Generation of complementary colors

randomcolors.js

// Adapted from http://martin.ankerl.com/2009/12/09/how-to-create-random-colors-programmatically/

var randomColor = (function(){
  var golden_ratio_conjugate = 0.618033988749895;
  var h = Math.random();

  var hslToRgb = function (h, s, l){
      var r, g, b;

      if(s == 0){
          r = g = b = l; // achromatic
      }else{
          function hue2rgb(p, q, t){
              if(t < 0) t += 1;
              if(t > 1) t -= 1;
              if(t < 1/6) return p + (q - p) * 6 * t;
              if(t < 1/2) return q;
              if(t < 2/3) return p + (q - p) * (2/3 - t) * 6;
              return p;
          }

          var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
          var p = 2 * l - q;
          r = hue2rgb(p, q, h + 1/3);
          g = hue2rgb(p, q, h);
          b = hue2rgb(p, q, h - 1/3);
      }

      return '#'+Math.round(r * 255).toString(16)+Math.round(g * 255).toString(16)+Math.round(b * 255).toString(16);
  };
  
  return function(){
    h += golden_ratio_conjugate;
    h %= 1;
    return hslToRgb(h, 0.5, 0.60);
  };
})();