!7

sclass LockMatrix > DynModule {
  transient int n;
  transient BitSet data;
  transient JComponent canvas;
  
  JComponent visualize() {
    ret awtDoEvery(canvas = JComponent() {
      public void paint(Graphics2D g) {
        int w = getWidth(), h = getHeight();
        int rows = ifloor(sqrt(n));
        if (rows == 0) fillRect(g, 0, 0, w, h, Color.white);
        int cols = (n+rows-1)/rows;
        for y to rows: {
          for x to cols: {
            fillRect(g, x1, y1, x2-x1, y2-y1, Color.white);
          }
        }
      }
    }, 1000, r updateMe);
  }
  
  void update {
    new BitSet bs;
    L l = dm_listModules();
    for i over l:
      if (getLockOwner((Lock) get(l, 'lock)) != null)
        bs.set(i);
    setFields(n := l(l), data := bs);
    repaint(canvas);
  }
}