private void getNewOffscreen() {
		log.logln(LogL.GUI_SEQ, "GraphPanel.getNewOffscreen: Allocating a new offscreen image.");
		imageSizeX = getWidth();
		imageSizeY = getHeight();
		offscreen = null;
		if(imageSizeX > 0 && imageSizeY > 0) {
			// update the transformation object 
			pt.setWidth(imageSizeX);
			pt.setHeight(imageSizeY);
			offscreen = createImage(imageSizeX, imageSizeY);
			newOffscreen = true;
		}
	}