/* CheltenhamCycle.js */

var cheltenhamFilenameArray = new Array ( 
"Cheltenham300.jpg",
"CheltenhamFront300.jpg"
 );
 
 
var opacity = 10;
 
var cheltenhamImageArray = new Array();

var cheltenhamCount = -1;
var cheltenhamStep = 2;

function initCheltenhamCycle()
{
    preloadImages();
    changeCheltenham();
    fadeIn();
}


function preloadImages() 
{
     var i = 0;
     
     // start preloading
     for(i=0; i<cheltenhamFilenameArray.length; i++)      
     {     
        var filename = cheltenhamFilenameArray[i];
        var pathname = "images/concerts/" + filename;
              
        cheltenhamImageArray[i] = new Image();
        cheltenhamImageArray[i].src = pathname;
     }

}

function changeCheltenham()
{
    var element =  document.getElementById("cheltenhamImage");
    if ( element == null ) return;
    ///////////////////////////////

    cheltenhamCount = cheltenhamCount + 1;
    if ( cheltenhamCount >= cheltenhamFilenameArray.length ) cheltenhamCount = 0;
    
    var filename = cheltenhamFilenameArray[cheltenhamCount];
        

    element.src = cheltenhamImageArray[cheltenhamCount].src;

} 

function fadeOut()
{
    var element =  document.getElementById("cheltenhamImage");
    if ( element != null )
    {   
        opacity = opacity - cheltenhamStep;
        element.style.opacity = opacity/10;
        element.style.filter = 'alpha(opacity=' + opacity*10 + ')';    
    }
    
    if ( opacity <= 0 ) 
    {
        changeCheltenham();
        fadeIn();
    }
    else
    {
        setTimeout("fadeOut()", 10);
    } 
}

function fadeIn()
{
    var element =  document.getElementById("cheltenhamImage");
    if ( element != null )
    {     
        opacity = opacity + cheltenhamStep;
        element.style.opacity = opacity/10;
        element.style.filter = 'alpha(opacity=' + opacity*10 + ')';    
     }  
      
    if ( opacity >= 10 ) 
    {
        setTimeout("fadeOut()", 3000);
    }
    else
    {
        setTimeout("fadeIn()", 50);
    } 

}