// ISF1.11 :: Image swap-fade 
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************
//global object
var isf = { 'clock' : null, 'fade' : true, 'count' : 1 }
/*******************************************************

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

function fnXIn()
{

    var i=0;
    var sEval = "isf.imgs = [" 
    for (i=0; i < iMAX-1; i++)
    {
      sEval = sEval + "'" + fnImgPath(i+1) + "', "
    }
    sEval = sEval + "'" + fnImgPath(i+1) + "' ];"
    
    //alert(sEval);
    eval(sEval);
    
    //cache the images
    isf.imgsLen = isf.imgs.length;
  
    isf.cache = [];
    for(var i=0; i<isf.imgsLen; i++)
    {
	    isf.cache[i] = new Image;
	    isf.cache[i].src = isf.imgs[i];
    }
}

//swapfade setup function
function swapfade()
{
	//if the timer is not already going
	if(isf.clock == null)
	{
		//copy the image object 
		isf.obj = arguments[0];
		
		//copy the image src argument 
		isf.src = arguments[1];
		
		//store the supported form of opacity
		if (typeof isf.obj.style.opacity != 'undefined') {
		    isf.type = 'w3c';
		}
		else if (typeof isf.obj.style.MozOpacity != 'undefined') {
		    isf.type = 'moz';
		}
		else if (typeof isf.obj.style.KhtmlOpacity != 'undefined') {
		    isf.type = 'khtml';
		}
		else if (typeof isf.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
		    isf.type = (isf.obj.filters.length > 0 && typeof isf.obj.filters.alpha == 'object' && typeof isf.obj.filters.alpha.opacity == 'number') ? 'ie' : 'none';
		}
		else {
		    isf.type = 'none';
		}
		
		//change the image alt text if defined
		if(typeof arguments[3] != 'undefined' && arguments[3] != '')
		{
			isf.obj.alt = arguments[3];
			isf.obj.title = arguments[3];
		}
		
		//if any kind of opacity is supported
		if(isf.type != 'none')
		{
			//copy and convert fade duration argument 
			//the duration specifies the whole transition
			//but the swapfade is two distinct transitions
			isf.length = parseInt(arguments[2], 10) * 500;
			
			//create fade resolution argument as 20 steps per transition
			//again, split for the two distrinct transitions
			isf.resolution = parseInt(arguments[2], 10) * 10;
			
			//start the timer
			isf.clock = setInterval('isf.swapfade()', isf.length/isf.resolution);
		}
		
		//otherwise if opacity is not supported
		else
		{
			//just do the image swap
			isf.obj.src = isf.src;
		}
		
	}
};


//swapfade timer function
isf.swapfade = function () {
    //increase or reduce the counter on an exponential scale
    isf.count = (isf.fade) ? isf.count * 0.9 : (isf.count * (1 / 0.9));

    //if the counter has reached the bottom
    if (isf.count < (1 / isf.resolution)) {
        //clear the timer
        clearInterval(isf.clock);
        isf.clock = null;

        //do the image swap
        isf.obj.src = isf.src;

        //reverse the fade direction flag
        isf.fade = false;

        //restart the timer
        isf.clock = setInterval('isf.swapfade()', isf.length / isf.resolution);
        fnRenInfo(iIndex);
        //alert("Here");

    }

    //if the counter has reached the top
    if (isf.count > (1 - (1 / isf.resolution))) {
        //clear the timer
        clearInterval(isf.clock);
        isf.clock = null;

        //reset the fade direction flag
        isf.fade = true;

        //reset the counter
        isf.count = 1;
    }

    //set new opacity value on element
    //using whatever method is supported
    switch (isf.type) {
        case 'ie':
            isf.obj.filters.alpha.opacity = isf.count * 100;
            break;

        case 'khtml':
            isf.obj.style.KhtmlOpacity = isf.count;
            break;

        case 'moz':
            //restrict max opacity to prevent a visual popping effect in firefox
            isf.obj.style.MozOpacity = (isf.count == 1 ? 0.9999999 : isf.count);
            break;

        default:
            //restrict max opacity to prevent a visual popping effect in firefox
            // alert(isf.obj.style.opacity);
            isf.obj.style.opacity = (isf.count == 1 ? 0.9999999 : isf.count);
    }
};