/*******************************************************************************
file:			slideshow.js
author:			oh@design-aspekt.com
version:		1.6
changes:		preLoading onerror-Handler fixed
date:			14-01-2004

requires:		Array with Image-Paths
				image with distinctive name

input params:	essential: Array with Image-Paths, image-name
				optional: layerID, direction, autostart
********************************************************************************/
var slideObject = null;						// very important: stores the Slideshow-Object, because setTimeout cannot call function with "this"
var runCounter = 0;							// necessary to fill Preload-Array independently from var i, in case that the loading process is erroneous

function slideshow() {	// Object constructor
	// object attributes defined by input params
	this.aSlides = arguments[0];			// Array with Image-Paths
	this.imgName = arguments[1];			// name of the image to be rotated
	if(arguments[2]) {
		this.layerID = arguments[2];		// name of the layer in which the image is located: relevant for NS4, otherwise var can be empty
	} else { this.layerID = null; }
	if(arguments[3]) {
		this.direction = arguments[3];		// can be 1 or -1; e.g. the direction can be changed via mouse-click etc.
	} else { this.direction = 1; }
	if(arguments[4]) {
		this.autostart = arguments[4];		// can be "true" or "false"
	} else { this.autostart = "true"; }
	
	// further object attributes
	this.start = "true";					// initial state to prevent counting in rotate() before first rotation
	this.counter = 0;
	this.delay = false;
	this.slide = false;
	this.aPreLoad = new Array();			// Array used to preload images by creating new Image-Objects
	
	// global var to handle timeout
	slideObject = this;						// stores the Object for use in setTimeout()
	
	// object methods
	this.getImage = getImage;				// infamous cross-browser method to retrieve the image
	this.checkImg1 = checkImg1;				// checks if first image is loaded and then starts preLoader and rotation
	this.preLoader = preLoader;				// method creating new Image-Objects and thus forcing the browser to load the images at once
	this.rotateImg = rotateImg;				// method for rotating the image
	this.changeDirection = changeDirection;	// method to change the direction, e.g. triggered by Event-Handler
	this.stopSlide = stopSlide;				// method to to manually start slideshow, e.g. triggered by Event-Handler
	this.startSlide = startSlide;			// method to to manually interrupt slideshow, e.g. triggered by Event-Handler
	this.jumpToSlide = jumpToSlide;			// method to to manually start slideshow, e.g. triggered by Event-Handler
	this.skipBack = skipBack;				// method to skip one image back, e.g. triggered by Event-Handler
	this.skipForward = skipForward;			// method to skip one image forward, e.g. triggered by Event-Handler
	
	// init actions
	this.aPreLoad[0] = new Image();			// loads first Image into preLoad-Array
	this.aPreLoad[0].onerror = function replace() {	// if loaded image data is corrupt, the image is deleted from the array to prevent interruption during rotation
		//alert(runCounter);
		slideObject.aPreLoad[0].src = "pix/onepix.gif";
	}
	this.aPreLoad[0].src = this.aSlides[0];
	this.checkImg1();
}

function getImage(imgName,layerID) {
	return (document.all || document.getElementById ? window.document.images[imgName] : layerID ? document.layers[layerID].document.images[imgName] : window.document.images[imgName]);
}

function checkImg1() {
	if(this.aPreLoad[0].complete == true) {
		this.preLoader();	// preloads images after first image has been loaded
		if(this.autostart == "true") { this.rotateImg(); }
	}
	else { setTimeout('slideObject.checkImg1()',100); }
}

function preLoader() {
	for(i=1; i<this.aSlides.length; i++) {
		this.aPreLoad[i] = new Image();
		runCounter = i;
		this.aPreLoad[i].onerror = function replace() {	// if loaded image data is corrupt, the image is deleted from the array to prevent interruption during rotation
			//alert(runCounter);
			slideObject.aPreLoad[runCounter].src = "pix/onepix.gif";
		}
		this.aPreLoad[i].src = this.aSlides[i];
	}
}

function rotateImg() {
	if(this.aPreLoad[this.counter].complete == true) {	// checks if current image has been loaded
		if(this.direction == 1 && this.start == "false") { (this.counter == (this.aPreLoad.length-1)) ? this.counter=0 : this.counter++; }
		else if(this.direction == -1  && this.start == "false") { (this.counter < 1) ? this.counter=this.aPreLoad.length-1 : this.counter--; }
		this.getImage(this.imgName,this.layerID).src = this.aPreLoad[this.counter].src;
		self.status = "Picture "+ (this.counter+1) + " of " + this.aSlides.length;
		if(this.start == "true") { this.start = "false"; }
		this.slide = setTimeout('slideObject.rotateImg()',3000);
	}
	else { // if image has still not been loaded, the function is called again with less delay
		self.status = "Picture "+ (this.counter+1) + " is still loading...";
		this.slide = setTimeout('slideObject.rotateImg()',100);
	}
}

function changeDirection() {
	if(this.direction == 1) { this.direction = -1; }
	else if(this.direction == -1) { this.direction = 1; }
}

function startSlide() { this.rotateImg(); }
function stopSlide() {
	if(this.slide != false) { clearTimeout(this.slide); }
}

function jumpToSlide(slideImg,method) {	
	if(method == "stop" && this.slide != false) { clearTimeout(this.slide); }
	this.counter = slideImg;
	this.getImage(this.imgName,this.layerID).src = this.aPreLoad[this.counter].src;
}

function skipBack() {
	if(this.slide != false) { clearTimeout(this.slide); }
	if(this.delay != false) { clearTimeout(this.delay); }
	(this.counter < 1) ? this.counter=this.aPreLoad.length-1 : this.counter--;
	this.getImage(this.imgName,this.layerID).src = this.aPreLoad[this.counter].src;
	self.status = "Picture "+ (this.counter+1) + " of " + this.aPreLoad.length;
	this.delay = setTimeout('slideObject.rotateImg()',3000);
}

function skipForward() {
	if(this.slide != false) { clearTimeout(this.slide); }
	if(this.delay != false) { clearTimeout(this.delay); }
	(this.counter == (this.aPreLoad.length-1)) ? this.counter=0 : this.counter++;
	this.getImage(this.imgName,this.layerID).src = this.aPreLoad[this.counter].src;
	self.status = "Picture "+ (this.counter+1) + " of " + this.aPreLoad.length;
	this.delay = setTimeout('slideObject.rotateImg()',3000);
}