// IXF1.0 :: Image cross-fade 
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************
//global object
var ixw = { 'clock' : null, 'count' : 1 }
/*******************************************************



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

ixw.imgs = [
	'buttons/udm4-greenbutton88x31.gif',
	'buttons/udm4-whitebutton88x31.gif',
	'buttons/udm4-bluebutton88x31.gif',
	'buttons/udm4-redbutton88x31.gif',
	'buttons/udm4-purplebutton88x31.gif',
	'buttons/udm4-blackbutton88x31.gif',
	];

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



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


//crosswipe setup function
function crosswipe()
{
	//if the timer is not already going
	if(ixw.clock == null)
	{
		//copy the image object 
		ixw.obj = arguments[0];
		
		//get its dimensions
		ixw.size = { 'w' : ixw.obj.width, 'h' : ixw.obj.height };
		
		//copy the image src argument 
		ixw.src = arguments[1];
		
		//change the image alt text if defined
		if(typeof arguments[4] != 'undefined' && arguments[4] != '')
		{
			ixw.obj.alt = arguments[4];
		}

		//if dynamic element creation is supported
		if(typeof document.createElementNS != 'undefined' || typeof document.createElement != 'undefined')
		{
			//create a new image object and append it to body
			//detecting support for namespaced element creation, in case we're in the XML DOM
			ixw.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
			ixw.newimg.className = 'idupe';
			ixw.newimg.style.zIndex = '11';

			//set src to new image src
			ixw.newimg.src = ixw.src

			//move it to superimpose original image
			ixw.newimg.style.left = ixw.getRealPosition(ixw.obj, 'x') + 'px';
			ixw.newimg.style.top = ixw.getRealPosition(ixw.obj, 'y') + 'px';

			//set it to be completely hidden with clip
			ixw.newimg.style.clip = 'rect(0, 0, 0, 0)';

			//show the image 
			ixw.newimg.style.visibility = 'visible';

			//copy and convert fade duration argument 
			ixw.length = parseInt(arguments[2], 10) * 1000;

			//create fade resolution argument as 20 steps per transition
			ixw.resolution = parseInt(arguments[2], 10) * 20;

			//copy slide direction argument
			ixw.dir = arguments[3];

			//start the timer
			ixw.clock = setInterval('ixw.crosswipe()', ixw.length/ixw.resolution);
		}
		
		//otherwise if dynamic element creation is not supported
		else
		{
			//just do the image swap
			ixw.obj.src = ixw.src;
		}
		
	}
};


//crosswipe timer function
ixw.crosswipe = function()
{
	//decrease the counter on a linear scale
	ixw.count -= (1 / ixw.resolution);
	
	//if the counter has reached the bottom
	if(ixw.count < (1 / ixw.resolution))
	{
		//clear the timer
		clearInterval(ixw.clock);
		ixw.clock = null;
		
		//reset the counter
		ixw.count = 1;
		
		//set the original image to the src of the new image
		ixw.obj.src = ixw.src;
	}
	
	//animate the clip of the new image
	//using the width and height properties we saved earlier
	ixw.newimg.style.clip = 'rect('
		+ ( (/bt|bltr|brtl/.test(ixw.dir)) ? (ixw.size.h * ixw.count) : (/che|cc/.test(ixw.dir)) ? ((ixw.size.h * ixw.count) / 2) : (0) )
		+ 'px, '
		+ ( (/lr|tlbr|bltr/.test(ixw.dir)) ? (ixw.size.w - (ixw.size.w * ixw.count)) : (/cve|cc/.test(ixw.dir)) ? (ixw.size.w - ((ixw.size.w * ixw.count) / 2)) : (ixw.size.w) )
		+ 'px, '
		+ ( (/tb|tlbr|trbl/.test(ixw.dir)) ? (ixw.size.h - (ixw.size.h * ixw.count)) : (/che|cc/.test(ixw.dir)) ? (ixw.size.h - ((ixw.size.h * ixw.count) / 2)) : (ixw.size.h) )
		+ 'px, '
		+ ( (/lr|tlbr|bltr/.test(ixw.dir)) ? (0) : (/tb|bt|che/.test(ixw.dir)) ? (0) : (/cve|cc/.test(ixw.dir)) ? ((ixw.size.w * ixw.count) / 2) : (ixw.size.w * ixw.count) ) 
		+ 'px)';
			
	//keep new image in position with original image
	//in case text size changes mid transition or something
	ixw.newimg.style.left = ixw.getRealPosition(ixw.obj, 'x') + 'px';
	ixw.newimg.style.top = ixw.getRealPosition(ixw.obj, 'y') + 'px';
	
	//if the counter is at the top, which is just after the timer has finished
	if(ixw.count == 1)
	{
		//remove the duplicate image
		ixw.newimg.parentNode.removeChild(ixw.newimg);
	}
};



//get real position method
ixw.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;
};