private void UpdateLabel()
    {
        labelNum = stack != null ? stack.Count : -1;
        Vector2 position = index != -1 ?
                           rect.Position + SIZE / 2 :
                           rect.Position;

        if (labelNum <= 1)
        {
            labelChild.Hide();
        }
        else
        {
            labelChild.Text = "" + labelNum;
            labelChild.Show();
        }
    }
 public override void OnHover()
 {
     hoverLabel.Show();
 }