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/* Copyright 2017 Jason Williams
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "color.h"
#include "led_tables.h"
#include "progmem.h"
RGB hsv_to_rgb(HSV hsv) {
RGB rgb;
uint8_t region, remainder, p, q, t;
uint16_t h, s, v;
if (hsv.s == 0) {
#ifdef USE_CIE1931_CURVE
rgb.r = rgb.g = rgb.b = pgm_read_byte(&CIE1931_CURVE[hsv.v]);
#else
rgb.r = hsv.v;
rgb.g = hsv.v;
rgb.b = hsv.v;
#endif
return rgb;
}
h = hsv.h;
s = hsv.s;
#ifdef USE_CIE1931_CURVE
v = pgm_read_byte(&CIE1931_CURVE[hsv.v]);
#else
v = hsv.v;
#endif
region = h * 6 / 255;
remainder = (h * 2 - region * 85) * 3;
p = (v * (255 - s)) >> 8;
q = (v * (255 - ((s * remainder) >> 8))) >> 8;
t = (v * (255 - ((s * (255 - remainder)) >> 8))) >> 8;
switch (region) {
case 6:
case 0:
rgb.r = v;
rgb.g = t;
rgb.b = p;
break;
case 1:
rgb.r = q;
rgb.g = v;
rgb.b = p;
break;
case 2:
rgb.r = p;
rgb.g = v;
rgb.b = t;
break;
case 3:
rgb.r = p;
rgb.g = q;
rgb.b = v;
break;
case 4:
rgb.r = t;
rgb.g = p;
rgb.b = v;
break;
default:
rgb.r = v;
rgb.g = p;
rgb.b = q;
break;
}
return rgb;
}