// IXF1.11 :: Image cross-fade
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************
//global object
var ixf = { 'clock' : null, 'count' : 1, 'leftVal' : '10px', 'topVal' : '10px'}
/*******************************************************


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

ixf.imgs = [
//	'/img/photos/namesti.jpg',
	'/img/photos/jidlo1.png',
	'/img/photos/jidlo2.png',
	'/img/photos/jidlo3.png'
	];

ixf.lefts = [
//	'20px',
	'30px',
	'30px',
	'30px'
	];

ixf.tops = [
//	'10px',
	'-10px',
	'0px',
	'0px'
	];

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

var cyclerInterval,cyclerCounter=1;

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

		ixf.obj.style.position = 'absolute';
		ixf.obj.style.left = ixf.leftVal;
		ixf.obj.style.top = ixf.topVal;

		//copy the image src argument
		ixf.src = arguments[1];

		ixf.leftVal = arguments[3];
		ixf.topVal = arguments[4];

		//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[5] != 'undefined' && arguments[5] != '')
		{
			ixf.obj.alt = arguments[5];
		}

		//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'));
			document.getElementById('crosscontainer').style.display='none';
			ixf.newimg = document.getElementById('crossobject').appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') : document.createElement('img'));

			//set positioning classname
			ixf.newimg.className = 'idupe';

			ixf.newimg.style.visibility = 'hidden';
			ixf.newimg.style.position = 'absolute';

			//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';*/
			ixf.newimg.style.left = '-5000px';
			ixf.newimg.style.top = '0px';

			//set src to new image src
			ixf.newimg.src = ixf.src;
			document.getElementById('crosscontainer').style.display='block';

			//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()
{
	var resetclk = 0;
	//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.style.display = 'none';
		ixf.obj.style.left = ixf.leftVal;
		ixf.obj.style.top = ixf.topVal;
		ixf.obj.src = ixf.src;
		ixf.obj.style.display = 'block';

		switch(ixf.type)
		{
			case 'ie' :
				ixf.obj.filters.alpha.opacity = ixf.count * 100;
				ixf.newimg.filters.alpha.opacity = ixf.count * 100;
				break;

			case 'khtml' :
				ixf.obj.style.KhtmlOpacity = ixf.count;
				ixf.newimg.style.KhtmlOpacity = 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 = (ixf.count >= 1 ? 0.9999999 : 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 = (ixf.count >= 1 ? 0.9999999 : ixf.count);
		}

		resetclk=1;
	}
	else{
		//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) >= 1? 0.9999999 : (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) >= 1? 0.9999999 : (1 - ixf.count));
		}
	}

	//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';
// 	ixf.newimg.style.left = (ixf.type!='ie')?'4px':'0px';
	ixf.newimg.style.left = ixf.leftVal;
	ixf.newimg.style.top = ixf.topVal;

	//now that we've gone through one fade iteration
	//we can show the image that's fading in
	ixf.newimg.style.visibility = 'visible';



	//if the counter is at the top, which is just after the timer has finished
	if(ixf.count == 1)
	{
		ixf.newimg.style.visibility = 'hidden';
		//document.getElementById('crosscontainer').style.display='none';
		//remove the duplicate image
		ixf.newimg.parentNode.removeChild(ixf.newimg);

	}
	if (resetclk == 1){
		cyclerInterval = setInterval('cycler()', 8000);
	}

};



//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 cycler(){
	clearInterval(cyclerInterval);
	crossfade(document.getElementById('crossinter'), ixf.imgs[cyclerCounter], '2', ixf.lefts[cyclerCounter], ixf.tops[cyclerCounter], 'Snímky interiéru a okolí');
	cyclerCounter+=1;
	cyclerCounter%=ixf.imgs.length;
}