idt wid rom get image object from bitmap color

/// <summary>
/// 改變鼠標指針
/// </summary>
/// <param name="cursor"></param>
/// <param name="hotPoint"></param>
public void SetCursor(Bitmap cursor, Point hotPoint)
{
int hotX = hotPoint.X;
int hotY = hotPoint.Y;
Bitmap myNewCursor = new Bitmap(cursor.Width * 2 - hotX, cursor.Height * 2 - hotY);
Graphics g = Graphics.FromImage(myNewCursor);
g.Clear(Color.FromArgb(0, 0, 0, 0));
g.DrawImage(cursor, cursor.Width - hotX, cursor.Height - hotY-21, cursor.Width, cursor.Height);
this.Cursor = new Cursor(myNewCursor.GetHicon());
g.Dispose();
myNewCursor.Dispose();
}

private void pic_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
Bitmap bm = (Bitmap)Bitmap.FromFile("鋼筆2_03.png");
SetCursor(bm, new Point(0, 0));
}
}

private void pic_MouseUp(object sender, MouseEventArgs e)
{
Cursor = Cursors.Default;
}

自定義鼠標指針