neo-blessed/lib/colors.js

/**
 * colors.js - color-related functions for blessed.
 * Copyright (c) 2013-2015, Christopher Jeffrey and contributors (MIT License).
 * https://github.com/chjj/blessed
 */

exports.match = function(r1, g1, b1) {
  if (typeof r1 === 'string') {
    var hex = r1;
    if (hex[0] !== '#') {
      return -1;
    }
    hex = exports.hexToRGB(hex);
    r1 = hex[0], g1 = hex[1], b1 = hex[2];
  } else if (Array.isArray(r1)) {
    b1 = r1[2], g1 = r1[1], r1 = r1[0];
  }

  var hash = (r1 << 16) | (g1 << 8) | b1;

  if (exports._cache[hash] != null) {
    return exports._cache[hash];
  }

  var ldiff = Infinity
    , li = -1
    , i = 0
    , c
    , r2
    , g2
    , b2
    , diff;

  for (; i < exports.vcolors.length; i++) {
    c = exports.vcolors[i];
    r2 = c[0];
    g2 = c[1];
    b2 = c[2];

    diff = colorDistance(r1, g1, b1, r2, g2, b2);

    if (diff === 0) {
      li = i;
      break;
    }

    if (diff < ldiff) {
      ldiff = diff;
      li = i;
    }
  }

  return exports._cache[hash] = li;
};

exports.RGBToHex = function(r, g, b) {
  if (Array.isArray(r)) {
    b = r[2], g = r[1], r = r[0];
  }

  function hex(n) {
    n = n.toString(16);
    if (n.length < 2) n = '0' + n;
    return n;
  }

  return '#' + hex(r) + hex(g) + hex(b);
};

exports.hexToRGB = function(hex) {
  if (hex.length === 4) {
    hex = hex[0]
      + hex[1] + hex[1]
      + hex[2] + hex[2]
      + hex[3] + hex[3];
  }

  var col = parseInt(hex.substring(1), 16)
    , r = (col >> 16) & 0xff
    , g = (col >> 8) & 0xff
    , b = col & 0xff;

  return [r, g, b];
};

// As it happens, comparing how similar two colors are is really hard. Here is
// one of the simplest solutions, which doesn't require conversion to another
// color space, posted on stackoverflow[1]. Maybe someone better at math can
// propose a superior solution.
// [1] http://stackoverflow.com/questions/1633828

function colorDistance(r1, g1, b1, r2, g2, b2) {
  return Math.pow(30 * (r1 - r2), 2)
    + Math.pow(59 * (g1 - g2), 2)
    + Math.pow(11 * (b1 - b2), 2);
}

// This might work well enough for a terminal's colors: treat RGB as XYZ in a
// 3-dimensional space and go midway between the two points.
exports.mixColors = function(c1, c2) {
  // if (c1 === 0x1ff) return c1;
  // if (c2 === 0x1ff) return c1;
  if (c1 === 0x1ff) c1 = 0;
  if (c2 === 0x1ff) c2 = 0;

  c1 = exports.vcolors[c1];
  var r1 = c1[0];
  var g1 = c1[1];
  var b1 = c1[2];

  c2 = exports.vcolors[c2];
  var r2 = c2[0];
  var g2 = c2[1];
  var b2 = c2[2];

  // XXX Maybe allow opacity instead of 0.5?
  r1 += (r2 - r1) * 0.5 | 0;
  g1 += (g2 - g1) * 0.5 | 0;
  b1 += (b2 - b1) * 0.5 | 0;

  return exports.match([r1, g1, b1]);
};

exports._cache = {};

// XTerm Colors
// These were actually tough to track down. The xterm source only uses color
// keywords. The X11 source needed to be examined to find the actual values.
// They then had to be mapped to rgb values and then converted to hex values.
exports.xterm = [
  '#000000', // black
  '#cd0000', // red3
  '#00cd00', // green3
  '#cdcd00', // yellow3
  '#0000ee', // blue2
  '#cd00cd', // magenta3
  '#00cdcd', // cyan3
  '#e5e5e5', // gray90
  '#7f7f7f', // gray50
  '#ff0000', // red
  '#00ff00', // green
  '#ffff00', // yellow
  '#5c5cff', // rgb:5c/5c/ff
  '#ff00ff', // magenta
  '#00ffff', // cyan
  '#ffffff'  // white
];

// Seed all 256 colors. Assume xterm defaults.
// Ported from the xterm color generation script.
exports.colors = (function() {
  var cols = exports.colors = []
    , _cols = exports.vcolors = []
    , r
    , g
    , b
    , i
    , l;

  function hex(n) {
    n = n.toString(16);
    if (n.length < 2) n = '0' + n;
    return n;
  }

  function push(i, r, g, b) {
    cols[i] = '#' + hex(r) + hex(g) + hex(b);
    _cols[i] = [r, g, b];
  }

  // 0 - 15
  exports.xterm.forEach(function(c, i) {
    c = parseInt(c.substring(1), 16);
    push(i, (c >> 16) & 0xff, (c >> 8) & 0xff, c & 0xff);
  });

  // 16 - 231
  for (r = 0; r < 6; r++) {
    for (g = 0; g < 6; g++) {
      for (b = 0; b < 6; b++) {
        i = 16 + (r * 36) + (g * 6) + b;
        push(i,
          r ? (r * 40 + 55) : 0,
          g ? (g * 40 + 55) : 0,
          b ? (b * 40 + 55) : 0);
      }
    }
  }

  // 232 - 255 are grey.
  for (g = 0; g < 24; g++) {
    l = (g * 10) + 8;
    i = 232 + g;
    push(i, l, l, l);
  }

  return cols;
})();

// Map higher colors to the first 8 colors.
// This allows translation of high colors to low colors on 8-color terminals.
exports.ccolors = (function() {
  var _cols = exports.vcolors.slice()
    , cols = exports.colors.slice()
    , out;

  exports.vcolors = exports.vcolors.slice(0, 8);
  exports.colors = exports.colors.slice(0, 8);

  out = cols.map(exports.match);

  exports.colors = cols;
  exports.vcolors = _cols;
  exports.ccolors = out;

  return out;
})();

var colorNames = exports.colorNames = {
  default: -1,
  normal: -1,
  bg: -1,
  fg: -1,
  black: 0,
  red: 1,
  green: 2,
  yellow: 3,
  blue: 4,
  magenta: 5,
  cyan: 6,
  white: 7,
  lightblack: 8,
  lightred: 9,
  lightgreen: 10,
  lightyellow: 11,
  lightblue: 12,
  lightmagenta: 13,
  lightcyan: 14,
  lightwhite: 15
};

exports.convert = function(color) {
  if (typeof color === 'number') {
    ;
  } else if (typeof color === 'string') {
    color = color.replace(/[\- ]/g, '');
    if (colorNames[color] != null) {
      color = colorNames[color];
    } else {
      color = exports.match(color);
    }
  } else if (Array.isArray(color)) {
    color = exports.match(color);
  } else {
    color = -1;
  }
  return color !== -1 ? color : 0x1ff;
};

// Map higher colors to the first 8 colors.
// This allows translation of high colors to low colors on 8-color terminals.
// Why the hell did I do this by hand?
exports.ccolors = {
  blue: [
    4,
    12,
    [17, 21],
    [24, 27],
    [31, 33],
    [38, 39],
    45,
    [54, 57],
    [60, 63],
    [67, 69],
    [74, 75],
    81,
    [91, 93],
    [97, 99],
    [103, 105],
    [110, 111],
    117,
    [128, 129],
    [134, 135],
    [140, 141],
    [146, 147],
    153,
    165,
    171,
    177,
    183,
    189
  ],

  green: [
    2,
    10,
    22,
    [28, 29],
    [34, 36],
    [40, 43],
    [46, 50],
    [64, 65],
    [70, 72],
    [76, 79],
    [82, 86],
    [106, 108],
    [112, 115],
    [118, 122],
    [148, 151],
    [154, 158],
    [190, 194]
  ],

  cyan: [
    6,
    14,
    23,
    30,
    37,
    44,
    51,
    66,
    73,
    80,
    87,
    109,
    116,
    123,
    152,
    159,
    195
  ],

  red: [
    1,
    9,
    52,
    [88, 89],
    [94, 95],
    [124, 126],
    [130, 132],
    [136, 138],
    [160, 163],
    [166, 169],
    [172, 175],
    [178, 181],
    [196, 200],
    [202, 206],
    [208, 212],
    [214, 218],
    [220, 224]
  ],

  magenta: [
    5,
    13,
    53,
    90,
    96,
    127,
    133,
    139,
    164,
    170,
    176,
    182,
    201,
    207,
    213,
    219,
    225
  ],

  yellow: [
    3,
    11,
    58,
    [100, 101],
    [142, 144],
    [184, 187],
    [226, 230]
  ],

  black: [
    0,
    8,
    16,
    59,
    102,
    [232, 243]
  ],

  white: [
    7,
    15,
    145,
    188,
    231,
    [244, 255]
  ]
};

exports.ncolors = [];

Object.keys(exports.ccolors).forEach(function(name) {
  exports.ccolors[name].forEach(function(offset) {
    if (typeof offset === 'number') {
      exports.ncolors[offset] = name;
      exports.ccolors[offset] = exports.colorNames[name];
      return;
    }
    for (var i = offset[0], l = offset[1]; i <= l; i++) {
      exports.ncolors[i] = name;
      exports.ccolors[i] = exports.colorNames[name];
    }
  });
  delete exports.ccolors[name];
});