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[ColorUtil] New methods kelvinToXY and xyToKelvin (#4367)

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Signed-off-by: AndrewFG <software@whitebear.ch>
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Andrew Fiddian-Green 2024-09-17 00:01:51 +01:00 committed by GitHub
parent 3c7b4b89b1
commit 5f14cd1c5f
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bundles/org.openhab.core/src/main/java/org/openhab/core/util/ColorUtil.java
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@ -650,4 +650,530 @@ public class ColorUtil {
return retVal;
}
}
/**
* Lookup table for converting colour temperatures in Kelvin to a point in the CIE XY colour space.
* Elements of the array comprise three parts: colour temperature (K), X coordinate, Y coordinate.
*/
private static final double[][] KELVIN_TO_XY_LOOKUP_TABLE = {
//@formatter:off
{ 2000, 0.526676280311873, 0.41329727450763 },
{ 2010, 0.52558700949522, 0.413461772751086 },
{ 2020, 0.524501547047308, 0.413618464845305 },
{ 2030, 0.523419902728187, 0.413767442985273 },
{ 2040, 0.522342085989252, 0.413908799143933 },
{ 2050, 0.521268105968449, 0.414042625047528 },
{ 2060, 0.520197971485871, 0.414169012151805 },
{ 2070, 0.519131691039726, 0.414288051619026 },
{ 2080, 0.518069272802678, 0.414399834295808 },
{ 2090, 0.51701072461855, 0.41450445069175 },
{ 2100, 0.515956053999373, 0.414601990958848 },
{ 2110, 0.514905268122789, 0.414692544871688 },
{ 2120, 0.513858373829776, 0.414776201808388 },
{ 2130, 0.512815377622702, 0.414853050732289 },
{ 2140, 0.511776285663697, 0.414923180174373 },
{ 2150, 0.510741103773325, 0.414986678216401 },
{ 2160, 0.509709837429556, 0.415043632474748 },
{ 2170, 0.508682491767023, 0.415094130084932 },
{ 2180, 0.507659071576558, 0.415138257686807 },
{ 2190, 0.506639581304996, 0.415176101410431 },
{ 2200, 0.505624025055233, 0.415207746862562 },
{ 2210, 0.504612406586543, 0.415233279113804 },
{ 2220, 0.50360472931513, 0.415252782686356 },
{ 2230, 0.502600996314909, 0.415266341542373 },
{ 2240, 0.501601210318512, 0.41527403907292 },
{ 2250, 0.500605373718514, 0.415275958087495 },
{ 2260, 0.499613488568853, 0.415272180804119 },
{ 2270, 0.498625556586457, 0.415262788839981 },
{ 2280, 0.497641579153048, 0.415247863202608 },
{ 2290, 0.496661557317139, 0.415227484281571 },
{ 2300, 0.495685491796189, 0.415201731840687 },
{ 2310, 0.494713382978936, 0.415170685010734 },
{ 2320, 0.49374523092787, 0.415134422282633 },
{ 2330, 0.492781035381868, 0.415093021501115 },
{ 2340, 0.491820795758963, 0.415046559858839 },
{ 2350, 0.490864511159246, 0.414995113890958 },
{ 2360, 0.489912180367896, 0.414938759470118 },
{ 2370, 0.488963801858331, 0.414877571801882 },
{ 2380, 0.488019373795462, 0.414811625420557 },
{ 2390, 0.48707889403907, 0.41474099418543 },
{ 2400, 0.486142360147258, 0.414665751277374 },
{ 2410, 0.485209769380024, 0.414585969195845 },
{ 2420, 0.484281118702893, 0.41450171975623 },
{ 2430, 0.483356404790651, 0.414413074087558 },
{ 2440, 0.482435624031141, 0.41432010263054 },
{ 2450, 0.481518772529133, 0.414222875135951 },
{ 2460, 0.480605846110259, 0.414121460663327 },
{ 2470, 0.479696840325004, 0.414015927579967 },
{ 2480, 0.478791750452749, 0.413906343560247 },
{ 2490, 0.477890571505866, 0.413792775585208 },
{ 2500, 0.476993298233858, 0.413675289942435 },
{ 2510, 0.476099925127525, 0.413553952226202 },
{ 2520, 0.475210446423188, 0.413428827337877 },
{ 2530, 0.474324856106916, 0.413299979486579 },
{ 2540, 0.473443147918802, 0.413167472190078 },
{ 2550, 0.472565315357245, 0.413031368275923 },
{ 2560, 0.471691351683258, 0.412891729882807 },
{ 2570, 0.470821249924792, 0.412748618462133 },
{ 2580, 0.469955002881062, 0.412602094779799 },
{ 2590, 0.469092603126886, 0.412452218918178 },
{ 2600, 0.468234043017033, 0.41229905027829 },
{ 2610, 0.46737931469056, 0.412142647582159 },
{ 2620, 0.466528410075157, 0.411983068875347 },
{ 2630, 0.465681320891482, 0.411820371529656 },
{ 2640, 0.464838038657489, 0.411654612245991 },
{ 2650, 0.463998554692746, 0.411485847057383 },
{ 2660, 0.463162860122743, 0.411314131332149 },
{ 2670, 0.462330945883173, 0.411139519777208 },
{ 2680, 0.461502802724214, 0.41096206644152 },
{ 2690, 0.460678421214773, 0.410781824719658 },
{ 2700, 0.459857791746717, 0.410598847355503 },
{ 2710, 0.459040904539081, 0.410413186446054 },
{ 2720, 0.458227749642249, 0.410224893445347 },
{ 2730, 0.457418316942099, 0.410034019168485 },
{ 2740, 0.456612596164132, 0.409840613795755 },
{ 2750, 0.455810576877562, 0.409644726876854 },
{ 2760, 0.455012248499377, 0.409446407335191 },
{ 2770, 0.45421760029836, 0.40924570347228 },
{ 2780, 0.453426621399085, 0.409042662972206 },
{ 2790, 0.452639300785869, 0.408837332906172 },
{ 2800, 0.451855627306685, 0.408629759737106 },
{ 2810, 0.451075589677048, 0.408419989324343 },
{ 2820, 0.450299176483844, 0.408208066928357 },
{ 2830, 0.449526376189136, 0.407994037215556 },
{ 2840, 0.448757177133914, 0.407777944263126 },
{ 2850, 0.447991567541816, 0.407559831563923 },
{ 2860, 0.447229535522791, 0.407339742031414 },
{ 2870, 0.446471069076735, 0.407117718004646 },
{ 2880, 0.445716156097067, 0.406893801253269 },
{ 2890, 0.444964784374273, 0.406668032982576 },
{ 2900, 0.444216941599399, 0.406440453838584 },
{ 2910, 0.443472615367494, 0.406211103913138 },
{ 2920, 0.442731793181017, 0.405980022749035 },
{ 2930, 0.441994462453189, 0.405747249345174 },
{ 2940, 0.441260610511305, 0.405512822161723 },
{ 2950, 0.440530224599989, 0.405276779125295 },
{ 2960, 0.439803291884415, 0.405039157634144 },
{ 2970, 0.439079799453468, 0.404799994563365 },
{ 2980, 0.438359734322871, 0.404559326270101 },
{ 2990, 0.437643083438248, 0.404317188598758 },
{ 3000, 0.436929833678155, 0.404073616886221 },
{ 3010, 0.436219971857052, 0.403828645967064 },
{ 3020, 0.435513484728235, 0.403582310178768 },
{ 3030, 0.434810358986718, 0.403334643366923 },
{ 3040, 0.434110581272061, 0.403085678890438 },
{ 3050, 0.433414138171168, 0.402835449626724 },
{ 3060, 0.432721016221012, 0.402583987976887 },
{ 3070, 0.43203120191134, 0.402331325870893 },
{ 3080, 0.431344681687312, 0.402077494772728 },
{ 3090, 0.4306614419521, 0.401822525685539 },
{ 3100, 0.429981469069442, 0.401566449156763 },
{ 3110, 0.429304749366147, 0.401309295283229 },
{ 3120, 0.428631269134558, 0.401051093716253 },
{ 3130, 0.427961014634963, 0.400791873666696 },
{ 3140, 0.427293972097967, 0.400531663910017 },
{ 3150, 0.426630127726814, 0.400270492791288 },
{ 3160, 0.425969467699671, 0.400008388230194 },
{ 3170, 0.425311978171859, 0.399745377726 },
{ 3180, 0.424657645278049, 0.399481488362498 },
{ 3190, 0.424006455134406, 0.399216746812922 },
{ 3200, 0.423358393840696, 0.398951179344833 },
{ 3210, 0.422713447482352, 0.39868481182498 },
{ 3220, 0.422071602132489, 0.398417669724122 },
{ 3230, 0.421432843853882, 0.39814977812183 },
{ 3240, 0.420797158700909, 0.397881161711245 },
{ 3250, 0.42016453272144, 0.39761184480381 },
{ 3260, 0.419534951958697, 0.397341851333969 },
{ 3270, 0.418908402453069, 0.397071204863828 },
{ 3280, 0.418284870243884, 0.396799928587787 },
{ 3290, 0.41766434137115, 0.396528045337128 },
{ 3300, 0.417046801877253, 0.396255577584578 },
{ 3310, 0.416432237808611, 0.395982547448827 },
{ 3320, 0.415820635217303, 0.395708976699012 },
{ 3330, 0.415211980162654, 0.395434886759171 },
{ 3340, 0.414606258712775, 0.395160298712644 },
{ 3350, 0.414003456946084, 0.394885233306455 },
{ 3360, 0.41340356095278, 0.394609710955639 },
{ 3370, 0.41280655683628, 0.394333751747546 },
{ 3380, 0.412212430714629, 0.39405737544609 },
{ 3390, 0.411621168721873, 0.393780601495975 },
{ 3400, 0.411032757009395, 0.393503449026874 },
{ 3410, 0.410447181747219, 0.393225936857565 },
{ 3420, 0.409864429125286, 0.392948083500039 },
{ 3430, 0.409284485354692, 0.392669907163558 },
{ 3440, 0.408707336668894, 0.39239142575868 },
{ 3450, 0.408132969324891, 0.39211265690124 },
{ 3460, 0.407561369604368, 0.391833617916295 },
{ 3470, 0.406992523814813, 0.391554325842027 },
{ 3480, 0.406426418290599, 0.391274797433607 },
{ 3490, 0.405863039394048, 0.390995049167019 },
{ 3500, 0.405302373516452, 0.390715097242847 },
{ 3510, 0.404744407079075, 0.390434957590016 },
{ 3520, 0.404189126534126, 0.390154645869498 },
{ 3530, 0.403636518365702, 0.389874177477982 },
{ 3540, 0.403086569090702, 0.389593567551495 },
{ 3550, 0.402539265259722, 0.389312830968992 },
{ 3560, 0.401994593457919, 0.389031982355903 },
{ 3570, 0.401452540305847, 0.388751036087639 },
{ 3580, 0.400913092460274, 0.388470006293066 },
{ 3590, 0.400376236614968, 0.388188906857933 },
{ 3600, 0.399841959501467, 0.387907751428262 },
{ 3610, 0.399310247889814, 0.387626553413704 },
{ 3620, 0.398781088589278, 0.387345325990855 },
{ 3630, 0.398254468449049, 0.387064082106531 },
{ 3640, 0.397730374358909, 0.386782834481003 },
{ 3650, 0.397208793249882, 0.386501595611205 },
{ 3660, 0.396689712094866, 0.386220377773894 },
{ 3670, 0.396173117909235, 0.385939193028774 },
{ 3680, 0.395658997751428, 0.385658053221589 },
{ 3690, 0.395147338723516, 0.385376969987172 },
{ 3700, 0.394638127971748, 0.38509595475246 },
{ 3710, 0.394131352687072, 0.384815018739475 },
{ 3720, 0.393627000105649, 0.384534172968266 },
{ 3730, 0.393125057509339, 0.384253428259816 },
{ 3740, 0.392625512226168, 0.383972795238911 },
{ 3750, 0.392128351630781, 0.383692284336979 },
{ 3760, 0.391633563144876, 0.383411905794889 },
{ 3770, 0.391141134237623, 0.383131669665717 },
{ 3780, 0.390651052426057, 0.382851585817475 },
{ 3790, 0.390163305275465, 0.382571663935814 },
{ 3800, 0.389677880399752, 0.382291913526683 },
{ 3810, 0.389194765461792, 0.382012343918955 },
{ 3820, 0.388713948173757, 0.38173296426703 },
{ 3830, 0.388235416297444, 0.381453783553394 },
{ 3840, 0.387759157644574, 0.38117481059115 },
{ 3850, 0.387285160077084, 0.380896054026513 },
{ 3860, 0.386813411507402, 0.380617522341278 },
{ 3870, 0.386343899898705, 0.380339223855255 },
{ 3880, 0.385876613265173, 0.380061166728665 },
{ 3890, 0.385411539672215, 0.379783358964516 },
{ 3900, 0.384948667236696, 0.37950580841094 },
{ 3910, 0.384487984127144, 0.3792285227635 },
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{ 3960, 0.382216998007281, 0.377846327067982 },
{ 3970, 0.38176920530878, 0.377570784203772 },
{ 3980, 0.381323520577382, 0.377295556030402 },
{ 3990, 0.380879932400953, 0.377020649102431 },
{ 4000, 0.380438429420364, 0.376746069841299 },
{ 4010, 0.379999000329579, 0.376471824537343 },
{ 4020, 0.379561633875749, 0.376197919351794 },
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{ 4070, 0.377405351042622, 0.374833702050712 },
{ 4080, 0.376980127087195, 0.374561959975396 },
{ 4090, 0.376556888493043, 0.37429059769367 },
{ 4100, 0.376135624434723, 0.374019620402386 },
{ 4110, 0.37571632414033, 0.373749033186026 },
{ 4120, 0.375298976891495, 0.373478841018437 },
{ 4130, 0.37488357202338, 0.373209048764539 },
{ 4140, 0.374470098924658, 0.372939661182012 },
{ 4150, 0.374058547037489, 0.372670682922962 },
{ 4160, 0.373648905857491, 0.372402118535558 },
{ 4170, 0.373241164933703, 0.372133972465647 },
{ 4180, 0.372835313868541, 0.371866249058352 },
{ 4190, 0.372431342317747, 0.371598952559641 },
{ 4200, 0.372029239990332, 0.371332087117875 },
{ 4210, 0.371628996648516, 0.371065656785341 },
{ 4220, 0.371230602107658, 0.370799665519753 },
{ 4230, 0.37083404623618, 0.370534117185738 },
{ 4240, 0.370439318955492, 0.370269015556301 },
{ 4250, 0.370046410239904, 0.370004364314267 },
{ 4260, 0.369655310116535, 0.369740167053704 },
{ 4270, 0.369266008665223, 0.369476427281325 },
{ 4280, 0.368878496018416, 0.369213148417869 },
{ 4290, 0.368492762361075, 0.368950333799466 },
{ 4300, 0.368108797930561, 0.368687986678976 },
{ 4310, 0.36772659301652, 0.36842611022732 },
{ 4320, 0.367346137960767, 0.368164707534776 },
{ 4330, 0.36696742315716, 0.36790378161227 },
{ 4340, 0.366590439051477, 0.367643335392644 },
{ 4350, 0.366215176141282, 0.367383371731904 },
{ 4360, 0.36584162497579, 0.36712389341045 },
{ 4370, 0.365469776155733, 0.366864903134292 },
{ 4380, 0.365099620333213, 0.366606403536243 },
{ 4390, 0.364731148211558, 0.366348397177103 },
{ 4400, 0.364364350545175, 0.366090886546814 },
{ 4410, 0.363999218139393, 0.365833874065608 },
{ 4420, 0.363635741850315, 0.365577362085137 },
{ 4430, 0.363273912584652, 0.365321352889581 },
{ 4440, 0.362913721299567, 0.365065848696745 },
{ 4450, 0.362555159002508, 0.36481085165914 },
{ 4460, 0.362198216751042, 0.364556363865043 },
{ 4470, 0.361842885652686, 0.36430238733955 },
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{ 4830, 0.350052964375366, 0.355512249389855 },
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{ 4860, 0.349152291255876, 0.35481151612724 },
{ 4870, 0.348854664762465, 0.354579039672309 },
{ 4880, 0.348558325487217, 0.35434711417881 },
{ 4890, 0.348263266459433, 0.354115739787415 },
{ 4900, 0.347969480749661, 0.353884916608634 },
{ 4910, 0.347676961469483, 0.353654644723354 },
{ 4920, 0.3473857017713, 0.353424924183371 },
{ 4930, 0.347095694848114, 0.353195755011921 },
{ 4940, 0.346806933933317, 0.352967137204187 },
{ 4950, 0.346519412300469, 0.352739070727817 },
{ 4960, 0.346233123263089, 0.352511555523418 },
{ 4970, 0.345948060174438, 0.352284591505058 },
{ 4980, 0.345664216427301, 0.352058178560741 },
{ 4990, 0.345381585453779, 0.351832316552895 },
{ 5000, 0.345100160725069, 0.35160700531884 },
{ 5010, 0.344819935751253, 0.35138224467125 },
{ 5020, 0.344540904081086, 0.351158034398612 },
{ 5030, 0.344263059301778, 0.350934374265679 },
{ 5040, 0.343986395038783, 0.350711264013907 },
{ 5050, 0.343710904955591, 0.350488703361895 },
{ 5060, 0.34343658275351, 0.350266692005812 },
{ 5070, 0.343163422171456, 0.350045229619827 },
{ 5080, 0.342891416985746, 0.349824315856515 },
{ 5090, 0.34262056100988, 0.349603950347275 },
{ 5100, 0.342350848094336, 0.349384132702732 },
{ 5110, 0.342082272126361, 0.349164862513132 },
{ 5120, 0.341814827029758, 0.348946139348737 },
{ 5130, 0.34154850676468, 0.348727962760208 },
{ 5140, 0.341283305327422, 0.348510332278986 },
{ 5150, 0.341019216750211, 0.348293247417664 },
{ 5160, 0.340756235101003, 0.348076707670355 },
{ 5170, 0.340494354483275, 0.347860712513058 },
{ 5180, 0.340233569035817, 0.347645261404009 },
{ 5190, 0.339973872932533, 0.347430353784033 },
{ 5200, 0.339715260382228, 0.347215989076895 },
{ 5210, 0.339457725628414, 0.347002166689633 },
{ 5220, 0.339201262949099, 0.346788886012898 },
{ 5230, 0.33894586665659, 0.346576146421281 },
{ 5240, 0.338691531097289, 0.346363947273638 },
{ 5250, 0.338438250651491, 0.346152287913411 },
{ 5260, 0.338186019733187, 0.345941167668941 },
{ 5270, 0.337934832789862, 0.34573058585378 },
{ 5280, 0.337684684302299, 0.345520541766991 },
{ 5290, 0.337435568784377, 0.345311034693453 },
{ 5300, 0.337187480782876, 0.345102063904155 },
{ 5310, 0.336940414877284, 0.344893628656486 },
{ 5320, 0.336694365679595, 0.344685728194521 },
{ 5330, 0.336449327834117, 0.344478361749302 },
{ 5340, 0.336205296017281, 0.34427152853912 },
{ 5350, 0.335962264937442, 0.344065227769781 },
{ 5360, 0.335720229334691, 0.34385945863488 },
{ 5370, 0.335479183980662, 0.343654220316063 },
{ 5380, 0.335239123678341, 0.343449511983289 },
{ 5390, 0.335000043261875, 0.343245332795082 },
{ 5400, 0.334761937596386, 0.343041681898789 },
{ 5410, 0.334524801577778, 0.342838558430825 },
{ 5420, 0.334288630132555, 0.342635961516917 },
{ 5430, 0.33405341821763, 0.342433890272344 },
{ 5440, 0.33381916082014, 0.342232343802175 },
{ 5450, 0.333585852957265, 0.342031321201502 },
{ 5460, 0.333353489676037, 0.341830821555668 },
{ 5470, 0.333122066053165, 0.341630843940493 },
{ 5480, 0.332891577194843, 0.341431387422495 },
{ 5490, 0.33266201823658, 0.341232451059109 },
{ 5500, 0.332433384343009, 0.341034033898904 },
{ 5510, 0.332205670707715, 0.34083613498179 },
{ 5520, 0.331978872553048, 0.34063875333923 },
{ 5530, 0.331752985129957, 0.340441887994442 },
{ 5540, 0.3315280037178, 0.340245537962605 },
{ 5550, 0.331303923624177, 0.340049702251049 },
{ 5560, 0.331080740184751, 0.339854379859459 },
{ 5570, 0.330858448763073, 0.339659569780063 },
{ 5580, 0.330637044750413, 0.339465270997818 },
{ 5590, 0.330416523565582, 0.339271482490602 },
{ 5600, 0.330196880654761, 0.339078203229392 },
{ 5610, 0.329978111491335, 0.338885432178446 },
{ 5620, 0.329760211575718, 0.338693168295479 },
{ 5630, 0.329543176435188, 0.338501410531837 },
{ 5640, 0.329327001623714, 0.338310157832671 },
{ 5650, 0.329111682721794, 0.338119409137101 },
{ 5660, 0.328897215336285, 0.337929163378386 },
{ 5670, 0.32868359510024, 0.337739419484084 },
{ 5680, 0.328470817672741, 0.337550176376214 },
{ 5690, 0.328258878738739, 0.337361432971415 },
{ 5700, 0.328047774008889, 0.337173188181098 },
{ 5710, 0.327837499219387, 0.3369854409116 },
{ 5720, 0.32762805013181, 0.336798190064338 },
{ 5730, 0.32741942253296, 0.33661143453595 },
{ 5740, 0.327211612234699, 0.336425173218445 },
{ 5750, 0.327004615073793, 0.336239404999346 },
{ 5760, 0.326798426911756, 0.336054128761828 },
{ 5770, 0.326593043634692, 0.335869343384858 },
{ 5780, 0.326388461153141, 0.33568504774333 },
{ 5790, 0.326184675401921, 0.3355012407082 },
{ 5800, 0.325981682339978, 0.335317921146619 },
{ 5810, 0.325779477950234, 0.335135087922056 },
{ 5820, 0.325578058239428, 0.334952739894432 },
{ 5830, 0.325377419237973, 0.334770875920243 },
{ 5840, 0.325177556999802, 0.334589494852681 },
{ 5850, 0.324978467602219, 0.334408595541759 },
{ 5860, 0.324780147145748, 0.334228176834424 },
{ 5870, 0.324582591753991, 0.33404823757468 },
{ 5880, 0.324385797573479, 0.333868776603699 },
{ 5890, 0.324189760773522, 0.333689792759937 },
{ 5900, 0.323994477546069, 0.333511284879243 },
{ 5910, 0.323799944105563, 0.333333251794967 },
{ 5920, 0.323606156688797, 0.33315569233807 },
{ 5930, 0.32341311155477, 0.332978605337232 },
{ 5940, 0.323220804984549, 0.332801989618949 },
{ 5950, 0.323029233281125, 0.33262584400764 },
{ 5960, 0.322838392769274, 0.332450167325745 },
{ 5970, 0.322648279795422, 0.332274958393826 },
{ 5980, 0.322458890727498, 0.332100216030663 },
{ 5990, 0.322270221954808, 0.331925939053347 },
{ 6000, 0.322082269887888, 0.331752126277376 },
{ 6010, 0.321895030958374, 0.331578776516748 },
{ 6020, 0.321708501618868, 0.331405888584047 },
{ 6030, 0.321522678342801, 0.331233461290538 },
{ 6040, 0.3213375576243, 0.331061493446248 },
{ 6050, 0.32115313597806, 0.330889983860056 },
{ 6060, 0.320969409939206, 0.330718931339777 },
{ 6070, 0.320786376063166, 0.330548334692243 },
{ 6080, 0.320604030925542, 0.330378192723386 },
{ 6090, 0.32042237112198, 0.330208504238316 },
{ 6100, 0.32024139326804, 0.330039268041404 },
{ 6110, 0.320061093999071, 0.329870482936352 },
{ 6120, 0.319881469970083, 0.329702147726276 },
{ 6130, 0.319702517855622, 0.329534261213777 },
{ 6140, 0.319524234349642, 0.329366822201013 },
{ 6150, 0.319346616165388, 0.329199829489774 },
{ 6160, 0.319169660035263, 0.32903328188155 },
{ 6170, 0.318993362710712, 0.328867178177603 },
{ 6180, 0.3188177209621, 0.328701517179031 },
{ 6190, 0.318642731578585, 0.32853629768684 },
{ 6200, 0.318468391368004, 0.328371518502004 },
{ 6210, 0.318294697156752, 0.328207178425535 },
{ 6220, 0.31812164578966, 0.328043276258542 },
{ 6230, 0.31794923412988, 0.327879810802294 },
{ 6240, 0.317777459058767, 0.327716780858286 },
{ 6250, 0.317606317475763, 0.32755418522829 },
{ 6260, 0.317435806298278, 0.32739202271442 },
{ 6270, 0.317265922461579, 0.327230292119189 },
{ 6280, 0.317096662918675, 0.327068992245565 },
{ 6290, 0.316928024640201, 0.326908121897025 },
{ 6300, 0.316760004614306, 0.326747679877612 },
{ 6310, 0.316592599846543, 0.326587664991987 },
{ 6320, 0.316425807359756, 0.326428076045483 },
{ 6330, 0.316259624193968, 0.326268911844154 },
{ 6340, 0.316094047406274, 0.326110171194829 },
{ 6350, 0.315929074070729, 0.325951852905159 },
{ 6360, 0.315764701278241, 0.325793955783666 },
{ 6370, 0.315600926136464, 0.325636478639792 },
{ 6380, 0.315437745769688, 0.325479420283945 },
{ 6390, 0.315275157318735, 0.325322779527545 },
{ 6400, 0.315113157940854, 0.325166555183068 },
{ 6410, 0.314951744809611, 0.325010746064094 },
{ 6420, 0.314790915114793, 0.324855350985344 },
{ 6430, 0.314630666062295, 0.324700368762729 },
{ 6440, 0.314470994874025, 0.324545798213387 },
{ 6450, 0.314311898787797, 0.324391638155726 },
{ 6460, 0.314153375057231, 0.324237887409465 },
{ 6470, 0.31399542095165, 0.324084544795669 },
{ 6480, 0.313838033755984, 0.323931609136792 },
{ 6490, 0.313681210770667, 0.323779079256713 },
{ 6500, 0.313524949311538, 0.323626953980771 },
{ 6510, 0.313369246709745, 0.323475232135805 },
{ 6520, 0.313214100311644, 0.323323912550187 },
{ 6530, 0.313059507478705, 0.323172994053855 },
{ 6540, 0.312905465587415, 0.323022475478352 },
//@formatter:on
};
/**
* Search the 'KELVIN_TO_XY_LOOKUP_TABLE' for the XY entry closest to the given colour temperature.
* Uses a recursive 'QuickSearch' algorithm.
*
* @param kelvin the colour temperature in K to find
* @param min the first index in the lookup table
* @param max the last index in the lookup table
* @return an array with the found CIE colour XY values
* @throws IndexOutOfBoundsException if the colour temperature is out of range 'min' .. 'max'
*/
private static double[] kelvinToXY(double kelvin, int min, int max) throws IndexOutOfBoundsException {
if (min < 0 || max < min || max >= KELVIN_TO_XY_LOOKUP_TABLE.length) {
throw new IndexOutOfBoundsException("kelvinToXY() 'min' or 'max' index out of bounds");
}
int mid = (min + max) / 2;
double delta = kelvin - KELVIN_TO_XY_LOOKUP_TABLE[mid][0];
if (delta >= 10) {
return kelvinToXY(kelvin, mid + 1, max);
}
if (delta <= -10) {
return kelvinToXY(kelvin, min, mid - 1);
}
return new double[] { KELVIN_TO_XY_LOOKUP_TABLE[mid][1], KELVIN_TO_XY_LOOKUP_TABLE[mid][2] };
}
/**
* Convert a colour temperature in Kelvin to a point in the CIE XY colour space.
* Uses a lookup table as described <a href=
* "https://www.waveformlighting.com/tech/calculate-cie-1931-xy-coordinates-from-cct">here</a>.
*
* @param kelvin the colour temperature in K to be converted
* @return an array with the found CIE colour XY values
* @throws IndexOutOfBoundsException if the colour temperature is out of range 2000K .. 6500K
*/
public static double[] kelvinToXY(double kelvin) throws IndexOutOfBoundsException {
int indexMax = KELVIN_TO_XY_LOOKUP_TABLE.length - 1;
double kelvinMin = KELVIN_TO_XY_LOOKUP_TABLE[0][0];
double kelvinMax = KELVIN_TO_XY_LOOKUP_TABLE[indexMax][0];
if (kelvin < kelvinMin || kelvin > kelvinMax) {
throw new IndexOutOfBoundsException(
String.format("kelvinToXY() %.0f K out of range %.0f K .. %.0f K", kelvin, kelvinMin, kelvinMax));
}
return kelvinToXY(kelvin, 0, indexMax);
}
/**
* Convert a point in the CIE XY colour space to a colour temperature in Kelvin.
* Uses McCamy's approximation as described <a href=
* "https://www.waveformlighting.com/tech/calculate-color-temperature-cct-from-cie-1931-xy-coordinates">here</a>.
*
* @param xy an array with the CIE colour XY values to be converted
* @return the colour temperature in K
* @throws IndexOutOfBoundsException if the wrong number of arguments is provided
*/
public static double xyToKelvin(double[] xy) {
if (xy.length != 2) {
throw new IllegalArgumentException("xyToKelvin() requires 2 arguments");
}
double n = (xy[0] - 0.3320) / (0.1858 - xy[1]);
return (437 * Math.pow(n, 3)) + (3601 * Math.pow(n, 2)) + (6861 * n) + 5517;
}
}

19
bundles/org.openhab.core/src/test/java/org/openhab/core/util/ColorUtilTest.java
View File

@ -16,6 +16,7 @@ import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.lessThan;
import static org.hamcrest.Matchers.lessThanOrEqualTo;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
@ -641,4 +642,22 @@ public class ColorUtilTest {
rgbw2[3].doubleValue() / 100, e.getMessage()));
}
}
/**
* Test conversion between colour temperature in Kelvin and points on the colour
* temperature locus in the CIE XY colour space
*/
@Test
void testKelvinXyConversion() {
// test minimum and maximum limits 500..153 Mirek i.e. 2000..6536 Kelvin
assertThrows(IndexOutOfBoundsException.class, () -> ColorUtil.kelvinToXY(1000000 / 501));
assertDoesNotThrow(() -> ColorUtil.kelvinToXY(1000000 / 500));
assertDoesNotThrow(() -> ColorUtil.kelvinToXY(1000000 / 153));
assertThrows(IndexOutOfBoundsException.class, () -> ColorUtil.kelvinToXY(1000000 / 152));
// test round trips K => XY => K
for (double kelvin = 2000; kelvin <= 6536; kelvin += 5) {
assertEquals(kelvin, ColorUtil.xyToKelvin(ColorUtil.kelvinToXY(kelvin)), 15);
}
}
}