var Drag = {

	obj : null,

	init : function(o, oRoot, minX, maxX, minY, maxY, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper)
	{
		o.onmousedown	= Drag.start;

		o.hmode			= bSwapHorzRef ? false : true ;
		o.vmode			= bSwapVertRef ? false : true ;

		o.root = oRoot && oRoot != null ? oRoot : o ;

		if (o.hmode  && isNaN(parseInt(o.root.style.left  ))) o.root.style.left   = "0px";
		if (o.vmode  && isNaN(parseInt(o.root.style.top   ))) o.root.style.top    = "0px";
		if (!o.hmode && isNaN(parseInt(o.root.style.right ))) o.root.style.right  = "0px";
		if (!o.vmode && isNaN(parseInt(o.root.style.bottom))) o.root.style.bottom = "0px";

		o.minX	= typeof minX != 'undefined' ? minX : null;
		o.minY	= typeof minY != 'undefined' ? minY : null;
		o.maxX	= typeof maxX != 'undefined' ? maxX : null;
		o.maxY	= typeof maxY != 'undefined' ? maxY : null;

		o.xMapper = fXMapper ? fXMapper : null;
		o.yMapper = fYMapper ? fYMapper : null;

		o.root.onDragStart	= new Function();
		o.root.onDragEnd	= new Function();
		o.root.onDrag		= new Function();
	},

	start : function(e)
	{
		var o = Drag.obj = this;
		e = Drag.fixE(e);
		var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom);
		var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right );
		o.root.onDragStart(x, y);

		o.lastMouseX	= e.clientX;
		o.lastMouseY	= e.clientY;

		if (o.hmode) {
			if (o.minX != null)	o.minMouseX	= e.clientX - x + o.minX;
			if (o.maxX != null)	o.maxMouseX	= o.minMouseX + o.maxX - o.minX;
		} else {
			if (o.minX != null) o.maxMouseX = -o.minX + e.clientX + x;
			if (o.maxX != null) o.minMouseX = -o.maxX + e.clientX + x;
		}

		if (o.vmode) {
			if (o.minY != null)	o.minMouseY	= e.clientY - y + o.minY;
			if (o.maxY != null)	o.maxMouseY	= o.minMouseY + o.maxY - o.minY;
		} else {
			if (o.minY != null) o.maxMouseY = -o.minY + e.clientY + y;
			if (o.maxY != null) o.minMouseY = -o.maxY + e.clientY + y;
		}

		document.onmousemove	= Drag.drag;
		document.onmouseup		= Drag.end;

		return false;
	},

	drag : function(e)
	{
		e = Drag.fixE(e);
		var o = Drag.obj;

		var ey	= e.clientY;
		var ex	= e.clientX;
		var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom);
		var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right );
		var nx, ny;

		if (o.minX != null) ex = o.hmode ? Math.max(ex, o.minMouseX) : Math.min(ex, o.maxMouseX);
		if (o.maxX != null) ex = o.hmode ? Math.min(ex, o.maxMouseX) : Math.max(ex, o.minMouseX);
		if (o.minY != null) ey = o.vmode ? Math.max(ey, o.minMouseY) : Math.min(ey, o.maxMouseY);
		if (o.maxY != null) ey = o.vmode ? Math.min(ey, o.maxMouseY) : Math.max(ey, o.minMouseY);

		nx = x + ((ex - o.lastMouseX) * (o.hmode ? 1 : -1));
		ny = y + ((ey - o.lastMouseY) * (o.vmode ? 1 : -1));

		if (o.xMapper)		nx = o.xMapper(y)
		else if (o.yMapper)	ny = o.yMapper(x)

		Drag.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";
		Drag.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";
		Drag.obj.lastMouseX	= ex;
		Drag.obj.lastMouseY	= ey;

		Drag.obj.root.onDrag(nx, ny);
		return false;
	},

	end : function()
	{
		document.onmousemove = null;
		document.onmouseup   = null;
		Drag.obj.root.onDragEnd(	parseInt(Drag.obj.root.style[Drag.obj.hmode ? "left" : "right"]), 
									parseInt(Drag.obj.root.style[Drag.obj.vmode ? "top" : "bottom"]));
		Drag.obj = null;
	},

	fixE : function(e)
	{
		if (typeof e == 'undefined') e = window.event;
		if (typeof e.layerX == 'undefined') e.layerX = e.offsetX;
		if (typeof e.layerY == 'undefined') e.layerY = e.offsetY;
		return e;
	}
};


function Point(x, y) {  
  this.x = x;
  this.y = y;
  }
function getOffsetXY(obj) {  
  var xPos = obj.offsetLeft;
  var yPos = obj.offsetTop;
  var parent = obj.offsetParent;
  while (parent != null) {
    xPos += parent.offsetLeft;
    yPos += parent.offsetTop;
    parent = parent.offsetParent;
    }
  return new Point(xPos, yPos);
  }
function boxmoveTo(obj, x, y) {  
  obj.style.left = x + "px";
  obj.style.top = y + "px";
  }
function getOffsetX(obj) {  
  var xPos = obj.offsetLeft;
  var parent = obj.offsetParent;
  while (parent != null) {
    xPos += parent.offsetLeft;
    parent = parent.offsetParent;
    }
  return xPos;
  }
function getOffsetY(obj) {  
  var yPos = obj.offsetTop;
  var parent = obj.offsetParent;
  while (parent != null) {
    yPos += parent.offsetTop;
    parent = parent.offsetParent;
    }
  return yPos;
  }
function windowOffsetX() {  
  if (window.screenX) return window.screenX + (window.outerWidth-window.innerWidth) - window.pageXOffset;
  else return document.body.scrollLeft + window.screenLeft;
  }
function windowOffsetY() {  
  if (window.screenY) return window.screenY + (window.outerHeight-24-window.innerHeight) - window.pageYOffset;
  else return document.body.scrollTop + window.screenTop;
  }
function getChromeY() {  
  return window.screenTop ? window.screenTop : (window.outerHeight - window.innerHeight - 24);
  }      
function divOnScrn(divOnScrn) {
  var divPos = getOffsetXY(divOnScrn);
  var newX = divPos.x;
  var newY = divPos.y;
  if (divPos.x + divOnScrn.offsetWidth - document.body.scrollLeft > document.body.clientWidth) newX = document.body.scrollLeft + document.body.clientWidth - divOnScrn.offsetWidth;
  if (divPos.x < document.body.scrollLeft) newX = document.body.scrollLeft;
  if (divPos.y + divOnScrn.offsetHeight - document.body.scrollTop > document.body.clientHeight) newY = document.body.scrollTop + document.body.clientHeight - divOnScrn.offsetHeight;
  if (divPos.y < document.body.scrollTop) newY = document.body.scrollTop;
  if ((newX != divPos.x) || (newY != divPos.y)) boxmoveTo(divOnScrn, newX, newY);
  }