https://ijrpns.com/js/jquery.backgroundPosition.js

1/**
2 * @author Alexander Farkas
3 * v. 1.22
4 */
5
6
7(function($) {
8	if(!document.defaultView || !document.defaultView.getComputedStyle){ // IE6-IE8
9		var oldCurCSS = $.curCSS;
10		$.curCSS = function(elem, name, force){
11			if(name === 'background-position'){
12				name = 'backgroundPosition';
13			}
14			if(name !== 'backgroundPosition' || !elem.currentStyle || elem.currentStyle[ name ]){
15				return oldCurCSS.apply(this, arguments);
16			}
17			var style = elem.style;
18			if ( !force && style && style[ name ] ){
19				return style[ name ];
20			}
21			return oldCurCSS(elem, 'backgroundPositionX', force) +' '+ oldCurCSS(elem, 'backgroundPositionY', force);
22		};
23	}
24	
25	var oldAnim = $.fn.animate;
26	$.fn.animate = function(prop){
27		if('background-position' in prop){
28			prop.backgroundPosition = prop['background-position'];
29			delete prop['background-position'];
30		}
31		if('backgroundPosition' in prop){
32			prop.backgroundPosition = '('+ prop.backgroundPosition;
33		}
34		return oldAnim.apply(this, arguments);
35	};
36	
37	function toArray(strg){
38		strg = strg.replace(/left|top/g,'0px');
39		strg = strg.replace(/right|bottom/g,'100%');
40		strg = strg.replace(/([0-9\.]+)(\s|\)|$)/g,"$1px$2");
41		var res = strg.match(/(-?[0-9\.]+)(px|\%|em|pt)\s(-?[0-9\.]+)(px|\%|em|pt)/);
42		return [parseFloat(res[1],10),res[2],parseFloat(res[3],10),res[4]];
43	}
44	
45	$.fx.step. backgroundPosition = function(fx) {
46		if (!fx.bgPosReady) {
47			var start = $.curCSS(fx.elem,'backgroundPosition');
48			if(!start){//FF2 no inline-style fallback
49				start = '0px 0px';
50			}
51			
52			start = toArray(start);
53			fx.start = [start[0],start[2]];
54			var end = toArray(fx.end);
55			fx.end = [end[0],end[2]];
56			
57			fx.unit = [end[1],end[3]];
58			fx.bgPosReady = true;
59		}
60		//return;
61		var nowPosX = [];
62		nowPosX[0] = ((fx.end[0] - fx.start[0]) * fx.pos) + fx.start[0] + fx.unit[0];
63		nowPosX[1] = ((fx.end[1] - fx.start[1]) * fx.pos) + fx.start[1] + fx.unit[1];           
64		fx.elem.style.backgroundPosition = nowPosX[0]+' '+nowPosX[1];
65
66	};
67})(jQuery);