var slideGroup=null;

var imgUpLow=2000; //Minimum number of milliseconds to show image
var imgUpHigh=6000; //Maximum number of milliseconds to show image
var fadeInTime=10; //Number of milliseconds to fade in
var fadeOutTime=25; //Number of milliseconds to fade out
var imgDownTime=1000; //Number of milliseconds between image fades
var fadeDelta=10; //The opacity step size

var opa=0;
var iIndex;
var tNext;
var tSwap;
var iPre=0;

function updateProgress(group) {
    //alert("Updating progress " + group.numLoaded);
    if (group.numToLoad==0)
        return;
    
        
    var progress = parseFloat(group.numLoaded)/parseFloat(group.numToLoad);
    progress *= document.getElementById("displayProgress").width;
    document.getElementById("progressWidth").width=progress;

    if (!group.IsComplete())
        return;
        
    slideGroup=group;

    document.getElementById("displayProgress").style.visibility = "hidden"

    getNextSlide();
}

function getUpTime() {
    var range = imgUpHigh - imgUpLow + 1;
    return Math.floor(Math.random() * range) + imgUpLow;
}

function getNextSlide() {
    iIndex = Math.floor(Math.random() * slideGroup.items.length);
    var slide = GetImage(slideGroup.items[iIndex]);
    var dispHeight = 300;
    var dispWidth = 500;
    
    if ((slide.width/slide.height) > (dispWidth/dispHeight)){
        dispHeight = (dispWidth/slide.width)*slide.height;
    }else{
        dispWidth = (dispHeight/slide.height)*slide.width;
    }
    
    document.all.activeSlide.height = dispHeight;
    document.all.activeSlide.width = dispWidth;
    document.all.activeSlide.src = slide.src;
    
    showSlide();
}

function showSlide() {
    //alert("about to show image");
	if (opa<=100) {
	    document.getElementById("activeSlide").style.filter="alpha(opacity="+opa+")";
	    //imagePane.innerHTML="<img style='filter:alpha(opacity="+opa+")' src="+imageURLs[iIndex]+" border=0 width='380px' />";
		opa+=fadeDelta;
		t=setTimeout("showSlide()",fadeInTime);
	}else{
	    clearTimeout(t);
		t=setTimeout("hideSlide()",getUpTime());
	}
}


function hideSlide() {
	if (opa>=0) {
	    document.getElementById("activeSlide").style.filter="alpha(opacity="+opa+")";
		//imagePane.innerHTML="<img style='filter:alpha(opacity="+opa+")' src="+imageURLs[iIndex]+" border=0 width='380px' />";
		opa-=fadeDelta;
		t=setTimeout("hideSlide()",fadeOutTime);
	}
	else {
		clearTimeout(t)
		opa=0;
		t=setTimeout("getNextSlide()",imgDownTime);
	}
}