// Offset adjustments based on position of page's containing divs.
var offsetLeftAdj = 500;
var offsetTopAdj = 250;
var expansionDelay = 25;
var currentScrollLeftPos = 0;
var currentScrollTopPos = 0;

function setScroll(val) {
/*	currentScrollLeftPos = val.scrollLeft;*/
	currentScrollTopPos = val.scrollTop;
}
	function ImageExpander(oThumb, sImgSrc, overprint)
	{
	  // store thumbnail image and overwrite its onclick handler.
	  this.oThumb = oThumb;
	  this.oThumb.expander = this;
	  this.oThumb.onclick = function() { this.expander.expand(); }
	
	  // record original size
	  this.smallWidth = oThumb.offsetWidth;
	  this.smallHeight = oThumb.offsetHeight;
	
	  this.bExpand = true;
	  this.bTicks = false;
	
	  // self organized list
	  if ( !window.aImageExpanders )
	  {
	    window.aImageExpanders = new Array();
	  }
	  window.aImageExpanders.push(this);
	
	  // create the full sized image.
	  this.oImg = new Image();
	  this.oImg.expander = this;
	  this.oImg.onload = function(){this.expander.onload();}
	  this.oImg.src = sImgSrc;
	}
	
	ImageExpander.prototype.onload = function()
	{
	  this.oDiv = document.createElement("div");
	  this.oDiv.className = "test";			//DAVE
	  document.body.appendChild(this.oDiv);
	  this.oDiv.appendChild(this.oImg);
	  this.oDiv.style.position = "absolute";
	  this.oDiv.expander = this;
	  this.oDiv.onclick = function() {this.expander.toggle();};
	  this.oImg.title = "Click to reduce.";
	  this.bigWidth = this.oImg.width;
	  this.bigHeight = this.oImg.height;
	
	  if ( this.bExpand )
	  {
	    this.expand();
	  }
	  else
	  {
	    this.oDiv.style.visibility = "hidden";
	    this.oImg.style.visibility = "hidden";
	  }
	}
	ImageExpander.prototype.toggle = function()
	{
	  this.bExpand = !this.bExpand;
	  if ( this.bExpand )
	  {
	    for ( var i in window.aImageExpanders )
	      if ( window.aImageExpanders[i] !== this )
	        window.aImageExpanders[i].reduce();
	  }
	}
	ImageExpander.prototype.expand = function()
	{
	  // set direction of expansion.
	  this.bExpand = true;
	
	  // set all other images to reduce
	  for ( var i in window.aImageExpanders )
	    if ( window.aImageExpanders[i] !== this )
	      window.aImageExpanders[i].reduce();
	
	  // if not loaded, don't continue just yet
	  if ( !this.oDiv ) return;
	
	  // hide the thumbnail
	  this.oThumb.style.visibility = "hidden";
	
	  // calculate initial dimensions
	  this.x = findPosX(this.oThumb);
	  this.y = findPosY(this.oThumb);
	  this.w = this.oThumb.clientWidth;
	  this.h = this.oThumb.clientHeight;
	
	  this.oDiv.style.left = this.x + "px";
	  this.oDiv.style.top = this.y + "px";
	  this.oImg.style.width = this.w + "px";
	  this.oImg.style.height = this.h + "px";
	  this.oDiv.style.visibility = "visible";
	  this.oImg.style.visibility = "visible";
	
	  // start the animation engine.
	  if ( !this.bTicks )
	  {
	    this.bTicks = true;
	    var pThis = this;
	    window.setTimeout(function(){pThis.tick();},expansionDelay);
	  }
	}
	ImageExpander.prototype.reduce = function()
	{
	  // set direction of expansion.
	  this.bExpand = false;
	}
	ImageExpander.prototype.tick = function()
	{
	  // calculate screen dimensions
	  var cw = document.body.clientWidth;
	  var ch = document.body.clientHeight;
	  var cx = document.body.scrollLeft + cw / 2;
	  var cy = document.body.scrollTop + ch / 2;
	
	  // calculate target
	  var tw,th,tx,ty;
	  if ( this.bExpand )
	  {
	    tw = this.bigWidth;
	    th = this.bigHeight;
	    if ( tw > cw )
	    {
	      th *= cw / tw;
	      tw = cw;
	    }
	    if ( th > ch )
	    {
	      tw *= ch / th;
	      th = ch;
	    }
	    tx = cx - tw / 2;
	    ty = cy - th / 2;
	  }
	  else
	  {
	    tw = this.smallWidth;
	    th = this.smallHeight;
	    tx = findPosX(this.oThumb);
	    ty = findPosY(this.oThumb);
	  }
	  // move 5% closer to target
	  var nHit = 0;
	  var fMove = function(n,tn)
	  {
	    var dn = tn - n;
	    /*if ( Math.abs(dn) < 3 )*/
	    if ( Math.abs(dn) < 5 )
	    {
	      nHit++;
	      return tn;
	    }
	    else
	    {
	      //return n + dn / 10;
	      return n + dn / 5;
	    }
	  }
	  this.x = fMove(this.x, tx);
	  this.y = fMove(this.y, ty);
	  this.w = fMove(this.w, tw);
	  this.h = fMove(this.h, th);
	
	  this.oDiv.style.left = this.x + "px";
	  this.oDiv.style.top = this.y + "px";
	  this.oImg.style.width = this.w + "px";
	  this.oImg.style.height = this.h + "px";
	
	  // if reducing and size/position is a match, stop the tick
	  if ( !this.bExpand && (nHit == 4) )
	  {
	    this.oImg.style.visibility = "hidden";
	    this.oDiv.style.visibility = "hidden";
	    this.oThumb.style.visibility = "visible";
	
	    this.bTicks = false;
	  }
	
	  if ( this.bTicks )
	  {
	    var pThis = this;
	    window.setTimeout(function(){pThis.tick();},expansionDelay);
	  }
	}
	
	
	function findPosX(obj)
	{
	  var curleft = 0;
	  if (obj.offsetParent)
	  {
	    while (obj.offsetParent)
	    {
	      curleft += obj.offsetLeft
	      obj = obj.offsetParent;
	    }
	  }
	  else if (obj.x)
	    curleft += obj.x;
	  return curleft;
	}
	
	function findPosY(obj)
	{
	  var curtop = 0;
	  if (obj.offsetParent)
	  {
	    while (obj.offsetParent)
	    {
	      curtop += obj.offsetTop
	      obj = obj.offsetParent;
	    }
	  }
	  else if (obj.y)
	    curtop += obj.y;
	  return curtop - currentScrollTopPos;
	}