def modify_state_for_body(s, body):
            s.layers['segmentation'].segments = frozenset([body.segment_id])
            s.voxel_coordinates = body.bbox_start + body.bbox_size // 2
def EVT_MOUSEWHEEL(event):
  global zoomdist
  dy = event.WheelRotation
  zoomdist *= np.power(0.95, -dy)
  refresh()