/* MIT license */
/* eslint-disable no-mixed-operators */
const cssKeywords = require('color-name');
// NOTE: conversions should only return primitive values (i.e. arrays, or
// values that give correct `typeof` results).
// do not use box values types (i.e. Number(), String(), etc.)
const reverseKeywords = {};
for (const key of Object.keys(cssKeywords)) {
reverseKeywords[cssKeywords[key]] = key;
}
const convert = {
rgb: {channels: 3, labels: 'rgb'},
hsl: {channels: 3, labels: 'hsl'},
hsv: {channels: 3, labels: 'hsv'},
hwb: {channels: 3, labels: 'hwb'},
cmyk: {channels: 4, labels: 'cmyk'},
xyz: {channels: 3, labels: 'xyz'},
lab: {channels: 3, labels: 'lab'},
lch: {channels: 3, labels: 'lch'},
hex: {channels: 1, labels: ['hex']},
keyword: {channels: 1, labels: ['keyword']},
ansi16: {channels: 1, labels: ['ansi16']},
ansi256: {channels: 1, labels: ['ansi256']},
hcg: {channels: 3, labels: ['h', 'c', 'g']},
apple: {channels: 3, labels: ['r16', 'g16', 'b16']},
gray: {channels: 1, labels: ['gray']}
};
module.exports = convert;
// Hide .channels and .labels properties
for (const model of Object.keys(convert)) {
if (!('channels' in convert[model])) {
throw new Error('missing channels property: ' + model);
}
if (!('labels' in convert[model])) {
throw new Error('missing channel labels property: ' + model);
}
if (convert[model].labels.length !== convert[model].channels) {
throw new Error('channel and label counts mismatch: ' + model);
}
const {channels, labels} = convert[model];
delete convert[model].channels;
delete convert[model].labels;
Object.defineProperty(convert[model], 'channels', {value: channels});
Object.defineProperty(convert[model], 'labels', {value: labels});
}
convert.rgb.hsl = function (rgb) {
const r = rgb[0] / 255;
const g = rgb[1] / 255;
const b = rgb[2] / 255;
const min = Math.min(r, g, b);
const max = Math.max(r, g, b);
const delta = max - min;
let h;
let s;
if (max === min) {
h = 0;
} else if (r === max) {
h = (g - b) / delta;
} else if (g === max) {
h = 2 + (b - r) / delta;
} else if (b === max) {
h = 4 + (r - g) / delta;
}
h = Math.min(h * 60, 360);
if (h < 0) {
h += 360;
}
const l = (min + max) / 2;
if (max === min) {
s = 0;
} else if (l <= 0.5) {
s = delta / (max + min);
} else {
s = delta / (2 - max - min);
}
return [h, s * 100, l * 100];
};
convert.rgb.hsv = function (rgb) {
let rdif;
let gdif;
let bdif;
let h;
let s;
const r = rgb[0] / 255;
const g = rgb[1] / 255;
const b = rgb[2] / 255;
const v = Math.max(r, g, b);
const diff = v - Math.min(r, g, b);
const diffc = function (c) {
return (v - c) / 6 / diff + 1 / 2;
};
if (diff === 0) {
h = 0;
s = 0;
} else {
s = diff / v;
rdif = diffc(r);
gdif = diffc(g);
bdif = diffc(b);
if (r === v) {
h = bdif - gdif;
} else if (g === v) {
h = (1 / 3) + rdif - bdif;
} else if (b === v) {
h = (2 / 3) + gdif - rdif;
}
if (h < 0) {
h += 1;
} else if (h > 1) {
h -= 1;
}
}
return [
h * 360,
s * 100,
v * 100
];
};
convert.rgb.hwb = function (rgb) {
const r = rgb[0];
const g = rgb[1];
let b = rgb[2];
const h = convert.rgb.hsl(rgb)[0];
const w = 1 / 255 * Math.min(r, Math.min(g, b));
b = 1 - 1 / 255 * Math.max(r, Math.max(g, b));
return [h, w * 100, b * 100];
};
convert.rgb.cmyk = function (rgb) {
const r = rgb[0] / 255;
const g = rgb[1] / 255;
const b = rgb[2] / 255;
const k = Math.min(1 - r, 1 - g, 1 - b);
const c = (1 - r - k) / (1 - k) || 0;
const m = (1 - g - k) / (1 - k) || 0;
const y = (1 - b - k) / (1 - k) || 0;
return [c * 100, m * 100, y * 100, k * 100];
};
function comparativeDistance(x, y) {
/*
See https://en.m.wikipedia.org/wiki/Euclidean_distance#Squared_Euclidean_distance
*/
return (
((x[0] - y[0]) ** 2) +
((x[1] - y[1]) ** 2) +
((x[2] - y[2]) ** 2)
);
}
convert.rgb.keyword = function (rgb) {
const reversed = reverseKeywords[rgb];
if (reversed) {
return reversed;
}
let currentClosestDistance = Infinity;
let currentClosestKeyword;
for (const keyword of Object.keys(cssKeywords)) {
const value = cssKeywords[keyword];
// Compute comparative distance
const distance = comparativeDistance(rgb, value);
// Check if its less, if so set as closest
if (distance < currentClosestDistance) {
currentClosestDistance = distance;
currentClosestKeyword = keyword;
}
}
return currentClosestKeyword;
};
convert.keyword.rgb = function (keyword) {
return cssKeywords[keyword];
};
convert.rgb.xyz = function (rgb) {
let r = rgb[0] / 255;
let g = rgb[1] / 255;
let b = rgb[2] / 255;
// Assume sRGB
r = r > 0.04045 ? (((r + 0.055) / 1.055) ** 2.4) : (r / 12.92);
g = g > 0.04045 ? (((g + 0.055) / 1.055) ** 2.4) : (g / 12.92);
b = b > 0.04045 ? (((b + 0.055) / 1.055) ** 2.4) : (b / 12.92);
const x = (r * 0.4124) + (g * 0.3576) + (b * 0.1805);
const y = (r * 0.2126) + (g * 0.7152) + (b * 0.0722);
const z = (r * 0.0193) + (g * 0.1192) + (b * 0.9505);
return [x * 100, y * 100, z * 100];
};
convert.rgb.lab = function (rgb) {
const xyz = convert.rgb.xyz(rgb);
let x = xyz[0];
let y = xyz[1];
let z = xyz[2];
x /= 95.047;
y /= 100;
z /= 108.883;
x = x > 0.008856 ? (x ** (1 / 3)) : (7.787 * x) + (16 / 116);
y = y > 0.008856 ? (y ** (1 / 3)) : (7.787 * y) + (16 / 116);
z = z > 0.008856 ? (z ** (1 / 3)) : (7.787 * z) + (16 / 116);
const l = (116 * y) - 16;
const a = 500 * (x - y);
const b = 200 * (y - z);
return [l, a, b];
};
convert.hsl.rgb = function (hsl) {
const h = hsl[0] / 360;
const s = hsl[1] / 100;
const l = hsl[2] / 100;
let t2;
let t3;
let val;
if (s === 0) {
val = l * 255;
return [val, val, val];
}
if (l < 0.5) {
t2 = l * (1 + s);
} else {
t2 = l + s - l * s;
}
const t1 = 2 * l - t2;
const rgb = [0, 0, 0];
for (let i = 0; i < 3; i++) {
t3 = h + 1 / 3 * -(i - 1);
if (t3 < 0) {
t3++;
}
if (t3 > 1) {
t3--;
}
if (6 * t3 < 1) {
val = t1 + (t2 - t1) * 6 * t3;
} else if (2 * t3 < 1) {
val = t2;
} else if (3 * t3 < 2) {
val = t1 + (t2 - t1) * (2 / 3 - t3) * 6;
} else {
val = t1;
}
rgb[i] = val * 255;
}
return rgb;
};
convert.hsl.hsv = function (hsl) {
const h = hsl[0];
let s = hsl[1] / 100;
let l = hsl[2] / 100;
let smin = s;
const lmin = Math.max(l, 0.01);
l *= 2;
s *= (l <= 1) ? l : 2 - l;
smin *= lmin <= 1 ? lmin : 2 - lmin;
const v = (l + s) / 2;
const sv = l === 0 ? (2 * smin) / (lmin + smin) : (2 * s) / (l + s);
return [h, sv * 100, v * 100];
};
convert.hsv.rgb = function (hsv) {
const h = hsv[0] / 60;
const s = hsv[1] / 100;
let v = hsv[2] / 100;
const hi = Math.floor(h) % 6;
const f = h - Math.floor(h);
const p = 255 * v * (1 - s);
const q = 255 * v * (1 - (s * f));
const t = 255 * v * (1 - (s * (1 - f)));
v *= 255;
switch (hi) {
case 0:
return [v, t, p];
case 1:
return [q, v, p];
case 2:
return [p, v, t];
case 3:
return [p, q, v];
case 4:
return [t, p, v];
case 5:
return [v, p, q];
}
};
convert.hsv.hsl = function (hsv) {
const h = hsv[0];
const s = hsv[1] / 100;
const v = hsv[2] / 100;
const vmin = Math.max(v, 0.01);
let sl;
let l;
l = (2 - s) * v;
const lmin = (2 - s) * vmin;
sl = s * vmin;
sl /= (lmin <= 1) ? lmin : 2 - lmin;
sl = sl || 0;
l /= 2;
return [h, sl * 100, l * 100];
};
// http://dev.w3.org/csswg/css-color/#hwb-to-rgb
convert.hwb.rgb = function (hwb) {
const h = hwb[0] / 360;
let wh = hwb[1] / 100;
let bl = hwb[2] / 100;
const ratio = wh + bl;
let f;
// Wh + bl cant be > 1
if (ratio > 1) {
wh /= ratio;
bl /= ratio;
}
const i = Math.floor(6 * h);
const v = 1 - bl;
f = 6 * h - i;
if ((i & 0x01) !== 0) {
f = 1 - f;
}
const n = wh + f * (v - wh); // Linear interpolation
let r;
let g;
let b;
/* eslint-disable max-statements-per-line,no-multi-spaces */
switch (i) {
default:
case 6:
case 0: r = v; g = n; b = wh; break;
case 1: r = n; g = v; b = wh; break;
case 2: r = wh; g = v; b = n; break;
case 3: r = wh; g = n; b = v; break;
case 4: r = n; g = wh; b = v; break;
case 5: r = v; g = wh; b = n; break;
}
/* eslint-enable max-statements-per-line,no-multi-spaces */
return [r * 255, g * 255, b * 255];
};
convert.cmyk.rgb = function (cmyk) {
const c = cmyk[0] / 100;
const m = cmyk[1] / 100;
const y = cmyk[2] / 100;
const k = cmyk[3] / 100;
const r = 1 - Math.min(1, c * (1 - k) + k);
const g = 1 - Math.min(1, m * (1 - k) + k);
const b = 1 - Math.min(1, y * (1 - k) + k);
return [r * 255, g * 255, b * 255];
};
convert.xyz.rgb = function (xyz) {
const x = xyz[0] / 100;
const y = xyz[1] / 100;
const z = xyz[2] / 100;
let r;
let g;
let b;
r = (x * 3.2406) + (y * -1.5372) + (z * -0.4986);
g = (x * -0.9689) + (y * 1.8758) + (z * 0.0415);
b = (x * 0.0557) + (y * -0.2040) + (z * 1.0570);
// Assume sRGB
r = r > 0.0031308
? ((1.055 * (r ** (1.0 / 2.4))) - 0.055)
: r * 12.92;
g = g > 0.0031308
? ((1.055 * (g ** (1.0 / 2.4))) - 0.055)
: g * 12.92;
b = b > 0.0031308
? ((1.055 * (b ** (1.0 / 2.4))) - 0.055)
: b * 12.92;
r = Math.min(Math.max(0, r), 1);
g = Math.min(Math.max(0, g), 1);
b = Math.min(Math.max(0, b), 1);
return [r * 255, g * 255, b * 255];
};
convert.xyz.lab = function (xyz) {
let x = xyz[0];
let y = xyz[1];
let z = xyz[2];
x /= 95.047;
y /= 100;
z /= 108.883;
x = x > 0.008856 ? (x ** (1 / 3)) : (7.787 * x) + (16 / 116);
y = y > 0.008856 ? (y ** (1 / 3)) : (7.787 * y) + (16 / 116);
z = z > 0.008856 ? (z ** (1 / 3)) : (7.787 * z) + (16 / 116);
const l = (116 * y) - 16;
const a = 500 * (x - y);
const b = 200 * (y - z);
return [l, a, b];
};
convert.lab.xyz = function (lab) {
const l = lab[0];
const a = lab[1];
const b = lab[2];
let x;
let y;
let z;
y = (l + 16) / 116;
x = a / 500 + y;
z = y - b / 200;
const y2 = y ** 3;
const x2 = x ** 3;
const z2 = z ** 3;
y = y2 > 0.008856 ? y2 : (y - 16 / 116) / 7.787;
x = x2 > 0.008856 ? x2 : (x - 16 / 116) / 7.787;
z = z2 > 0.008856 ? z2 : (z - 16 / 116) / 7.787;
x *= 95.047;
y *= 100;
z *= 108.883;
return [x, y, z];
};
convert.lab.lch = function (lab) {
const l = lab[0];
const a = lab[1];
const b = lab[2];
let h;
const hr = Math.atan2(b, a);
h = hr * 360 / 2 / Math.PI;
if (h < 0) {
h += 360;
}
const c = Math.sqrt(a * a + b * b);
return [l, c, h];
};
convert.lch.lab = function (lch) {
const l = lch[0];
const c = lch[1];
const h = lch[2];
const hr = h / 360 * 2 * Math.PI;
const a = c * Math.cos(hr);
const b = c * Math.sin(hr);
return [l, a, b];
};
convert.rgb.ansi16 = function (args, saturation = null) {
const [r, g, b] = args;
let value = saturation === null ? convert.rgb.hsv(args)[2] : saturation; // Hsv -> ansi16 optimization
value = Math.round(value / 50);
if (value === 0) {
return 30;
}
let ansi = 30
+ ((Math.round(b / 255) << 2)
| (Math.round(g / 255) << 1)
| Math.round(r / 255));
if (value === 2) {
ansi += 60;
}
return ansi;
};
convert.hsv.ansi16 = function (args) {
// Optimization here; we already know the value and don't need to get
// it converted for us.
return convert.rgb.ansi16(convert.hsv.rgb(args), args[2]);
};
convert.rgb.ansi256 = function (args) {
const r = args[0];
const g = args[1];
const b = args[2];
// We use the extended greyscale palette here, with the exception of
// black and white. normal palette only has 4 greyscale shades.
if (r === g && g === b) {
if (r < 8) {
return 16;
}
if (r > 248) {
return 231;
}
return Math.round(((r - 8) / 247) * 24) + 232;
}
const ansi = 16
+ (36 * Math.round(r / 255 * 5))
+ (6 * Math.round(g / 255 * 5))
+ Math.round(b / 255 * 5);
return ansi;
};
convert.ansi16.rgb = function (args) {
let color = args % 10;
// Handle greyscale
if (color === 0 || color === 7) {
if (args > 50) {
color += 3.5;
}
color = color / 10.5 * 255;
return [color, color, color];
}
const mult = (~~(args > 50) + 1) * 0.5;
const r = ((color & 1) * mult) * 255;
const g = (((color >> 1) & 1) * mult) * 255;
const b = (((color >> 2) & 1) * mult) * 255;
return [r, g, b];
};
convert.ansi256.rgb = function (args) {
// Handle greyscale
if (args >= 232) {
const c = (args - 232) * 10 + 8;
return [c, c, c];
}
args -= 16;
let rem;
const r = Math.floor(args / 36) / 5 * 255;
const g = Math.floor((rem = args % 36) / 6) / 5 * 255;
const b = (rem % 6) / 5 * 255;
return [r, g, b];
};
convert.rgb.hex = function (args) {
const integer = ((Math.round(args[0]) & 0xFF) << 16)
+ ((Math.round(args[1]) & 0xFF) << 8)
+ (Math.round(args[2]) & 0xFF);
const string = integer.toString(16).toUpperCase();
return '000000'.substring(string.length) + string;
};
convert.hex.rgb = function (args) {
const match = args.toString(16).match(/[a-f0-9]{6}|[a-f0-9]{3}/i);
if (!match) {
return [0, 0, 0];
}
let colorString = match[0];
if (match[0].length === 3) {
colorString = colorString.split('').map(char => {
return char + char;
}).join('');
}
const integer = parseInt(colorString, 16);
const r = (integer >> 16) & 0xFF;
const g = (integer >> 8) & 0xFF;
const b = integer & 0xFF;
return [r, g, b];
};
convert.rgb.hcg = function (rgb) {
const r = rgb[0] / 255;
const g = rgb[1] / 255;
const b = rgb[2] / 255;
const max = Math.max(Math.max(r, g), b);
const min = Math.min(Math.min(r, g), b);
const chroma = (max - min);
let grayscale;
let hue;
if (chroma < 1) {
grayscale = min / (1 - chroma);
} else {
grayscale = 0;
}
if (chroma <= 0) {
hue = 0;
} else
if (max === r) {
hue = ((g - b) / chroma) % 6;
} else
if (max === g) {
hue = 2 + (b - r) / chroma;
} else {
hue = 4 + (r - g) / chroma;
}
hue /= 6;
hue %= 1;
return [hue * 360, chroma * 100, grayscale * 100];
};
convert.hsl.hcg = function (hsl) {
const s = hsl[1] / 100;
const l = hsl[2] / 100;
const c = l < 0.5 ? (2.0 * s * l) : (2.0 * s * (1.0 - l));
let f = 0;
if (c < 1.0) {
f = (l - 0.5 * c) / (1.0 - c);
}
return [hsl[0], c * 100, f * 100];
};
convert.hsv.hcg = function (hsv) {
const s = hsv[1] / 100;
const v = hsv[2] / 100;
const c = s * v;
let f = 0;
if (c < 1.0) {
f = (v - c) / (1 - c);
}
return [hsv[0], c * 100, f * 100];
};
convert.hcg.rgb = function (hcg) {
const h = hcg[0] / 360;
const c = hcg[1] / 100;
const g = hcg[2] / 100;
if (c === 0.0) {
return [g * 255, g * 255, g * 255];
}
const pure = [0, 0, 0];
const hi = (h % 1) * 6;
const v = hi % 1;
const w = 1 - v;
let mg = 0;
/* eslint-disable max-statements-per-line */
switch (Math.floor(hi)) {
case 0:
pure[0] = 1; pure[1] = v; pure[2] = 0; break;
case 1:
pure[0] = w; pure[1] = 1; pure[2] = 0; break;
case 2:
pure[0] = 0; pure[1] = 1; pure[2] = v; break;
case 3:
pure[0] = 0; pure[1] = w; pure[2] = 1; break;
case 4:
pure[0] = v; pure[1] = 0; pure[2] = 1; break;
default:
pure[0] = 1; pure[1] = 0; pure[2] = w;
}
/* eslint-enable max-statements-per-line */
mg = (1.0 - c) * g;
return [
(c * pure[0] + mg) * 255,
(c * pure[1] + mg) * 255,
(c * pure[2] + mg) * 255
];
};
convert.hcg.hsv = function (hcg) {
const c = hcg[1] / 100;
const g = hcg[2] / 100;
const v = c + g * (1.0 - c);
let f = 0;
if (v > 0.0) {
f = c / v;
}
return [hcg[0], f * 100, v * 100];
};
convert.hcg.hsl = function (hcg) {
const c = hcg[1] / 100;
const g = hcg[2] / 100;
const l = g * (1.0 - c) + 0.5 * c;
let s = 0;
if (l > 0.0 && l < 0.5) {
s = c / (2 * l);
} else
if (l >= 0.5 && l < 1.0) {
s = c / (2 * (1 - l));
}
return [hcg[0], s * 100, l * 100];
};
convert.hcg.hwb = function (hcg) {
const c = hcg[1] / 100;
const g = hcg[2] / 100;
const v = c + g * (1.0 - c);
return [hcg[0], (v - c) * 100, (1 - v) * 100];
};
convert.hwb.hcg = function (hwb) {
const w = hwb[1] / 100;
const b = hwb[2] / 100;
const v = 1 - b;
const c = v - w;
let g = 0;
if (c < 1) {
g = (v - c) / (1 - c);
}
return [hwb[0], c * 100, g * 100];
};
convert.apple.rgb = function (apple) {
return [(apple[0] / 65535) * 255, (apple[1] / 65535) * 255, (apple[2] / 65535) * 255];
};
convert.rgb.apple = function (rgb) {
return [(rgb[0] / 255) * 65535, (rgb[1] / 255) * 65535, (rgb[2] / 255) * 65535];
};
convert.gray.rgb = function (args) {
return [args[0] / 100 * 255, args[0] / 100 * 255, args[0] / 100 * 255];
};
convert.gray.hsl = function (args) {
return [0, 0, args[0]];
};
convert.gray.hsv = convert.gray.hsl;
convert.gray.hwb = function (gray) {
return [0, 100, gray[0]];
};
convert.gray.cmyk = function (gray) {
return [0, 0, 0, gray[0]];
};
convert.gray.lab = function (gray) {
return [gray[0], 0, 0];
};
convert.gray.hex = function (gray) {
const val = Math.round(gray[0] / 100 * 255) & 0xFF;
const integer = (val << 16) + (val << 8) + val;
const string = integer.toString(16).toUpperCase();
return '000000'.substring(string.length) + string;
};
convert.rgb.gray = function (rgb) {
const val = (rgb[0] + rgb[1] + rgb[2]) / 3;
return [val / 255 * 100];
};