/*
vorher (in index.php) definierte Variablen:
	cat - Name der Kategorie (und des Ordners der die Bilder enhält)
	pics - Array mit Namen der Bilder der entsprechenden Galerie
*/

var maxT = 10; // Anzahl der angezeigten Thumbnails
var scrollT = 10;	// Scroll-Weite
var startT = 0;
var numT = pics.length;
var b = new Array();

function updateT(end, offset) {
	for(var i = 0; i < end; i++) {
		thumb = "t" + i;
		document.getElementById(thumb).src = b[startT + i + offset].src;
	}
}

function initT() {
//	document.getElementById("arrowL").style.visibility = "hidden";
	for(var i = 0; i < numT; i++) {
		b[i] = new Image();
		b[i].src = "_photos/" + cat + "/" + pics[i] + "-t.jpg";
	}
	if(numT <= maxT) {
		document.getElementById("arrowR").style.visibility = "hidden";
	}
}

function showP(pNum) {
	document.getElementById("photo").src = "/_photos/" + cat + "/" + pics[pNum + startT] + ".jpg";
}

function goBack() {
	dist = scrollT;
	if(scrollT >= startT) {
		dist = startT;
		document.getElementById("arrowL").style.visibility = "hidden";
	}
	document.getElementById("arrowR").style.visibility = "visible";
	updateT(maxT, (-1 * dist));
	startT -= dist;
}
function goNext() {
	dist = scrollT;
	if(scrollT >= (numT - (startT + maxT))) {
		dist = numT - (startT + maxT);
		document.getElementById("arrowR").style.visibility = "hidden";
	}
	document.getElementById("arrowL").style.visibility = "visible";
	updateT(maxT, dist);
	startT += dist;
}