/* This script is used to scroll through the images in a category
 * Author: Bryn Smith (bryn.a.smith AT gmail DOT com)
 */

var SCROLLER_PERIOD = 8000;

var nextImages = [];
var titles = [];
var years = [];
var images = [];
var categories;
var categoryIds;
var preloadedImages = [];

function scroller_init()
{
   var i;
   
   for(i = 0; i < categoryIds.length; i++)
   {
      nextImages[i] = 0;
      preloadedImages[i] = document.createElement('img');
   }
   scroller_reloadTrigger();
   scroller_preload();
}

function scroller_reloadTrigger()
{
   window.setTimeout('scroller_task()', SCROLLER_PERIOD);
}

function scroller_task()
{
   var i;
   for(i = 0; i < categoryIds.length; i++)
   {
      var categoryId = categoryIds[i];
      var categoryName = categories[i];
      var workTitle = titles[categoryId][nextImages[i]];
      var workYear  = years[categoryId][nextImages[i]];
      var workImage = images[categoryId][nextImages[i]];
      
      document.getElementById("paletteimage" + categoryId).src = "image.php?thumb=1&id=" + workImage;
      document.getElementById("paletteimage" + categoryId).alt = workTitle.toUpperCase() + " (" + workYear + ")";
      document.getElementById("palettetitle" + categoryId).innerHTML = "<b>" + workTitle.toUpperCase() + " (" + workYear + ")</b>";
      
      nextImages[i]++;
      if(nextImages[i] >= titles[categoryId].length)
      {
         nextImages[i] = 0;
      }
   }

   scroller_reloadTrigger();
   scroller_preload();
}

function scroller_preload()
{
   for(i = 0; i < categoryIds.length; i++)
   {
      var categoryId = categoryIds[i];
      var workImage = images[categoryId][nextImages[i]];
      preloadedImages[i].setAttribute('src', "image.php?thumb=1&id=" + workImage);
   }
}