/**
 * @author Alexander Farkas
 * v. 1.21
 */


(function($) {
if(!document.defaultView || !document.defaultView.getComputedStyle){ // IE6-IE8
var oldCurCSS = jQuery.curCSS;
jQuery.curCSS = function(elem, name, force){
if(name === 'background-position'){
name = 'backgroundPosition';
}
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);
};
}

var oldAnim = $.fn.animate;
$.fn.animate = function(prop){
if('background-position' in prop){
prop.backgroundPosition = prop['background-position'];
delete prop['background-position'];
}
if('backgroundPosition' in prop){
prop.backgroundPosition = '('+ prop.backgroundPosition;
}
return oldAnim.apply(this, arguments);
};

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;
}
//return;
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);