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

window.onload = f_init;

function f_init() {
  if (nMaxImg>-1){
    var oPrev = null;
    var iter = 0;
    for(iter=0; iter<=nMaxImg; iter++) {
      oPrev = document.getElementById("prevImg"+iter);
      if(oPrev) {
        oPrev.setAttribute("nImage", iter);
        oPrev.onclick     = f_goImg;
        oPrev.onmouseover = f_mover;
        oPrev.onmouseout  = f_mout;
      }
    }
    oLoc = document.getElementById("indiceimgs");
    f_refreshUI();
    // alert(document.getElementById('areaPreview').clientWidth);
  }
}
function f_goRel1(nRel) {
	if(nRel<0 && nCurImg>0) 
		nCurImg--;
	if(nRel>0 && nCurImg<nMaxImg) 
		nCurImg++;
	f_recalc();
	f_refreshUI();
}

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_goImg() {
	var nImage = this.getAttribute("nImage");
	f_goAbs(nImage);
}
function f_mover() {
	if(this.getAttribute("nImage")!=nCurImg) {
		this.setAttribute("class", "ovr");
		this.setAttribute("className", "ovr");
	}
}
function f_mout() {
	if(this.getAttribute("nImage")!=nCurImg) {
		this.setAttribute("class", "");
		this.setAttribute("className", "");
	}
}
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++) {
		oPrev = document.getElementById("prevImg"+iter);
		if(oPrev) {
			if(iter<nFirVis || iter>nLasVis) {
				oPrev.style.display = "none";
				oPrev.setAttribute("class", "");
				oPrev.setAttribute("className", "");
			} else {
				oPrev.style.display = "inline";
				oPrev.setAttribute("class", (iter==nCurImg?"sel":""));
				oPrev.setAttribute("className", (iter==nCurImg?"sel":""));
			}
		}
	}
	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 = (nCurImg+1) + " / " + (nMaxImg+1);
}