// overlay.js
/*
	This code is part of:
	************************************************************************************************
	Lightbox JS: Fullsize Image Overlays
	by Lokesh Dhakar - http://www.huddletogether.com
	For more information on the original script, visit: http://huddletogether.com/projects/lightbox/
	************************************************************************************************
	
	Many thanks to Lokesh!!! 
*/
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;
}
		

function getPageSize(){

	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else 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;
}

function showOverlay() {
	var objOverlay = document.getElementById('overlay');
	objOverlay.style.display = 'block';
	var objLoadingImage = document.getElementById('loadingImage');
	objLoadingImage.style.display = 'block';
	
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();
	
	objOverlay.style.height = (arrayPageSize[1] + 'px');
	
	positionOverlay();
}

function hideOverlay() {
	var objOverlay = document.getElementById('overlay');
	objOverlay.style.display = 'none';
	var objLoadingImage = document.getElementById('loadingImage');
	objLoadingImage.style.display = 'none';
}

function positionOverlay() {
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();
	var objLoadingImage = document.getElementById('loadingImage');
	if (objLoadingImage) {
		objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 100) / 2) + 'px');
		objLoadingImage.style.left = (((arrayPageSize[0] - 100) / 2) + 'px');
	}
	var objOverlay = document.getElementById('overlay');
	objOverlay.style.height = (arrayPageSize[1] + 'px');
}

function checkVisible() {
	var objOverlay = document.getElementById('overlay');
	if (objOverlay) {
		return objOverlay.style.display == 'block';
	}
	return true;
}

window.onresize = function() {
	if (checkVisible())	positionOverlay();
}

window.onscroll = function() {
	if (checkVisible()) positionOverlay();
}

function refreshOverlay() {
	if (checkVisible()) {
		positionOverlay();
	} else {
		window.clearInterval(refreshOverlayIntervalId);
	}
}