Hex / RGB translation helpers

hexRGB.js

// http://stackoverflow.com/questions/5623838/rgb-to-hex-and-hex-to-rgb
hexToRgb = (function() {
  var cache = {}
  return function(hex) {
    if (cache[hex]) return cache[hex]
    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex)
    return result ? cache[hex] = {
      r: parseInt(result[1], 16)
    , g: parseInt(result[2], 16)
    , b: parseInt(result[3], 16)
    } : null
  }
})()

var hexToRgba = (function() {
  var cache = {}
  return function(hex, alpha) {
    if (cache[hex]) return cache[hex]
    var rgb = hexToRgb(hex)
    return 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + alpha + ')'
  }
})()

var rgbToHex = function(r, g, b) {
  return "#" + (
    (1 << 24) 
    + (r << 16) 
    + (g << 8) + b
  ).toString(16).slice(1)
}