var offsetfrommouse=[45,25]; //posun x,y obrázku od pozice ukazatele (v pixelech).
//var displayduration=0; // doba, po kterou má být obrázek zobrazen. 0 = stále.

var defaultimageheight = 40;	// minimální velikost obrázku.
var defaultimagewidth = 40;	// minimální velikost obrázku.

var timer;

function gettrailobj(){
  if (document.getElementById)
    return document.getElementById("preview_div").style;
}

function gettrailobjnostyle(){
  if (document.getElementById)
  return document.getElementById("preview_div");
}


function truebody(){
  return (!window.opera && document.compatMode && document.compatMode!="BackCompat")? document.documentElement : document.body;
}


function hidetrail(){	
	gettrailobj().display= "none";
	document.onmousemove="";
	gettrailobj().left="-500px";
	clearTimeout(timer);
}

function showtrail(imagename,title,width,height){
	i = imagename;
	t = title;
	w = width;
	h = height;
	document.onmousemove=followmouse; 
	timer = setTimeout("show('"+i+"',t,w,h);",200);
}
function show(imagename,title,width,height){
  var docwidth=document.all? truebody().scrollLeft+truebody().clientWidth : pageXOffset+window.innerWidth - offsetfrommouse[0];
	var docheight=document.all? Math.min(truebody().scrollHeight, truebody().clientHeight) : Math.min(window.innerHeight);

	if( (navigator.userAgent.indexOf("Konqueror")==-1  || navigator.userAgent.indexOf("Firefox")!=-1 || (navigator.userAgent.indexOf("Opera")==-1 && navigator.appVersion.indexOf("MSIE")!=-1)) && (docwidth>650 && docheight>500)) {
		( width == 0 ) ? width = defaultimagewidth: '';
		( height == 0 ) ? height = defaultimageheight: '';

			
		width+=30;
		height+=55;
		defaultimageheight = height;
		defaultimagewidth = width;
			
		newHTML = '<div class="border_preview" style="width:'+  width +'px;height:'+ height +'px"><div id="loader_container"><div id="loader"><div align="center">Náhled obrázku...</div><div id="loader_bg"><div id="progress"> </div></div></div></div>';
		newHTML = newHTML + '<h2 class="title_h2">' + ' '+title + '</h2>';
		
    newHTML = newHTML + '<div class="preview_temp_load"><img onload="javascript:remove_loading();" src="' + imagename + '" border="0" height="' + ( height - 50 )+ '" width="' + ( width - 50 )+ '"></div>';
		newHTML = newHTML + '</div>'; 
		
		if(navigator.userAgent.indexOf("MSIE")!=-1 && navigator.userAgent.indexOf("Opera")==-1 ){
			newHTML = newHTML+'<iframe src="about:blank" scrolling="no" frameborder="0" width="'+width+'" height="'+height+'"></iframe>';
		}		


		gettrailobjnostyle().innerHTML = newHTML;
		document.onmousemove=followmouse; 
		gettrailobj().display="block";
		document.onmousemove=followmouse; 
	}
}

function followmouse(e){

	var xcoord=offsetfrommouse[0];
	var ycoord=offsetfrommouse[1];

	var docwidth=document.all? truebody().scrollLeft+truebody().clientWidth : pageXOffset+window.innerWidth-15;
	var docheight=document.all? Math.min(truebody().scrollHeight, truebody().clientHeight) : Math.min(window.innerHeight);

	if (typeof e != "undefined"){
		if (docwidth - e.pageX < defaultimagewidth + 2*offsetfrommouse[0]){
			xcoord = e.pageX - xcoord - defaultimagewidth; // Posun na levou stranu ukazatele myši.
		} else {
			xcoord += e.pageX;
		}
		if (docheight - e.pageY < defaultimageheight + 2*offsetfrommouse[1]){
			ycoord += e.pageY - Math.max(0,(2*offsetfrommouse[1] + defaultimageheight + e.pageY - docheight - truebody().scrollTop));
		} else {
			ycoord += e.pageY;
		}

	} else if (typeof window.event != "undefined"){
		if (docwidth - event.clientX < defaultimagewidth + 2*offsetfrommouse[0]){
			xcoord = event.clientX + truebody().scrollLeft - xcoord - defaultimagewidth; // Posun na levou stranu ukazatele myši.
		} else {
			xcoord += truebody().scrollLeft+event.clientX;
		}
		if (docheight - event.clientY < (defaultimageheight + 2*offsetfrommouse[1])){
			ycoord += event.clientY + truebody().scrollTop - Math.max(0,(2*offsetfrommouse[1] + defaultimageheight + event.clientY - docheight));
		} else {
			ycoord += truebody().scrollTop + event.clientY;
		}
	}
	gettrailobj().left=xcoord+"px";
	gettrailobj().top=ycoord+"px";

}