code: def redraw_data(self, whence=0):
          
          if not self._imgwin_set:
              # window has not been realized yet
              return
  
          if not self._self_scaling:
              rgbobj = self.get_rgb_object(whence=whence)
              self.renderer.render_image(rgbobj, self._dst_x, self._dst_y)
  
          self.private_canvas.draw(self)
  
          self.make_callback('redraw', whence)
  
          if whence < 2:
              self.check_cursor_location()
docs: Render image from RGB map and redraw private canvas.
  
          .. note::
  
              Do not call this method unless you are implementing a subclass.
  
          Parameters
          ----------
          whence
              See :meth:`get_rgb_object`.