function point( x, y )
{
	this.x = x; 
	this.y = y;
}

function face( x, y, name, title )
{
	this.x = x;
	this.y = y;
	this.name = name;
	this.title = title;
}

function getTargetElement( inEvent )
{
	var targ;
	
	if (inEvent.target) targ = inEvent.target; // Moz
	else if (inEvent.srcElement) targ = inEvent.srcElement; // IE
	
	if (targ.nodeType == 3) // Safari
		targ = targ.parentNode;	
		
	return targ;
}

function getElementOrigin( inElement )
{
	var x_off = 0; 
	var y_off = 0;
	
	var el = inElement;
	
	while ( el )
	{
		x_off = x_off + el.offsetLeft;
		y_off = y_off + el.offsetTop;
		el = el.offsetParent;
	}
	
	return new point( x_off, y_off );
}

function getTargetElementOffset( inEvent, targElem )
{
	var xPos = 0;
	var yPos = 0;
	
	if (!inEvent) var inEvent = window.event;
	
	if (inEvent.pageX || inEvent.pageY)
	{
		xPos = inEvent.pageX;
		yPos = inEvent.pageY;
	}
	else if (inEvent.clientX || inEvent.clientY)
	{
		xPos = inEvent.clientX + document.body.scrollLeft;
		yPos = inEvent.clientY + document.body.scrollTop;
	}	
	
	if ( targElem )
	{
		var origin = getElementOrigin( targElem );
		
		xPos = xPos - origin.x;
		yPos = yPos - origin.y;
	}
	
	return new point( xPos, yPos );
}

function findFaceForPos( faces, x, y )
{
	var result;
	
	for ( var i = 0; i < faces.length; ++i )
	{
		if ( x >= (faces[i].x - 10) && x < (faces[i].x + 10)
			 && y >= (faces[i].y - 10) && y < (faces[i].y + 10) )
		{
			result = faces[i];
			break;
		}
	}
	
	return result;
}

function getElementByIdCrossBrowser( id )
{
	var el;
	
	if ( document.getElementById )
	{
		el = document.getElementById(id);
	}
	else if ( document.all )
	{
		el = document.all[id];
	}
	
	return el;
}

function setDivText( divID, msg )
{			
	if ( document.getElementById )
	{
		var parent = document.getElementById( divID );
		var child = parent.firstChild;
		
		if ( child.nodeValue != msg )
		{
			// this forces KHTML-derived browsers to reflow
			if ( child.cloneNode && parent.replaceChild )
			{
				var new_child = child.cloneNode( false );
				new_child.nodeValue = msg;
				parent.replaceChild( new_child, child );
			}
			else
			{
				child.nodeValue = msg;
			}
		}
	}
	else if ( document.all )
	{
		document.all[divID].innerHTML = msg;
	}
}

function scrollZoomerTo( zoomableViewID, x, y )
{
	try
	{
		x_pos = parseInt( x );
		y_pos = parseInt( y );
		
		var el = getElementByIdCrossBrowser(zoomableViewID );
	
		if ( el && el.style )
		{
			el.style.left = -x + "px";
			el.style.top = -y + "px";
		}
	}
	catch( error )
	{
		if ( document.location.search && document.location.search.indexOf("debug=true") >=0  )
		{
			// debugging
			alert("Got an exception in scrollZoomerTo");
		}
	}
}

function scrollZoomerToMouse(inEvent, faces, zoomableViewID, descViewID, titleViewID)
{
	try
	{
		var name = "";
		var targetElement;
	
		var el = getTargetElement(inEvent);
		
		var hit = getTargetElementOffset( inEvent, el );


		if ( hit )
		{
			var x_pos = hit.x;
			var y_pos = hit.y;
			
			face = findFaceForPos( faces, x_pos, y_pos )
			
			if ( face )
			{
				setDivText( descViewID, face.name );
				setDivText( titleViewID, face.title );
			}
			else
			{
				if ( document.location.search && document.location.search.indexOf("debug=true") >=0  )
				{
					// debugging
					setDivText( descViewID, "X: " + x_pos + ", Y: " + y_pos );
					setDivText( titleViewID, document.location.search );
				}
				else
				{
					setDivText( descViewID, "" );
					setDivText( titleViewID, "" );
				}
					
			
			}
			
			// remember that we want the top of the scroll area to
			// be up and left of the actual mouse pos, to center 
			// the mouse
			x_pos = 4 * x_pos - 50;
			y_pos = 4 * y_pos - 50;
			
			scrollZoomerTo( zoomableViewID, x_pos, y_pos ); 
		}
		else
		{
			if ( document.location.search && document.location.search.indexOf("debug=true") >=0  )
			{
				setDivText( descViewID, "Nothing hit!" );		
			}
		}
	}
	catch( error )
	{
		if ( document.location.search && document.location.search.indexOf("debug=true") >=0  )
		{
			// debugging
			alert("Got an exception in scrollZoomerToMouse");
		}
	}
}