// CSS Photo Shuffler v1.0 by
//   Carl Camera
//   http://iamacamera.org 
//
// SetOpacity Function and inpiration from Photo Fade by
//   Richard Rutter
//   http://clagnut.com
//
// License: Creative Commons Attribution 2.5  License
//   http://creativecommons.org/licenses/by/2.5/

var gblPhotoShufflerDivId = "photo_div";
var gblPhotoShufflerImgId = "photo_img"; 

var gblPauseSeconds = 3;
var gblFadeSeconds = .85;
var gblRotations = 100;

// End Customization section


var gblOpacity = 100;
var gblOnDeck = 0;
var gblStartImg;
							

window.onload = photoShufflerLaunch;

function photoShufflerLaunch(){
	
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	gblStartImg = theimg.src; // save away to show as final image
	
	document.getElementById(gblPhotoShufflerDivId).style.backgroundImage='url(' + gblImg[gblOnDeck] + ')';
	setTimeout("photoShufflerFade()",gblPauseSeconds*1000);
}

function photoShufflerFade(){
	
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	
	// determine delta based on number of fade seconds
	// the slower the fade the more increments needed
		var fadeDelta = 100 / (30 * gblFadeSeconds);
	
	// fade top out to reveal bottom image
	if (gblOpacity < 2*fadeDelta ) {
	  gblOpacity = 100;
	  // stop the rotation if we're done
	  if (gblImageRotations < 1) return;
	  photoShufflerShuffle();
	  // pause before next fade
		  setTimeout("photoShufflerFade()",gblPauseSeconds*1000);
	}else{
		
	  gblOpacity -= fadeDelta;
	  setOpacity(theimg,gblOpacity);
	  setTimeout("photoShufflerFade()",30);  // 1/60th of a second
	}
}

function photoShufflerShuffle(){
	
	var thediv = document.getElementById(gblPhotoShufflerDivId);
	var theimg = document.getElementById(gblPhotoShufflerImgId);
	
	// copy div background-image to img.src
	theimg.src = gblImg[gblOnDeck];
	// set img opacity to 100
	setOpacity(theimg,100);
	
	// shuffle the deck
	gblOnDeck = ++gblOnDeck % gblDeckSize;
	// decrement rotation counter
	if (--gblImageRotations < 1)
	{
	  // insert start/final image if we're done
	  gblImg[gblOnDeck] = gblStartImg;
	}
	
	// slide next image underneath
	thediv.style.backgroundImage='url(' + gblImg[gblOnDeck] + ')';
}

function setOpacity(obj, opacity) {
	
	opacity = (opacity == 100)?99.999:opacity;
	
	// IE/Win
	obj.style.filter = "alpha(opacity:"+opacity+")";
	
	// Safari<1.2, Konqueror
	obj.style.KHTMLOpacity = opacity/100;
	
	// Older Mozilla and Firefox
	obj.style.MozOpacity = opacity/100;
	
	// Safari 1.2, newer Firefox and Mozilla, CSS3
	obj.style.opacity = opacity/100;
}