Draw the screen area.

def draw_screen(self, surf):
    """Draw the screen area."""
    # surf.fill(colors.black)
    if (self._render_rgb and self._obs.observation.HasField("render_data") and
        self._obs.observation.render_data.HasField("map")):
      self.draw_rendered_map(surf)
    else:
      self.draw_base_map(surf)
      self.draw_units(surf)
    self.draw_selection(surf)
    self.draw_build_target(surf)
    self.draw_overlay(surf)
    self.draw_commands(surf)
    self.draw_panel(surf)