text: /**
   * @module color-space/hsp
   */
  'use strict'
  
  var rgb = require('./rgb'),
    Pr = 0.299,
    Pg = 0.587,
    Pb = 0.114;
  
  module.exports = {
    name: 'hsp',
    min: [0, 0, 0],
    max: [360, 100, 255],
    channel: ['hue', 'saturation', 'perceived_brightness'],
    alias: ['HSP'],
  
    rgb: function (hsp) {
      var h = hsp[0]/360.0,
        s = hsp[1]/100.0,
        p = hsp[2],
        r, g, b, part,
        minOverMax = 1.0 - s;
  
      if (minOverMax > 0.0) {
        if (h < 1.0 / 6.0) { //  R>G>B
          h = 6.0 * (h - 0.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          b = p / Math.sqrt(Pr / minOverMax / minOverMax + Pg * part * part + Pb);
          r = (b) / minOverMax;
          g = (b) + h * ((r) - (b));
        } else if (h < 2.0 / 6.0) { //  G>R>B
          h = 6.0 * (-h + 2.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          b = p / Math.sqrt(Pg / minOverMax / minOverMax + Pr * part * part + Pb);
          g = (b) / minOverMax;
          r = (b) + h * ((g) - (b));
        } else if (h < 3.0 / 6.0) { //  G>B>R
          h = 6.0 * (h - 2.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          r = p / Math.sqrt(Pg / minOverMax / minOverMax + Pb * part * part + Pr);
          g = (r) / minOverMax;
          b = (r) + h * ((g) - (r));
        } else if (h < 4.0 / 6.0) { //  B>G>R
          h = 6.0 * (-h + 4.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          r = p / Math.sqrt(Pb / minOverMax / minOverMax + Pg * part * part + Pr);
          b = (r) / minOverMax;
          g = (r) + h * ((b) - (r));
        } else if (h < 5.0 / 6.0) { //  B>R>G
          h = 6.0 * (h - 4.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          g = p / Math.sqrt(Pb / minOverMax / minOverMax + Pr * part * part + Pg);
          b = (g) / minOverMax;
          r = (g) + h * ((b) - (g));
        } else { //  R>B>G
          h = 6.0 * (-h + 6.0 / 6.0);
          part = 1.0 + h * (1.0 / minOverMax - 1.0);
          g = p / Math.sqrt(Pr / minOverMax / minOverMax + Pb * part * part + Pg);
          r = (g) / minOverMax;
          b = (g) + h * ((r) - (g));
        }
      } else {
        if (h < 1.0 / 6.0) { //  R>G>B
          h = 6.0 * (h - 0.0 / 6.0);
          r = Math.sqrt(p * p / (Pr + Pg * h * h));
          g = (r) * h;
          b = 0.0;
        } else if (h < 2.0 / 6.0) { //  G>R>B
          h = 6.0 * (-h + 2.0 / 6.0);
          g = Math.sqrt(p * p / (Pg + Pr * h * h));
          r = (g) * h;
          b = 0.0;
        } else if (h < 3.0 / 6.0) { //  G>B>R
          h = 6.0 * (h - 2.0 / 6.0);
          g = Math.sqrt(p * p / (Pg + Pb * h * h));
          b = (g) * h;
          r = 0.0;
        } else if (h < 4.0 / 6.0) { //  B>G>R
          h = 6.0 * (-h + 4.0 / 6.0);
          b = Math.sqrt(p * p / (Pb + Pg * h * h));
          g = (b) * h;
          r = 0.0;
        } else if (h < 5.0 / 6.0) { //  B>R>G
          h = 6.0 * (h - 4.0 / 6.0);
          b = Math.sqrt(p * p / (Pb + Pr * h * h));
          r = (b) * h;
          g = 0.0;
        } else { //  R>B>G
          h = 6.0 * (-h + 6.0 / 6.0);
          r = Math.sqrt(p * p / (Pr + Pb * h * h));
          b = (r) * h;
          g = 0.0;
        }
      }
  
  	return [Math.round(r), Math.round(g), Math.round(b)];
    }
  
    
  };
  
  
  //append rgb
  rgb.hsp = function (rgb) {
    var r = parseInt(rgb[0], 10),
      g = parseInt(rgb[1], 10),
      b = parseInt(rgb[2], 10),
      h, s, p;
  
    //  Calculate the Perceived brightness
    p = Math.sqrt(r * r * Pr + g * g * Pg + b * b * Pb);
  
    //  Calculate the Hue and Saturation
    if (r === g && r === b) {
      h = 0.0;
      s = 0.0;
    } else {    
      //  R is largest
      if (r >= g && r >= b) {
        if (b >= g) {
          h = 6.0 / 6.0 - 1.0 / 6.0 * (b - g) / (r - g);
          s = 1.0 - g / r;
        } else {
          h = 0.0 / 6.0 + 1.0 / 6.0 * (g - b) / (r - b);
          s = 1.0 - b / r;
        }
      }
  
      // G is largest
      if (g >= r && g >= b) {
        if (r >= b) {
          h = 2.0 / 6.0 - 1.0 / 6.0 * (r - b) / (g - b);
          s = 1 - b / g;
        } else {
          h = 2.0 / 6.0 + 1.0 / 6.0 * (b - r) / (g - r);
          s = 1.0 - r / g;
        }
      }
  
      // B is largest
      if (b >= r && b >= g) {
        if (g >= r) {
          h = 4.0 / 6.0 - 1.0 / 6.0 * (g - r) / (b - r);
          s = 1.0 - r / b;
        } else {
          h = 4.0 / 6.0 + 1.0 / 6.0 * (r - g) / (b - g);
          s = 1.0 - g / b;
        }
      }
    }
      
    return [Math.round(h*360.0), s*100.0, Math.round(p)];
  };
  