/* Javascript code for slideshow */

var interval = 4500; 
var random_display = 0;
var image_dir = ""
var ImageNum = 0;
imageArray = new Array();

imageArray[ImageNum++] = new imageItem(image_dir + "images/slideshow/t.gif");
imageArray[ImageNum++] = new imageItem(image_dir + "images/slideshow/cn.gif");
imageArray[ImageNum++] = new imageItem(image_dir + "images/slideshow/qs.gif");
imageArray[ImageNum++] = new imageItem(image_dir + "images/slideshow/ce.gif");

var number_of_image = imageArray.length;

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

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

function getPrevImage() {
ImageNum = (ImageNum-1) % number_of_image;
var new_image = get_ImageItemLocation(imageArray[ImageNum]);
return(new_image);
}

function prevImage(place) {
var new_image = getPrevImage();
document[place].src = new_image;
}

function rotateImage(place) {
var new_image = getNextImage();
document[place].src = new_image;
var recur_call = "rotateImage('"+place+"')";
timerID = setTimeout(recur_call, interval);
}