/**

 * @author Alexander Farkas

 * v. 1.02

 */

(function($) {

	$.extend($.fx.step,{

	    backgroundPosition: function(fx) {

            if (fx.state === 0 && typeof fx.end == 'string') {

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

                start = toArray(start);

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

                var end = toArray(fx.end);

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

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

			}

            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];



           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]];

           }

        }

	});

})(jQuery);