var nCurImg = 0;
var nPrevs  = 4;
var nFirVis = 0;
var nLasVis = nFirVis + nPrevs - 1;
var oLoc    = null;

window.onload = f_init;

function f_init() {
	var oPrev = null;
	var iter = 0;
	
	oLoc = document.getElementById("localizador");
	document.getElementById("areaLoading").style.display = "none";
	if (nMaxImg<0){
		//document.getElementById("zoomArrows"   ).style.display = "none";
		//document.getElementById("zoomArrows"   ).parentNode.parentNode.childNodes[1].style.display = "none";
		//document.getElementById("zoomArrows"   ).parentNode.parentNode.parentNode.childNodes[2].style.display = "none";
	}else{
	document.getElementById("areaZoom"   ).style.display = "block";
	f_refreshUI();
	}
	// alert(document.getElementById('areaPreview').clientWidth);
}
function f_goRel(nRel) {
	if(nRel<0){
		if(nCurImg>0){
		nCurImg--;
		}else{
		nCurImg=nMaxImg
		}
	}
	if(nRel>0){
    if(nCurImg<nMaxImg){
      nCurImg++;
    }else{
      nCurImg=0
    }
  }
	//f_recalc();
	f_refreshUI();
}
function f_goAbs(nAbs) {
	if(!(nAbs<0 || nAbs>nMaxImg)) 
		nCurImg = nAbs;
	//f_recalc();
	f_refreshUI();
}

function f_recalc() {
	if(nFirVis>nCurImg) {
		nFirVis = nCurImg;
		nLasVis = nFirVis + nPrevs - 1;
	} else if(nLasVis<nCurImg) {
		nFirVis = Math.max(0, nCurImg - nPrevs + 1);
		nLasVis = nFirVis + nPrevs - 1;
	}
}
function f_refreshUI() {
	var oPrev = null;
	var oZoom = null;
	var oFoot = null;
	var iter = 0;
	
	for(iter=0; iter<=nMaxImg; iter++) {
		oZoom = document.getElementById("zoomImg"+iter);
		if(oZoom) 
			if(iter!=nCurImg)
				oZoom.style.display = "none";
			else
				oZoom.style.display = "inline";
	}	
	for(iter=0; iter<=nMaxImg; iter++) {
		oFoot = document.getElementById("zoomFootImg"+iter);
		if(oFoot) 
			if(iter!=nCurImg)
				oFoot.style.display = "none";
			else
				oFoot.style.display = "inline";
	}	
	oLoc.innerHTML = (parseInt(nCurImg)+1) + " / " + (nMaxImg+1);
}