// IXF1.11 :: Image cross-fade 
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************
//global object
//var ixf = { 'clock' : null, 'count' : 1 }
/*****************************************************************************/
// the images that need to be cached
/*
var ixf = { 'clock' : null, 'count' : 1 }
ixf.imgs = new Array(
  "images/rotation/bath_index.jpg",
  "images/rotation/builtins_index.jpg",
  "images/rotation/customhomes_index.jpg",
  "images/rotation/exterior_index.jpg",
  "images/rotation/kitchen_index.jpg",
  "images/rotation/mantle_index.jpg",
  "images/rotation/specialrooms_index.jpg",
  "images/rotation/stair_index.jpg"
);*/
/*****************************************************************************/
// Note: ixf.imgs array set in page via php
//ixf.imgs = imgs;
/*****************************************************************************/
var STEPS  = 20;   //orig = 20
var MILLIS = 1000; // should be 1000

function getNextImage() {
    if (currentImageIndex == ixf.imgs.length - 1) {
        currentImageIndex = 0;
    } else {
        currentImageIndex++;
    }
	  crossfade(document.getElementById('rotationImage'), ixf.imgs[currentImageIndex], DURATION, '');
}

/*****************************************************************************/


//cache the images
ixf.imgsLen = ixf.imgs.length;
ixf.cache = [];
for(var i = 0; i < ixf.imgsLen; i++) {
	ixf.cache[i] = new Image;
	ixf.cache[i].src = ixf.imgs[i];
}


//crossfade setup function
function crossfade() {
    //alert("here");
	//if the timer is not already going
	if (ixf.clock == null) {
	    
		// get the image object 
		ixf.obj = arguments[0];
		//alert("obj=" + ixf.obj);
		
		// get the image src argument 
		ixf.src = arguments[1];
		//alert("src=" + ixf.src);
		
		// store the supported form of opacity
		if(typeof ixf.obj.style.opacity != 'undefined') {
			ixf.type = 'w3c';
		} else if(typeof ixf.obj.style.MozOpacity != 'undefined') {
			ixf.type = 'moz';
		} else if(typeof ixf.obj.style.KhtmlOpacity != 'undefined') {
			ixf.type = 'khtml';
		} else if(typeof ixf.obj.filters == 'object') {
			//weed out win/ie5.0 by testing the length of the filters collection (where filters is an object with no data)
			//then weed out mac/ie5 by testing first the existence of the alpha object (to prevent errors in win/ie5.0)
			//then the returned value type, which should be a number, but in mac/ie5 is an empty string
			ixf.type = (ixf.obj.filters.length > 0 && typeof ixf.obj.filters.alpha == 'object' && typeof ixf.obj.filters.alpha.opacity == 'number') ? 'ie' : 'none';
		} else {
			ixf.type = 'none';
		}
		
		// change the image alt text if defined
		if (typeof arguments[3] != 'undefined' && arguments[3] != '') {
			ixf.obj.alt = arguments[3];
		}
		
		// if any kind of opacity is supported
		if (ixf.type != 'none') {
		    
			// create a new image object and append it to body
			// detecting support for namespaced element creation, in case we're in the XML DOM
			ixf.newimg = document.getElementsByTagName('body')[0].appendChild((typeof document.createElementNS != 'undefined') 
    			? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') 
    			: document.createElement('img'));

			// set positioning classname
			ixf.newimg.className = 'idupe';
			
			// move it to superimpose original image
			ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x') + 'px';
			ixf.newimg.style.top  = ixf.getRealPosition(ixf.obj, 'y') + 'px';
			
			// set src to new image src
			ixf.newimg.src = ixf.src
			ixf.newimg.style.zIndex = 4;

			// get length of fade duration 
			ixf.length = parseInt(arguments[2]) * MILLIS;
			
			// create fade resolution argument as 20 steps per transition
			ixf.resolution = parseInt(arguments[2]) * STEPS;
			
			// start the timer
			ixf.clock = setInterval('ixf.crossfade()', ixf.length/ixf.resolution);
		}
		
		// otherwise if opacity is not supported
		else {
			// just do the image swap
			ixf.obj.src = ixf.src;
		}
	}
};


//crossfade timer function
ixf.crossfade = function() {

	// decrease the counter on a linear scale
	ixf.count -= (1 / ixf.resolution);
	
	// if the counter has reached the bottom
	if(ixf.count < (1 / ixf.resolution)) {
		//clear the timer
		clearInterval(ixf.clock);
		ixf.clock = null;
		
		//reset the counter
		ixf.count = 1;
		
		//set the original image to the src of the new image
		ixf.obj.src = ixf.src;
	}
	
	// set new opacity value on both elements
	// using whatever method is supported
	switch (ixf.type) {
	    
		case 'ie' :
			ixf.obj.filters.alpha.opacity = ixf.count * 100;
			ixf.newimg.filters.alpha.opacity = (1 - ixf.count) * 100;
			break;
			
		case 'khtml' :
			ixf.obj.style.KhtmlOpacity = ixf.count;
			ixf.newimg.style.KhtmlOpacity = (1 - ixf.count);
			break;
			
		case 'moz' : 
			// restrict max opacity to prevent a visual popping effect in firefox
			ixf.obj.style.MozOpacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
			ixf.newimg.style.MozOpacity = (1 - ixf.count);
			break;
			
		default : 
			// restrict max opacity to prevent a visual popping effect in firefox
			ixf.obj.style.opacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
			ixf.newimg.style.opacity = (1 - ixf.count);
	}
	
	// now that we've gone through one fade iteration 
	// we can show the image that's fading in
	ixf.newimg.style.visibility = 'visible';
	
	// keep new image in position with original image
	// in case text size changes mid-transition or something
	ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x') + 'px';
	ixf.newimg.style.top  = ixf.getRealPosition(ixf.obj, 'y') + 'px';
	
	// if the counter is at the top, which is just after the timer has finished
	if (ixf.count == 1) {
		// remove the duplicate image
		ixf.newimg.parentNode.removeChild(ixf.newimg);
		getNextImage();		
	}
};


// get real position method
ixf.getRealPosition = function() {
	this.pos = (arguments[1] == 'x') ? arguments[0].offsetLeft : arguments[0].offsetTop;
	this.tmp = arguments[0].offsetParent;
	while (this.tmp != null) {
		this.pos += (arguments[1] == 'x') ? this.tmp.offsetLeft : this.tmp.offsetTop;
		this.tmp = this.tmp.offsetParent;
	}
	return this.pos;
};


function debug(txt) {
    document.getElementById('debug').innerHTML += '<br/>' + txt;
}