var MooScroller=new Class({options:{maxThumbSize:10,mode:'vertical',width:0,scrollSteps:10,wheel:true,scrollLinks:{forward:'scrollForward',back:'scrollBack'},onScroll:Class.empty,onPage:Class.empty},initialize:function(content,knob,options){this.setOptions(options);this.horz=(this.options.mode=="horizontal");this.content=$(content).setStyle('overflow','hidden');this.knob=$(knob);this.track=this.knob.getParent();this.setPositions();if(this.horz&&this.options.width){this.wrapper=new Element('div');this.content.getChildren().each(function(child){this.wrapper.adopt(child);});this.wrapper.injectInside(this.content).setStyle('width',this.options.width);}
this.bound={'start':this.start.bind(this),'end':this.end.bind(this),'drag':this.drag.bind(this),'wheel':this.wheel.bind(this),'page':this.page.bind(this)};this.position={};this.mouse={};this.update();this.attach();var clearScroll=function(){$clear(this.scrolling);}.bind(this);['forward','back'].each(function(direction){var lnk=$(this.options.scrollLinks[direction]);if(lnk){lnk.addEvents({mousedown:function(){this.scrolling=this[direction].periodical(50,this);}.bind(this),mouseup:clearScroll.bind(this),click:clearScroll.bind(this)});}},this);this.knob.addEvent('click',clearScroll.bind(this));window.addEvent('domready',function(){try{$(document.body).addEvent('mouseup',clearScroll.bind(this));}catch(e){}}.bind(this));},setPositions:function(){[this.track,this.knob].each(function(el){if(el.getStyle('position')=='static')el.setStyle('position','relative');});},update:function(){var plain=this.horz?'Width':'Height';this.contentSize=this.content['offset'+plain];this.contentScrollSize=this.content['scroll'+plain];this.trackSize=this.track['offset'+plain];this.contentRatio=this.contentSize/this.contentScrollSize;this.knobSize=(this.trackSize*this.contentRatio).limit(this.options.maxThumbSize,this.trackSize);this.scrollRatio=this.contentScrollSize/this.trackSize;this.knob.setStyle(plain.toLowerCase(),this.knobSize+'px');this.updateThumbFromContentScroll();this.updateContentFromThumbPosition();},updateContentFromThumbPosition:function(){this.content[this.horz?'scrollLeft':'scrollTop']=this.position.now*this.scrollRatio;},updateThumbFromContentScroll:function(){this.position.now=(this.content[this.horz?'scrollLeft':'scrollTop']/this.scrollRatio).limit(0,(this.trackSize-this.knobSize));this.knob.setStyle(this.horz?'left':'top',this.position.now+'px');},attach:function(){this.knob.addEvent('mousedown',this.bound.start);if(this.options.scrollSteps)this.content.addEvent('mousewheel',this.bound.wheel);this.track.addEvent('mouseup',this.bound.page);},wheel:function(event){event=new Event(event);this.scroll(-(event.wheel*this.options.scrollSteps));this.updateThumbFromContentScroll();event.stop();},scroll:function(steps){steps=steps||this.options.scrollSteps;this.content[this.horz?'scrollLeft':'scrollTop']+=steps;this.updateThumbFromContentScroll();},forward:function(steps){this.scroll(steps);},back:function(steps){steps=steps||this.options.scrollSteps;this.scroll(-steps);},page:function(event){var axis=this.horz?'x':'y';event=new Event(event);var forward=(event.page[axis]>this.knob.getPosition()[axis]);this.scroll((forward?1:-1)*this.content['offset'+(this.horz?'Width':'Height')]);this.updateThumbFromContentScroll();this.fireEvent('onPage',forward);event.stop();},start:function(event){event=new Event(event);var axis=this.horz?'x':'y';this.mouse.start=event.page[axis];this.position.start=this.knob.getStyle(this.horz?'left':'top').toInt();document.addEvent('mousemove',this.bound.drag);document.addEvent('mouseup',this.bound.end);this.knob.addEvent('mouseup',this.bound.end);event.stop();},end:function(event){event=new Event(event);document.removeEvent('mousemove',this.bound.drag);document.removeEvent('mouseup',this.bound.end);this.knob.removeEvent('mouseup',this.bound.end);event.stop();},drag:function(event){event=new Event(event);var axis=this.horz?'x':'y';this.mouse.now=event.page[axis];this.position.now=(this.position.start+(this.mouse.now-this.mouse.start)).limit(0,(this.trackSize-this.knobSize));this.updateContentFromThumbPosition();this.updateThumbFromContentScroll();event.stop();}});MooScroller.implement(new Events);MooScroller.implement(new Options);