// IXF1.11 :: Image cross-fade
// ******************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
// Modified by b!tech berlin (image links will be updated)
// 2009-11-12 (BB): Niemoeller&Abel removed
// ******************************************************
//global object
var ixf = { 'clock' : null, 'count' : 1, 'iCounter' : -1 }

/*****************************************************************************
 List the images that need to be cached
*****************************************************************************/

ixf.imgs        = new Array(2);
// Image source
ixf.imgs[0]     = [
		'upload/logos/rotation/cts.png',
		'upload/logos/rotation/rescue_fire.png',
		'upload/logos/rotation/elsevier.png',
		'upload/logos/rotation/ambu.png',
		// 'upload/logos/rotation/niemoeller_abel.png',
		'upload/logos/rotation/zoll.png',
		'upload/logos/rotation/smedex.png',
		'upload/logos/rotation/rescue_trade.png'
		];
// Information text (alt)
ixf.imgs[1]     = [
		'CTS Medizintechnik',
		'rescue-fire.de',
		'Elsevier',
		'Ambu',
		// 'Niemöller und Abel',
		'ZOLL',
		'SMEDEX AG',
		'Rescue Trade'
		];
// Link
ixf.imgs[2]     = [
		'http://www.cts-medical.de',
		'http://www.rescue-fire.de',
		'http://www.elsevier.de/artikel/833815',
		'http://www.ambu.de',
		// 'http://www.nunda.de',
		'http://www.zollmedical.de',
		'http://www.smedex.ch',
		'http://www.rescuetrade.de'
		];

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

/*****************************************************************************
 Crossfade setup function
*****************************************************************************/
function crossfade()
{
	ixf.iCounter++;

	if (ixf.iCounter == ixf.imgsLen) {
		ixf.iCounter = 0;
	}

	//if the timer is not already going
	if(ixf.clock == null)
	{
		//copy the image object
		ixf.obj = arguments[0];

		//copy the image src argument
		ixf.src = ixf.imgs[0][ixf.iCounter];
		
		//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
		ixf.obj.alt = ixf.imgs[1][ixf.iCounter];

		//change the link
		arguments[1].href = ixf.imgs[2][ixf.iCounter];

		//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'));
			ixf.newimg = document.getElementById('tdrotation').appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') : document.createElement('img'));

			//set positioning classname
			ixf.newimg.className = 'idupe';
			
			//set src to new image src
			ixf.newimg.src = ixf.src

			//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';
			
			//copy and convert fade duration argument 
			ixf.length = parseInt(arguments[2], 10) * 1000;
			
			//create fade resolution argument as 20 steps per transition
			ixf.resolution = parseInt(arguments[2], 10) * 20;
			
			//start the timer
			ixf.clock = setInterval('ixf.crossfade()', ixf.length/ixf.resolution);
		}
		else //otherwise if opacity is not supported
		{
			//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);
	}
};

//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;
};