code: public void registerFont (String name, java.awt.Font font) {
      if (font == null) throw new NullPointerException();
      fonts.put(name, font);
    }
docs: Registers a font with the graphics system.
  
  @param name the name under which to register the font.
  @param font the Java font, which can be loaded from a path via {@link JavaAssets#getFont}.