var slideCache = new Array(); 
var opac = 0;
var mode = -1;

/*
	changeOpac (opacitiy, id)
		id = id van plaatje en/of div
*/
function changeOpac(opacity, id) 
{ 
  var obj = document.getElementById(id).style; 
	obj.opacity = (opacity / 100); 
	obj.MozOpacity = (opacity / 100);
	obj.KhtmlOpacity = (opacity / 100); 
	obj.filter = "alpha(opacity=" + opacity + ")"; 
} 
/*
	functiion blendimage(divid, imageid, imagefile, millisec)
		divid 			= id van waarin plaatje staat
		imageid 		= naam van image
		imagefile 	= filename van image
		millisec 		= aantal milliseconden dat het plaatje zichtbaar moet zijn
*/
function blendimage(divid, imageid, imagefile, millisec) 
{ 
	var speed = Math.round(millisec / 10); 
	var timer = 0; 
	
	mode = -mode;
		
	//TODO: fade image snelheid aanpassen
	
	for(cycle = 0; cycle <= 99; cycle++) 
	{ 
		opac = opac + mode; //in of uit faden
		setTimeout("changeOpac(" + opac + ",'" + imageid + "')",(timer*speed)); 
		timer++;
	
	} 
	
	//Voor en achter image files.
	if (mode == 1)
	{
		document.getElementById(imageid).src = imagefile; 
	} 
	else
	{
		document.getElementById(divid).style.backgroundImage = "url(" + imagefile + ")";
	}
	
} 

function RunSlideShow(divid,imageid,imageFiles,displaySecs) {
	changeOpac(0,imageid);
	StartSlideShow(divid,imageid,imageFiles,displaySecs);
}

function StartSlideShow(divid,imageid,imageFiles,displaySecs) 
{ 
	var imageSeparator = imageFiles.indexOf(";"); 
	var nextImage = imageFiles.substring(0,imageSeparator); 
	
	blendimage(divid,imageid,nextImage,100); 
	
	var futureImages= imageFiles.substring(imageSeparator+1,imageFiles.length)+ ';' + nextImage; 
	setTimeout("StartSlideShow('"+divid+"','"+imageid+"','"+futureImages+"',"+displaySecs+")",displaySecs*1000); 
	
	// Cache the next image to improve performance. 
	imageSeparator = futureImages.indexOf(";"); 
	nextImage = futureImages.substring(0,imageSeparator); 
	if (slideCache[nextImage] == null) 
	{ 
		slideCache[nextImage] = new Image; 
		slideCache[nextImage].src = nextImage; 
	} 
}

window.onload = init;
/*
	Start after whole HTML page has loaded.

*/
function init()
{
	var divid = "i_header";
	var imgid = "i_headerimg";
	if(!document.getElementById("i_header") || !document.getElementById("i_headerimg")) alert("Error in header.js: div_id or img id not correctly set");
	else slideimages(divid, imgid, current_page_id, 9);
}