/* Timothy Groves - brandspankingnew.net */


var useBSNns;
if (useBSNns){
   if (typeof(bsn) == "undefined")
      bsn = {}
   var _bsn = bsn;
}
else
{
   var _bsn = this;
}


_bsn.Crossfader = function (divs, ctype, fadetime, delay )
{

   this.aDivs = divs;
   this.xtype = ctype;

   if ( ctype  > 0 )
   {
      this.nAct = 1;
      for (var i=0;i<divs.length;i++)
      {
         document.getElementById(divs[i]).style.opacity = 0;
         document.getElementById(divs[i]).style.filter = "alpha(opacity=0)";
      }
   }
   else
   {
      this.nAct = 1;
      for (var i=0;i<divs.length;i++)
      {
         document.getElementById(divs[i]).style.opacity = 1;
         document.getElementById(divs[i]).style.filter = "alpha(opacity=100)";
      }
   }

   this.nDur = fadetime;
   this.nDelay = delay;
   this._newfade();
}

_bsn.Crossfader.prototype._newfade = function()
{
   if (this.nID1)
      clearInterval(this.nID1);

   this.nOldAct = this.nAct;
   this.nAct++;
   if (!this.aDivs[this.nAct])
      this.nAct = 0;
   if (this.nAct == this.nOldAct)
      return false;

   document.getElementById( this.aDivs[this.nAct] ).style.visibility = "visible";
   this.nInt = 50;
   this.nTime = 0;
   var p=this;
   this.nID2 = setInterval(function() { p._fade() }, this.nInt);
}



_bsn.Crossfader.prototype._fade = function()
{
   this.nTime += this.nInt;
   var ieop = Math.round( this._easeInOut(this.nTime, 0, 1, this.nDur) * 100 );
   var op = ieop / 100;

//alert( op + " vs.  " + ieop);
   obj = document.getElementById( this.aDivs[this.nAct] );
   if ( obj != null)
   {
      if ( this.xtype > 0)
      {
         obj.style.opacity = op;
         obj.style.filter = "alpha(opacity="+ ieop +")";
      }
      else
      {
         obj.style.opacity = 1-op;
         obj.style.filter = "alpha(opacity="+ ( 100 -  ieop) +")";
      }
   }

   if (this.nTime == this.nDur)
   {
      clearInterval( this.nID2 );

      var p=this;
      this.nID1 = setInterval(function() { p._newfade() }, this.nDelay);
   }
}

_bsn.Crossfader.prototype._easeInOut = function(t,b,c,d)
{
    return c/2 * (1 - Math.cos(Math.PI*t/d)) + b;
}