function Preload(x, max) {
	if ( x >= max ) { return; }
	
	var prl = new Image();
	prl.src = 'img/slideshow/thumb_' + x + '.jpg';
	
	var preload = document.getElementById('prel');
	preload.src='img/slideshow/thumb_' + x + '.jpg';
	
	opacity("prel", 100, 0, 800);
	
	setTimeout( function () {
		opacity("prel", 0, 100, 800);
		setTimeout( function () {
			x++;
			Preload(x, max);
		}, 800);
	}, 800);
}

function opacity(id, opacStart, opacEnd, millisec) {
    var speed = Math.round(millisec / 100);
    var timer = 0;
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            timer++;
        }
    }
    
    return 1;
}

function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
}

function ShowIt(tElement, how ) {
	if ( how == 0 ) { how='block'; }
	var element = document.getElementById(tElement).style.display = how;
	return;
}

function HideIt(tElement) {
	var element = document.getElementById(tElement).style.display='none';
	return;
}

function slideshow( go, prefix, suffix, max) {
	HideIt('slcp');
	ShowIt('slcp_load','inline');

	/** Inicializace potrebnych obrazku **/
	preload = new Image();
	slide_pre = new Image();
	
	var slide = document.getElementById('slide');
	
	if ( go == 'N' ) {
		cil = (parseInt(slide.name) + 1);
		if ( cil > max ) {
			ShowIt('slcp','inline'); 
			HideIt('slcp_load'); 
			return; 
		}
		preload.src = prefix + (cil + 1) + suffix;
	} else {
		cil = (parseInt(slide.name) - 1);
		if ( cil < 1 ) { ShowIt('slcp','inline'); HideIt('slcp_load'); return; }
		preload.src = prefix + (cil - 1) + suffix;
	}
	slide.name = cil;
	
	slide_pre.src = prefix + cil + suffix;
	
	//opacity("slide", 100, 0, 300);
	
	
	
	slide_pre.onload=setTimeout( function () {
			slide.src = prefix + cil + suffix;
			//opacity("slide", 0, 100, 300);
			setTimeout( function () { document.getElementById('count').innerHTML = cil;ShowIt('slcp','inline'); HideIt('slcp_load'); }, 400);
		}, 2000);
		
		
	cil = parseInt(slide.name);
	if ( cil == max ) { 
		document.getElementById('sln').style.color="#AAA";
	} else {
		document.getElementById('sln').style.color="#974646";
	}
	
	if ( cil == 1 ) { 
		document.getElementById('slp').style.color="#AAA";
	} else {
		document.getElementById('slp').style.color="#974646";
	}
	return;
}



// predstahneme si loading image
window.onload = function () {
	document.getElementById('slp').style.color="#AAA";
	preload = new Image();
	preload.src = 'img/slideshow/loading.gif';
	//Preload(1,23);
}