横向打印图像?

我正在将控件转换为位图并打印它:

using (MemoryStream ms = new MemoryStream())
{
    chart1.SaveImage(ms, ChartImageFormat.Bmp);
    Bitmap bm = new Bitmap(ms);

    PrintDocument doc = new PrintDocument();
    doc.PrintPage += (s, ev) =>
    {
        ev.Graphics.DrawImage(bm, Point.Empty); // adjust this to put the image elsewhere
        ev.HasMorePages = false;
    };

    doc.Print();
}