var galpos = 0,oldpos = 0,maxpos=1000;
var inc=0;
var gal, bigpic, picdesc,pics;

function init_gal() {
	bigpic = document.getElementById('bigpic');
	picdesc = document.getElementById('picdesc');
	gal = document.getElementById('preview_inner');
	pics = gal.getElementsByTagName('img');
	cp(pics[0]);
}
function move_left() {oldpos=galpos;inc=-50;setTimeout(do_slide,50);}
function move_right() {oldpos=galpos;inc=50;setTimeout(do_slide,50);}
function do_slide() {
	maxpos = 0;
	for(i=0;i<pics.length;i++) {maxpos += pics[i].width;}
	var gn = galpos + inc;
	if(gn < 0) {inc = -galpos;}
	if(gn > maxpos) {inc = (maxpos-galpos);}
	gn = galpos + inc;
	if ((gn  >= 0) && (gn <= maxpos) ) {
		galpos=gn;
		gal.style.marginLeft = -galpos+"px";
		if(Math.abs(oldpos-galpos) > 300 && Math.abs(inc) > 1) {inc *= 0.8;}
		if(Math.abs(oldpos-galpos) < 500) {setTimeout(do_slide,50);}
	}
}

function cp(obj) {
	bigpic.src=obj.src.replace("t_","");
	bigpic.alt=bigpic.title=picdesc.innerHTML=obj.alt;
}