svoid scrollToCenter(JScrollPane sp) {
  if (sp == null) ret;
  swing {
    var viewPort = sp.getViewport();
    Dimension viewSize = viewPort.getExtentSize();
    Dimension contentSize = viewPort.getViewSize();
    int x = max(0, contentSize.width-viewSize.width)/2;
    int y = max(0, contentSize.height-viewSize.height)/2;
    viewPort.setViewPosition(new Point(x, y));
  }
}