 0;
void (*process)(struct stream *colour, struct stream *satur, size_t n) = NULL;
ARGBEGIN {
case 'w':
whitepoint = 1;
break;
default:
usage();
} ARGEND;
if (argc != 1)
usage();
eopen_stream(&colour, NULL);
eopen_stream(&satur, argv[0]);
if (!strcmp(colour.pixfmt, "xyza"))
process = whitepoint ? process_xyza_w : process_xyza;
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, &satur, STDOUT_FILENO, "<stdout>", process);
return 0;
}
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