// This class uses the border of the component that caught
// the mouse event to determine the drag direction.

sclass WindowResizeDragger extends MouseAdapter {
  int cornerSize = 10; // how big do we assume the corners are
  
  MouseEvent mouseDownEvent;
  JComponent src;
  Window window;
  Rect originalPosition;
  int dragX, dragY; // -1, 0 or 1 depending on what we are dragging
  
  *(MouseEvent *mouseDownEvent) {
    if (mouseDownEvent == null) ret;
    src = optCast JComponent(mouseDownEvent.getComponent());
    if (src == null) ret;
    window = getWindow(src);
    if (window == null) ret;
    
    srcBounds = toRect(boundsOnScreen(src));
    originalPosition = toRect(getBounds(window));
    
    Pt mouse = pt(mouseDownEvent.getXOnScreen(), mouseDownEvent.getYOnScreen());
    
    if (distance(mouse.y, srcBounds.y2()) <= cornerSize)
      dragY = 1;
    else if (distance(mouse.y, srcBounds.y1()) <= cornerSize)
      dragY = -1;
    
    if (distance(mouse.x, srcBounds.x2()) <= cornerSize)
      dragX = 1;
    else if (distance(mouse.x, srcBounds.x1()) <= cornerSize)
      dragX = -1;
    
    addMouseAndMotionListener(src, this);
  }

  public void mouseDragged(MouseEvent e) {
    updatePosition(e);
  }
  
  public void mouseReleased(MouseEvent e) {
    if (e.getButton() != mouseDownEvent.getButton()) ret;
    updatePosition(e);
    removeMouseAdapter(window, this);
    dragDone();
  }
  
  void updatePosition(MouseEvent e) {
    Rect w = toRect(window.getBounds());
    Pt a = topLeftCorner(w), b = bottomRightCorner(w);
    Pt mouse = pt(mouseDownEvent.getXOnScreen(), mouseDownEvent.getYOnScreen());
    
    if (dragX < 0)
      a.x = mouse.x + originalPosition.x - mouseDownEvent.getXOnScreen();
    else
      b.x = mouse.x + originalPosition.x2() - mouseDownEvent.getXOnScreen();
      
    if (dragY < 0)
      a.y = mouse.y + originalPosition.y - mouseDownEvent.getYOnScreen();
    else
      b.y = mouse.y + originalPosition.y2() - mouseDownEvent.getYOnScreen();
      
    window.setBounds(toRectangle(rectFromPoints(a, b)));
  }
  
  void dragDone {}
}