code: def update_position(params):
      
      cx = params.plane_x0 + params.plane_w / 2.0
      cy = params.plane_y0 + params.plane_h / 2.0
      params.mb_cx, params.mb_cy = get_coords(cx, cy, params)
docs: Computes the center of the viewport's Mandelbrot-space coordinates.
  
      :param params: Current application parameters.
      :type params: params.Params