text: (function(global) {
      'use strict';
  
      /**
       * This class is to represent color.
       * @param {number} red This argument is between 0 and 255.
       * @param {number} green This argument is between 0 and 255.
       * @param {number} blue This argument is between 0 and 255.
       * @param {number} alpha This argument is between 0 and 1.
       * @constructor
       */
      function Color(red, green, blue, alpha) {
          this.red   = 0;
          this.green = 0;
          this.blue  = 0;
          this.alpha = 1;
  
          var r = parseInt(red);
          var g = parseInt(green);
          var b = parseInt(blue);
          var a = parseFloat(alpha);
  
          if (!isNaN(r) && (r >= 0) && (r <= 255)) {
              this.red = r;
          }
  
          if (!isNaN(g) && (g >= 0) && (g <= 255)) {
              this.green = g;
          }
  
          if (!isNaN(b) && (b >= 0) && (b <= 255)) {
              this.blue = b;
          }
  
          if (!isNaN(a) && (a >= 0) && (a <= 1)) {
              this.alpha = a;
          }
      }
  
      /**
       * This method gets value of red.
       * @return {number} This is returned as value of red.
       */
      Color.prototype.getRed = function() {
          return this.red;
      };
  
      /**
       * This method gets value of green.
       * @return {number} This is returned as value of green.
       */
      Color.prototype.getGreen = function() {
          return this.green;
      };
  
      /**
       * This method gets value of blue.
       * @return {number} This is returned as value of blue.
       */
      Color.prototype.getBlue = function() {
          return this.blue;
      };
  
      /**
       * This method gets value of alpha.
       * @return {number} This is returned as value of alpha.
       */
      Color.prototype.getAlpha = function() {
          return this.alpha;
      };
  
      /**
       * This method gets color string as rgba format.
       * @return {string} This is returned as color string as rgba format.
       * @override
       */
      Color.prototype.toString = function() {
          var rgba = 'rgba(' + this.red + ', ' + this.green + ', ' + this.blue + ', ' + this.alpha + ')';
  
           return rgba;
      };
  
      /**
       * This method gets color string as hex format.
       * @return {string} This is returned as color string as hex format.
       */
      Color.prototype.toHexString = function() {
          var hex = '#';
  
          hex += this.red.toString(16) + this.green.toString(16) + this.blue.toString(16);
  
          return hex;
      };
  
      // Export
      global.Color = Color;
  
  })(window);
  