// PictureCycle Object
// Duncan Littlefield
// Feel free to use this code.
// I do not assume any responsibility for the accuracy of this code.

// STATE_INIT			= 0
// STATE_IDLE			= 1
// STATE_CYCLE			= 2
// STATE_ENDING_CYCLE	= 3
// STATE_DISPLAY_1_PIC	= 4

//****************************************************
// PictureDisplay object definition / constructor
// ---------------------------------------------------
function PictureDisplay (sPictureName)
{
	//====================================
	// Member variables and initialization
	this.sPictureName	= sPictureName;	// The name of the picture on the web page
	this.iPictureIndex	= 0;
	this.iPictureCount	= 0;
	this.aPictureList	= new Array();
	this.aTimeoutList	= new Array();
	this.aFullSizeList	= new Array();
	this.iState			= 0;
	eval(this.oSelf + "=this");

	//====================================
	// Public Member methods
	this.CyclePictureList	= CyclePictureList;
	this.StopCycling		= StopCycling;
	this.AddPicture			= AddPicture;
	this.DisplayPicture		= DisplayPicture;
	this.ShowFullSize		= ShowFullSize;

	//====================================
	// Private Member methods
	this.PrivateCycleList  = PrivateCycleList;
}

//****************************************************
// AddPicture
// ---------------------------------------------------
function AddPicture (a_sPicture, a_iTimeout, a_sFullSizeName)
{
	this.aTimeoutList[this.iPictureCount]	  = a_iTimeout;
	this.aPictureList[this.iPictureCount]	  = new Image();
	this.aPictureList[this.iPictureCount].src = a_sPicture;
	this.aFullSizeList[this.iPictureCount]	  = a_sFullSizeName;
	this.iPictureCount++;
}

//****************************************************
// CyclePicture
// ---------------------------------------------------
function CyclePictureList()
{
	if ((this.iState != 2) && (this.iState != 3) && (this.aPictureList.length > 0))
	{
		this.iState = 2;
		this.PrivateCycleList ();
	}
}

function PrivateCycleList ()
{
	//==================================================
	// Enter cycle as long as we have not been told to stop
	if ((this.iState == 2) && (this.aPictureList.length > 0))
	{
		//------------------------------------------------------
		// Calculate next picture
		this.iPictureIndex++;
		if (this.iPictureIndex >= this.aPictureList.length)
		{
			this.iPictureIndex = 0;
		}

		//------------------------------------------------------
		// Display next picture
		document.images[this.sPictureName].src = this.aPictureList[this.iPictureIndex].src;

		//------------------------------------------------------
		// Wait for some time, then display the next picture
		// This call is non-blocking - it does not sleep, so this is not bad recursion
		setTimeout(this.oSelf+".PrivateCycleList()", this.aTimeoutList[this.iPictureIndex])
	}

	//==================================================
	// If the stop flag has been set, then go back to idle
	if (this.iState == 3)
	{
		this.iState = 1;
	}
}

//****************************************************
// Stop Cycling
// Set flag so that loop will stop. I use a flag so that I do not get
// several loops running at the same time.
// ---------------------------------------------------
function StopCycling()
{
	if (this.iState == 2)
		this.iState	= 3;	// Set so that loop stops
}

//****************************************************
// DisplayPicture
// ---------------------------------------------------
function DisplayPicture (a_iPictureIndex)
{
	//====================================
	// Stop any cycling
	this.StopCycling();

	//====================================
	// Validate the picture index
	if (a_iPictureIndex < this.iPictureCount)
	{
		this.iPictureIndex = a_iPictureIndex;
	}

	//====================================
	// Display selected picture
	this.iState = 4;
	document.images[this.sPictureName].src = this.aPictureList[this.iPictureIndex].src;
}

//****************************************************
// ShowFullSize
// ---------------------------------------------------
function ShowFullSize ()
{
	//====================================
	// Stop any cycling
	this.StopCycling();

	//====================================
	// Display selected picture in a new window
	if (this.iPictureIndex < this.iPictureCount)
	{
		this.iState = 4;
		window.location.href = this.aFullSizeList[this.iPictureIndex];
	}
}