var kShadowPadding = 17;
		
var kDefaultMagnifierSize = 0; // index into the arrays below

var kMagnifierSizes = new Array(0, 100, 150, 300);
var kMagnifierSizeNames = new Array('off', 'small', 'medium', 'large');

//var kControllerPrefix = '<img src=img/magnify.gif>&nbsp;';
var kControllerPrefix = 'Magnifier:';

function hello(){
	alert("hello there")
}


function MagnifierPosition()
{			
	this.style.left = Math.round(this.xPosition - 1 - this.size/2) + "px"; // -1 to account for the border
	this.style.top = Math.round(this.yPosition - 1 - this.size/2) + "px";
	
	this.shadow.style.left = Math.round(this.xPosition - this.size/2 - kShadowPadding) + "px";
	this.shadow.style.top = Math.round(this.yPosition - this.size/2 - kShadowPadding) + "px";
	
	var magnifierCenterX = Math.round(this.xPosition * this.xMultiplier - this.size/2);
	var	magnifierCenterY = Math.round(this.yPosition * this.yMultiplier - this.size/2);
	
	this.style.backgroundPosition = -magnifierCenterX + "px " +	-magnifierCenterY + "px";
}
		
function ControllerSizeButtonClick(event)
{
	if (!event) event = window.event;
	
	var button = event.currentTarget || event.srcElement;
	
	button.parentNode.magnifier.resize(button.magnifierSize);
}
		
function MagnifierResize(size)
{
	this.size = kMagnifierSizes[size];
	
	for (var i=0; i < this.controller.sizeButtons.length; i++)
	{
		if (i == size)
			this.controller.sizeButtons[i].className = "magnifierControllerButtonSelected";
		else
			this.controller.sizeButtons[i].className = "magnifierControllerButton";
	}
	
	if (this.size == 0)
	{
		this.shadow.style.display = "none";
		this.style.display = "none";
	}
	else
	{
		var shadow = this.shadow;
		var shadowSize = this.size + 2 * kShadowPadding;
		
		// MSIE 5.x/6.x must be treated specially in order to make them use the PNG alpha channel
		var shadowImageSrc = "img/zoomer-shadow" + size + ".png";
		if (shadow.runtimeStyle)
			shadow.runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" +
											  shadowImageSrc +
											"', sizingMethod='scale')";
		else
			shadow.style.backgroundImage = "url(" + shadowImageSrc + ")";
		shadow.style.width = shadowSize + "px";
		shadow.style.height = shadowSize + "px";
		shadow.style.display = "block";
		
		if (this.runtimeStyle) // msie counts the border as being part of the width
			this.size += 2; // must compensate
		
		this.style.width = this.size + "px";
		this.style.height = this.size + "px";
		this.style.display = "block";
		this.position();
	}
}
		
function MagnifierMouseDown(event)
{
	if (!event) event = window.event;

	//capture the close event
	var sSource = event.srcElement.id
	if (sSource=="imgClose"){
		this.resize(0)
		return
	}
	
	
	
	document.body.magnifier = this;
	this.inDrag = true;
	if (event.pageX)
	{
		this.startX = event.pageX;
		this.startY = event.pageY;
	}
	else if (event.clientX)
	{
		this.startX = event.clientX;
		this.startY = event.clientY;
	}
	else
	{
		alert("don't know how to get position out of event");
		return;
	}
	this.savedCursor = this.style.cursor;
	this.style.cursor = "crosshair";
}
		
function MagnifierMouseUp()
{
	if (this.inDrag)
	{
		this.inDrag = false;
		this.style.cursor = this.savedCursor;
		document.body.magnifier = null;
	}
}

function MagnifierDrag(event)
{
	if (!event) event = window.event;
	var magnifier = this.magnifier; // we're actually in the body's onmousemove handler
	
	if (magnifier && magnifier.inDrag)
	{
		var eventX;
		var eventY;
		
		if (event.pageX)
		{
			eventX = event.pageX;
			eventY = event.pageY;
		}
		else if (event.clientX)
		{
			eventX = event.clientX;
			eventY = event.clientY;
		}
		else
		{
			return;
		}
		
		magnifier.xPosition += eventX - magnifier.startX;
		magnifier.yPosition += eventY - magnifier.startY;
		
		magnifier.startX = eventX;
		magnifier.startY = eventY;
		
		magnifier.position();
	}
}

function loadMagnifier(baseID, zoomedURL, zoomedWidth, zoomedHeight)
{
	var sHtml
	
	// get the zoomed image (load as early as possible)
	var zoomedImage = document.createElement("img");
	zoomedImage.src = zoomedURL;
	
	// get the div's
	var base = document.getElementById(baseID);
	var magnifier = document.createElement("div");
	//magnifier.innerHTML = "<span style='border-bottom: 1px solid black; width:100%;background-color: silver;'>Zoom</span>"
	
	sHtml = "<table cellpadding=0 cellspacing=0 width='100%' style='border-bottom: 1px solid black; width:100%; background-color: silver;'>"
	sHtml += "<tr>"
	sHtml += "<td width='10%' background='img/zoomer-bar.gif'>&nbsp;</td>"
	sHtml += "<td width='80%' background='img/zoomer-bar.gif' align=center><B>Magnifier</b></td>"
	//sHtml += "<td background='img/zoomer-bar.gif'>&nbsp;</td>"
	sHtml += "<td width='10%' background='img/zoomer-bar.gif' align=right style='padding-right: 2px;'><img style='cursor: hand' id='imgClose' src='img/zoomer-close.gif'></td>"
	sHtml += "</tr></table>"

	magnifier.innerHTML = sHtml

	//var xbutton = createElement("button")
	//xbutton.onclick = "hello"

	// get the regular image
	var normalImage = null;
	for (var i=0; i < base.childNodes.length; i++)
	{
		if (base.childNodes[i].tagName &&
			base.childNodes[i].tagName.toLowerCase() == "img")
		{
			normalImage = base.childNodes[i];
			break;
		}
	}
	
	if (normalImage == null)
	{
		alert("couldn't find normal image for magnifier " + baseID);
		return;
	}
	
	//alert(normalImage.id)
	//alert(normalImage.width)
	//alert(document.all("baseImage").width)
	
	magnifier.xMultiplier = zoomedWidth/parseInt(normalImage.style.width);
	magnifier.yMultiplier = zoomedHeight/parseInt(normalImage.style.height);
	
	//magnifier.xMultiplier = zoomedWidth/220;
	//magnifier.yMultiplier = zoomedHeight/220;


	magnifier.size = kMagnifierSizes[kDefaultMagnifierSize];
	//magnifier.xPosition = normalImage.width - magnifier.size/2 - 20;
	//magnifier.yPosition = normalImage.height - magnifier.size/2 + 30;
	
	magnifier.xPosition = 50
	magnifier.yPosition = 50


	magnifier.id = baseID + "Magnifier";
	magnifier.className = "magnifier";
	
	// styles (only dynamic ones, rest are part of the class)
	magnifier.style.backgroundImage = "url(" + zoomedURL + ")";
	
	// functions
	magnifier.onmousedown = MagnifierMouseDown;
	magnifier.onmouseup = MagnifierMouseUp;
	document.body.onmousemove = MagnifierDrag; // we attach this handler to the body because if the user moves
													// the mouse fast enough, it'll go outside the boundaries of the
													// magnifier, and then the magnifier's mousemove handler won't fire

	magnifier.position = MagnifierPosition;
	magnifier.resize = MagnifierResize;
	
	// controller
	var controller = document.createElement("span");
	
	controller.id = baseID + "MagnifierController";
	controller.className = "magnifierController";
	
	var controllerPrefix = document.createElement("span");
	controllerPrefix.innerHTML = kControllerPrefix;

	controllerPrefix.className = "magnifierControllerPrefix";
	controller.appendChild(controllerPrefix);
	
	controller.sizeButtons = new Array(kMagnifierSizes.length);

	

	for (var i=0; i < kMagnifierSizes.length; i++)
	{
		var button = document.createElement("span");
		button.innerHTML = kMagnifierSizeNames[i];
		button.className = "magnifierControllerButton";
		button.onclick = ControllerSizeButtonClick;
		button.magnifierSize = i;
		
		controller.sizeButtons[i] = button;
		controller.appendChild(button);
	}
	
	// shadow
	var shadow = document.createElement("div");
	
	shadow.id = baseID + "MagnifierShadow";
	shadow.className = "magnifierShadow";
	
	// point objects at each other
	magnifier.controller = controller;
	controller.magnifier = magnifier;
	magnifier.shadow = shadow;
	
	// add to document and lay out

	var controllerContainer = document.createElement("div");

	controllerContainer.className = "magnifierControllerContainer";

	controllerContainer.appendChild(controller);

	base.insertBefore(controllerContainer, document.getElementById("message"));
	base.appendChild(shadow);
	base.appendChild(magnifier);
	magnifier.resize(kDefaultMagnifierSize); // also positions
}