var Fx=new Class({Implements:[Chain,Events,Options],options:{fps:50,unit:false,duration:500,link:'ignore',transition:function(p){return-(Math.cos(Math.PI*p)-1)/2;}},initialize:function(options){this.subject=this.subject||this;this.setOptions(options);this.options.duration=Fx.Durations[this.options.duration]||this.options.duration.toInt();var wait=this.options.wait;if(wait===false)this.options.link='cancel';},step:function(){var time=$time();if(time<this.time+this.options.duration){var delta=this.options.transition((time-this.time)/this.options.duration);this.set(this.compute(this.from,this.to,delta));}else{this.set(this.compute(this.from,this.to,1));this.complete();}},set:function(now){return now;},compute:function(from,to,delta){return Fx.compute(from,to,delta);},check:function(caller){if(!this.timer)return true;switch(this.options.link){case'cancel':this.cancel();return true;case'chain':this.chain(caller.bind(this,Array.slice(arguments,1)));return false;}
return false;},start:function(from,to){if(!this.check(arguments.callee,from,to))return this;this.from=from;this.to=to;this.time=0;this.startTimer();this.onStart();return this;},complete:function(){if(this.stopTimer())this.onComplete();return this;},cancel:function(){if(this.stopTimer())this.onCancel();return this;},onStart:function(){this.fireEvent('start',this.subject);},onComplete:function(){this.fireEvent('complete',this.subject);if(!this.callChain())this.fireEvent('chainComplete',this.subject);},onCancel:function(){this.fireEvent('cancel',this.subject).clearChain();},pause:function(){this.stopTimer();return this;},resume:function(){this.startTimer();return this;},stopTimer:function(){if(!this.timer)return false;this.time=$time()-this.time;this.timer=$clear(this.timer);return true;},startTimer:function(){if(this.timer)return false;this.time=$time()-this.time;this.timer=this.step.periodical(Math.round(1000/this.options.fps),this);return true;}});Fx.compute=function(from,to,delta){return(to-from)*delta+from;};Fx.Durations={'short':250,'normal':500,'long':1000};