var arrowImageHeight = 11;	// Height of arrow image in pixels;
var displayWaitMessage=false;	// Display a please wait message while images are loading?

var previewImage = false;
var previewImageParent = false;
var slideSpeed = 0;
var previewImagePane = false;
var slideEndMarker = false;
var galleryContainer = false;
var imageGalleryCaptions = new Array();

function getTopPos(inputObj) {		
  var returnValue = inputObj.offsetTop;
  while((inputObj = inputObj.offsetParent) != null)returnValue += inputObj.offsetTop;
  return returnValue;
}

function getLeftPos(inputObj) {
  var returnValue = inputObj.offsetLeft;
  while((inputObj = inputObj.offsetParent) != null)returnValue += inputObj.offsetLeft;
  return returnValue;
}
	
function showPreview(newSrc,imageIndex){
	if (!previewImage) {
		var images = document.getElementById('previewPane').getElementsByTagName('img');
		if(images.length>0){
			previewImage = images[0];
		}else{
			previewImage = document.createElement('img');
			document.getElementById('previewPane').appendChild(previewImage);	
		}
		
		
	}
	if(displayWaitMessage){
		document.getElementById('waitMessage').style.display='inline';
	}
	document.getElementById('largeImageCaption').style.display='none';
	previewImage.onload = function() { hideWaitMessageAndShowCaption(imageIndex-1); };				
	previewImage.src = newSrc;
}

function hideWaitMessageAndShowCaption(imageIndex){
	document.getElementById('waitMessage').style.display='none';	
	document.getElementById('largeImageCaption').innerHTML = imageGalleryCaptions[imageIndex];
	document.getElementById('largeImageCaption').style.display='block';
}	

function initSlide(e){
	if(document.all)e = event;
	
	if(this.src.indexOf('over')<0)this.src = this.src.replace('.gif','-over.gif');
	
	slideSpeed = e.clientY + Math.max(document.body.scrollTop,document.documentElement.scrollTop) - getTopPos(this);
	if(this.src.indexOf('down')>=0){
		slideSpeed = (slideSpeed)*-1;	
	}else{
		slideSpeed = arrowImageHeight - slideSpeed;
	}
	slideSpeed = Math.round(slideSpeed * 10 / arrowImageHeight);
}

function stopSlide(){		
	slideSpeed = 0;
	this.src = this.src.replace('-over','');
}

function slidePreviewPane() {
	if(slideSpeed!=0){
		var topPos = previewImagePane.style.top.replace(/[^\-0-9]/g,'')/1;	
	
		if(slideSpeed<0 && slideEndMarker.offsetTop<(previewImageParent.offsetHeight - topPos)){
			slideSpeed=0;

		}
		topPos = topPos + slideSpeed;
		if(topPos>0)topPos=0;

	 	previewImagePane.style.top = topPos + 'px';
 	
	}
 	setTimeout('slidePreviewPane()',30);		
}

//function revealThumbnail()
//{
	//this.style.filter = 'alpha(opacity=100)';
	//this.style.opacity = 1;
//}

//function hideThumbnail()
//{
	//this.style.filter = 'alpha(opacity=50)';
	//this.style.opacity = 0.5;
//}

function initGalleryScript() {
	previewImageParent = document.getElementById('theImages');
	previewImagePane = document.getElementById('theImages').getElementsByTagName('div')[0];
	previewImagePane.style.top = '0px';
	galleryContainer  = document.getElementById('galleryContainer');
	var images = previewImagePane.getElementsByTagName('img');
	//for(var no=0;no<images.length;no++){
		//images[no].onmouseover = revealThumbnail;
		//images[no].onmouseout = hideThumbnail;
	//}	
	slideEndMarker = document.getElementById('slideEnd');
	
	document.getElementById('arrow_up_image').onmousemove = initSlide;
	document.getElementById('arrow_up_image').onmouseout = stopSlide;
	
	document.getElementById('arrow_down_image').onmousemove = initSlide;
	document.getElementById('arrow_down_image').onmouseout = stopSlide;
	var divs = previewImageParent.getElementsByTagName('div');
	for(var no=0;no<divs.length;no++){
		if(divs[no].className=='imageCaption')imageGalleryCaptions[imageGalleryCaptions.length] = divs[no].innerHTML;
	}		
	slidePreviewPane();
}

window.onload = initGalleryScript;