Color Lib

;(function () {
  'use strict';

  // https://www.w3.org/TR/css3-color/#svg-color
  const COLORS = {
    aliceblue: 0xF0F8FF,
    antiquewhite: 0xFAEBD7,
    aqua: 0x00FFFF,
    aquamarine: 0x7FFFD4,
    azure: 0xF0FFFF,
    beige: 0xF5F5DC,
    bisque: 0xFFE4C4,
    black: 0x000000,
    blanchedalmond: 0xFFEBCD,
    blue: 0x0000FF,
    blueviolet: 0x8A2BE2,
    brown: 0xA52A2A,
    burlywood: 0xDEB887,
    cadetblue: 0x5F9EA0,
    chartreuse: 0x7FFF00,
    chocolate: 0xD2691E,
    coral: 0xFF7F50,
    cornflowerblue: 0x6495ED,
    cornsilk: 0xFFF8DC,
    crimson: 0xDC143C,
    cyan: 0x00FFFF,
    darkblue: 0x00008B,
    darkcyan: 0x008B8B,
    darkgoldenrod: 0xB8860B,
    darkgray: 0xA9A9A9,
    darkgreen: 0x006400,
    darkgrey: 0xA9A9A9,
    darkkhaki: 0xBDB76B,
    darkmagenta: 0x8B008B,
    darkolivegreen: 0x556B2F,
    darkorange: 0xFF8C00,
    darkorchid: 0x9932CC,
    darkred: 0x8B0000,
    darksalmon: 0xE9967A,
    darkseagreen: 0x8FBC8F,
    darkslateblue: 0x483D8B,
    darkslategray: 0x2F4F4F,
    darkslategrey: 0x2F4F4F,
    darkturquoise: 0x00CED1,
    darkviolet: 0x9400D3,
    deeppink: 0xFF1493,
    deepskyblue: 0x00BFFF,
    dimgray: 0x696969,
    dimgrey: 0x696969,
    dodgerblue: 0x1E90FF,
    firebrick: 0xB22222,
    floralwhite: 0xFFFAF0,
    forestgreen: 0x228B22,
    fuchsia: 0xFF00FF,
    gainsboro: 0xDCDCDC,
    ghostwhite: 0xF8F8FF,
    gold: 0xFFD700,
    goldenrod: 0xDAA520,
    gray: 0x808080,
    green: 0x008000,
    greenyellow: 0xADFF2F,
    grey: 0x808080,
    honeydew: 0xF0FFF0,
    hotpink: 0xFF69B4,
    indianred: 0xCD5C5C,
    indigo: 0x4B0082,
    ivory: 0xFFFFF0,
    khaki: 0xF0E68C,
    lavender: 0xE6E6FA,
    lavenderblush: 0xFFF0F5,
    lawngreen: 0x7CFC00,
    lemonchiffon: 0xFFFACD,
    lightblue: 0xADD8E6,
    lightcoral: 0xF08080,
    lightcyan: 0xE0FFFF,
    lightgoldenrodyellow: 0xFAFAD2,
    lightgray: 0xD3D3D3,
    lightgreen: 0x90EE90,
    lightgrey: 0xD3D3D3,
    lightpink: 0xFFB6C1,
    lightsalmon: 0xFFA07A,
    lightseagreen: 0x20B2AA,
    lightskyblue: 0x87CEFA,
    lightslategray: 0x778899,
    lightslategrey: 0x778899,
    lightsteelblue: 0xB0C4DE,
    lightyellow: 0xFFFFE0,
    lime: 0x00FF00,
    limegreen: 0x32CD32,
    linen: 0xFAF0E6,
    magenta: 0xFF00FF,
    maroon: 0x800000,
    mediumaquamarine: 0x66CDAA,
    mediumblue: 0x0000CD,
    mediumorchid: 0xBA55D3,
    mediumpurple: 0x9370DB,
    mediumseagreen: 0x3CB371,
    mediumslateblue: 0x7B68EE,
    mediumspringgreen: 0x00FA9A,
    mediumturquoise: 0x48D1CC,
    mediumvioletred: 0xC71585,
    midnightblue: 0x191970,
    mintcream: 0xF5FFFA,
    mistyrose: 0xFFE4E1,
    moccasin: 0xFFE4B5,
    navajowhite: 0xFFDEAD,
    navy: 0x000080,
    oldlace: 0xFDF5E6,
    olive: 0x808000,
    olivedrab: 0x6B8E23,
    orange: 0xFFA500,
    orangered: 0xFF4500,
    orchid: 0xDA70D6,
    palegoldenrod: 0xEEE8AA,
    palegreen: 0x98FB98,
    paleturquoise: 0xAFEEEE,
    palevioletred: 0xDB7093,
    papayawhip: 0xFFEFD5,
    peachpuff: 0xFFDAB9,
    peru: 0xCD853F,
    pink: 0xFFC0CB,
    plum: 0xDDA0DD,
    powderblue: 0xB0E0E6,
    purple: 0x800080,
    red: 0xFF0000,
    rosybrown: 0xBC8F8F,
    royalblue: 0x4169E1,
    saddlebrown: 0x8B4513,
    salmon: 0xFA8072,
    sandybrown: 0xF4A460,
    seagreen: 0x2E8B57,
    seashell: 0xFFF5EE,
    sienna: 0xA0522D,
    silver: 0xC0C0C0,
    skyblue: 0x87CEEB,
    slateblue: 0x6A5ACD,
    slategray: 0x708090,
    slategrey: 0x708090,
    snow: 0xFFFAFA,
    springgreen: 0x00FF7F,
    steelblue: 0x4682B4,
    tan: 0xD2B48C,
    teal: 0x008080,
    thistle: 0xD8BFD8,
    tomato: 0xFF6347,
    turquoise: 0x40E0D0,
    violet: 0xEE82EE,
    wheat: 0xF5DEB3,
    white: 0xFFFFFF,
    whitesmoke: 0xF5F5F5,
    yellow: 0xFFFF00,
    yellowgreen: 0x9ACD32
  };

  // sRGB D65 http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
  const RGB_XYZ = [
    0.4124564, 0.3575761, 0.1804375,
    0.2126729, 0.7151522, 0.072175,
    0.0193339, 0.119192, 0.9503041
  ];

  const XYZ_RGB = [
    3.2404542, -1.5371385, -0.4985314,
    -0.969266, 1.8760108, 0.041556,
    0.0556434, -0.2040259, 1.0572252
  ];

  const WHITE_REF = [0.95047, 1, 1.08883];

  function rgb2int(rgb) {
    return (rgb[0] & 255) << 16 | (rgb[1] & 255) << 8 | (rgb[2] & 255);
  }

  function int2rgb(v) {
    let rgb = new Uint8ClampedArray(3);
    rgb[0] = v >> 16;
    rgb[1] = v >> 8 & 255;
    rgb[2] = v & 255;
    return rgb;
  }

  function rgb2hex(rgb) {
    return '#' + (0x1000000 + rgb2int(rgb)).toString(16).slice(1);
  }

  function hex2rgb(h) {
    try {
      h = /^\s*#((?:[0-9A-Fa-f]{3}){1,2})\s*$/.exec(h)[1];
    } catch (e) {
      return null;
    }
    if (h.length === 3) {
      h = h[0] + h[0] + h[1] + h[1] + h[2] + h[2];
    }
    return int2rgb(parseInt(h, 16));
  }

  function name2rgb(c) {
    c = c.trim().toLowerCase();
    if (COLORS.hasOwnProperty(c)) {
      return int2rgb(COLORS[c]);
    }
    return null;
  }

  function rgb2xyz(rgb) {
    let f = c => c > 0.04045
      ? Math.pow((c + 0.055) / 1.055, 2.4)
      : c / 12.92;
    let r = f(rgb[0] / 255);
    let g = f(rgb[1] / 255);
    let b = f(rgb[2] / 255);
    let xyz = new Float64Array(3);
    xyz[0] = RGB_XYZ[0] * r + RGB_XYZ[1] * g + RGB_XYZ[2] * b;
    xyz[1] = RGB_XYZ[3] * r + RGB_XYZ[4] * g + RGB_XYZ[5] * b;
    xyz[2] = RGB_XYZ[6] * r + RGB_XYZ[7] * g + RGB_XYZ[8] * b;
    return xyz;
  }

  function xyz2rgb(xyz) {
    let f = c => c > 0.0031308
      ? 1.055 * Math.pow(c, 1 / 2.4) - 0.055
      : 12.92 * c;
    let r = XYZ_RGB[0] * xyz[0] + XYZ_RGB[1] * xyz[1] + XYZ_RGB[2] * xyz[2];
    let g = XYZ_RGB[3] * xyz[0] + XYZ_RGB[4] * xyz[1] + XYZ_RGB[5] * xyz[2];
    let b = XYZ_RGB[6] * xyz[0] + XYZ_RGB[7] * xyz[1] + XYZ_RGB[8] * xyz[2];
    let rgb = new Uint8ClampedArray(3);
    rgb[0] = f(r) * 255;
    rgb[1] = f(g) * 255;
    rgb[2] = f(b) * 255;
    return rgb;
  }

  // https://en.wikipedia.org/wiki/Lab_color_space
  function xyz2lab(xyz) {
    let f = t => t > 0.008856 ? Math.cbrt(t) : t / Math.pow(6 / 29, 2) + 4 / 29;
    let x = f(xyz[0] / WHITE_REF[0]);
    let y = f(xyz[1] / WHITE_REF[1]);
    let z = f(xyz[2] / WHITE_REF[2]);
    let lab = new Float64Array(3);
    lab[0] = 116 * y - 16;
    lab[1] = 500 * (x - y);
    lab[2] = 200 * (y - z);
    return lab;
  }

  function lab2xyz(lab) {
    let f = t => t > 6 / 29
      ? t * t * t
      : 3 * Math.pow(6 / 29, 2) * (t - 4 / 29);
    let xyz = new Float64Array(3);
    xyz[0] = WHITE_REF[0] * f((lab[0] + 16) / 116 + lab[1]/500);
    xyz[1] = WHITE_REF[1] * f((lab[0] + 16) / 116);
    xyz[2] = WHITE_REF[2] * f((lab[0] + 16) / 116 - lab[2]/200);
    return xyz;
  }

  function lab2lch(lab) {
    let h = Math.atan2(lab[2], lab[1]) * 180 / Math.PI;
    // Иногда угол получается отрицательным
    if (h < 0) {
      h += 360;
    }
    let lch = new Float64Array(3);
    lch[0] = lab[0];
    lch[1] = Math.sqrt(Math.pow(lab[1], 2) + Math.pow(lab[2], 2));
    lch[2] = h;
    return lch;
  }

  function lch2lab(lch) {
    let rads = lch[2] * Math.PI / 180;
    let lab = new Float64Array(3);
    lab[0] = lch[0];
    lab[1] = lch[1] * Math.cos(rads);
    lab[2] = lch[1] * Math.sin(rads);
    return lab;
  }

  function rgb2lab(rgb) {
    return xyz2lab(rgb2xyz(rgb));
  }

  function lab2rgb(lab) {
    return xyz2rgb(lab2xyz(lab));
  }

  function rgb2lch(rgb) {
    return lab2lch(rgb2lab(rgb));
  }

  function lch2rgb(lch) {
    return lab2rgb(lch2lab(lch));
  }

  function lighter(rgb, amount) {
    let lab = rgb2lab(rgb);
    lab[0] += (100 - lab[0]) * f;
    return lab2rgb(lab);
  }

  function darker(rgb, f = 0.5) {
    let lab = rgb2lab(rgb);
    lab[0] -= lab[0] * f;
    return lab2rgb(lab);
  }

  // Monochromatic colors

  // Add white
  // tints(name2rgb('orange')).forEach(showColor)
  function tints(rgb, amount = 5) {
    let lab = rgb2lab(rgb);
    let step = (100 - lab[0]) / amount;
    let ret = Array(amount + 1);
    ret[0] = rgb.slice();
    for (let i = 1; i <= amount; ++i) {
      ret[i] = lab2rgb([lab[0] + step * i, lab[1], lab[2]]);
    }
    return ret;
  }

  // Add black
  function shades(rgb, amount = 5) {
    let lab = rgb2lab(rgb);
    let step = lab[0] / amount;
    let ret = Array(amount + 1);
    ret[0] = rgb.slice();
    for (let i = 1; i <= amount; ++i) {
      ret[i] = lab2rgb([lab[0] - step * i, lab[1], lab[2]]);
    }
    return ret;
  }

  // Add grey
  function tones(rgb, amount = 5) {
    let lch = rgb2lch(rgb);
    let step = lch[1] / amount;
    let ret = Array(amount + 1);
    ret[0] = rgb.slice();
    for (let i = 1; i <= amount; ++i) {
      ret[i] = lch2rgb([lch[0], lch[1] - step * i, lch[2]]);
    }
    return ret;
  }

  function rotateHue(rgb, angle) {
    let lch = rgb2lch(rgb);
    // lch2rgb работает и с отрицательными углами
    lch[2] += angle;
    return lch2rgb(lch);
  }

  function complement(rgb) {
    return rotateHue(rgb, 180);
  }

  // Движемся по часовой стрелке
  function triad(rgb, angle = 120) {
    return [
      rgb.slice(),
      rotateHue(rgb, angle),
      rotateHue(rgb, -angle)
    ];
  }

  function splitComplements(rgb) {
    return triad(rgb, 150);
  }

  function analogous(rgb) {
    return triad(rgb, 30);
  }

  // Double split complementary
  function tetrad(rgb, angle = 90) {
    return [
      rgb.slice(),
      rotateHue(rgb, angle),
      complement(rgb),
      rotateHue(rgb, 180 + angle)
    ];
  }

  // https://www.w3.org/TR/WCAG20/#relativeluminancedef
  function luminance(rgb) {
    let f = c => c > 0.03928 ? Math.pow((c + 0.055) / 1.055, 2.4) : c / 12.92;
    let r = f(rgb[0] / 255);
    let g = f(rgb[1] / 255);
    let b = f(rgb[2] / 255);
    return 0.2126 * r + 0.7152 * g + 0.0722 * b;
  }

  // http://stackoverflow.com/a/3943023/2240578
  function getTextColor(rgb) {
    return luminance(rgb) > 0.179 ? 'black' : 'white';
  }

  function showColor(rgb) {
    let color = rgb2hex(rgb);
    let textColor = getTextColor(rgb);
    console.log('%c' + color, `background:${color};color:${textColor}`);
  }

  /*
  >>> found=re.findall(r'function\s+(\w+)', s)
   */
  let colorLib = {
    rgb2int,
    int2rgb,
    rgb2hex,
    hex2rgb,
    name2rgb,
    rgb2xyz,
    xyz2rgb,
    xyz2lab,
    lab2xyz,
    lab2lch,
    lch2lab,
    rgb2lab,
    lab2rgb,
    rgb2lch,
    lch2rgb,
    lighter,
    darker,
    tints,
    shades,
    tones,
    rotateHue,
    complement,
    triad,
    splitComplements,
    analogous,
    tetrad,
    luminance,
    getTextColor,
    showColor
  };
  if (typeof module === 'object' && module && module.exports) {
    module.exports = colorLib;
  } else {
    window.colorLib = colorLib;
  }
})();