// JavaScript Document
//=======================
//
// Javascript Slideshow
//
// http://www.astral-consultancy.co.uk/cgi-bin/hunbug/doco.cgi?11560
//
//=======================

const waitTime = 25;

var slideshowImage = new Array();
var slideshowIndex = new Array();
var slideshowAlpha = new Array();

function slideshowSetup()
{
  var id = arguments[0];
  var cl = arguments[1];
  slideshowImage[id] = new Array();
  slideshowIndex[id] = 0;
  slideshowAlpha[id] = 0;
  for(i=2; i<arguments.length; i++)
  {
    slideshowImage[id][slideshowImage[id].length]=new Image();
    slideshowImage[id][slideshowImage[id].length-1].src=arguments[i];
  }
  document.write('<div id="'+id+'"'+cl+' style="position:relative">');
  document.write('<input type="button" value="Prev" onClick="slideshowSwitch(\''+id+'\',-1);"/>');
  document.write('<input type="button" value="Next" onClick="slideshowSwitch(\''+id+'\',1);"/>');
  document.write('<div id="'+id+'inner" style="position:relative">');
  document.write('<img id="'+id+'img1" src="hunbugslideshow.js" style="position:absolute; top:0px; left:0px;"/>');
  document.write('<img id="'+id+'img2" src="hunbugslideshow.js" style="position:absolute; top:0px; left:0px;"/>');
  document.write('</div></div>');
}

function slideshowSwitch(id,d)
{
  if(slideshowAlpha[id]<1)
  {
    slideshowAlpha[id] = 100;
    slideshowIndex[id] += d;
    if(slideshowIndex[id] >= slideshowImage[id].length){slideshowIndex[id]=0;}
    else if(slideshowIndex[id] < 0){slideshowIndex[id]=slideshowImage[id].length-1;}
    var img1 = document.getElementById(id+'img1');
    var img2 = document.getElementById(id+'img2');
    img2.src = img1.src;
    img1.style.opacity = '0';
    img1.style.filter  = 'alpha(opacity=0)';
    img2.style.opacity = '1';
    img2.style.filter  = 'alpha(opacity=100)';
    img1.src = slideshowImage[id][slideshowIndex[id]].src;
    slideshowMerge(id);
  }
}

function slideshowMerge(id)
{
  slideshowAlpha[id] += -1;
  if(slideshowAlpha[id]>-1)
  {
    var img1 = document.getElementById(id+'img1');
    var img2 = document.getElementById(id+'img2');
    img1.style.opacity = ((100-slideshowAlpha[id])/100).toString();
    img1.style.filter  = "alpha(opacity="+(100-slideshowAlpha[id]).toString()+")";
    img2.style.opacity = (slideshowAlpha[id]/100).toString();
    img2.style.filter  = "alpha(opacity="+slideshowAlpha[id].toString()+")";
    setTimeout('slideshowMerge(\''+id+'\');',waitTime);
  }
}