var $slide = new Array();
var _slide = -1;
var $img;
var $alert;
function slideshow()
{
  var main = document.getElementById("main_frame");
  var img = new Image();
  main.appendChild(img);
  $slide[0] = {"src":"../images/index/blu_mps.jpg"};
  $slide[1] = {"src":"../images/index/cat.jpg"};
  $slide[2] = {"src":"../images/index/mps_downwind.jpg"};
  $slide[3] = {"src":"../images/index/mps_reaching.jpg"};
  $slide[4] = {"src":"../images/index/iss_clew_genoa.jpg"};
  $slide[5] = {"src":"../images/index/sails_x_3_downwind.jpg"};
  $slide[6] = {"src":"../images/index/iss_main_tack_rf.jpg"};
  $slide[7] = {"src":"../images/index/iss_tanbark_gen_clew.jpg"};
  for (var i=0; i<$slide.length; i++)
  {
    $slide[i]["width"] = 0;
  }
  nextslide();
}
function nextslide()
{
  var first = false;
  if (arguments.length > 0)
  {
    _slide = arguments[0];
    first = true;
  }
  else
  {
    _slide++;
  }
  if (_slide >= $slide.length) _slide = 0;
  if ($slide[_slide])
  {
    $alert = _slide + "\n";
    $alert += typeof($slide[_slide]["image"]) + "\n";
    for (var e in $slide[_slide])
    {
      $alert += e + "=" + $slide[_slide][e] + "\n";
    }
    if (typeof($slide[_slide]["image"]) == "undefined" || $slide[_slide]["width"] == 0)
    {
      $img = new Image();
      $img.src = $slide[_slide]["src"];
      $img.onload = function() { set_details() };
    }
    else
    {
      var main = document.getElementById("main_frame");
      var img = $slide[_slide]["image"];
      img.width = $slide[_slide]["width"];
      img.height = $slide[_slide]["height"];
      if ($slide[_slide]["marginTop"])
      {
        img.style.marginTop = $slide[_slide]["marginTop"] + "px";
      }
      else
      {
        img.style.marginTop = 0;
      }
      if ($slide[_slide]["marginLeft"])
      {
        img.style.marginLeft = $slide[_slide]["marginLeft"] + "px";
      }
      else
      {
        img.style.marginLeft = 0;
      }
      if (main.childNodes.length > 2)
      {
        smooze(2,1,0);
      }
      else
      {
        var div = document.createElement('div');
        div.style.position = "absolute";
        div.style.opacity = 0;
        div.style.zIndex = 3;
        div.onmouseover=new Function ("omu();");
        div.appendChild(img);
        main.appendChild(div);
      }
      if (first)
      {
        window.setTimeout("nextslide()",500);
      }
      else
      {
        window.setTimeout("nextslide()",6000);
      }
    }
  }
}
function smooze(sec,prim,c)
{
  var main = document.getElementById("main_frame");
  var p = main.childNodes[prim];
  var s = main.childNodes[sec];
  var op1 = c/100;
  var op2 = 1 - op1;
  if (p) p.style.opacity = op2;
  if (s) s.style.opacity = op1;
  c += 2;
  if (c < 100)
  {
    window.setTimeout("smooze(2,1,"+c+")",10);
  }
  else
  {
    if (p) main.removeChild(p);
  }
}
function set_details()
{
  var ww, wh;
  var mf = document.getElementById("main_frame");
  if (mf)
  {
    var w = mf.getBoundingClientRect();
    ww = w.right - w.left;
    wh = w.bottom - w.top;
  }
  else
  {
    ww = 776;
    wh = 768;
  }
  var height = $img.height;
  var width = $img.width;
  if (width > ww)
  {
    var f = ww/width;
    height = height * f;
    width = ww;
  }
  if (height > wh)
  {
    var f = wh/height;
    width = width * f;
    height = wh;
  }
  $slide[_slide]["image"] = $img;
  $slide[_slide]["width"] = width;
  $slide[_slide]["height"] = height;
  if (height < wh)
  {
    $slide[_slide]["marginTop"] = Math.floor((wh-height)/2);
  }
  if (width < ww)
  {
    $slide[_slide]["marginLeft"] = Math.floor((ww-width)/2);
  }
  $alert = _slide + "\n";
  for (var e in $slide[_slide])
  {
    $alert += e + "=" + $slide[_slide][e] + "\n";
  }
  if (_slide == 0)
  {
    nextslide(0);
  }
  else
  {
    window.setTimeout("nextslide()",100);
  }
}
function omo()
{
  textstep(1);
}
function omu()
{
  textstep(-1);
}
var $textopa = 1;
var $textv = 0;
var $textstep = null;
function textstep(textv)
{
  if (typeof(textv) != "undefined")
  {
    if ($textv != textv)
    {
      $textv = textv;
      window.clearTimeout($textstep);
    }
  }
  if ($textv == 1 && $textopa < 1)
  {
    $textopa += 0.05;
    if ($textopa >= 1) {$textopa = 1; $textv=0;}
  }
  if ($textv == -1 && $textopa > 0)
  {
    $textopa -= 0.05;
    if ($textopa <= 0) {$textopa = 0; $textv=0;}
  }
  var main = document.getElementById("main_frame");
  var prim = main.firstChild;
  prim.style.opacity = $textopa;
  if ($textv != 0)
  {
    $textstep = window.setTimeout("textstep()",100);
  }
}