Swing/ResizableComponents のバックアップ(No.13)

@Override public void mouseDragged(MouseEvent e) {
  if (startPos == null || startingBounds == null) return;
  Point p = SwingUtilities.convertPoint(e.getComponent(), e.getX(), e.getY(), null);
  int deltaX = startPos.x - p.x;
  int deltaY = startPos.y - p.y;
  int newX = getX();
  int newY = getY();
  int newW = getWidth();
  int newH = getHeight();

  JComponent parent = (JComponent) getParent();
  Rectangle parentBounds = parent.getBounds();
  Dimension min = new Dimension(50, 50);
  Dimension max = new Dimension(500, 500);

  switch (cursor) {
    case Cursor.N_RESIZE_CURSOR: {
      if (startingBounds.height + deltaY < min.height) {
        deltaY = -(startingBounds.height - min.height);
      } else if (startingBounds.height + deltaY > max.height) {
        deltaY = max.height - startingBounds.height;
      }
      if (startingBounds.y - deltaY < 0) {
        deltaY = startingBounds.y;
      }
      newX = startingBounds.x;
      newY = startingBounds.y - deltaY;
      newW = startingBounds.width;
      newH = startingBounds.height + deltaY;
      break;
    }
    case Cursor.NE_RESIZE_CURSOR: {
      if (startingBounds.height + deltaY < min.height) {
        deltaY = -(startingBounds.height - min.height);
// ...