/* 
*
* Original magnifier by mihai@persistant.info, modified by tboyd@rejuvenation.com
* (re)released under the Creative Commons Attribution-ShareAlike License:
* http://creativecommons.org/licenses/by-sa/2.0/
*/

var kShadowPadding = 17;

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

var kMagnifierSizes = new Array(0,300);
var kMagnifierSizeNames = new Array('off','on');

var kControllerPrefix = 'Click to Turn Magnifier: '; // more of a label, really
var kControllerSuffix = 'for More Detail.';

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";
	
    if(navigator.userAgent.indexOf("MSIE")==-1 || navigator.platform.indexOf("Mac")==1){ // gecko and friends, and IE on MacOS
        var magnifierCenterX = Math.round((this.xPosition-66) * this.xMultiplier);
    	var	magnifierCenterY = Math.round(this.yPosition * this.yMultiplier);
    }
    else{
        var magnifierCenterX = Math.round(this.xPosition * this.xMultiplier);
    	var	magnifierCenterY = Math.round(this.yPosition * this.yMultiplier);
    }
	
		
	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 use the PNG alpha channel
		var shadowImageSrc = "shadow3.png"; // one size fits all, for us
		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;
	
	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)
{
	// 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");

	// 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;
	}
	
	magnifier.xMultiplier = 2.25; // fairly good compromise settings
	magnifier.yMultiplier = 3;
    
    if(zoomedHeight > 1200){ // one extreme
        magnifier.yMultiplier = 2.25;
    }
    if(zoomedHeight < 950){ // the other extreme
        magnifier.yMultiplier = 3.25;
    }
	magnifier.size = kMagnifierSizes[kDefaultMagnifierSize];
	magnifier.xPosition = 200;
	magnifier.yPosition = 200;
    
	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);
	}
	
    var controllerSuffix = document.createElement("span");
	controllerSuffix.innerHTML = kControllerSuffix;

	controllerSuffix.className = "magnifierControllerSuffix";
	controller.appendChild(controllerSuffix);
    
	// 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
}