/*
 * Original from: http://brainerror.net/scripts/javascript/blendtrans/demo.html
 *
 * Edits by ASC:
 *   - Removed unnecessary OO code that caused MSIE to choke
 *   - Added pause between setting bg image and setting opacity to zero to
 *     prevent MSIE image flash
 *   - Increased opacity check argument to 103 for completely smooth fade
 *
 */

//find next image
function nextImage(o) {
    do o = o.nextSibling;
    while(o && o.tagName != 'IMG');
    return o;
}

//find first image inside an element
function firstChildImage(o) {
    
    o = o.firstChild;
        
    while(o && o.tagName != 'IMG') {
        o = o.nextSibling;
    }
    
    return o;
}



//make image invisible and set next one as current image
function getNextImage(image) {
	
    if (next = nextImage(image)) {
	    //image.style.display = 'none';
	    image.style.zIndex = 0;
    
	   // next.style.display = 'block';
	    next.style.zIndex = 0;

    } else {
	    //if there is not a next image, get the first image again
        next = firstChildImage(image.parentNode);
    }

    return next;
}

//set default values for parameters and starting image
function blendImages(id, speed, pause, caption) {

    if(speed == null) {
        speed = 30;
    }
    
    if(pause == null) {
        pause = 1500;
    }

    var blend = document.getElementById(id);

    var image = firstChildImage(blend);

    startBlending(image, speed, pause, caption, null, 100);
}

//make image a block-element and set the caption
function startBlending(image, speed, pause, caption, lastImage, o2) 
{
    image.style.display = 'block';

    if (caption != null) 
    {
	    document.getElementById(caption).innerHTML = image.alt;
    }

    continueFadeImage(image, 0, speed, pause, caption, lastImage, o2);
}

// ASC: copied from http://www.sean.co.uk/a/webdesign/javascriptdelay.shtm
function pausecomp(millis) {
    var date = new Date();
    var curDate = null;

    do { curDate = new Date(); }
    while(curDate-date < millis);
} 

//set the opacity of an element to a specified value
function setOpacity(obj, o, lastImage, o2) {

    obj.style.opacity = (o / 100);
    obj.style.MozOpacity = (o / 100);
    obj.style.KhtmlOpacity = (o / 100);
    obj.style.filter = 'alpha(opacity=' + o + ')';

    if (lastImage != null) {
        lastImage.style.opacity = (o2 / 100);
        lastImage.style.MozOpacity = (o2 / 100);
        lastImage.style.KhtmlOpacity = (o2 / 100);
        lastImage.style.filter = 'alpha(opacity=' + o2 + ')';
    }
}

//set an increased opacity and check if the image is done blending
function continueFadeImage(image, opacity, speed, pause, caption, lastImage, o2) 
{
    opacity = opacity + 5;
    o2 = o2 - 5;
   
    if (opacity < 105) {
        setTimeout(function() { fadeImage(image, opacity, speed, pause, caption, lastImage, o2) }, speed);
    }
    else {
        // ASC: pause 1sec here to prevent MSIE image flash ...
        var paws = pause - 1000;
        if (paws < 0) {
            paws = 0;
        }

        pausecomp(1000);

        lastImage = image;

        //get the next image and start blending it again
        image = getNextImage(image);

        setTimeout(function() { continueFadeImage(image, 0, speed, pause, caption, lastImage, 100) }, paws);
    }
}

//set the opacity to a new value and continue the fading
function fadeImage(image, opacity, speed, pause, caption, lastImage, o2) {
    setOpacity(image, opacity, lastImage, o2);
    continueFadeImage(image, opacity, speed, pause, caption, lastImage, o2);
}