var arrowImageHeight = 30;	// Height of arrow image in pixels;
var displayWaitMessage = true;	// 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.firstChild.src.indexOf('over')<0) this.firstChild.src = this.firstChild.src.replace('.gif','_over.gif');
	
	slideSpeed = e.clientY + Math.max(document.body.scrollTop,document.documentElement.scrollTop) - getTopPos(this);
	if (this.id.indexOf('down')>=0) {
		slideSpeed = (slideSpeed)*-1;	
	} else {
		slideSpeed = arrowImageHeight - slideSpeed;
	}
	slideSpeed = Math.round(slideSpeed * 20 / arrowImageHeight);
}
	
function stopSlide() {		
	slideSpeed = 0;
	this.firstChild.src = this.firstChild.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;
	this.style.borderColor = '#f29400';
}
	
function hideThumbnail() {
	this.style.filter = 'alpha(opacity=50)';
	this.style.opacity = 0.5;
	this.style.borderColor = '#ffffff';
}
	
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').onmousemove = initSlide;
	document.getElementById('arrow_up').onmouseout = stopSlide;
	
	document.getElementById('arrow_down').onmousemove = initSlide;
	document.getElementById('arrow_down').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();
}