/**

 * @author Alexander Farkas

 * v. 1.1

 * more info: http://www.protofunc.com/scripts/jquery/backgroundPosition/

 * Released under GPL and MIT license

 */



(function($){

	

	if(!document.defaultView || !document.defaultView.getComputedStyle){

		var oldCurCSS = jQuery.curCSS;

		jQuery.curCSS = function(elem, name, force){

			if(name !== 'backgroundPosition' || !elem.currentStyle || elem.currentStyle[ name ]){

				return oldCurCSS.apply(this, arguments);

			}

			var style = elem.style;

			if ( !force && style && style[ name ] ){

				return style[ name ];

			}

			return oldCurCSS(elem, 'backgroundPositionX', force) +' '+ oldCurCSS(elem, 'backgroundPositionY', force);

		};

	}

})(jQuery);



(function($) {

	

	function toArray(strg){

		strg = strg.replace(/left|top/g,'0px');

		strg = strg.replace(/right|bottom/g,'100%');

		strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");

		var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);

		return [parseFloat(res[1],10),res[2],parseFloat(res[3],10),res[4]];

	}

	

	$.fx.step. backgroundPosition = function(fx) {

		if (!fx.bgPosReady) {

			

			var start = $.curCSS(fx.elem,'backgroundPosition');

			if(!start){//FF2 no inline-style fallback

				start = '0px 0px';

			}

			

			start = toArray(start);

			fx.start = [start[0],start[2]];

			

			var end = toArray(fx.options.curAnim.backgroundPosition);

			fx.end = [end[0],end[2]];

			

			fx.unit = [end[1],end[3]];

			fx.bgPosReady = true;

		}

		

		var nowPosX = [];

		nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];

		nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];           

		fx.elem.style.backgroundPosition = nowPosX[0]+' '+nowPosX[1];



	};

})(jQuery);