code: protected final void update() {
  		BufferedImage image=getImageViewer()==null ? null : getImageViewer().getImage();
  		if (image==null || model.isInvalid() || model.getX()>=image.getWidth() || model.getY()>=image.getHeight())
  			updateLabelNoData();
  		else
  			updateLabel(image, model.getX(), model.getY(), statusBar.getWidth()-statusBarInsets.left-statusBarInsets.right);
  	}
docs: Updates the info label. This function is called when either the selected pixel
  or the image shown in the viewer is changed. You can call this method to indicate
  that the message should be updated for some different reason.