/* * Copyright 2016 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "SkColorPriv.h" #include "SkColorSpace_Base.h" #include "SkColorSpaceXform.h" #include "SkOpts.h" #include "SkSRGB.h" static constexpr float sk_linear_from_2dot2[256] = { 0.000000000000000000f, 0.000005077051900662f, 0.000023328004666099f, 0.000056921765712193f, 0.000107187362341244f, 0.000175123977503027f, 0.000261543754548491f, 0.000367136269815943f, 0.000492503787191433f, 0.000638182842167022f, 0.000804658499513058f, 0.000992374304074325f, 0.001201739522438400f, 0.001433134589671860f, 0.001686915316789280f, 0.001963416213396470f, 0.002262953160706430f, 0.002585825596234170f, 0.002932318323938360f, 0.003302703032003640f, 0.003697239578900130f, 0.004116177093282750f, 0.004559754922526020f, 0.005028203456855540f, 0.005521744850239660f, 0.006040593654849810f, 0.006584957382581690f, 0.007155037004573030f, 0.007751027397660610f, 0.008373117745148580f, 0.009021491898012130f, 0.009696328701658230f, 0.010397802292555300f, 0.011126082368383200f, 0.011881334434813700f, 0.012663720031582100f, 0.013473396940142600f, 0.014310519374884100f, 0.015175238159625200f, 0.016067700890886900f, 0.016988052089250000f, 0.017936433339950200f, 0.018912983423721500f, 0.019917838438785700f, 0.020951131914781100f, 0.022012994919336500f, 0.023103556157921400f, 0.024222942067534200f, 0.025371276904734600f, 0.026548682828472900f, 0.027755279978126000f, 0.028991186547107800f, 0.030256518852388700f, 0.031551391400226400f, 0.032875916948383800f, 0.034230206565082000f, 0.035614369684918800f, 0.037028514161960200f, 0.038472746320194600f, 0.039947171001525600f, 0.041451891611462500f, 0.042987010162657100f, 0.044552627316421400f, 0.046148842422351000f, 0.047775753556170600f, 0.049433457555908000f, 0.051122050056493400f, 0.052841625522879000f, 0.054592277281760300f, 0.056374097551979800f, 0.058187177473685400f, 0.060031607136313200f, 0.061907475605455800f, 0.063814870948677200f, 0.065753880260330100f, 0.067724589685424300f, 0.069727084442598800f, 0.071761448846239100f, 0.073827766327784600f, 0.075926119456264800f, 0.078056589958101900f, 0.080219258736215100f, 0.082414205888459200f, 0.084641510725429500f, 0.086901251787660300f, 0.089193506862247800f, 0.091518352998919500f, 0.093875866525577800f, 0.096266123063339700f, 0.098689197541094500f, 0.101145164209600000f, 0.103634096655137000f, 0.106156067812744000f, 0.108711149979039000f, 0.111299414824660000f, 0.113920933406333000f, 0.116575776178572000f, 0.119264013005047000f, 0.121985713169619000f, 0.124740945387051000f, 0.127529777813422000f, 0.130352278056244000f, 0.133208513184300000f, 0.136098549737202000f, 0.139022453734703000f, 0.141980290685736000f, 0.144972125597231000f, 0.147998022982685000f, 0.151058046870511000f, 0.154152260812165000f, 0.157280727890073000f, 0.160443510725344000f, 0.163640671485290000f, 0.166872271890766000f, 0.170138373223312000f, 0.173439036332135000f, 0.176774321640903000f, 0.180144289154390000f, 0.183548998464951000f, 0.186988508758844000f, 0.190462878822409000f, 0.193972167048093000f, 0.197516431440340000f, 0.201095729621346000f, 0.204710118836677000f, 0.208359655960767000f, 0.212044397502288000f, 0.215764399609395000f, 0.219519718074868000f, 0.223310408341127000f, 0.227136525505149000f, 0.230998124323267000f, 0.234895259215880000f, 0.238827984272048000f, 0.242796353254002000f, 0.246800419601550000f, 0.250840236436400000f, 0.254915856566385000f, 0.259027332489606000f, 0.263174716398492000f, 0.267358060183772000f, 0.271577415438375000f, 0.275832833461245000f, 0.280124365261085000f, 0.284452061560024000f, 0.288815972797219000f, 0.293216149132375000f, 0.297652640449211000f, 0.302125496358853000f, 0.306634766203158000f, 0.311180499057984000f, 0.315762743736397000f, 0.320381548791810000f, 0.325036962521076000f, 0.329729032967515000f, 0.334457807923889000f, 0.339223334935327000f, 0.344025661302187000f, 0.348864834082879000f, 0.353740900096629000f, 0.358653905926199000f, 0.363603897920553000f, 0.368590922197487000f, 0.373615024646202000f, 0.378676250929840000f, 0.383774646487975000f, 0.388910256539059000f, 0.394083126082829000f, 0.399293299902674000f, 0.404540822567962000f, 0.409825738436323000f, 0.415148091655907000f, 0.420507926167587000f, 0.425905285707146000f, 0.431340213807410000f, 0.436812753800359000f, 0.442322948819202000f, 0.447870841800410000f, 0.453456475485731000f, 0.459079892424160000f, 0.464741134973889000f, 0.470440245304218000f, 0.476177265397440000f, 0.481952237050698000f, 0.487765201877811000f, 0.493616201311074000f, 0.499505276603030000f, 0.505432468828216000f, 0.511397818884880000f, 0.517401367496673000f, 0.523443155214325000f, 0.529523222417277000f, 0.535641609315311000f, 0.541798355950137000f, 0.547993502196972000f, 0.554227087766085000f, 0.560499152204328000f, 0.566809734896638000f, 0.573158875067523000f, 0.579546611782525000f, 0.585972983949661000f, 0.592438030320847000f, 0.598941789493296000f, 0.605484299910907000f, 0.612065599865624000f, 0.618685727498780000f, 0.625344720802427000f, 0.632042617620641000f, 0.638779455650817000f, 0.645555272444935000f, 0.652370105410821000f, 0.659223991813387000f, 0.666116968775851000f, 0.673049073280942000f, 0.680020342172095000f, 0.687030812154625000f, 0.694080519796882000f, 0.701169501531402000f, 0.708297793656032000f, 0.715465432335048000f, 0.722672453600255000f, 0.729918893352071000f, 0.737204787360605000f, 0.744530171266715000f, 0.751895080583051000f, 0.759299550695091000f, 0.766743616862161000f, 0.774227314218442000f, 0.781750677773962000f, 0.789313742415586000f, 0.796916542907978000f, 0.804559113894567000f, 0.812241489898490000f, 0.819963705323528000f, 0.827725794455034000f, 0.835527791460841000f, 0.843369730392169000f, 0.851251645184515000f, 0.859173569658532000f, 0.867135537520905000f, 0.875137582365205000f, 0.883179737672745000f, 0.891262036813419000f, 0.899384513046529000f, 0.907547199521614000f, 0.915750129279253000f, 0.923993335251873000f, 0.932276850264543000f, 0.940600707035753000f, 0.948964938178195000f, 0.957369576199527000f, 0.965814653503130000f, 0.974300202388861000f, 0.982826255053791000f, 0.991392843592940000f, 1.000000000000000000f, }; static void build_table_linear_from_gamma(float* outTable, float exponent) { for (float x = 0.0f; x <= 1.0f; x += (1.0f/255.0f)) { *outTable++ = powf(x, exponent); } } // Interpolating lookup in a variably sized table. static float interp_lut(float input, const float* table, int tableSize) { float index = input * (tableSize - 1); float diff = index - sk_float_floor2int(index); return table[(int) sk_float_floor2int(index)] * (1.0f - diff) + table[(int) sk_float_ceil2int(index)] * diff; } // outTable is always 256 entries, inTable may be larger or smaller. static void build_table_linear_from_gamma(float* outTable, const float* inTable, int inTableSize) { if (256 == inTableSize) { memcpy(outTable, inTable, sizeof(float) * 256); return; } for (float x = 0.0f; x <= 1.0f; x += (1.0f/255.0f)) { *outTable++ = interp_lut(x, inTable, inTableSize); } } static void build_table_linear_from_gamma(float* outTable, float g, float a, float b, float c, float d, float e, float f) { // Y = (aX + b)^g + c for X >= d // Y = eX + f otherwise for (float x = 0.0f; x <= 1.0f; x += (1.0f/255.0f)) { if (x >= d) { *outTable++ = powf(a * x + b, g) + c; } else { *outTable++ = e * x + f; } } } static inline bool compute_gamut_xform(SkMatrix44* srcToDst, const SkMatrix44& srcToXYZ, const SkMatrix44& dstToXYZ) { if (!dstToXYZ.invert(srcToDst)) { return false; } srcToDst->postConcat(srcToXYZ); return true; } /////////////////////////////////////////////////////////////////////////////////////////////////// static constexpr uint8_t linear_to_srgb[1024] = { 0, 3, 6, 10, 13, 15, 18, 20, 22, 23, 25, 27, 28, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 49, 50, 51, 52, 53, 53, 54, 55, 56, 56, 57, 58, 58, 59, 60, 61, 61, 62, 62, 63, 64, 64, 65, 66, 66, 67, 67, 68, 68, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 75, 76, 76, 77, 77, 78, 78, 79, 79, 79, 80, 80, 81, 81, 82, 82, 83, 83, 84, 84, 85, 85, 85, 86, 86, 87, 87, 88, 88, 88, 89, 89, 90, 90, 91, 91, 91, 92, 92, 93, 93, 93, 94, 94, 95, 95, 95, 96, 96, 97, 97, 97, 98, 98, 98, 99, 99, 99, 100, 100, 101, 101, 101, 102, 102, 102, 103, 103, 103, 104, 104, 104, 105, 105, 106, 106, 106, 107, 107, 107, 108, 108, 108, 109, 109, 109, 110, 110, 110, 110, 111, 111, 111, 112, 112, 112, 113, 113, 113, 114, 114, 114, 115, 115, 115, 115, 116, 116, 116, 117, 117, 117, 118, 118, 118, 118, 119, 119, 119, 120, 120, 120, 121, 121, 121, 121, 122, 122, 122, 123, 123, 123, 123, 124, 124, 124, 125, 125, 125, 125, 126, 126, 126, 126, 127, 127, 127, 128, 128, 128, 128, 129, 129, 129, 129, 130, 130, 130, 130, 131, 131, 131, 131, 132, 132, 132, 133, 133, 133, 133, 134, 134, 134, 134, 135, 135, 135, 135, 136, 136, 136, 136, 137, 137, 137, 137, 138, 138, 138, 138, 138, 139, 139, 139, 139, 140, 140, 140, 140, 141, 141, 141, 141, 142, 142, 142, 142, 143, 143, 143, 143, 143, 144, 144, 144, 144, 145, 145, 145, 145, 146, 146, 146, 146, 146, 147, 147, 147, 147, 148, 148, 148, 148, 148, 149, 149, 149, 149, 150, 150, 150, 150, 150, 151, 151, 151, 151, 152, 152, 152, 152, 152, 153, 153, 153, 153, 153, 154, 154, 154, 154, 155, 155, 155, 155, 155, 156, 156, 156, 156, 156, 157, 157, 157, 157, 157, 158, 158, 158, 158, 158, 159, 159, 159, 159, 159, 160, 160, 160, 160, 160, 161, 161, 161, 161, 161, 162, 162, 162, 162, 162, 163, 163, 163, 163, 163, 164, 164, 164, 164, 164, 165, 165, 165, 165, 165, 166, 166, 166, 166, 166, 167, 167, 167, 167, 167, 168, 168, 168, 168, 168, 168, 169, 169, 169, 169, 169, 170, 170, 170, 170, 170, 171, 171, 171, 171, 171, 171, 172, 172, 172, 172, 172, 173, 173, 173, 173, 173, 173, 174, 174, 174, 174, 174, 175, 175, 175, 175, 175, 175, 176, 176, 176, 176, 176, 177, 177, 177, 177, 177, 177, 178, 178, 178, 178, 178, 178, 179, 179, 179, 179, 179, 179, 180, 180, 180, 180, 180, 181, 181, 181, 181, 181, 181, 182, 182, 182, 182, 182, 182, 183, 183, 183, 183, 183, 183, 184, 184, 184, 184, 184, 184, 185, 185, 185, 185, 185, 185, 186, 186, 186, 186, 186, 186, 187, 187, 187, 187, 187, 187, 188, 188, 188, 188, 188, 188, 189, 189, 189, 189, 189, 189, 190, 190, 190, 190, 190, 190, 191, 191, 191, 191, 191, 191, 191, 192, 192, 192, 192, 192, 192, 193, 193, 193, 193, 193, 193, 194, 194, 194, 194, 194, 194, 194, 195, 195, 195, 195, 195, 195, 196, 196, 196, 196, 196, 196, 197, 197, 197, 197, 197, 197, 197, 198, 198, 198, 198, 198, 198, 199, 199, 199, 199, 199, 199, 199, 200, 200, 200, 200, 200, 200, 200, 201, 201, 201, 201, 201, 201, 202, 202, 202, 202, 202, 202, 202, 203, 203, 203, 203, 203, 203, 203, 204, 204, 204, 204, 204, 204, 204, 205, 205, 205, 205, 205, 205, 206, 206, 206, 206, 206, 206, 206, 207, 207, 207, 207, 207, 207, 207, 208, 208, 208, 208, 208, 208, 208, 209, 209, 209, 209, 209, 209, 209, 210, 210, 210, 210, 210, 210, 210, 211, 211, 211, 211, 211, 211, 211, 212, 212, 212, 212, 212, 212, 212, 212, 213, 213, 213, 213, 213, 213, 213, 214, 214, 214, 214, 214, 214, 214, 215, 215, 215, 215, 215, 215, 215, 216, 216, 216, 216, 216, 216, 216, 216, 217, 217, 217, 217, 217, 217, 217, 218, 218, 218, 218, 218, 218, 218, 219, 219, 219, 219, 219, 219, 219, 219, 220, 220, 220, 220, 220, 220, 220, 221, 221, 221, 221, 221, 221, 221, 221, 222, 222, 222, 222, 222, 222, 222, 222, 223, 223, 223, 223, 223, 223, 223, 224, 224, 224, 224, 224, 224, 224, 224, 225, 225, 225, 225, 225, 225, 225, 225, 226, 226, 226, 226, 226, 226, 226, 227, 227, 227, 227, 227, 227, 227, 227, 228, 228, 228, 228, 228, 228, 228, 228, 229, 229, 229, 229, 229, 229, 229, 229, 230, 230, 230, 230, 230, 230, 230, 230, 231, 231, 231, 231, 231, 231, 231, 231, 232, 232, 232, 232, 232, 232, 232, 232, 233, 233, 233, 233, 233, 233, 233, 233, 234, 234, 234, 234, 234, 234, 234, 234, 235, 235, 235, 235, 235, 235, 235, 235, 236, 236, 236, 236, 236, 236, 236, 236, 236, 237, 237, 237, 237, 237, 237, 237, 237, 238, 238, 238, 238, 238, 238, 238, 238, 239, 239, 239, 239, 239, 239, 239, 239, 239, 240, 240, 240, 240, 240, 240, 240, 240, 241, 241, 241, 241, 241, 241, 241, 241, 241, 242, 242, 242, 242, 242, 242, 242, 242, 243, 243, 243, 243, 243, 243, 243, 243, 243, 244, 244, 244, 244, 244, 244, 244, 244, 245, 245, 245, 245, 245, 245, 245, 245, 245, 246, 246, 246, 246, 246, 246, 246, 246, 246, 247, 247, 247, 247, 247, 247, 247, 247, 248, 248, 248, 248, 248, 248, 248, 248, 248, 249, 249, 249, 249, 249, 249, 249, 249, 249, 250, 250, 250, 250, 250, 250, 250, 250, 250, 251, 251, 251, 251, 251, 251, 251, 251, 251, 252, 252, 252, 252, 252, 252, 252, 252, 252, 253, 253, 253, 253, 253, 253, 253, 253, 253, 254, 254, 254, 254, 254, 254, 254, 254, 254, 255, 255, 255, 255, 255 }; static constexpr uint8_t linear_to_2dot2[1024] = { 0, 11, 15, 18, 21, 23, 25, 26, 28, 30, 31, 32, 34, 35, 36, 37, 39, 40, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 50, 51, 52, 53, 54, 54, 55, 56, 56, 57, 58, 58, 59, 60, 60, 61, 62, 62, 63, 63, 64, 65, 65, 66, 66, 67, 68, 68, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 74, 75, 75, 76, 76, 77, 77, 78, 78, 79, 79, 80, 80, 81, 81, 81, 82, 82, 83, 83, 84, 84, 84, 85, 85, 86, 86, 87, 87, 87, 88, 88, 89, 89, 89, 90, 90, 91, 91, 91, 92, 92, 93, 93, 93, 94, 94, 94, 95, 95, 96, 96, 96, 97, 97, 97, 98, 98, 98, 99, 99, 99, 100, 100, 101, 101, 101, 102, 102, 102, 103, 103, 103, 104, 104, 104, 105, 105, 105, 106, 106, 106, 107, 107, 107, 108, 108, 108, 108, 109, 109, 109, 110, 110, 110, 111, 111, 111, 112, 112, 112, 112, 113, 113, 113, 114, 114, 114, 115, 115, 115, 115, 116, 116, 116, 117, 117, 117, 117, 118, 118, 118, 119, 119, 119, 119, 120, 120, 120, 121, 121, 121, 121, 122, 122, 122, 123, 123, 123, 123, 124, 124, 124, 124, 125, 125, 125, 125, 126, 126, 126, 127, 127, 127, 127, 128, 128, 128, 128, 129, 129, 129, 129, 130, 130, 130, 130, 131, 131, 131, 131, 132, 132, 132, 132, 133, 133, 133, 133, 134, 134, 134, 134, 135, 135, 135, 135, 136, 136, 136, 136, 137, 137, 137, 137, 138, 138, 138, 138, 138, 139, 139, 139, 139, 140, 140, 140, 140, 141, 141, 141, 141, 142, 142, 142, 142, 142, 143, 143, 143, 143, 144, 144, 144, 144, 144, 145, 145, 145, 145, 146, 146, 146, 146, 146, 147, 147, 147, 147, 148, 148, 148, 148, 148, 149, 149, 149, 149, 149, 150, 150, 150, 150, 151, 151, 151, 151, 151, 152, 152, 152, 152, 152, 153, 153, 153, 153, 154, 154, 154, 154, 154, 155, 155, 155, 155, 155, 156, 156, 156, 156, 156, 157, 157, 157, 157, 157, 158, 158, 158, 158, 158, 159, 159, 159, 159, 159, 160, 160, 160, 160, 160, 161, 161, 161, 161, 161, 162, 162, 162, 162, 162, 163, 163, 163, 163, 163, 164, 164, 164, 164, 164, 165, 165, 165, 165, 165, 165, 166, 166, 166, 166, 166, 167, 167, 167, 167, 167, 168, 168, 168, 168, 168, 168, 169, 169, 169, 169, 169, 170, 170, 170, 170, 170, 171, 171, 171, 171, 171, 171, 172, 172, 172, 172, 172, 173, 173, 173, 173, 173, 173, 174, 174, 174, 174, 174, 174, 175, 175, 175, 175, 175, 176, 176, 176, 176, 176, 176, 177, 177, 177, 177, 177, 177, 178, 178, 178, 178, 178, 179, 179, 179, 179, 179, 179, 180, 180, 180, 180, 180, 180, 181, 181, 181, 181, 181, 181, 182, 182, 182, 182, 182, 182, 183, 183, 183, 183, 183, 183, 184, 184, 184, 184, 184, 185, 185, 185, 185, 185, 185, 186, 186, 186, 186, 186, 186, 186, 187, 187, 187, 187, 187, 187, 188, 188, 188, 188, 188, 188, 189, 189, 189, 189, 189, 189, 190, 190, 190, 190, 190, 190, 191, 191, 191, 191, 191, 191, 192, 192, 192, 192, 192, 192, 192, 193, 193, 193, 193, 193, 193, 194, 194, 194, 194, 194, 194, 195, 195, 195, 195, 195, 195, 195, 196, 196, 196, 196, 196, 196, 197, 197, 197, 197, 197, 197, 197, 198, 198, 198, 198, 198, 198, 199, 199, 199, 199, 199, 199, 199, 200, 200, 200, 200, 200, 200, 201, 201, 201, 201, 201, 201, 201, 202, 202, 202, 202, 202, 202, 202, 203, 203, 203, 203, 203, 203, 204, 204, 204, 204, 204, 204, 204, 205, 205, 205, 205, 205, 205, 205, 206, 206, 206, 206, 206, 206, 206, 207, 207, 207, 207, 207, 207, 207, 208, 208, 208, 208, 208, 208, 209, 209, 209, 209, 209, 209, 209, 210, 210, 210, 210, 210, 210, 210, 211, 211, 211, 211, 211, 211, 211, 212, 212, 212, 212, 212, 212, 212, 213, 213, 213, 213, 213, 213, 213, 213, 214, 214, 214, 214, 214, 214, 214, 215, 215, 215, 215, 215, 215, 215, 216, 216, 216, 216, 216, 216, 216, 217, 217, 217, 217, 217, 217, 217, 218, 218, 218, 218, 218, 218, 218, 218, 219, 219, 219, 219, 219, 219, 219, 220, 220, 220, 220, 220, 220, 220, 221, 221, 221, 221, 221, 221, 221, 221, 222, 222, 222, 222, 222, 222, 222, 223, 223, 223, 223, 223, 223, 223, 223, 224, 224, 224, 224, 224, 224, 224, 225, 225, 225, 225, 225, 225, 225, 225, 226, 226, 226, 226, 226, 226, 226, 226, 227, 227, 227, 227, 227, 227, 227, 228, 228, 228, 228, 228, 228, 228, 228, 229, 229, 229, 229, 229, 229, 229, 229, 230, 230, 230, 230, 230, 230, 230, 230, 231, 231, 231, 231, 231, 231, 231, 232, 232, 232, 232, 232, 232, 232, 232, 233, 233, 233, 233, 233, 233, 233, 233, 234, 234, 234, 234, 234, 234, 234, 234, 235, 235, 235, 235, 235, 235, 235, 235, 236, 236, 236, 236, 236, 236, 236, 236, 237, 237, 237, 237, 237, 237, 237, 237, 238, 238, 238, 238, 238, 238, 238, 238, 238, 239, 239, 239, 239, 239, 239, 239, 239, 240, 240, 240, 240, 240, 240, 240, 240, 241, 241, 241, 241, 241, 241, 241, 241, 242, 242, 242, 242, 242, 242, 242, 242, 243, 243, 243, 243, 243, 243, 243, 243, 243, 244, 244, 244, 244, 244, 244, 244, 244, 245, 245, 245, 245, 245, 245, 245, 245, 245, 246, 246, 246, 246, 246, 246, 246, 246, 247, 247, 247, 247, 247, 247, 247, 247, 248, 248, 248, 248, 248, 248, 248, 248, 248, 249, 249, 249, 249, 249, 249, 249, 249, 249, 250, 250, 250, 250, 250, 250, 250, 250, 251, 251, 251, 251, 251, 251, 251, 251, 251, 252, 252, 252, 252, 252, 252, 252, 252, 252, 253, 253, 253, 253, 253, 253, 253, 253, 254, 254, 254, 254, 254, 254, 254, 254, 254, 255, 255, 255, 255, 255, }; // Expand range from 0-1 to 0-255, then convert. static uint8_t clamp_normalized_float_to_byte(float v) { // The ordering of the logic is a little strange here in order // to make sure we convert NaNs to 0. v = v * 255.0f; if (v >= 254.5f) { return 255; } else if (v >= 0.5f) { return (uint8_t) (v + 0.5f); } else { return 0; } } static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float exponent) { float toGammaExp = 1.0f / exponent; for (int i = 0; i < outTableSize; i++) { float x = ((float) i) * (1.0f / ((float) (outTableSize - 1))); outTable[i] = clamp_normalized_float_to_byte(powf(x, toGammaExp)); } } // Inverse table lookup. Ex: what index corresponds to the input value? This will // have strange results when the table is non-increasing. But any sane gamma // function will be increasing. static float inverse_interp_lut(float input, float* table, int tableSize) { if (input <= table[0]) { return table[0]; } else if (input >= table[tableSize - 1]) { return 1.0f; } for (int i = 1; i < tableSize; i++) { if (table[i] >= input) { // We are guaranteed that input is greater than table[i - 1]. float diff = input - table[i - 1]; float distance = table[i] - table[i - 1]; float index = (i - 1) + diff / distance; return index / (tableSize - 1); } } // Should be unreachable, since we'll return before the loop if input is // larger than the last entry. SkASSERT(false); return 0.0f; } static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float* inTable, int inTableSize) { for (int i = 0; i < outTableSize; i++) { float x = ((float) i) * (1.0f / ((float) (outTableSize - 1))); float y = inverse_interp_lut(x, inTable, inTableSize); outTable[i] = clamp_normalized_float_to_byte(y); } } static float inverse_parametric(float x, float g, float a, float b, float c, float d, float e, float f) { // We need to take the inverse of the following piecewise function. // Y = (aX + b)^g + c for X >= d // Y = eX + f otherwise // Assume that the gamma function is continuous, or this won't make much sense anyway. // Plug in |d| to the first equation to calculate the new piecewise interval. // Then simply use the inverse of the original functions. float interval = e * d + f; if (x < interval) { // X = (Y - F) / E if (0.0f == e) { // The gamma curve for this segment is constant, so the inverse is undefined. // Since this is the lower segment, guess zero. return 0.0f; } return (x - f) / e; } // X = ((Y - C)^(1 / G) - B) / A if (0.0f == a || 0.0f == g) { // The gamma curve for this segment is constant, so the inverse is undefined. // Since this is the upper segment, guess one. return 1.0f; } return (powf(x - c, 1.0f / g) - b) / a; } static void build_table_linear_to_gamma(uint8_t* outTable, int outTableSize, float g, float a, float b, float c, float d, float e, float f) { for (int i = 0; i < outTableSize; i++) { float x = ((float) i) * (1.0f / ((float) (outTableSize - 1))); float y = inverse_parametric(x, g, a, b, c, d, e, f); outTable[i] = clamp_normalized_float_to_byte(y); } } /////////////////////////////////////////////////////////////////////////////////////////////////// std::unique_ptr SkColorSpaceXform::New(const sk_sp& srcSpace, const sk_sp& dstSpace) { if (!srcSpace || !dstSpace) { // Invalid input return nullptr; } if (as_CSB(dstSpace)->colorLUT()) { // It would be really weird for a dst profile to have a color LUT. I don't think // we need to support this. return nullptr; } SkMatrix44 srcToDst(SkMatrix44::kUninitialized_Constructor); if (!compute_gamut_xform(&srcToDst, srcSpace->xyz(), dstSpace->xyz())) { return nullptr; } if (0.0f == srcToDst.getFloat(3, 0) && 0.0f == srcToDst.getFloat(3, 1) && 0.0f == srcToDst.getFloat(3, 2) && !as_CSB(srcSpace)->colorLUT()) { switch (dstSpace->gammaNamed()) { case SkColorSpace::kSRGB_GammaNamed: return std::unique_ptr( new SkFastXform(srcSpace, srcToDst, dstSpace)); case SkColorSpace::k2Dot2Curve_GammaNamed: return std::unique_ptr( new SkFastXform(srcSpace, srcToDst, dstSpace)); default: return std::unique_ptr( new SkFastXform(srcSpace, srcToDst, dstSpace)); } } return std::unique_ptr(new SkDefaultXform(srcSpace, srcToDst, dstSpace)); } /////////////////////////////////////////////////////////////////////////////////////////////////// static void build_src_to_dst(float srcToDstArray[12], const SkMatrix44& srcToDstMatrix) { // Build the following row major matrix: // rX gX bX 0 // rY gY bY 0 // rZ gZ bZ 0 // Swap R and B if necessary to make sure that we output SkPMColor order. #ifdef SK_PMCOLOR_IS_BGRA srcToDstArray[0] = srcToDstMatrix.getFloat(0, 2); srcToDstArray[1] = srcToDstMatrix.getFloat(0, 1); srcToDstArray[2] = srcToDstMatrix.getFloat(0, 0); srcToDstArray[3] = 0.0f; srcToDstArray[4] = srcToDstMatrix.getFloat(1, 2); srcToDstArray[5] = srcToDstMatrix.getFloat(1, 1); srcToDstArray[6] = srcToDstMatrix.getFloat(1, 0); srcToDstArray[7] = 0.0f; srcToDstArray[8] = srcToDstMatrix.getFloat(2, 2); srcToDstArray[9] = srcToDstMatrix.getFloat(2, 1); srcToDstArray[10] = srcToDstMatrix.getFloat(2, 0); srcToDstArray[11] = 0.0f; #else srcToDstArray[0] = srcToDstMatrix.getFloat(0, 0); srcToDstArray[1] = srcToDstMatrix.getFloat(0, 1); srcToDstArray[2] = srcToDstMatrix.getFloat(0, 2); srcToDstArray[3] = 0.0f; srcToDstArray[4] = srcToDstMatrix.getFloat(1, 0); srcToDstArray[5] = srcToDstMatrix.getFloat(1, 1); srcToDstArray[6] = srcToDstMatrix.getFloat(1, 2); srcToDstArray[7] = 0.0f; srcToDstArray[8] = srcToDstMatrix.getFloat(2, 0); srcToDstArray[9] = srcToDstMatrix.getFloat(2, 1); srcToDstArray[10] = srcToDstMatrix.getFloat(2, 2); srcToDstArray[11] = 0.0f; #endif } template SkFastXform::SkFastXform(const sk_sp& srcSpace, const SkMatrix44& srcToDst, const sk_sp& dstSpace) { build_src_to_dst(fSrcToDst, srcToDst); // Build tables to transform src gamma to linear. switch (srcSpace->gammaNamed()) { case SkColorSpace::kSRGB_GammaNamed: fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_from_gamma(fSrcGammaTableStorage, 1.0f); fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = fSrcGammaTableStorage; break; default: { const SkGammas* gammas = as_CSB(srcSpace)->gammas(); SkASSERT(gammas); for (int i = 0; i < 3; i++) { const SkGammaCurve& curve = (*gammas)[i]; if (i > 0) { // Check if this curve matches the first curve. In this case, we can // share the same table pointer. Logically, this should almost always // be true. I've never seen a profile where all three gamma curves // didn't match. But it is possible that they won't. // TODO (msarett): // This comparison won't catch the case where each gamma curve has a // pointer to its own look-up table, but the tables actually match. // Should we perform a deep compare of gamma tables here? Or should // we catch this when parsing the profile? Or should we not worry // about a bit of redundant work? if (curve.quickEquals((*gammas)[0])) { fSrcGammaTables[i] = fSrcGammaTables[0]; continue; } } if (curve.isNamed()) { switch (curve.fNamed) { case SkColorSpace::kSRGB_GammaNamed: fSrcGammaTables[i] = sk_linear_from_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fSrcGammaTables[i] = sk_linear_from_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], 1.0f); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; break; default: SkASSERT(false); break; } } else if (curve.isValue()) { build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fValue); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } else if (curve.isTable()) { build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fTable.get(), curve.fTableSize); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } else { SkASSERT(curve.isParametric()); build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fG, curve.fA, curve.fB, curve.fC, curve.fD, curve.fE, curve.fF); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } } } } // Build tables to transform linear to dst gamma. switch (dstSpace->gammaNamed()) { case SkColorSpace::kSRGB_GammaNamed: case SkColorSpace::k2Dot2Curve_GammaNamed: break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_to_gamma(fDstGammaTableStorage, kDstGammaTableSize, 1.0f); fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = fDstGammaTableStorage; break; default: { const SkGammas* gammas = as_CSB(dstSpace)->gammas(); SkASSERT(gammas); for (int i = 0; i < 3; i++) { const SkGammaCurve& curve = (*gammas)[i]; if (i > 0) { // Check if this curve matches the first curve. In this case, we can // share the same table pointer. Logically, this should almost always // be true. I've never seen a profile where all three gamma curves // didn't match. But it is possible that they won't. // TODO (msarett): // This comparison won't catch the case where each gamma curve has a // pointer to its own look-up table (but the tables actually match). // Should we perform a deep compare of gamma tables here? Or should // we catch this when parsing the profile? Or should we not worry // about a bit of redundant work? if (curve.quickEquals((*gammas)[0])) { fDstGammaTables[i] = fDstGammaTables[0]; continue; } } if (curve.isNamed()) { switch (curve.fNamed) { case SkColorSpace::kSRGB_GammaNamed: fDstGammaTables[i] = linear_to_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fDstGammaTables[i] = linear_to_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_to_gamma( &fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, 1.0f); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; break; default: SkASSERT(false); break; } } else if (curve.isValue()) { build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fValue); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } else if (curve.isTable()) { build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fTable.get(), curve.fTableSize); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } else { SkASSERT(curve.isParametric()); build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fG, curve.fA, curve.fB, curve.fC, curve.fD, curve.fE, curve.fF); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } } } } } template <> void SkFastXform ::xform_RGB1_8888(uint32_t* dst, const uint32_t* src, uint32_t len) const { SkOpts::color_xform_RGB1_to_srgb(dst, src, len, fSrcGammaTables, fSrcToDst); } template <> void SkFastXform ::xform_RGB1_8888(uint32_t* dst, const uint32_t* src, uint32_t len) const { SkOpts::color_xform_RGB1_to_2dot2(dst, src, len, fSrcGammaTables, fSrcToDst); } template <> void SkFastXform ::xform_RGB1_8888(uint32_t* dst, const uint32_t* src, uint32_t len) const { SkOpts::color_xform_RGB1_to_table(dst, src, len, fSrcGammaTables, fSrcToDst, fDstGammaTables); } /////////////////////////////////////////////////////////////////////////////////////////////////// SkDefaultXform::SkDefaultXform(const sk_sp& srcSpace, const SkMatrix44& srcToDst, const sk_sp& dstSpace) : fColorLUT(sk_ref_sp((SkColorLookUpTable*) as_CSB(srcSpace)->colorLUT())) , fSrcToDst(srcToDst) { // Build tables to transform src gamma to linear. switch (srcSpace->gammaNamed()) { case SkColorSpace::kSRGB_GammaNamed: fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = sk_linear_from_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_from_gamma(fSrcGammaTableStorage, 1.0f); fSrcGammaTables[0] = fSrcGammaTables[1] = fSrcGammaTables[2] = fSrcGammaTableStorage; break; default: { const SkGammas* gammas = as_CSB(srcSpace)->gammas(); SkASSERT(gammas); for (int i = 0; i < 3; i++) { const SkGammaCurve& curve = (*gammas)[i]; if (i > 0) { // Check if this curve matches the first curve. In this case, we can // share the same table pointer. Logically, this should almost always // be true. I've never seen a profile where all three gamma curves // didn't match. But it is possible that they won't. // TODO (msarett): // This comparison won't catch the case where each gamma curve has a // pointer to its own look-up table, but the tables actually match. // Should we perform a deep compare of gamma tables here? Or should // we catch this when parsing the profile? Or should we not worry // about a bit of redundant work? if (curve.quickEquals((*gammas)[0])) { fSrcGammaTables[i] = fSrcGammaTables[0]; continue; } } if (curve.isNamed()) { switch (curve.fNamed) { case SkColorSpace::kSRGB_GammaNamed: fSrcGammaTables[i] = sk_linear_from_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fSrcGammaTables[i] = sk_linear_from_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], 1.0f); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; break; default: SkASSERT(false); break; } } else if (curve.isValue()) { build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fValue); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } else if (curve.isTable()) { build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fTable.get(), curve.fTableSize); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } else { SkASSERT(curve.isParametric()); build_table_linear_from_gamma(&fSrcGammaTableStorage[i * 256], curve.fG, curve.fA, curve.fB, curve.fC, curve.fD, curve.fE, curve.fF); fSrcGammaTables[i] = &fSrcGammaTableStorage[i * 256]; } } } } // Build tables to transform linear to dst gamma. switch (dstSpace->gammaNamed()) { case SkColorSpace::kSRGB_GammaNamed: fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = linear_to_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = linear_to_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_to_gamma(fDstGammaTableStorage, kDstGammaTableSize, 1.0f); fDstGammaTables[0] = fDstGammaTables[1] = fDstGammaTables[2] = fDstGammaTableStorage; break; default: { const SkGammas* gammas = as_CSB(dstSpace)->gammas(); SkASSERT(gammas); for (int i = 0; i < 3; i++) { const SkGammaCurve& curve = (*gammas)[i]; if (i > 0) { // Check if this curve matches the first curve. In this case, we can // share the same table pointer. Logically, this should almost always // be true. I've never seen a profile where all three gamma curves // didn't match. But it is possible that they won't. // TODO (msarett): // This comparison won't catch the case where each gamma curve has a // pointer to its own look-up table (but the tables actually match). // Should we perform a deep compare of gamma tables here? Or should // we catch this when parsing the profile? Or should we not worry // about a bit of redundant work? if (curve.quickEquals((*gammas)[0])) { fDstGammaTables[i] = fDstGammaTables[0]; continue; } } if (curve.isNamed()) { switch (curve.fNamed) { case SkColorSpace::kSRGB_GammaNamed: fDstGammaTables[i] = linear_to_srgb; break; case SkColorSpace::k2Dot2Curve_GammaNamed: fDstGammaTables[i] = linear_to_2dot2; break; case SkColorSpace::kLinear_GammaNamed: build_table_linear_to_gamma( &fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, 1.0f); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; break; default: SkASSERT(false); break; } } else if (curve.isValue()) { build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fValue); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } else if (curve.isTable()) { build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fTable.get(), curve.fTableSize); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } else { SkASSERT(curve.isParametric()); build_table_linear_to_gamma(&fDstGammaTableStorage[i * kDstGammaTableSize], kDstGammaTableSize, curve.fG, curve.fA, curve.fB, curve.fC, curve.fD, curve.fE, curve.fF); fDstGammaTables[i] = &fDstGammaTableStorage[i * kDstGammaTableSize]; } } } } } static float byte_to_float(uint8_t byte) { return ((float) byte) * (1.0f / 255.0f); } // Clamp to the 0-1 range. static float clamp_normalized_float(float v) { if (v > 1.0f) { return 1.0f; } else if ((v < 0.0f) || (v != v)) { return 0.0f; } else { return v; } } static void interp_3d_clut(float dst[3], float src[3], const SkColorLookUpTable* colorLUT) { // Call the src components x, y, and z. uint8_t maxX = colorLUT->fGridPoints[0] - 1; uint8_t maxY = colorLUT->fGridPoints[1] - 1; uint8_t maxZ = colorLUT->fGridPoints[2] - 1; // An approximate index into each of the three dimensions of the table. float x = src[0] * maxX; float y = src[1] * maxY; float z = src[2] * maxZ; // This gives us the low index for our interpolation. int ix = sk_float_floor2int(x); int iy = sk_float_floor2int(y); int iz = sk_float_floor2int(z); // Make sure the low index is not also the max index. ix = (maxX == ix) ? ix - 1 : ix; iy = (maxY == iy) ? iy - 1 : iy; iz = (maxZ == iz) ? iz - 1 : iz; // Weighting factors for the interpolation. float diffX = x - ix; float diffY = y - iy; float diffZ = z - iz; // Constants to help us navigate the 3D table. // Ex: Assume x = a, y = b, z = c. // table[a * n001 + b * n010 + c * n100] logically equals table[a][b][c]. const int n000 = 0; const int n001 = 3 * colorLUT->fGridPoints[1] * colorLUT->fGridPoints[2]; const int n010 = 3 * colorLUT->fGridPoints[2]; const int n011 = n001 + n010; const int n100 = 3; const int n101 = n100 + n001; const int n110 = n100 + n010; const int n111 = n110 + n001; // Base ptr into the table. float* ptr = &colorLUT->fTable[ix*n001 + iy*n010 + iz*n100]; // The code below performs a tetrahedral interpolation for each of the three // dst components. Once the tetrahedron containing the interpolation point is // identified, the interpolation is a weighted sum of grid values at the // vertices of the tetrahedron. The claim is that tetrahedral interpolation // provides a more accurate color conversion. // blogs.mathworks.com/steve/2006/11/24/tetrahedral-interpolation-for-colorspace-conversion/ // // I have one test image, and visually I can't tell the difference between // tetrahedral and trilinear interpolation. In terms of computation, the // tetrahedral code requires more branches but less computation. The // SampleICC library provides an option for the client to choose either // tetrahedral or trilinear. for (int i = 0; i < 3; i++) { if (diffZ < diffY) { if (diffZ < diffX) { dst[i] = (ptr[n000] + diffZ * (ptr[n110] - ptr[n010]) + diffY * (ptr[n010] - ptr[n000]) + diffX * (ptr[n111] - ptr[n110])); } else if (diffY < diffX) { dst[i] = (ptr[n000] + diffZ * (ptr[n111] - ptr[n011]) + diffY * (ptr[n011] - ptr[n001]) + diffX * (ptr[n001] - ptr[n000])); } else { dst[i] = (ptr[n000] + diffZ * (ptr[n111] - ptr[n011]) + diffY * (ptr[n010] - ptr[n000]) + diffX * (ptr[n011] - ptr[n010])); } } else { if (diffZ < diffX) { dst[i] = (ptr[n000] + diffZ * (ptr[n101] - ptr[n001]) + diffY * (ptr[n111] - ptr[n101]) + diffX * (ptr[n001] - ptr[n000])); } else if (diffY < diffX) { dst[i] = (ptr[n000] + diffZ * (ptr[n100] - ptr[n000]) + diffY * (ptr[n111] - ptr[n101]) + diffX * (ptr[n101] - ptr[n100])); } else { dst[i] = (ptr[n000] + diffZ * (ptr[n100] - ptr[n000]) + diffY * (ptr[n110] - ptr[n100]) + diffX * (ptr[n111] - ptr[n110])); } } // Increment the table ptr in order to handle the next component. // Note that this is the how table is designed: all of nXXX // variables are multiples of 3 because there are 3 output // components. ptr++; } } void SkDefaultXform::xform_RGB1_8888(uint32_t* dst, const uint32_t* src, uint32_t len) const { while (len-- > 0) { uint8_t r = (*src >> 0) & 0xFF, g = (*src >> 8) & 0xFF, b = (*src >> 16) & 0xFF; if (fColorLUT) { float in[3]; float out[3]; in[0] = byte_to_float(r); in[1] = byte_to_float(g); in[2] = byte_to_float(b); interp_3d_clut(out, in, fColorLUT.get()); r = sk_float_round2int(255.0f * clamp_normalized_float(out[0])); g = sk_float_round2int(255.0f * clamp_normalized_float(out[1])); b = sk_float_round2int(255.0f * clamp_normalized_float(out[2])); } // Convert to linear. float srcFloats[3]; srcFloats[0] = fSrcGammaTables[0][r]; srcFloats[1] = fSrcGammaTables[1][g]; srcFloats[2] = fSrcGammaTables[2][b]; // Convert to dst gamut. float dstFloats[3]; dstFloats[0] = srcFloats[0] * fSrcToDst.getFloat(0, 0) + srcFloats[1] * fSrcToDst.getFloat(1, 0) + srcFloats[2] * fSrcToDst.getFloat(2, 0) + fSrcToDst.getFloat(3, 0); dstFloats[1] = srcFloats[0] * fSrcToDst.getFloat(0, 1) + srcFloats[1] * fSrcToDst.getFloat(1, 1) + srcFloats[2] * fSrcToDst.getFloat(2, 1) + fSrcToDst.getFloat(3, 1); dstFloats[2] = srcFloats[0] * fSrcToDst.getFloat(0, 2) + srcFloats[1] * fSrcToDst.getFloat(1, 2) + srcFloats[2] * fSrcToDst.getFloat(2, 2) + fSrcToDst.getFloat(3, 2); // Clamp to 0-1. dstFloats[0] = clamp_normalized_float(dstFloats[0]); dstFloats[1] = clamp_normalized_float(dstFloats[1]); dstFloats[2] = clamp_normalized_float(dstFloats[2]); // Convert to dst gamma. r = fDstGammaTables[0][sk_float_round2int((kDstGammaTableSize - 1) * dstFloats[0])]; g = fDstGammaTables[1][sk_float_round2int((kDstGammaTableSize - 1) * dstFloats[1])]; b = fDstGammaTables[2][sk_float_round2int((kDstGammaTableSize - 1) * dstFloats[2])]; *dst = SkPackARGB32NoCheck(0xFF, r, g, b); dst++; src++; } }