//public class DrawingTagHandler{
@Override
protected String getSubstitution(FormEntrySession session, FormSubmissionController controllerActions,
Map<String, String> parameters) throws BadFormDesignException {
DrawingSubmissionElement element = new DrawingSubmissionElement(session.getContext(), parameters);
session.getSubmissionController().addAction(element);
return element.generateHtml(session.getContext());
}