// *******************************************************************
//  Nexum Trilog, 2007
//  Jakub Havel, jakub.havel@nexum.cz
//
//  javascriptove prolinani obrazku
// *******************************************************************

  var NX_intervalZmena = 0; // id intervalu pro provadeni zmen
  var NX_iCounter = 0; // pocitadlo pro prochazeni pole obrazku
  var NX_browserdetect = NX_imgFront.filters? "ie" : typeof NX_imgFront.style.MozOpacity=="string"? "mozilla" : ""; // detekce prohlizece
  var NX_typZmeny = -1; // ridici promenna pro urceni kery obrazek se ma jak chovat

  // prvni nastaveni obrazku
  NX_imgFront.src = NX_Pictures[NX_iCounter]; 
  NX_imgBack.src = NX_Pictures[NX_iCounter+1];  
  NX_instantset(99, NX_imgFront);
  NX_instantset(1, NX_imgBack);

  // **** SPUSTENI SCRIPTU PROLINANI *******************************
  NX_changeImg();
  // ************************************************************

  // fce pro vyvolani zmeny obrazku
  function NX_changeImg() {
    clearInterval(NX_intervalZmena);
    NX_typZmeny = NX_typZmeny * (-1);
    NX_iCounter++;
    if (NX_iCounter >= NX_Pictures.length) NX_iCounter = 0;

    if (NX_typZmeny == 1) {
      NX_instantset(1, NX_imgBack);
      NX_instantset(99, NX_imgFront);
      NX_imgBack.src = NX_Pictures[NX_iCounter];
    } else {
      NX_instantset(99, NX_imgBack);
      NX_instantset(1, NX_imgFront);
      NX_imgFront.src = NX_Pictures[NX_iCounter];
    }
    
    NX_intervalZmena = setInterval("NX_gradualfade()", 30);
  }

  // fce pro zmenu kanalu APLHA u obrazku
  function NX_gradualfade() {
    if (NX_browserdetect == "mozilla" && NX_imgFront.style.MozOpacity < 1.00 && NX_imgFront.style.MozOpacity > 0) {
      if (NX_typZmeny == 1) {
        NX_imgFront.style.MozOpacity = Math.max(parseFloat(NX_imgFront.style.MozOpacity) - 0.1, 0);
        NX_imgBack.style.MozOpacity = Math.min(parseFloat(NX_imgBack.style.MozOpacity)   + 0.1, 1);
      } else {
        NX_imgBack.style.MozOpacity = Math.max(parseFloat(NX_imgBack.style.MozOpacity)  - 0.1, 0);
        NX_imgFront.style.MozOpacity = Math.min(parseFloat(NX_imgFront.style.MozOpacity)  + 0.1, 1);
      }
    } else if (NX_browserdetect == "ie" && NX_imgFront.filters.alpha.opacity < 100 && NX_imgFront.filters.alpha.opacity > 0) {
      if (NX_typZmeny == 1) {
        NX_imgFront.filters.alpha.opacity -= NX_rychlostPrirustku;
        NX_imgBack.filters.alpha.opacity += NX_rychlostPrirustku;
      } else {
        NX_imgBack.filters.alpha.opacity -= NX_rychlostPrirustku;
        NX_imgFront.filters.alpha.opacity += NX_rychlostPrirustku;
      }
    } else {
      clearInterval(NX_intervalZmena);
      NX_intervalZmena = setInterval("NX_changeImg();", NX_cekaniProZmenu * 5000);
    }
  }

  // nastaveni ALPHA kanalu u obrazku
  function NX_instantset(degree, imgObj) {
    if (NX_browserdetect == "mozilla") {
      imgObj.style.MozOpacity = degree / 100;
    } else if (NX_browserdetect == "ie") {
      imgObj.filters.alpha.opacity = degree;
    }
  }