/**
* @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);