/* Original:  Robert Bui (astrogate@hotmail.com) */
/* Web Site:  http://astrogate.virtualave.net */

/* adapted by WISE */

// you can mutate these in calling page
var interval = 5000; // milliseconds delay between rotating images
var random_display = 1; // 0 = no, 1 = yes

var image_index = 0;
image_list = new Array();
/* do this in the calling page
image_list[image_index++] = new imageItem("/images/kidsOnComputer.jpg");
image_list[image_index++] = new imageItem("/images/kidsinaquarium.jpg");
image_list[image_index++] = new imageItem("/images/deformedFrogs.jpg");
image_list[image_index++] = new imageItem("/images/Studentputdata.jpg");
*/
var number_of_image = 0;

function imageItem(image_location) {
  this.image_item = new Image();
  this.image_item.src = image_location;
}

function get_ImageItemLocation(imageObj) {
  return(imageObj.image_item.src);
}

function nextRandomIndex(x, y) {
  var range = y - x + 1;
  return Math.floor(Math.random() * range) + x;
}

function getNextImage() {
  if (random_display) {
    image_index = nextRandomIndex(0, number_of_image-1);
  }
  else {
    image_index = (image_index+1) % number_of_image;
  }
  var new_image = get_ImageItemLocation(image_list[image_index]);
  return(new_image);
}

function rotateImage(place) {
  // update these static vars
  number_of_image = image_list.length;

  var new_image = getNextImage();
  imgElement = document.getElementById(place);
  imgElement.src = new_image;
  var recur_call = "rotateImage('"+place+"')";
  setTimeout(recur_call, interval);
}