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talk-android/app/src/main/java/hct/HctSolver.java
Andy Scherzinger 58dc6a9aae
add material 3 color calculation/scheme classes 
Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>
2022-08-11 09:50:47 +02:00

673 lines
21 KiB
Java
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/*
* Copyright 2021 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// This file is automatically generated. Do not modify it.
package hct;
import utils.ColorUtils;
import utils.MathUtils;
/** A class that solves the HCT equation. */
public class HctSolver {
private HctSolver() {}
static final double[][] SCALED_DISCOUNT_FROM_LINRGB =
new double[][] {
new double[] {
0.001200833568784504, 0.002389694492170889, 0.0002795742885861124,
},
new double[] {
0.0005891086651375999, 0.0029785502573438758, 0.0003270666104008398,
},
new double[] {
0.00010146692491640572, 0.0005364214359186694, 0.0032979401770712076,
},
};
static final double[][] LINRGB_FROM_SCALED_DISCOUNT =
new double[][] {
new double[] {
1373.2198709594231, -1100.4251190754821, -7.278681089101213,
},
new double[] {
-271.815969077903, 559.6580465940733, -32.46047482791194,
},
new double[] {
1.9622899599665666, -57.173814538844006, 308.7233197812385,
},
};
static final double[] Y_FROM_LINRGB = new double[] {0.2126, 0.7152, 0.0722};
static final double[] CRITICAL_PLANES =
new double[] {
0.015176349177441876,
0.045529047532325624,
0.07588174588720938,
0.10623444424209313,
0.13658714259697685,
0.16693984095186062,
0.19729253930674434,
0.2276452376616281,
0.2579979360165119,
0.28835063437139563,
0.3188300904430532,
0.350925934958123,
0.3848314933096426,
0.42057480301049466,
0.458183274052838,
0.4976837250274023,
0.5391024159806381,
0.5824650784040898,
0.6277969426914107,
0.6751227633498623,
0.7244668422128921,
0.775853049866786,
0.829304845476233,
0.8848452951698498,
0.942497089126609,
1.0022825574869039,
1.0642236851973577,
1.1283421258858297,
1.1946592148522128,
1.2631959812511864,
1.3339731595349034,
1.407011200216447,
1.4823302800086415,
1.5599503113873272,
1.6398909516233677,
1.7221716113234105,
1.8068114625156377,
1.8938294463134073,
1.9832442801866852,
2.075074464868551,
2.1693382909216234,
2.2660538449872063,
2.36523901573795,
2.4669114995532007,
2.5710888059345764,
2.6777882626779785,
2.7870270208169257,
2.898822059350997,
3.0131901897720907,
3.1301480604002863,
3.2497121605402226,
3.3718988244681087,
3.4967242352587946,
3.624204428461639,
3.754355295633311,
3.887192587735158,
4.022731918402185,
4.160988767090289,
4.301978482107941,
4.445716283538092,
4.592217266055746,
4.741496401646282,
4.893568542229298,
5.048448422192488,
5.20615066083972,
5.3666897647573375,
5.5300801301023865,
5.696336044816294,
5.865471690767354,
6.037501145825082,
6.212438385869475,
6.390297286737924,
6.571091626112461,
6.7548350853498045,
6.941541251256611,
7.131223617812143,
7.323895587840543,
7.5195704746346665,
7.7182615035334345,
7.919981813454504,
8.124744458384042,
8.332562408825165,
8.543448553206703,
8.757415699253682,
8.974476575321063,
9.194643831691977,
9.417930041841839,
9.644347703669503,
9.873909240696694,
10.106627003236781,
10.342513269534024,
10.58158024687427,
10.8238400726681,
11.069304815507364,
11.317986476196008,
11.569896988756009,
11.825048221409341,
12.083451977536606,
12.345119996613247,
12.610063955123938,
12.878295467455942,
13.149826086772048,
13.42466730586372,
13.702830557985108,
13.984327217668513,
14.269168601521828,
14.55736596900856,
14.848930523210871,
15.143873411576273,
15.44220572664832,
15.743938506781891,
16.04908273684337,
16.35764934889634,
16.66964922287304,
16.985093187232053,
17.30399201960269,
17.62635644741625,
17.95219714852476,
18.281524751807332,
18.614349837764564,
18.95068293910138,
19.290534541298456,
19.633915083172692,
19.98083495742689,
20.331304511189067,
20.685334046541502,
21.042933821039977,
21.404114048223256,
21.76888489811322,
22.137256497705877,
22.50923893145328,
22.884842241736916,
23.264076429332462,
23.6469514538663,
24.033477234264016,
24.42366364919083,
24.817520537484558,
25.21505769858089,
25.61628489293138,
26.021211842414342,
26.429848230738664,
26.842203703840827,
27.258287870275353,
27.678110301598522,
28.10168053274597,
28.529008062403893,
28.96010235337422,
29.39497283293396,
29.83362889318845,
30.276079891419332,
30.722335150426627,
31.172403958865512,
31.62629557157785,
32.08401920991837,
32.54558406207592,
33.010999283389665,
33.4802739966603,
33.953417292456834,
34.430438229418264,
34.911345834551085,
35.39614910352207,
35.88485700094671,
36.37747846067349,
36.87402238606382,
37.37449765026789,
37.87891309649659,
38.38727753828926,
38.89959975977785,
39.41588851594697,
39.93615253289054,
40.460400508064545,
40.98864111053629,
41.520882981230194,
42.05713473317016,
42.597404951718396,
43.141702194811224,
43.6900349931913,
44.24241185063697,
44.798841244188324,
45.35933162437017,
45.92389141541209,
46.49252901546552,
47.065252796817916,
47.64207110610409,
48.22299226451468,
48.808024568002054,
49.3971762874833,
49.9904556690408,
50.587870934119984,
51.189430279724725,
51.79514187861014,
52.40501387947288,
53.0190544071392,
53.637271562750364,
54.259673423945976,
54.88626804504493,
55.517063457223934,
56.15206766869424,
56.79128866487574,
57.43473440856916,
58.08241284012621,
58.734331877617365,
59.39049941699807,
60.05092333227251,
60.715611475655585,
61.38457167773311,
62.057811747619894,
62.7353394731159,
63.417162620860914,
64.10328893648692,
64.79372614476921,
65.48848194977529,
66.18756403501224,
66.89098006357258,
67.59873767827808,
68.31084450182222,
69.02730813691093,
69.74813616640164,
70.47333615344107,
71.20291564160104,
71.93688215501312,
72.67524319850172,
73.41800625771542,
74.16517879925733,
74.9167682708136,
75.67278210128072,
76.43322770089146,
77.1981124613393,
77.96744375590167,
78.74122893956174,
79.51947534912904,
80.30219030335869,
81.08938110306934,
81.88105503125999,
82.67721935322541,
83.4778813166706,
84.28304815182372,
85.09272707154808,
85.90692527145302,
86.72564993000343,
87.54890820862819,
88.3767072518277,
89.2090541872801,
90.04595612594655,
90.88742016217518,
91.73345337380438,
92.58406282226491,
93.43925555268066,
94.29903859396902,
95.16341895893969,
96.03240364439274,
96.9059996312159,
97.78421388448044,
98.6670533535366,
99.55452497210776,
};
/**
* Sanitizes a small enough angle in radians.
*
* @param angle An angle in radians; must not deviate too much from 0.
* @return A coterminal angle between 0 and 2pi.
*/
static double sanitizeRadians(double angle) {
return (angle + Math.PI * 8) % (Math.PI * 2);
}
/**
* Delinearizes an RGB component, returning a floating-point number.
*
* @param rgbComponent 0.0 <= rgb_component <= 100.0, represents linear R/G/B channel
* @return 0.0 <= output <= 255.0, color channel converted to regular RGB space
*/
static double trueDelinearized(double rgbComponent) {
double normalized = rgbComponent / 100.0;
double delinearized = 0.0;
if (normalized <= 0.0031308) {
delinearized = normalized * 12.92;
} else {
delinearized = 1.055 * Math.pow(normalized, 1.0 / 2.4) - 0.055;
}
return delinearized * 255.0;
}
static double chromaticAdaptation(double component) {
double af = Math.pow(Math.abs(component), 0.42);
return MathUtils.signum(component) * 400.0 * af / (af + 27.13);
}
/**
* Returns the hue of a linear RGB color in CAM16.
*
* @param linrgb The linear RGB coordinates of a color.
* @return The hue of the color in CAM16, in radians.
*/
static double hueOf(double[] linrgb) {
double[] scaledDiscount = MathUtils.matrixMultiply(linrgb, SCALED_DISCOUNT_FROM_LINRGB);
double rA = chromaticAdaptation(scaledDiscount[0]);
double gA = chromaticAdaptation(scaledDiscount[1]);
double bA = chromaticAdaptation(scaledDiscount[2]);
// redness-greenness
double a = (11.0 * rA + -12.0 * gA + bA) / 11.0;
// yellowness-blueness
double b = (rA + gA - 2.0 * bA) / 9.0;
return Math.atan2(b, a);
}
static boolean areInCyclicOrder(double a, double b, double c) {
double deltaAB = sanitizeRadians(b - a);
double deltaAC = sanitizeRadians(c - a);
return deltaAB < deltaAC;
}
/**
* Solves the lerp equation.
*
* @param source The starting number.
* @param mid The number in the middle.
* @param target The ending number.
* @return A number t such that lerp(source, target, t) = mid.
*/
static double intercept(double source, double mid, double target) {
return (mid - source) / (target - source);
}
static double[] lerpPoint(double[] source, double t, double[] target) {
return new double[] {
source[0] + (target[0] - source[0]) * t,
source[1] + (target[1] - source[1]) * t,
source[2] + (target[2] - source[2]) * t,
};
}
/**
* Intersects a segment with a plane.
*
* @param source The coordinates of point A.
* @param coordinate The R-, G-, or B-coordinate of the plane.
* @param target The coordinates of point B.
* @param axis The axis the plane is perpendicular with. (0: R, 1: G, 2: B)
* @return The intersection point of the segment AB with the plane R=coordinate, G=coordinate, or
* B=coordinate
*/
static double[] setCoordinate(double[] source, double coordinate, double[] target, int axis) {
double t = intercept(source[axis], coordinate, target[axis]);
return lerpPoint(source, t, target);
}
static boolean isBounded(double x) {
return 0.0 <= x && x <= 100.0;
}
/**
* Returns the nth possible vertex of the polygonal intersection.
*
* @param y The Y value of the plane.
* @param n The zero-based index of the point. 0 <= n <= 11.
* @return The nth possible vertex of the polygonal intersection of the y plane and the RGB cube,
* in linear RGB coordinates, if it exists. If this possible vertex lies outside of the cube,
* [-1.0, -1.0, -1.0] is returned.
*/
static double[] nthVertex(double y, int n) {
double kR = Y_FROM_LINRGB[0];
double kG = Y_FROM_LINRGB[1];
double kB = Y_FROM_LINRGB[2];
double coordA = n % 4 <= 1 ? 0.0 : 100.0;
double coordB = n % 2 == 0 ? 0.0 : 100.0;
if (n < 4) {
double g = coordA;
double b = coordB;
double r = (y - g * kG - b * kB) / kR;
if (isBounded(r)) {
return new double[] {r, g, b};
} else {
return new double[] {-1.0, -1.0, -1.0};
}
} else if (n < 8) {
double b = coordA;
double r = coordB;
double g = (y - r * kR - b * kB) / kG;
if (isBounded(g)) {
return new double[] {r, g, b};
} else {
return new double[] {-1.0, -1.0, -1.0};
}
} else {
double r = coordA;
double g = coordB;
double b = (y - r * kR - g * kG) / kB;
if (isBounded(b)) {
return new double[] {r, g, b};
} else {
return new double[] {-1.0, -1.0, -1.0};
}
}
}
/**
* Finds the segment containing the desired color.
*
* @param y The Y value of the color.
* @param targetHue The hue of the color.
* @return A list of two sets of linear RGB coordinates, each corresponding to an endpoint of the
* segment containing the desired color.
*/
static double[][] bisectToSegment(double y, double targetHue) {
double[] left = new double[] {-1.0, -1.0, -1.0};
double[] right = left;
double leftHue = 0.0;
double rightHue = 0.0;
boolean initialized = false;
boolean uncut = true;
for (int n = 0; n < 12; n++) {
double[] mid = nthVertex(y, n);
if (mid[0] < 0) {
continue;
}
double midHue = hueOf(mid);
if (!initialized) {
left = mid;
right = mid;
leftHue = midHue;
rightHue = midHue;
initialized = true;
continue;
}
if (uncut || areInCyclicOrder(leftHue, midHue, rightHue)) {
uncut = false;
if (areInCyclicOrder(leftHue, targetHue, midHue)) {
right = mid;
rightHue = midHue;
} else {
left = mid;
leftHue = midHue;
}
}
}
return new double[][] {left, right};
}
static double[] midpoint(double[] a, double[] b) {
return new double[] {
(a[0] + b[0]) / 2, (a[1] + b[1]) / 2, (a[2] + b[2]) / 2,
};
}
static int criticalPlaneBelow(double x) {
return (int) Math.floor(x - 0.5);
}
static int criticalPlaneAbove(double x) {
return (int) Math.ceil(x - 0.5);
}
/**
* Finds a color with the given Y and hue on the boundary of the cube.
*
* @param y The Y value of the color.
* @param targetHue The hue of the color.
* @return The desired color, in linear RGB coordinates.
*/
static double[] bisectToLimit(double y, double targetHue) {
double[][] segment = bisectToSegment(y, targetHue);
double[] left = segment[0];
double leftHue = hueOf(left);
double[] right = segment[1];
for (int axis = 0; axis < 3; axis++) {
if (left[axis] != right[axis]) {
int lPlane = -1;
int rPlane = 255;
if (left[axis] < right[axis]) {
lPlane = criticalPlaneBelow(trueDelinearized(left[axis]));
rPlane = criticalPlaneAbove(trueDelinearized(right[axis]));
} else {
lPlane = criticalPlaneAbove(trueDelinearized(left[axis]));
rPlane = criticalPlaneBelow(trueDelinearized(right[axis]));
}
for (int i = 0; i < 8; i++) {
if (Math.abs(rPlane - lPlane) <= 1) {
break;
} else {
int mPlane = (int) Math.floor((lPlane + rPlane) / 2.0);
double midPlaneCoordinate = CRITICAL_PLANES[mPlane];
double[] mid = setCoordinate(left, midPlaneCoordinate, right, axis);
double midHue = hueOf(mid);
if (areInCyclicOrder(leftHue, targetHue, midHue)) {
right = mid;
rPlane = mPlane;
} else {
left = mid;
leftHue = midHue;
lPlane = mPlane;
}
}
}
}
}
return midpoint(left, right);
}
static double inverseChromaticAdaptation(double adapted) {
double adaptedAbs = Math.abs(adapted);
double base = Math.max(0, 27.13 * adaptedAbs / (400.0 - adaptedAbs));
return MathUtils.signum(adapted) * Math.pow(base, 1.0 / 0.42);
}
/**
* Finds a color with the given hue, chroma, and Y.
*
* @param hueRadians The desired hue in radians.
* @param chroma The desired chroma.
* @param y The desired Y.
* @return The desired color as a hexadecimal integer, if found; 0 otherwise.
*/
static int findResultByJ(double hueRadians, double chroma, double y) {
// Initial estimate of j.
double j = Math.sqrt(y) * 11.0;
// ===========================================================
// Operations inlined from Cam16 to avoid repeated calculation
// ===========================================================
ViewingConditions viewingConditions = ViewingConditions.DEFAULT;
double tInnerCoeff = 1 / Math.pow(1.64 - Math.pow(0.29, viewingConditions.getN()), 0.73);
double eHue = 0.25 * (Math.cos(hueRadians + 2.0) + 3.8);
double p1 = eHue * (50000.0 / 13.0) * viewingConditions.getNc() * viewingConditions.getNcb();
double hSin = Math.sin(hueRadians);
double hCos = Math.cos(hueRadians);
for (int iterationRound = 0; iterationRound < 5; iterationRound++) {
// ===========================================================
// Operations inlined from Cam16 to avoid repeated calculation
// ===========================================================
double jNormalized = j / 100.0;
double alpha = chroma == 0.0 || j == 0.0 ? 0.0 : chroma / Math.sqrt(jNormalized);
double t = Math.pow(alpha * tInnerCoeff, 1.0 / 0.9);
double ac =
viewingConditions.getAw()
* Math.pow(jNormalized, 1.0 / viewingConditions.getC() / viewingConditions.getZ());
double p2 = ac / viewingConditions.getNbb();
double gamma = 23.0 * (p2 + 0.305) * t / (23.0 * p1 + 11 * t * hCos + 108.0 * t * hSin);
double a = gamma * hCos;
double b = gamma * hSin;
double rA = (460.0 * p2 + 451.0 * a + 288.0 * b) / 1403.0;
double gA = (460.0 * p2 - 891.0 * a - 261.0 * b) / 1403.0;
double bA = (460.0 * p2 - 220.0 * a - 6300.0 * b) / 1403.0;
double rCScaled = inverseChromaticAdaptation(rA);
double gCScaled = inverseChromaticAdaptation(gA);
double bCScaled = inverseChromaticAdaptation(bA);
double[] linrgb =
MathUtils.matrixMultiply(
new double[] {rCScaled, gCScaled, bCScaled}, LINRGB_FROM_SCALED_DISCOUNT);
// ===========================================================
// Operations inlined from Cam16 to avoid repeated calculation
// ===========================================================
if (linrgb[0] < 0 || linrgb[1] < 0 || linrgb[2] < 0) {
return 0;
}
double kR = Y_FROM_LINRGB[0];
double kG = Y_FROM_LINRGB[1];
double kB = Y_FROM_LINRGB[2];
double fnj = kR * linrgb[0] + kG * linrgb[1] + kB * linrgb[2];
if (fnj <= 0) {
return 0;
}
if (iterationRound == 4 || Math.abs(fnj - y) < 0.002) {
if (linrgb[0] > 100.01 || linrgb[1] > 100.01 || linrgb[2] > 100.01) {
return 0;
}
return ColorUtils.argbFromLinrgb(linrgb);
}
// Iterates with Newton method,
// Using 2 * fn(j) / j as the approximation of fn'(j)
j = j - (fnj - y) * j / (2 * fnj);
}
return 0;
}
/**
* Finds an sRGB color with the given hue, chroma, and L*, if possible.
*
* @param hueDegrees The desired hue, in degrees.
* @param chroma The desired chroma.
* @param lstar The desired L*.
* @return A hexadecimal representing the sRGB color. The color has sufficiently close hue,
* chroma, and L* to the desired values, if possible; otherwise, the hue and L* will be
* sufficiently close, and chroma will be maximized.
*/
public static int solveToInt(double hueDegrees, double chroma, double lstar) {
if (chroma < 0.0001 || lstar < 0.0001 || lstar > 99.9999) {
return ColorUtils.argbFromLstar(lstar);
}
hueDegrees = MathUtils.sanitizeDegreesDouble(hueDegrees);
double hueRadians = hueDegrees / 180 * Math.PI;
double y = ColorUtils.yFromLstar(lstar);
int exactAnswer = findResultByJ(hueRadians, chroma, y);
if (exactAnswer != 0) {
return exactAnswer;
}
double[] linrgb = bisectToLimit(y, hueRadians);
return ColorUtils.argbFromLinrgb(linrgb);
}
/**
* Finds an sRGB color with the given hue, chroma, and L*, if possible.
*
* @param hueDegrees The desired hue, in degrees.
* @param chroma The desired chroma.
* @param lstar The desired L*.
* @return An CAM16 object representing the sRGB color. The color has sufficiently close hue,
* chroma, and L* to the desired values, if possible; otherwise, the hue and L* will be
* sufficiently close, and chroma will be maximized.
*/
public static Cam16 solveToCam(double hueDegrees, double chroma, double lstar) {
return Cam16.fromInt(solveToInt(hueDegrees, chroma, lstar));
}
}
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