code: def _showxy(self, viewer, data_x, data_y):
          
          self._cursor_last_update = time.time()
          try:
              image = viewer.get_image()
              if (image is None) or not isinstance(image, BaseImage.BaseImage):
                  # No compatible image loaded for this channel
                  return
  
              settings = viewer.get_settings()
              info = image.info_xy(data_x, data_y, settings)
  
              # Are we reporting in data or FITS coordinates?
              off = self.settings.get('pixel_coords_offset', 0.0)
              info.x += off
              info.y += off
  
          except Exception as e:
              self.logger.warning(
                  "Can't get info under the cursor: %s" % (str(e)))
              return
  
          # TODO: can this be made more efficient?
          chname = self.get_channel_name(viewer)
          channel = self.get_channel(chname)
  
          self.make_callback('field-info', channel, info)
  
          self.update_pending()
          return True
docs: Update the info from the last position recorded under the cursor.