randomColor.js

// randomColor by David Merfield under the CC0 license
// https://github.com/davidmerfield/randomColor/

;(function(root, factory) {

	// Support CommonJS
	if (typeof exports === 'object') {
	  var randomColor = factory();

	  // Support NodeJS & Component, which allow module.exports to be a function
	  if (typeof module === 'object' && module && module.exports) {
		exports = module.exports = randomColor;
	  }

	  // Support CommonJS 1.1.1 spec
	  exports.randomColor = randomColor;

	// Support AMD
	} else if (typeof define === 'function' && define.amd) {
	  define([], factory);

	// Support vanilla script loading
	} else {
	  root.randomColor = factory();
	}

  }(this, function() {

	// Seed to get repeatable colors
	var seed = null;

	// Shared color dictionary
	var colorDictionary = {};

	// Populate the color dictionary
	loadColorBounds();

	// check if a range is taken
	var colorRanges = [];

	var randomColor = function (options) {

	  options = options || {};

	  // Check if there is a seed and ensure it's an
	  // integer. Otherwise, reset the seed value.
	  if (options.seed !== undefined && options.seed !== null && options.seed === parseInt(options.seed, 10)) {
		seed = options.seed;

	  // A string was passed as a seed
	  } else if (typeof options.seed === 'string') {
		seed = stringToInteger(options.seed);

	  // Something was passed as a seed but it wasn't an integer or string
	  } else if (options.seed !== undefined && options.seed !== null) {
		throw new TypeError('The seed value must be an integer or string');

	  // No seed, reset the value outside.
	  } else {
		seed = null;
	  }

	  var H,S,B;

	  // Check if we need to generate multiple colors
	  if (options.count !== null && options.count !== undefined) {

		var totalColors = options.count,
			colors = [];
		// Value false at index i means the range i is not taken yet.
		for (var i = 0; i < options.count; i++) {
		  colorRanges.push(false)
		  }
		options.count = null;

		while (totalColors > colors.length) {

		  // Since we're generating multiple colors,
		  // incremement the seed. Otherwise we'd just
		  // generate the same color each time...
		  if (seed && options.seed) options.seed += 1;

		  colors.push(randomColor(options));
		}

		options.count = totalColors;

		return colors;
	  }

	  // First we pick a hue (H)
	  H = pickHue(options);

	  // Then use H to determine saturation (S)
	  S = pickSaturation(H, options);

	  // Then use S and H to determine brightness (B).
	  B = pickBrightness(H, S, options);

	  // Then we return the HSB color in the desired format
	  return setFormat([H,S,B], options);
	};

	function pickHue(options) {
	  if (colorRanges.length > 0) {
		var hueRange = getRealHueRange(options.hue)

		var hue = randomWithin(hueRange)

		//Each of colorRanges.length ranges has a length equal approximatelly one step
		var step = (hueRange[1] - hueRange[0]) / colorRanges.length

		var j = parseInt((hue - hueRange[0]) / step)

		//Check if the range j is taken
		if (colorRanges[j] === true) {
		  j = (j + 2) % colorRanges.length
		}
		else {
		  colorRanges[j] = true
			 }

		var min = (hueRange[0] + j * step) % 359,
			max = (hueRange[0] + (j + 1) * step) % 359;

		hueRange = [min, max]

		hue = randomWithin(hueRange)

		if (hue < 0) {hue = 360 + hue;}
		return hue
	  }
	  else {
		var hueRange = getHueRange(options.hue)

		hue = randomWithin(hueRange);
		// Instead of storing red as two seperate ranges,
		// we group them, using negative numbers
		if (hue < 0) {
		  hue = 360 + hue;
		}

		return hue;
	  }
	}

	function pickSaturation (hue, options) {

	  if (options.hue === 'monochrome') {
		return 0;
	  }

	  if (options.luminosity === 'random') {
		return randomWithin([0,100]);
	  }

	  var saturationRange = getSaturationRange(hue);

	  var sMin = saturationRange[0],
		  sMax = saturationRange[1];

	  switch (options.luminosity) {

		case 'bright':
		  sMin = 55;
		  break;

		case 'dark':
		  sMin = sMax - 10;
		  break;

		case 'light':
		  sMax = 55;
		  break;
	 }

	  return randomWithin([sMin, sMax]);

	}

	function pickBrightness (H, S, options) {

	  var bMin = getMinimumBrightness(H, S),
		  bMax = 100;

	  switch (options.luminosity) {

		case 'dark':
		  bMax = bMin + 20;
		  break;

		case 'light':
		  bMin = (bMax + bMin)/2;
		  break;

		case 'random':
		  bMin = 0;
		  bMax = 100;
		  break;
	  }

	  return randomWithin([bMin, bMax]);
	}

	function setFormat (hsv, options) {

	  switch (options.format) {

		case 'hsvArray':
		  return hsv;

		case 'hslArray':
		  return HSVtoHSL(hsv);

		case 'hsl':
		  var hsl = HSVtoHSL(hsv);
		  return 'hsl('+hsl[0]+', '+hsl[1]+'%, '+hsl[2]+'%)';

		case 'hsla':
		  var hslColor = HSVtoHSL(hsv);
		  var alpha = options.alpha || Math.random();
		  return 'hsla('+hslColor[0]+', '+hslColor[1]+'%, '+hslColor[2]+'%, ' + alpha + ')';

		case 'rgbArray':
		  return HSVtoRGB(hsv);

		case 'rgb':
		  var rgb = HSVtoRGB(hsv);
		  return 'rgb(' + rgb.join(', ') + ')';

		case 'rgba':
		  var rgbColor = HSVtoRGB(hsv);
		  var alpha = options.alpha || Math.random();
		  return 'rgba(' + rgbColor.join(', ') + ', ' + alpha + ')';

		default:
		  return HSVtoHex(hsv);
	  }

	}

	function getMinimumBrightness(H, S) {

	  var lowerBounds = getColorInfo(H).lowerBounds;

	  for (var i = 0; i < lowerBounds.length - 1; i++) {

		var s1 = lowerBounds[i][0],
			v1 = lowerBounds[i][1];

		var s2 = lowerBounds[i+1][0],
			v2 = lowerBounds[i+1][1];

		if (S >= s1 && S <= s2) {

		   var m = (v2 - v1)/(s2 - s1),
			   b = v1 - m*s1;

		   return m*S + b;
		}

	  }

	  return 0;
	}

	function getHueRange (colorInput) {

	  if (typeof parseInt(colorInput) === 'number') {

		var number = parseInt(colorInput);

		if (number < 360 && number > 0) {
		  return [number, number];
		}

	  }

	  if (typeof colorInput === 'string') {

		if (colorDictionary[colorInput]) {
		  var color = colorDictionary[colorInput];
		  if (color.hueRange) {return color.hueRange;}
		} else if (colorInput.match(/^#?([0-9A-F]{3}|[0-9A-F]{6})$/i)) {
		  var hue = HexToHSB(colorInput)[0];
		  return [ hue, hue ];
		}
	  }

	  return [0,360];

	}

	function getSaturationRange (hue) {
	  return getColorInfo(hue).saturationRange;
	}

	function getColorInfo (hue) {

	  // Maps red colors to make picking hue easier
	  if (hue >= 334 && hue <= 360) {
		hue-= 360;
	  }

	  for (var colorName in colorDictionary) {
		 var color = colorDictionary[colorName];
		 if (color.hueRange &&
			 hue >= color.hueRange[0] &&
			 hue <= color.hueRange[1]) {
			return colorDictionary[colorName];
		 }
	  } return 'Color not found';
	}

	function randomWithin (range) {
	  if (seed === null) {
		//generate random evenly destinct number from : https://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/
		var golden_ratio = 0.618033988749895
		var r=Math.random()
		r += golden_ratio
		r %= 1
		return Math.floor(range[0] + r*(range[1] + 1 - range[0]));
	  } else {
		//Seeded random algorithm from http://indiegamr.com/generate-repeatable-random-numbers-in-js/
		var max = range[1] || 1;
		var min = range[0] || 0;
		seed = (seed * 9301 + 49297) % 233280;
		var rnd = seed / 233280.0;
		return Math.floor(min + rnd * (max - min));
  }
	}

	function HSVtoHex (hsv){

	  var rgb = HSVtoRGB(hsv);

	  function componentToHex(c) {
		  var hex = c.toString(16);
		  return hex.length == 1 ? '0' + hex : hex;
	  }

	  var hex = '#' + componentToHex(rgb[0]) + componentToHex(rgb[1]) + componentToHex(rgb[2]);

	  return hex;

	}

	function defineColor (name, hueRange, lowerBounds) {

	  var sMin = lowerBounds[0][0],
		  sMax = lowerBounds[lowerBounds.length - 1][0],

		  bMin = lowerBounds[lowerBounds.length - 1][1],
		  bMax = lowerBounds[0][1];

	  colorDictionary[name] = {
		hueRange: hueRange,
		lowerBounds: lowerBounds,
		saturationRange: [sMin, sMax],
		brightnessRange: [bMin, bMax]
	  };

	}

	function loadColorBounds () {

	  defineColor(
		'monochrome',
		null,
		[[0,0],[100,0]]
	  );

	  defineColor(
		'red',
		[-26,18],
		[[20,100],[30,92],[40,89],[50,85],[60,78],[70,70],[80,60],[90,55],[100,50]]
	  );

	  defineColor(
		'orange',
		[19,46],
		[[20,100],[30,93],[40,88],[50,86],[60,85],[70,70],[100,70]]
	  );

	  defineColor(
		'yellow',
		[47,62],
		[[25,100],[40,94],[50,89],[60,86],[70,84],[80,82],[90,80],[100,75]]
	  );

	  defineColor(
		'green',
		[63,178],
		[[30,100],[40,90],[50,85],[60,81],[70,74],[80,64],[90,50],[100,40]]
	  );

	  defineColor(
		'blue',
		[179, 257],
		[[20,100],[30,86],[40,80],[50,74],[60,60],[70,52],[80,44],[90,39],[100,35]]
	  );

	  defineColor(
		'purple',
		[258, 282],
		[[20,100],[30,87],[40,79],[50,70],[60,65],[70,59],[80,52],[90,45],[100,42]]
	  );

	  defineColor(
		'pink',
		[283, 334],
		[[20,100],[30,90],[40,86],[60,84],[80,80],[90,75],[100,73]]
	  );

	}

	function HSVtoRGB (hsv) {

	  // this doesn't work for the values of 0 and 360
	  // here's the hacky fix
	  var h = hsv[0];
	  if (h === 0) {h = 1;}
	  if (h === 360) {h = 359;}

	  // Rebase the h,s,v values
	  h = h/360;
	  var s = hsv[1]/100,
		  v = hsv[2]/100;

	  var h_i = Math.floor(h*6),
		f = h * 6 - h_i,
		p = v * (1 - s),
		q = v * (1 - f*s),
		t = v * (1 - (1 - f)*s),
		r = 256,
		g = 256,
		b = 256;

	  switch(h_i) {
		case 0: r = v; g = t; b = p;  break;
		case 1: r = q; g = v; b = p;  break;
		case 2: r = p; g = v; b = t;  break;
		case 3: r = p; g = q; b = v;  break;
		case 4: r = t; g = p; b = v;  break;
		case 5: r = v; g = p; b = q;  break;
	  }

	  var result = [Math.floor(r*255), Math.floor(g*255), Math.floor(b*255)];
	  return result;
	}

	function HexToHSB (hex) {
	  hex = hex.replace(/^#/, '');
	  hex = hex.length === 3 ? hex.replace(/(.)/g, '$1$1') : hex;

	  var red = parseInt(hex.substr(0, 2), 16) / 255,
			green = parseInt(hex.substr(2, 2), 16) / 255,
			blue = parseInt(hex.substr(4, 2), 16) / 255;

	  var cMax = Math.max(red, green, blue),
			delta = cMax - Math.min(red, green, blue),
			saturation = cMax ? (delta / cMax) : 0;

	  switch (cMax) {
		case red: return [ 60 * (((green - blue) / delta) % 6) || 0, saturation, cMax ];
		case green: return [ 60 * (((blue - red) / delta) + 2) || 0, saturation, cMax ];
		case blue: return [ 60 * (((red - green) / delta) + 4) || 0, saturation, cMax ];
	  }
	}

	function HSVtoHSL (hsv) {
	  var h = hsv[0],
		s = hsv[1]/100,
		v = hsv[2]/100,
		k = (2-s)*v;

	  return [
		h,
		Math.round(s*v / (k<1 ? k : 2-k) * 10000) / 100,
		k/2 * 100
	  ];
	}

	function stringToInteger (string) {
	  var total = 0
	  for (var i = 0; i !== string.length; i++) {
		if (total >= Number.MAX_SAFE_INTEGER) break;
		total += string.charCodeAt(i)
	  }
	  return total
	}

	// get The range of given hue when options.count!=0
	function getRealHueRange(colorHue)
	{ if (!isNaN(colorHue)) {
	  var number = parseInt(colorHue);

	  if (number < 360 && number > 0) {
		return getColorInfo(colorHue).hueRange
	  }
	}
	  else if (typeof colorHue === 'string') {

		if (colorDictionary[colorHue]) {
		  var color = colorDictionary[colorHue];

		  if (color.hueRange) {
			return color.hueRange
		 }
	  } else if (colorHue.match(/^#?([0-9A-F]{3}|[0-9A-F]{6})$/i)) {
		  var hue = HexToHSB(colorHue)[0]
		  return getColorInfo(hue).hueRange
	  }
	}

	  return [0,360]
  }
	return randomColor;
  }));