mirror of https://github.com/axmolengine/axmol.git
62 lines
1.6 KiB
C
62 lines
1.6 KiB
C
/*
|
|
* cmyk.h
|
|
*
|
|
* Copyright (C) 2017-2018, D. R. Commander.
|
|
* For conditions of distribution and use, see the accompanying README.ijg
|
|
* file.
|
|
*
|
|
* This file contains convenience functions for performing quick & dirty
|
|
* CMYK<->RGB conversion. This algorithm is suitable for testing purposes
|
|
* only. Properly converting between CMYK and RGB requires a color management
|
|
* system.
|
|
*/
|
|
|
|
#ifndef CMYK_H
|
|
#define CMYK_H
|
|
|
|
#include <jinclude.h>
|
|
#define JPEG_INTERNALS
|
|
#include <jpeglib.h>
|
|
#include "jconfigint.h"
|
|
|
|
|
|
/* Fully reversible */
|
|
|
|
INLINE
|
|
LOCAL(void)
|
|
rgb_to_cmyk(JSAMPLE r, JSAMPLE g, JSAMPLE b, JSAMPLE *c, JSAMPLE *m,
|
|
JSAMPLE *y, JSAMPLE *k)
|
|
{
|
|
double ctmp = 1.0 - ((double)r / 255.0);
|
|
double mtmp = 1.0 - ((double)g / 255.0);
|
|
double ytmp = 1.0 - ((double)b / 255.0);
|
|
double ktmp = MIN(MIN(ctmp, mtmp), ytmp);
|
|
|
|
if (ktmp == 1.0) ctmp = mtmp = ytmp = 0.0;
|
|
else {
|
|
ctmp = (ctmp - ktmp) / (1.0 - ktmp);
|
|
mtmp = (mtmp - ktmp) / (1.0 - ktmp);
|
|
ytmp = (ytmp - ktmp) / (1.0 - ktmp);
|
|
}
|
|
*c = (JSAMPLE)(255.0 - ctmp * 255.0 + 0.5);
|
|
*m = (JSAMPLE)(255.0 - mtmp * 255.0 + 0.5);
|
|
*y = (JSAMPLE)(255.0 - ytmp * 255.0 + 0.5);
|
|
*k = (JSAMPLE)(255.0 - ktmp * 255.0 + 0.5);
|
|
}
|
|
|
|
|
|
/* Fully reversible only for C/M/Y/K values generated with rgb_to_cmyk() */
|
|
|
|
INLINE
|
|
LOCAL(void)
|
|
cmyk_to_rgb(JSAMPLE c, JSAMPLE m, JSAMPLE y, JSAMPLE k, JSAMPLE *r, JSAMPLE *g,
|
|
JSAMPLE *b)
|
|
{
|
|
*r = (JSAMPLE)((double)c * (double)k / 255.0 + 0.5);
|
|
*g = (JSAMPLE)((double)m * (double)k / 255.0 + 0.5);
|
|
*b = (JSAMPLE)((double)y * (double)k / 255.0 + 0.5);
|
|
}
|
|
|
|
|
|
#endif /* CMYK_H */
|