/*


PUBLIC
.activate 						activate antigrav  
.deactivate 					deactivate antgrav  (does not turn any sub functions, such as autopan)
.disableSelect					disable text selection
.enableSelect					enable text selection
.xMultiplier					scale x pan speed 
.yMultiplier					scale y pan speed

.autoPan (element)				pan to element's x,y
	"	 (int,int)				pan to given x/y

.drag(event,[target])			makes element draggable.  if target, then target drags instead.
//.resize(event,[target])		no such function
//.close(event[target])			no such function
//.fade	(target)				no such function

.findPos(element) = [int,int]	returns an element's absolute location (in px)
.mouseX(event) = int			returns mouse's X at event
.mouseY(event) = int			returns mouse's Y at event
.scrollX = int					returns the current scroll X of the window
.scrollY = int					returns the current scroll Y of the window
.windowWidth = int				returns the width of the window					
.windowHeight = int				returns the height of the window	
.docWidth = int
.docHeight = int				

.panAction 						function to be activated on pan 		(null default) 	
//.endPanAction					function to be activated on pan start 	(null default) 	
//.startPanAction				function to be activated on pan end 	(null default) 	
		
.granularity 					size of quads to be tracked by getNewQuads		
.getNewQuads = array			returns a poorly structured array of quads that are visible to the user, and have not been seen by the user.




PRIVATE (but not really)
.noPxEm	(string) = string		removes last 2 chgaracters of a srtring, returns it.
.startPan
.doPan
.endPan
.ease(b,c,t,d)					penner's magic easing finction
.doDrag (event)
.endDrag
.doAutoPan
.endAutoPan

*/



var antigrav={
	xMultiplier:2,
	yMultiplier:2,
    mouseXOld:0,
	mouseYOld:0,
	panXount:0,
	panAction:function(){},

    activate:function(){
        document.body.onmousedown = antigrav.startPan;
        antigrav.disableSelect();
        if (!document.getElementById('scrollsheild')){        // create scroll shield
   		 	var shield = document.createElement("div");
			shield.setAttribute('id', 'flashshield');
			shield.style.position='fixed';
			shield.style.height='100%'; 
			shield.style.width='100%'; 
			shield.style.zIndex='10000000';
			shield.style.top='0px'; 
			shield.style.left='0px';  
			shield.style.display='none'; 
			document.body.appendChild(shield);
        }
    },
    
    deactivate:function(){
        document.body.onmousedown = null;
        document.body.onmousemove = null;
        document.body.onmouseup = null;
	},
	
    startPan:function(event){
    	document.body.onmouseup = antigrav.endPan;
		document.body.onmousemove = antigrav.doPan;
		antigrav.mouseXOld=antigrav.mouseX(event);
		antigrav.mouseYOld=antigrav.mouseY(event);
		this.panCount=0;
    },
    
    doPan:function(event){
		window.scrollBy((antigrav.mouseXOld-antigrav.mouseX(event))*antigrav.xMultiplier,(antigrav.mouseYOld-antigrav.mouseY(event))*antigrav.yMultiplier);
		antigrav.mouseXOld=antigrav.mouseX(event);
		antigrav.mouseYOld=antigrav.mouseY(event);
		this.panCount++;
		if (this.panCount>4){
			document.getElementById('flashshield').style.display='block';	
		}
		antigrav.panAction();
	},
	
	endPan:function(event){	
		document.body.onmouseup = null;
		document.body.onmousemove = null;
		document.getElementById('flashshield').style.display='none';
	},

	autoPan:function(theelement,y){
		if (typeof theelement == 'object'){
			x=antigrav.findPos(theelement)[0]-antigrav.windowWidth()/2;
			y=antigrav.findPos(theelement)[1]-antigrav.windowHeight()/2+100;
		}else{var x=theelement}
		if (x<=1){x=1}
		if (y<=1){y=1}
		this.pStartX=antigrav.scrollX();
		this.pStartY=antigrav.scrollY();
		this.pDistX=x-antigrav.scrollX();
		this.pDistY=y-antigrav.scrollY();
		this.pFrame=1;
		this.pFrames=40;
		this.doAutoPan();
	},
	
	doAutoPan:function(){
		if (this.pFrame<this.pFrames){
			setTimeout("antigrav.doAutoPan()",40);
			this.pFrame++;
			var panSpeedX=  antigrav.ease(this.pStartX,this.pDistX,this.pFrame,this.pFrames);
			var panSpeedY=  antigrav.ease(this.pStartY,this.pDistY,this.pFrame,this.pFrames);
			scrollTo(panSpeedX,panSpeedY);
		}
	},
	
	dontdrag:false,

	drag:function (event, thedragged){
		if (!antigrav.dontdrag){
			
			antigrav.deactivate();
			document.body.onmousemove=antigrav.doDrag;
		   	document.body.onmouseup=antigrav.endDrag;
		   	if (!thedragged){
				if (!event) var event = window.event;
				if (event.target) targ = event.target;
				else if (event.srcElement) targ = event.srcElement;
				//	if (targ.nodeType == 3) // defeat Safari bug	
			}else{
				targ=document.getElementById(thedragged);
			}			
			thisPic++;
			targ.style.zIndex=thisPic+1;
			antigrav.mouseXOld=antigrav.mouseX(event);	
			antigrav.mouseYOld=antigrav.mouseY(event);
			this.panCount=0;
		}
	},
	
	doDrag:function (event) {						//update a move
		var mousex=antigrav.mouseX(event);
		var mousey=antigrav.mouseY(event);
		var xdif=mousex-antigrav.mouseXOld;
		var ydif=mousey-antigrav.mouseYOld;
		var currentx=targ.style.left;
		var currenty=targ.style.top;
		var newx=antigrav.noPxEm(currentx)+xdif;
		var newy=antigrav.noPxEm(currenty)+ydif;
		targ.style.left=newx+'px';
		targ.style.top=newy+'px';
		antigrav.mouseXOld=mousex;
		antigrav.mouseYOld=mousey;

/*		if (this.panCount>4){
			document.getElementById('flashshield').style.display='block';	
		}*/
		
	},

	endDrag:function () {							// end a move
		antigrav.activate();
		document.body.onmousemove=null;
   		document.body.onmouseup=null;
		/*document.getElementById('flashshield').style.display='none';	   		*/
	},
	
	close:function (event, toClose){
	   	if (!toClose){
			if (!event) var event = window.event;
			if (event.target) targ = event.target;
			else if (event.srcElement) targ = event.srcElement;
			//	if (targ.nodeType == 3) // defeat Safari bug	
		}else{
			targ=document.getElementById(toClose);
		}	
		targ.parentNode.removeChild(targ);
	},
	
	setOpacity:function(element,opacity){
		document.getElementById(element).style.opacity=opacity;		
		document.getElementById(element).filters.alpha.opacity=opacity*100;
	},
	
	ease:function(b,c,t,d){   					   // robert penner's magic formula
		if (t < d/2) {return 2*c*t*t/(d*d) + b;}
		var ts = t - d/2;
		return -2*c*ts*ts/(d*d) + 2*c*ts/d + c/2 + b;
	},
	
	mouseX:function(event){
		if (document.all)	{return window.event.screenX;}
		else				{return event.screenX;}
	},

	mouseY:function(event){
		if (document.all)	{return window.event.screenY;}
		else				{return event.screenY;}
	},	

	scrollX:function() {
//  	return  (document.all)?document.body.scrollLeft:window.pageXOffset;
		if (document.all)	{return document.documentElement.scrollLeft;}
		else				{return window.pageXOffset;}
	} ,

	scrollY:function() {
//  		return  (document.all)?document.body.scrollTop:window.pageYOffset;
		if (document.all)	{return document.documentElement.scrollTop;}
		else				{return window.pageYOffset;}
	} ,
	
	windowHeight:function(){
		if (document.all){
			return document.documentElement.offsetHeight;		
		}else{
			return window.innerHeight;
		}
	},

	windowWidth:function(){
		return document.body.clientWidth;
		//return document.width ? document.width : document.documentElement.offsetWidth;
	},
	
	docHeight:function() {
		return document.body.scrollHeight;
	},
	
	docWidth:function() {
		return document.body.scrollWidth;	
	},
	

	findPos:function(obj) {     				
		var curleft = curtop = 0;
		if (obj.offsetParent) {
			curleft = obj.offsetLeft
			curtop = obj.offsetTop
			while (obj = obj.offsetParent) {
				curleft += obj.offsetLeft
				curtop += obj.offsetTop
			}
		}
		return [curleft,curtop];
	},
	
	disable:function (e)   {return false;},  	//disable text highlighting.
	reEnable:function (e)  {return true;},
	
	disableSelect:function(){	
	if (window.sidebar) {
			document.onmousedown=antigrav.disable;
			document.onclick=antigrav.reEnable;
		}else{
			window.document.ondrag=antigrav.disable;
			window.document.onselectstart=antigrav.disable;
			window.document.ondragstart=antigrav.disable;
		}
	},
	
	enableSelect:function(){	
		if (window.sidebar) {
			document.onmousedown=antigrav.reEnable;
	//		document.onclick=antigrav.disable;
		}else{

			window.document.ondrag=antigrav.reEnable;
			window.document.onselectstart=antigrav.reEnable;
			window.document.ondragstart=antigrav.reEnable;
		}
	},
	noPxEm:function (themeasure){  //takes the stupid px or em off of the end of the css widths and heights
		strlength=themeasure.length-2;
		themeasure=themeasure.slice(0,strlength);
		themeasure=parseInt(themeasure,10);
		return themeasure;
	},
	
	granularity:300,
	thisQuad:null,
	
	getNewQuads:function(){
		if (typeof (visited) == 'undefined'){visited = []; firstrun=true;}
		var justVisited = [];
		//how big is the window?
		var winWidth=Math.round(antigrav.windowWidth()/antigrav.granularity);
		var winHeight=Math.round(antigrav.windowHeight()/antigrav.granularity);
		//where are we?  	

		var myX=Math.round(antigrav.scrollX()/antigrav.granularity) ;
		var myY=Math.round(antigrav.scrollY()/antigrav.granularity) ;

		oldQuad=antigrav.thisQuad;
		antigrav.thisQuad=myX*1000+myY;
		if (antigrav.thisQuad!=oldQuad){

/*
			for (i=myX-1;  i < myX+winWidth+1; i++){
				for (j=myY-1;  j < myY+winHeight+1; j++){
				//	debug (i+' '+j);
					if (visited[i*1000+j] !=true){
						visited[i*1000+j] =true;
						justVisited[i*1000+j]=true;
					}
				}				
			}
*/
			
			var distance=1;
			var direction="right";
			startX=myX;
			startY=myY;			
			myX+=Math.floor(winWidth/2);
			myY+=Math.ceil(winHeight/2)-2;	
			while ((distance<(winWidth+4))||(distance<(winHeight+4))){				
				if 	    (direction=="right"){direction="up"; xAdd=0; yAdd=1;}
				else if (direction=="up")	{direction="left"; xAdd=-1; yAdd=0;}
				else if (direction=="left")	{direction="down"; xAdd=0; yAdd=-1;}
				else if (direction=="down")	{direction="right"; xAdd=1; yAdd=0;}								
				for (run=1; run<=distance; run++){				
					if ((visited[(myX)*1000+myY] !=true)&&(myX>startX-2)&&(myY>startY-2)&&(myY<startY+winHeight)&&(myX<startX+winWidth)){
						visited[myX*1000+myY] =true;
						justVisited[myX*1000+myY]=true;
					}	
					myX+=xAdd;
					myY+=yAdd;						
				}
				
				if ((direction=="up")||(direction=="down")){
					distance+=1;
				}	
			}
		}
		return justVisited;
	}	
}


antigrav.activate();