/* colorramp.c -- color temperature calculation source
This file is part of Redshift.
Redshift 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 3 of the License, or
(at your option) any later version.
Redshift 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 Redshift. If not, see <http://www.gnu.org/licenses/>.
Copyright (c) 2013-2014 Jon Lund Steffensen <jonlst@gmail.com>
Copyright (c) 2013 Ingo Thies <ithies@astro.uni-bonn.de>
*/
#include <stdint.h>
#include <math.h>
#include "redshift.h"
/* Whitepoint values for temperatures at 100K intervals.
These will be interpolated for the actual temperature.
This table was provided by Ingo Thies, 2013. See
the file README-colorramp for more information. */
static const float blackbody_color[] = {
1.00000000, 0.18172716, 0.00000000, /* 1000K */
1.00000000, 0.25503671, 0.00000000, /* 1100K */
1.00000000, 0.30942099, 0.00000000, /* 1200K */
1.00000000, 0.35357379, 0.00000000, /* ... */
1.00000000, 0.39091524, 0.00000000,
1.00000000, 0.42322816, 0.00000000,
1.00000000, 0.45159884, 0.00000000,
1.00000000, 0.47675916, 0.00000000,
1.00000000, 0.49923747, 0.00000000,
1.00000000, 0.51943421, 0.00000000,
1.00000000, 0.54360078, 0.08679949,
1.00000000, 0.56618736, 0.14065513,
1.00000000, 0.58734976, 0.18362641,
1.00000000, 0.60724493, 0.22137978,
1.00000000, 0.62600248, 0.25591950,
1.00000000, 0.64373109, 0.28819679,
1.00000000, 0.66052319, 0.31873863,
1.00000000, 0.67645822, 0.34786758,
1.00000000, 0.69160518, 0.37579588,
1.00000000, 0.70602449, 0.40267128,
1.00000000, 0.71976951, 0.42860152,
1.00000000, 0.73288760, 0.45366838,
1.00000000, 0.74542112, 0.47793608,
1.00000000, 0.75740814, 0.50145662,
1.00000000, 0.76888303, 0.52427322,
1.00000000, 0.77987699, 0.54642268,
1.00000000, 0.79041843, 0.56793692,
1.00000000, 0.80053332, 0.58884417,
1.00000000, 0.81024551, 0.60916971,
1.00000000, 0.81957693, 0.62893653,
1.00000000, 0.82854786, 0.64816570,
1.00000000, 0.83717703, 0.66687674,
1.00000000, 0.84548188, 0.68508786,
1.00000000, 0.85347859, 0.70281616,
1.00000000, 0.86118227, 0.72007777,
1.00000000, 0.86860704, 0.73688797,
1.00000000, 0.87576611, 0.75326132,
1.00000000, 0.88267187, 0.76921169,
1.00000000, 0.88933596, 0.78475236,
1.00000000, 0.89576933, 0.79989606,
1.00000000, 0.90198230, 0.81465502,
1.00000000, 0.90963069, 0.82838210,
1.00000000, 0.91710889, 0.84190889,
1.00000000, 0.92441842, 0.85523742,
1.00000000, 0.93156127, 0.86836903,
1.00000000, 0.93853986, 0.88130458,
1.00000000, 0.94535695, 0.89404470,
1.00000000, 0.95201559, 0.90658983,
1.00000000, 0.95851906, 0.91894041,
1.00000000, 0.96487079, 0.93109690,
1.00000000, 0.97107439, 0.94305985,
1.00000000, 0.97713351, 0.95482993,
1.00000000, 0.98305189, 0.96640795,
1.00000000, 0.98883326, 0.97779486,
1.00000000, 0.99448139, 0.98899179,
1.00000000, 1.00000000, 1.00000000, /* 6500K */
0.98947904, 0.99348723, 1.00000000,
0.97940448, 0.98722715, 1.00000000,
0.96975025, 0.98120637, 1.00000000,
0.96049223, 0.97541240, 1.00000000,
0.95160805, 0.96983355, 1.00000000,
0.94303638, 0.96443333, 1.00000000,
0.93480451, 0.95923080, 1.00000000,
0.92689056, 0.95421394, 1.00000000,
0.91927697, 0.94937330, 1.00000000,
0.91194747, 0.94470005, 1.00000000,
0.90488690, 0.94018594, 1.00000000,
0.89808115, 0.93582323, 1.00000000,
0.89151710, 0.93160469, 1.00000000,
0.88518247, 0.92752354, 1.00000000,
0.87906581, 0.92357340, 1.00000000,
0.87315640, 0.91974827, 1.00000000,
0.86744421, 0.91604254, 1.00000000,
0.86191983, 0.91245088, 1.00000000,
0.85657444, 0.90896831, 1.00000000,
0.85139976, 0.90559011, 1.00000000,
0.84638799, 0.90231183, 1.00000000,
0.84153180, 0.89912926, 1.00000000,
0.83682430, 0.89603843, 1.00000000,
0.83225897, 0.89303558, 1.00000000,
0.82782969, 0.89011714, 1.00000000,
0.82353066, 0.88727974, 1.00000000,
0.81935641, 0.88452017, 1.00000000,
0.81530175, 0.88183541, 1.00000000,
0.81136180, 0.87922257, 1.00000000,
0.80753191, 0.87667891, 1.00000000,
0.80380769, 0.87420182, 1.00000000,
0.80018497, 0.87178882, 1.00000000,
0.79665980, 0.86943756, 1.00000000,
0.79322843, 0.86714579, 1.00000000,
0.78988728, 0.86491137, 1.00000000, /* 10000K */
0.78663296, 0.86273225, 1.00000000,
0.78346225, 0.86060650, 1.00000000,
0.78037207, 0.85853224, 1.00000000,
0.77735950, 0.85650771, 1.00000000,
0.77442176, 0.85453121, 1.00000000,
0.77155617, 0.85260112, 1.00000000,
0.76876022, 0.85071588, 1.00000000,
0.76603147, 0.84887402, 1.00000000,
0.76336762, 0.84707411, 1.00000000,
0.76076645, 0.84531479, 1.00000000,
0.75822586, 0.84359476, 1.00000000,
0.75574383, 0.84191277, 1.00000000,
0.75331843, 0.84026762, 1.00000000,
0.75094780, 0.83865816, 1.00000000,
0.74863017, 0.83708329, 1.00000000,
0.74636386, 0.83554194, 1.00000000,
0.74414722, 0.83403311, 1.00000000,
0.74197871, 0.83255582, 1.00000000,
0.73985682, 0.83110912, 1.00000000,
0.73778012, 0.82969211, 1.00000000,
0.73574723, 0.82830393, 1.00000000,
0.73375683, 0.82694373, 1.00000000,
0.73180765, 0.82561071, 1.00000000,
0.72989845, 0.82430410, 1.00000000,
0.72802807, 0.82302316, 1.00000000,
0.72619537, 0.82176715, 1.00000000,
0.72439927, 0.82053539, 1.00000000,
0.72263872, 0.81932722, 1.00000000,
0.72091270, 0.81814197, 1.00000000,
0.71922025, 0.81697905, 1.00000000,
0.71756043, 0.81583783, 1.00000000,
0.71593234, 0.81471775, 1.00000000,
0.71433510, 0.81361825, 1.00000000,
0.71276788, 0.81253878, 1.00000000,
0.71122987, 0.81147883, 1.00000000,
0.70972029, 0.81043789, 1.00000000,
0.70823838, 0.80941546, 1.00000000,
0.70678342, 0.80841109, 1.00000000,
0.70535469, 0.80742432, 1.00000000,
0.70395153, 0.80645469, 1.00000000,
0.70257327, 0.80550180, 1.00000000,
0.70121928, 0.80456522, 1.00000000,
0.69988894, 0.80364455, 1.00000000,
0.69858167, 0.80273941, 1.00000000,
0.69729688, 0.80184943, 1.00000000,
0.69603402, 0.80097423, 1.00000000,
0.69479255, 0.80011347, 1.00000000,
0.69357196, 0.79926681, 1.00000000,
0.69237173, 0.79843391, 1.00000000,
0.69119138, 0.79761446, 1.00000000, /* 15000K */
0.69003044, 0.79680814, 1.00000000,
0.68888844, 0.79601466, 1.00000000,
0.68776494, 0.79523371, 1.00000000,
0.68665951, 0.79446502, 1.00000000,
0.68557173, 0.79370830, 1.00000000,
0.68450119, 0.79296330, 1.00000000,
0.68344751, 0.79222975, 1.00000000,
0.68241029, 0.79150740, 1.00000000,
0.68138918, 0.79079600, 1.00000000,
0.68038380, 0.79009531, 1.00000000,
0.67939381, 0.78940511, 1.00000000,
0.67841888, 0.78872517, 1.00000000,
0.67745866, 0.78805526, 1.00000000,
0.67651284, 0.78739518, 1.00000000,
0.67558112, 0.78674472, 1.00000000,
0.67466317, 0.78610368, 1.00000000,
0.67375872, 0.78547186, 1.00000000,
0.67286748, 0.78484907, 1.00000000,
0.67198916, 0.78423512, 1.00000000,
0.67112350, 0.78362984, 1.00000000,
0.67027024, 0.78303305, 1.00000000,
0.66942911, 0.78244457, 1.00000000,
0.66859988, 0.78186425, 1.00000000,
0.66778228, 0.78129191, 1.00000000,
0.66697610, 0.78072740, 1.00000000,
0.66618110, 0.78017057, 1.00000000,
0.66539706, 0.77962127, 1.00000000,
0.66462376, 0.77907934, 1.00000000,
0.66386098, 0.77854465, 1.00000000,
0.66310852, 0.77801705, 1.00000000,
0.66236618, 0.77749642, 1.00000000,
0.66163375, 0.77698261, 1.00000000,
0.66091106, 0.77647551, 1.00000000,
0.66019791, 0.77597498, 1.00000000,
0.65949412, 0.77548090, 1.00000000,
0.65879952, 0.77499315, 1.00000000,
0.65811392, 0.77451161, 1.00000000,
0.65743716, 0.77403618, 1.00000000,
0.65676908, 0.77356673, 1.00000000,
0.65610952, 0.77310316, 1.00000000,
0.65545831, 0.77264537, 1.00000000,
0.65481530, 0.77219324, 1.00000000,
0.65418036, 0.77174669, 1.00000000,
0.65355332, 0.77130560, 1.00000000,
0.65293404, 0.77086988, 1.00000000,
0.65232240, 0.77043944, 1.00000000,
0.65171824, 0.77001419, 1.00000000,
0.65112144, 0.76959404, 1.00000000,
0.65053187, 0.76917889, 1.00000000,
0.64994941, 0.76876866, 1.00000000, /* 20000K */
0.64937392, 0.76836326, 1.00000000,
0.64880528, 0.76796263, 1.00000000,
0.64824339, 0.76756666, 1.00000000,
0.64768812, 0.76717529, 1.00000000,
0.64713935, 0.76678844, 1.00000000,
0.64659699, 0.76640603, 1.00000000,
0.64606092, 0.76602798, 1.00000000,
0.64553103, 0.76565424, 1.00000000,
0.64500722, 0.76528472, 1.00000000,
0.64448939, 0.76491935, 1.00000000,
0.64397745, 0.76455808, 1.00000000,
0.64347129, 0.76420082, 1.00000000,
0.64297081, 0.76384753, 1.00000000,
0.64247594, 0.76349813, 1.00000000,
0.64198657, 0.76315256, 1.00000000,
0.64150261, 0.76281076, 1.00000000,
0.64102399, 0.76247267, 1.00000000,
0.64055061, 0.76213824, 1.00000000,
0.64008239, 0.76180740, 1.00000000,
0.63961926, 0.76148010, 1.00000000,
0.63916112, 0.76115628, 1.00000000,
0.63870790, 0.76083590, 1.00000000,
0.63825953, 0.76051890, 1.00000000,
0.63781592, 0.76020522, 1.00000000,
0.63737701, 0.75989482, 1.00000000,
0.63694273, 0.75958764, 1.00000000,
0.63651299, 0.75928365, 1.00000000,
0.63608774, 0.75898278, 1.00000000,
0.63566691, 0.75868499, 1.00000000,
0.63525042, 0.75839025, 1.00000000,
0.63483822, 0.75809849, 1.00000000,
0.63443023, 0.75780969, 1.00000000,
0.63402641, 0.75752379, 1.00000000,
0.63362667, 0.75724075, 1.00000000,
0.63323097, 0.75696053, 1.00000000,
0.63283925, 0.75668310, 1.00000000,
0.63245144, 0.75640840, 1.00000000,
0.63206749, 0.75613641, 1.00000000,
0.63168735, 0.75586707, 1.00000000,
0.63131096, 0.75560036, 1.00000000,
0.63093826, 0.75533624, 1.00000000,
0.63056920, 0.75507467, 1.00000000,
0.63020374, 0.75481562, 1.00000000,
0.62984181, 0.75455904, 1.00000000,
0.62948337, 0.75430491, 1.00000000,
0.62912838, 0.75405319, 1.00000000,
0.62877678, 0.75380385, 1.00000000,
0.62842852, 0.75355685, 1.00000000,
0.62808356, 0.75331217, 1.00000000,
0.62774186, 0.75306977, 1.00000000, /* 25000K */
0.62740336, 0.75282962, 1.00000000 /* 25100K */
};
static void
interpolate_color(float a, const float *c1, const float *c2, float *c)
{
c[0] = (1.0-a)*c1[0] + a*c2[0];
c[1] = (1.0-a)*c1[1] + a*c2[1];
c[2] = (1.0-a)*c1[2] + a*c2[2];
}
/* Helper macro used in the fill functions */
#define F(Y, C) pow((Y) * setting->brightness * \
white_point[C], 1.0/setting->gamma[C])
void
colorramp_fill(uint16_t *gamma_r, uint16_t *gamma_g, uint16_t *gamma_b,
int size, const color_setting_t *setting)
{
/* Approximate white point */
float white_point[3];
float alpha = (setting->temperature % 100) / 100.0;
int temp_index = ((setting->temperature - 1000) / 100)*3;
interpolate_color(alpha, &blackbody_color[temp_index],
&blackbody_color[temp_index+3], white_point);
for (int i = 0; i < size; i++) {
gamma_r[i] = F((double)gamma_r[i]/(UINT16_MAX+1), 0) *
(UINT16_MAX+1);
gamma_g[i] = F((double)gamma_g[i]/(UINT16_MAX+1), 1) *
(UINT16_MAX+1);
gamma_b[i] = F((double)gamma_b[i]/(UINT16_MAX+1), 2) *
(UINT16_MAX+1);
}
}
void
colorramp_fill_float(float *gamma_r, float *gamma_g, float *gamma_b,
int size, const color_setting_t *setting)
{
/* Approximate white point */
float white_point[3];
float alpha = (setting->temperature % 100) / 100.0;
int temp_index = ((setting->temperature - 1000) / 100)*3;
interpolate_color(alpha, &blackbody_color[temp_index],
&blackbody_color[temp_index+3], white_point);
for (int i = 0; i < size; i++) {
gamma_r[i] = F((double)gamma_r[i], 0);
gamma_g[i] = F((double)gamma_g[i], 1);
gamma_b[i] = F((double)gamma_b[i], 2);
}
}
#undef F