function hide_arrow(id)
{
   document.getElementById(id).childNodes[0].childNodes[0].src=www_root + 'img/' + id + 'UN.gif';
}

function show_arrow(id)
{
   document.getElementById(id).childNodes[0].childNodes[0].src=www_root + 'img/' + id + '.gif';
   hover_arrow(id,'out');
}

function hover_arrow(id,hover)
{
   var off;
   off = document.getElementById(id).childNodes[0].childNodes[0].src; 
   if (off.indexOf('UN.gif') != -1)
   		return;
   if (hover == "on")
   {
      document.getElementById(id).childNodes[0].childNodes[0].src= www_root + 'img/' + id + 'H.gif';
   } else {
      document.getElementById(id).childNodes[0].childNodes[0].src= www_root + 'img/' + id + '.gif';
   }
}

function check_fl()
{
   cur = document.getElementById('currentpic');
   dida = document.getElementById('dida');
   cont = document.getElementById("sfondoArt");
   preload();
   cur.src = works[currentpic].image;
   dida.innerHTML = works[currentpic].html;
   
   if (currentpic == 0)
   		hide_arrow('back');
   else
   		show_arrow('back');
   
   if (currentpic == works.length -1 )
   		hide_arrow('next');
   else
   		show_arrow('next');
   
   center_photo();
}

function next_img()
{
	currentpic += 1;
	change_photo();
}

function prev_img()
{
	currentpic -= 1;
	change_photo();
}

function change_photo()
{
	a = new Effect.Highlight('dida', {duration: 1.0, restorecolor:'#c7f4f7'});	
	check_fl();	
}

function preload()
{
	nextpic = currentpic +1;
	if (nextpic < works.length )
	{
		fakep.src = works[nextpic].image;
	}
}

function center_photo()
{
	
	cont = document.getElementById('sfondoArt')
	
	if (cur.offsetHeight >= cont.offsetHeight)
	{
		cur.style.top = "";
		return;
	}
	
	var top_offset = Math.round((cont.offsetHeight - cur.offsetHeight) / 2);
	cur.style.top = top_offset + "px";
	cur.style.position = "relative";
}

var cur;
var dida;
var cont;
var fakep = new Image();