 	import weave.api.primitives.IBounds2D;
 	import weave.api.registerLinkableChild;
 	import weave.api.setSessionState;
+	import weave.compiler.MathLib;
 	import weave.core.LinkableBoolean;
 	import weave.core.LinkableNumber;
 	import weave.core.SessionManager;

		
		private const _dataBounds:Bounds2D = new Bounds2D();
		private const _screenBounds:Bounds2D = new Bounds2D();
		private const _useCenterCoords:Boolean = false;
		private const _cc:ICallbackCollection = getCallbackCollection(this);
		
		public function getSessionState():Object
		{
			return null;

	/**
	 * This object defines the data bounds of a visualization, either directly with
	 * absolute coordinates or indirectly with center coordinates and a scale value.
	 * Screen coordinates are never directly specified in the session state.
	 * 
	 * @author adufilie
	 */
