srecord noeq ComponentDragger extends MouseAdapter {

  Component component;

  MouseEvent mouseDownEvent;

  Component clickedOn;

  Pt rel;

  settable bool debug;

  // bring component to front when clicked?

  settable bool bringToFront;

  *(Component *component, MouseEvent *mouseDownEvent) {}

  void start {

    if (mouseDownEvent == null) ret;

    clickedOn = mouseDownEvent.getComponent();

    if (bringToFront) {

      print("Bringing to front: " + component);

      componentToFront(component);

      repaint(getParent(component));

    }

    rel = pt(

      mouseDownEvent.getXOnScreen()-component.getX(),

      mouseDownEvent.getYOnScreen()-component.getY());

    addMouseAndMotionListener(clickedOn, this);

  }

  public void mouseDragged(MouseEvent e) {

    updatePosition(e);

  }

  public void mouseReleased(MouseEvent e) {

    if (e.getButton() != mouseDownEvent.getButton()) ret;

    updatePosition(e);

    removeMouseAdapter(clickedOn, this);

    if (debug) printVars("ComponentDragger done");

    dragDone();

  }

  void updatePosition(MouseEvent e) {

    int x = e.getXOnScreen()-rel.x, y = e.getYOnScreen()-rel.y;

    // safety

    x = max(x, 0);

    y = max(y, 0);

    updatePosition(x, y);

  }

  swappable void updatePosition(int x, int y) {

    if (debug) printVars("ComponentDragger", +rel, +x, +y);

    component.setLocation(x, y);

  }

  void dragDone {}

}