/*
** Copyright (C) 2009 by Roger E Critchlow Jr,
** Santa Fe, New Mexico, USA
** rec@elf.org
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License
** as published by the Free Software Foundation; either version 2
** of the License, or (at your option) any later version.
** 
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
** 
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
**
** The home page for this source is
**	http://www.elf.org/quantum-classical-clock/
** a copy of the GNU GPL may be found at
**	http://www.gnu.org/copyleft/gpl.html,
*/

/*
** a color constructor
*/
function make_color(red, green, blue) {
  function hex(gun) {
	function hexval(i) {
	  return "0123456789abcdef"[i&15];
	}
	gun = gun > 1.0 ? 1.0 : gun < 0.0 ? 0.0 : gun;
	gun = Math.floor(255*gun);
	return hexval(gun>>4) + hexval(gun);
  }
  return "#"+hex(red)+hex(green)+hex(blue);
}

function interpolate_color(high, low, val) {
  function i(h, l) { return val*h+(1-val)*l; }
  var ch = rgb_to_hsl(new Color(high));
  var cl = rgb_to_hsl(new Color(low));
  var h = ((ch.h < cl.h ? i(ch.h+360, cl.h) : i(ch.h, cl.h)) + 360) % 360;
  var hsl = {h: h, s: i(ch.s, cl.s), l: i(ch.l, cl.l)};
  var rgb = hsl_to_rgb(hsl);
  return 'rgb('+rgb.r+','+rgb.g+','+rgb.b+')';
}

function hsl_to_string(hsl) {
  return "{h: "+hsl.h+", s: "+hsl.s+", l: "+hsl.l+"}";
}

function rgb_to_string(rgb) {
  return "{r: "+rgb.r+", g: "+rgb.g+", b: "+rgb.b+"}";
}

function rgb_to_hsl(rgb) {
  var r = rgb.r / 255;
  var g = rgb.g / 255;
  var b = rgb.b / 255;
  var min = Math.min(r, g, b);
  var max = Math.max(r, g, b);
  var rng = max - min;
  var h = rng == 0 ? 0 :
	(max == r) ? (60 * (g - b) / rng + 360) % 360 :
	(max == g) ? (60 * (b - r) / rng + 120) : (60 * (r - g) / rng + 240);
  var l = rng / 2;
  var s = rng == 0 ? 0 :
	l <= 0.5 ? rng / (2 * l) :
	rng / (2 - 2 * l);
  return { h: h, s: s, l: l };
}

function hsl_to_rgb(hsl) {
  var h = hsl.h;
  var s = hsl.s;
  var l = hsl.l;
  var q = l < 0.5 ? l * (1 - s) :
	l + s - l * s;
  var p = 2 * l - q;
  var hk = h / 360;
  function reduce(x) {
	return x < 0 ? x + 1 :
	  x > 1 ? x - 1 :
	  x;
  }
  var tr = reduce(hk + 1/3);
  var tg = reduce(hk);
  var tb = reduce(hk - 1/3);
  function gun(tc) {
	return tc < 1/6 ? p + (q-p) * 6 * tc :
	  tc < 1/2 ? q :
	  tc < 2/3 ? p + (q-p) * 6 * (2/3 - tc) :
	  p;
  }
  return { r: Math.floor(255*gun(tr)), g: Math.floor(255*gun(tg)), b: Math.floor(255*gun(tb)) };
}

/*
** Color object taken from
** http://www.ozzu.com/programming-forum/javascript-color-object-t66915.html
** on February 12, 2009
*/
/*
   Converts INT to HEX
   If Prototype library is loaded, use theirs, else use ours.
*/
if(!Number.toColorPart){Number.prototype.toColorPart = function(){return ((this < 16 ? '0' : '') + this.toString(16));}}

/*
   Constructor
   @String c : hexadecimal, shorthand hex, or rgb()
   #returns : Object reference to instance or false
*/
function Color(c){
   if(!c || !(c = Color.getFilteredObject(c))){return false;}
   this.original = c;
   this.r=c.r;this.g=c.g;this.b=c.b;
   this.check();
   this.gray = Math.round(.3*this.r + .59*this.g + .11*this.b);
   this.hex = this.getHex();
   this.rgb = this.getRGB();
   return this;
}

/*
   Screens color strings.
   @String str : hexadecimal, shorthand hex, or rgb()
   #returns : Object {r: XXX, g: XXX, b: XXX} or false
*/
Color.getFilteredObject = function(str){
   if(/^#?([\da-f]{3}|[\da-f]{6})$/i.test(str)){
      function _(s,i){return parseInt(s.substr(i,2), 16);}
      str = str.replace(/^#/, '').replace(/^([\da-f])([\da-f])([\da-f])$/i, "$1$1$2$2$3$3");
      return {r:_(str,0), g:_(str,2), b:_(str,4)}
   }else if(/^rgb *\( *\d{0,3} *, *\d{0,3} *, *\d{0,3} *\)$/i.test(str)){
      str = str.match(/^rgb *\( *(\d{0,3}) *, *(\d{0,3}) *, *(\d{0,3}) *\)$/i);
      return {r:parseInt(str[1]), g:parseInt(str[2]), b:parseInt(str[3])};
   }
   return false;
}

/*
   Checks the internal RGB registers for out of range values.
   Resets out of range values.
   #returns : Object reference to instance
*/
Color.prototype.check = function(){
   if(this.r>255){this.r=255;}else if(this.r<0){this.r=0;}
   if(this.g>255){this.g=255;}else if(this.g<0){this.g=0;}
   if(this.b>255){this.b=255;}else if(this.b<0){this.b=0;}
   return this;
}

/*
   Resets color to the original color passed to the constructor.
   #returns : Object reference to instance
*/
Color.prototype.revert = function(){
   this.r=this.original.r;this.g=this.original.g;this.b=this.original.b;
   return this;
}

/*
   Inverts the color.
   Black to White, vice versa
   #returns : Object reference to instance
*/
Color.prototype.invert = function(){
   this.check();
   this.r = 255-this.r;
   this.g = 255-this.g;
   this.b = 255-this.b;
   return this;
}

/*
   Lightens the color.
   @Int amount : 1-254 -- RGB amount to lighten the color
   #returns : Object reference to instance
*/
Color.prototype.lighten = function(amount){
   this.r += parseInt(amount);
   this.g += parseInt(amount);
   this.b += parseInt(amount);
   return this;
}

/*
   Darkens the color.
   @Int amount : 1-254 -- RGB amount to darken the color
   #returns : Object reference to instance
*/
Color.prototype.darken = function(amount){
   return this.lighten(parseInt('-'+amount));
}

/*
   Converts the color to Grayscale
   #returns : Object reference to instance
*/
Color.prototype.grayscale = function(){
   this.check();
   this.gray = Math.round(.3*this.r + .59*this.g + .11*this.b);
   this.r=this.gray;this.g=this.gray;this.b=this.gray;
   return this;
}

/*
   Convenience function for lightening color.
   @Int amount : amount to lighten color
   @Bool returnRGB : true uses RGB return string, false uses HEX return string.
   #returns : String color
*/
Color.prototype.getLighter = function(amount, returnRGB){
   return this.lighten(amount).check()[returnRGB ? 'getRGB' : 'getHex']();
}

/*
   Convenience function for darkening color.
   @Int amount : amount to darken color
   @Bool returnRGB : true uses RGB return string, false uses HEX return string.
   #returns : String color
*/
Color.prototype.getDarker = function(amount, returnRGB){
   return this.darken(amount).check()[returnRGB ? 'getRGB' : 'getHex']();
}

/*
   Convenience function for grayscaling color.
   @Bool returnRGB : true uses RGB return string, false uses HEX return string.
   #returns : String color
*/
Color.prototype.getGrayscale = function(returnRGB){
   this.grayscale();
   return (returnRGB ? ('rgb('+this.gray+','+this.gray+','+this.gray+')') : this.gray.toColorPart().replace(/^([\da-f]{2})$/i, "#$1$1$1"));
}

/*
   Convenience function for inverting color.
   @Bool returnRGB : true uses RGB return string, false uses HEX return string.
   #returns : String color
*/
Color.prototype.getInverted = function(returnRGB){
   return this.invert()[returnRGB ? 'getRGB' : 'getHex']();
}

/*
   Gets the rgb(x,x,x) value of the color
   #returns : String rgb color
*/
Color.prototype.getRGB = function(){
   this.check();
   this.rgb = 'rgb('+this.r+','+this.g+','+this.b+')';
   return this.rgb;
}

/*
   Gets the hex value of the color
   @Bool shorthandReturnAcceptable : true will return #333 instead of #333333
   #returns : String hex color
*/
Color.prototype.getHex = function(shorthandReturnAcceptable){
   this.check();
   this.hex = '#' + this.r.toColorPart() + this.g.toColorPart() + this.b.toColorPart();
   if(shorthandReturnAcceptable){return this.hex.replace(/^#([\da-f])\1([\da-f])\2([\da-f])\3$/i, "#$1$2$3");}
   return this.hex;
}