| /* |
| * 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 */ |
