//MooTools More, <http://mootools.net/more>. Copyright (c) 2006-2008 Valerio Proietti, <http://mad4milk.net>, MIT Style License.

var Scroller=new Class({Implements:[Events,Options],options:{area:20,velocity:1,onChange:function(A,B){this.element.scrollTo(A,B);}},initialize:function(B,A){this.setOptions(A);
this.element=$(B);this.listener=($type(this.element)!="element")?$(this.element.getDocument().body):this.element;this.timer=null;this.coord=this.getCoords.bind(this);
},start:function(){this.listener.addEvent("mousemove",this.coord);},stop:function(){this.listener.removeEvent("mousemove",this.coord);this.timer=$clear(this.timer);
},getCoords:function(A){this.page=(this.listener.get("tag")=="body")?A.client:A.page;if(!this.timer){this.timer=this.scroll.periodical(50,this);}},scroll:function(){var B=this.element.getSize(),A=this.element.getScroll(),E=this.element.getPosition(),D={x:0,y:0};
for(var C in this.page){if(this.page[C]<(this.options.area+E[C])&&A[C]!=0){D[C]=(this.page[C]-this.options.area-E[C])*this.options.velocity;}else{if(this.page[C]+this.options.area>(B[C]+E[C])&&B[C]+B[C]!=A[C]){D[C]=(this.page[C]-B[C]+this.options.area-E[C])*this.options.velocity;
}}}if(D.y||D.x){this.fireEvent("change",[A.x+D.x,A.y+D.y]);}}});