/**************************************************


 * dom-drag.js


 * 09.25.2001


 * www.youngpup.net


 * Script featured on Dynamic Drive (http://www.dynamicdrive.com) 12.08.2005


 **************************************************


 * 10.28.2001 - fixed minor bug where events


 * sometimes fired off the handle, not the root.


 **************************************************/





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)


	{


		updateScroll();


		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;


	}


};