/*
	Lightbox JS: Fullsize Image Overlays 
	by Lokesh Dhakar - http://www.huddletogether.com

	For more information on this script, visit:
	http://huddletogether.com/projects/lightbox/

	Table of Contents
	-----------------
	Configuration
	
	Functions
	- getPageScroll()
	- getPageSize()
	- pause()
	- showLightbox()
	- hideLightbox()
	- initLightbox()
	- addLoadEvent()
	
	Function Calls
	- addLoadEvent(initLightbox)

*/



//
// getPageScroll()
// Returns array with x,y page scroll values.
// Core code from - quirksmode.org
//
function getPageScroll(){

	var yScroll;

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){	 // Explorer 6 Strict
		yScroll = document.documentElement.scrollTop;
	} else if (document.body) {// all other Explorers
		yScroll = document.body.scrollTop;
	}

	arrayPageScroll = new Array('',yScroll) 
	return arrayPageScroll;
}



//
// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
//
function getPageSize(){
	
	var xScroll, yScroll;

	if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	var windowWidth, windowHeight;
	if (self.innerHeight) {	// all except Explorer
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
	
	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight){
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}


	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}


//
// showLightbox()
// Preloads images. Pleaces new image in lightbox then centers and displays.
//
function showLightbox(objLink)
{
	// prep objects
	var objLightbox = document.getElementById('lightbox');
	var objImage = document.getElementById('lightboxImage');
	
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();

	// preload image
	imgPreload = new Image();

	imgPreload.onload=function(){
		objImage.src = objLink.href;

		// center lightbox
		objLightbox.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2) + 'px');
		objLightbox.style.left = (((arrayPageSize[0] - 40 - imgPreload.width) / 2) + 'px');

		// A small pause between the image loading and displaying is required with IE,
		// this prevents the previous image displaying for a short burst causing flicker.
		if (navigator.appVersion.indexOf("MSIE")!=-1){
			pause(250);
		} 

		objLightbox.style.display = 'block';

		return false;
	}

	imgPreload.src = objLink.href;
	
}





//
// hideLightbox()
//
function hideLightbox()
{
	objLightbox = document.getElementById('lightbox');
	objLightbox.style.display = 'none';
}




//
// initLightbox()
// Function runs on window load, going through link tags looking for rel="lightbox".
// These links receive onclick events that enable the lightbox display for their targets.
// The function also inserts html markup at the top of the page which will be used as a
// container for the overlay pattern and the inline image.
//
function initLightbox()
{
	
	if (!document.getElementsByTagName){ return; }
	var anchors = document.getElementsByTagName("a");

	// loop through all anchor tags
	for (var i=0; i<anchors.length; i++){
		var anchor = anchors[i];

		if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "lightbox")){
			anchor.onclick = function () {showLightbox(this); return false;}
		}
	}

	// the rest of this code inserts html at the top of the page that looks like this:
	//
	// <div id="lightbox">
	//		<a href="#" onclick="hideLightbox(); return false;"><img /></a>
	// </div>
	
	var objBody = document.getElementsByTagName("body").item(0);
	
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();

	// preload and create loader image
	var imgPreloader = new Image();
	
	// create lightbox div, same note about styles as above
	var objLightbox = document.createElement("div");
	objLightbox.setAttribute('id','lightbox');
	objLightbox.style.display = 'none';
	objLightbox.style.position = 'absolute';
	objLightbox.style.zIndex = '100';	
	objBody.insertBefore(objLightbox, objBody.firstChild); // Chris: was: objOverlay.nextSibling);
	
	// create link
	var objLink = document.createElement("a");
	objLink.setAttribute('href','#');
	objLink.onclick = function () {hideLightbox(); return false;}
	objLightbox.appendChild(objLink);
	
	// create image
	var objImage = document.createElement("img");
	objImage.setAttribute('id','lightboxImage');
	objLink.appendChild(objImage);
}


addLoadEvent(initLightbox);	// run initLightbox onLoad