/*
   Based on code at
   http://www.switchonthecode.com/tutorials/javascript-tutorial-simple-fade-animation
*/

var TimeToFade = 10000.0;

function fadeIn(eid) { fade(eid, 2); }
function fadeOut(eid) { fade(eid, -2); }

function fade(eid, direction)
{
  var element = document.getElementById(eid);
  if(element == null)
    return;
   
  if(element.FadeState == null)
  {
    if(element.style.opacity == null
        || element.style.opacity == ''
        || element.style.opacity == '1')
    {
      element.FadeState = -2;
    }
    else
    {
      element.FadeState = 2;
    }
  }
   
  if(element.FadeState == 1 || element.FadeState == -1)
  {
    element.FadeState = element.FadeState == 1 ? -1 : 1;
    element.FadeTimeLeft = TimeToFade - element.FadeTimeLeft;
  }
  else
  {
    //element.FadeState = element.FadeState == 2 ? -1 : 1;
    element.FadeState = direction == -2 ? -1 : 1;
    element.FadeTimeLeft = TimeToFade;
    setTimeout("animateFade(" + new Date().getTime() + ",'" + eid + "')", 33);
  }  
}

function animateFade(lastTick, eid)
{  
  var curTick = new Date().getTime();
  var elapsedTicks = curTick - lastTick;
 
  var element = document.getElementById(eid);
 
  if(element.FadeTimeLeft <= elapsedTicks)
  {
    element.style.opacity = element.FadeState == 1 ? '1' : '0.4';
    //element.style.opacity = element.FadeState == 1 ? '1' : '0';
    element.style.filter = 'alpha(opacity = '
        + (element.FadeState == 1 ? '100' : '40') + ')';
        //+ (element.FadeState == 1 ? '100' : '0') + ')';
    element.FadeState = element.FadeState == 1 ? 2 : -2;
    return;
  }
 
  element.FadeTimeLeft -= elapsedTicks;
  var newOpVal = element.FadeTimeLeft/TimeToFade;
  if(element.FadeState == 1)
    newOpVal = 1 - newOpVal;

  //element.style.opacity = newOpVal;
  element.style.opacity = (1 + newOpVal)*0.4;
  element.style.filter = 'alpha(opacity = ' + (newOpVal*100) + ')';
 
  setTimeout("animateFade(" + curTick + ",'" + eid + "')", 33);
}

function animateMarker(eid) {
  var curTick = new Date().getTime() % 10000;
  var element = document.getElementById(eid);
  
  if(element == null)
      return;
  
  if (element.Styletop == null) { element.Styletop = 60; }
  if (element.Styleright == null) { element.Styleright = 10; }

  element.StyleSIN = Math.sin(curTick*Math.PI/5000);
  element.StyleCOS = Math.cos(curTick*Math.PI/5000);
  element.style.top = element.Styletop + 20*element.StyleSIN + "px";
  element.style.right = element.Styleright + 20*element.StyleCOS + "px";

  setTimeout("animateMarker('" + eid + "')", 33);
}