// IXF1.11 :: Image cross-fade 
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************

//global object
var ixf = { 'clock' : null, 'count' : 1 };

ixf.imgs = [
	    '/images/workshop1.jpg',
	    '/images/workshop2.jpg',
	    '/images/workshopOver.jpg',
	    'images/pic9.jpg',
	    'images/pic10.jpg',
	    'images/pic1.jpg',
	    'images/pic2.jpg',
	    'images/pic3.jpg',
	    'images/pic4.jpg',
	    'images/pic5.jpg',
	    'images/pic6.jpg',
	    'images/pic7.jpg',
	    'images/pic8.jpg'
	    ];




//transition data
var idp = 0;
var imageids = [
		'ixf1',
		'ixf2',
		'workshoplink', 
		'ixf4', 
		'ixf5', 
		'ixf6', 
		'ixf7', 
		'ixf8'
		];

var ilp = 0;
var imagelist = [
		 'images/pic9.jpg',
		 'images/pic10.jpg',
		 'images/pic1.jpg',
		 'images/pic2.jpg',
		 'images/pic3.jpg',
		 'images/pic4.jpg',
		 'images/pic5.jpg',
		 'images/pic6.jpg',
		 'images/pic7.jpg',
		 'images/pic8.jpg'
		 ];
var wsp = 0;
var wsPics = [
	      'images/workshop2.jpg',
	      'images/workshop1.jpg'
	      ];


var currentWorkshopPic = null;

function findPos(obj) {
    var curleft = 0;
    var curtop = 0;
    if (obj.offsetParent) {
	do {
	    curleft += obj.offsetLeft;
	    curtop += obj.offsetTop;
	} while (obj = obj.offsetParent);
	
    }
    return [curleft,curtop];
}


var wsOrig = null;
var wsSuperImg = null;

function mouseOverWorkshop(){

    // if not already, superimpose image over existing one

    if( wsSuperImg == null ){


	aSuper = document.getElementsByTagName('body')[0].appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'a') : document.createElement('a'));
	
	aSuper.id='aSuper';
	aSuper.href='workshops.html';

	wsSuperImg = aSuper.appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') : document.createElement('img'));
	
	//set positioning classname
	wsSuperImg.className = 'idupe';
	wsSuperImg.id = 'wsSuperImg';
	//wsSuperImg.style.z-index='30001';
	
	wsOrig = document.getElementById('workshoplink');
	
	//set src to superimposed image
	wsSuperImg.src = 'images/workshopOver.jpg';
	aSuper.height = wsOrig.height;
	aSuper.width = wsOrig.width;
	wsSuperImg.height = wsOrig.height;
	wsSuperImg.width = wsOrig.width;
	
	//move it to superimpose original image
	var _pos = findPos(wsOrig);

	newleft = _pos[0];
	aSuper.style.left = _pos[0] + 'px';
	aSuper.style.top = _pos[1] + 'px';
	wsSuperImg.style.left = _pos[0] + 'px';
	wsSuperImg.style.top = _pos[1] + 'px';

	wsSuperImg.setAttribute("onmouseover","mouseOffOverWorkshop();");
	wsSuperImg.setAttribute("onmouseout","mouseOffWorkshop();");
    }

    // set as visible
    wsSuperImg.style.visibility = 'visible';
}

function mouseOffWorkshop(){
    //hide the superimposed image
    wsSuperImg.style.visibility = 'hidden';
}

function imgSwap(img_name, img_src)
{
    document[img_name].src = img_src;
}


//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];
    }


function fadeall()
{
    if(ixf.clock === null){

	if( imageids[idp] == 'workshoplink'){
	    crossfade(document.getElementById(imageids[idp]), wsPics[wsp], '2');
	    idp+=1; if( idp >= imageids.length ) idp=0;
	    wsp+=1; if( wsp >= wsPics.length ) wsp=0;
	}
	else{
	    crossfade(document.getElementById(imageids[idp]), imagelist[ilp], '2');
	    idp+=1; if( idp >= imageids.length ) idp=0;
	    ilp+=1; if( ilp >= imagelist.length ) ilp=0;
	}

	setInterval('fadeall()', 5000 );
    }
}

//crossfade setup function
function crossfade()
{
    //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 = arguments[1];
	    
	    //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';
		    
		    //set src to new image src
		    ixf.newimg.src = ixf.src;
		    ixf.newimg.height = ixf.obj.height;
		    ixf.newimg.width = ixf.obj.width;
		    
		    //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);
		}
	    
	    //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);
	}
};



//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;
};