colorramp: Use new color ramp table provided by Ingo Thies.

This table is calculated by the actual Planckian locus below 5000K, and by CIE daylight standard above 5000K.
Also, the new table applies proper gamma correction according to sRGB.
More information can be found in README-colorramp.

1 files changed, 248 insertions, 94 deletions

diff --git a/src/colorramp.c b/src/colorramp.c
index 4d32d7e..158f7cd 100644
--- a/src/colorramp.c
+++ b/src/colorramp.c
@@ -14,107 +14,261 @@
    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) 2010  Jon Lund Steffensen <jonlst@gmail.com>
+   Copyright (c) 2013  Jon Lund Steffensen <jonlst@gmail.com>
+   Copyright (c) 2013  Ingo Thies <ithies@astro.uni-bonn.de>
 */
 
 #include <stdint.h>
 #include <math.h>
 
 
-/* Source: http://www.vendian.org/mncharity/dir3/blackbody/
-   Rescaled to make exactly 6500K equal to full intensity in all channels. */
+/* 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[] = {
-	1.0000, 0.0425, 0.0000, /* 1000K */
-	1.0000, 0.0668, 0.0000, /* 1100K */
-	1.0000, 0.0911, 0.0000, /* 1200K */
-	1.0000, 0.1149, 0.0000, /* ... */
-	1.0000, 0.1380, 0.0000,
-	1.0000, 0.1604, 0.0000,
-	1.0000, 0.1819, 0.0000,
-	1.0000, 0.2024, 0.0000,
-	1.0000, 0.2220, 0.0000,
-	1.0000, 0.2406, 0.0000,
-	1.0000, 0.2630, 0.0062,
-	1.0000, 0.2868, 0.0155,
-	1.0000, 0.3102, 0.0261,
-	1.0000, 0.3334, 0.0379,
-	1.0000, 0.3562, 0.0508,
-	1.0000, 0.3787, 0.0650,
-	1.0000, 0.4008, 0.0802,
-	1.0000, 0.4227, 0.0964,
-	1.0000, 0.4442, 0.1136,
-	1.0000, 0.4652, 0.1316,
-	1.0000, 0.4859, 0.1505,
-	1.0000, 0.5062, 0.1702,
-	1.0000, 0.5262, 0.1907,
-	1.0000, 0.5458, 0.2118,
-	1.0000, 0.5650, 0.2335,
-	1.0000, 0.5839, 0.2558,
-	1.0000, 0.6023, 0.2786,
-	1.0000, 0.6204, 0.3018,
-	1.0000, 0.6382, 0.3255,
-	1.0000, 0.6557, 0.3495,
-	1.0000, 0.6727, 0.3739,
-	1.0000, 0.6894, 0.3986,
-	1.0000, 0.7058, 0.4234,
-	1.0000, 0.7218, 0.4485,
-	1.0000, 0.7375, 0.4738,
-	1.0000, 0.7529, 0.4992,
-	1.0000, 0.7679, 0.5247,
-	1.0000, 0.7826, 0.5503,
-	1.0000, 0.7970, 0.5760,
-	1.0000, 0.8111, 0.6016,
-	1.0000, 0.8250, 0.6272,
-	1.0000, 0.8384, 0.6529,
-	1.0000, 0.8517, 0.6785,
-	1.0000, 0.8647, 0.7040,
-	1.0000, 0.8773, 0.7294,
-	1.0000, 0.8897, 0.7548,
-	1.0000, 0.9019, 0.7801,
-	1.0000, 0.9137, 0.8051,
-	1.0000, 0.9254, 0.8301,
-	1.0000, 0.9367, 0.8550,
-	1.0000, 0.9478, 0.8795,
-	1.0000, 0.9587, 0.9040,
-	1.0000, 0.9694, 0.9283,
-	1.0000, 0.9798, 0.9524,
-	1.0000, 0.9900, 0.9763,
-	1.0000, 1.0000, 1.0000, /* 6500K */
-	0.9771, 0.9867, 1.0000,
-	0.9554, 0.9740, 1.0000,
-	0.9349, 0.9618, 1.0000,
-	0.9154, 0.9500, 1.0000,
-	0.8968, 0.9389, 1.0000,
-	0.8792, 0.9282, 1.0000,
-	0.8624, 0.9179, 1.0000,
-	0.8465, 0.9080, 1.0000,
-	0.8313, 0.8986, 1.0000,
-	0.8167, 0.8895, 1.0000,
-	0.8029, 0.8808, 1.0000,
-	0.7896, 0.8724, 1.0000,
-	0.7769, 0.8643, 1.0000,
-	0.7648, 0.8565, 1.0000,
-	0.7532, 0.8490, 1.0000,
-	0.7420, 0.8418, 1.0000,
-	0.7314, 0.8348, 1.0000,
-	0.7212, 0.8281, 1.0000,
-	0.7113, 0.8216, 1.0000,
-	0.7018, 0.8153, 1.0000,
-	0.6927, 0.8092, 1.0000,
-	0.6839, 0.8032, 1.0000,
-	0.6755, 0.7975, 1.0000,
-	0.6674, 0.7921, 1.0000,
-	0.6595, 0.7867, 1.0000,
-	0.6520, 0.7816, 1.0000,
-	0.6447, 0.7765, 1.0000,
-	0.6376, 0.7717, 1.0000,
-	0.6308, 0.7670, 1.0000,
-	0.6242, 0.7623, 1.0000,
-	0.6179, 0.7579, 1.0000,
-	0.6117, 0.7536, 1.0000,
-	0.6058, 0.7493, 1.0000,
-	0.6000, 0.7453, 1.0000,
-	0.5944, 0.7414, 1.0000 /* 10000K */
+	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 */
 };