C# Graphics 字体倒置

还没知道设置倒置方向

Graphics g = e.Graphics;
SolidBrush brush = new SolidBrush(Color.FromArgb(50, 50, 50));
StringFormat fmC = new StringFormat();
fmC.Alignment = StringAlignment.Center;
fmC.FormatFlags = StringFormatFlags.DirectionVertical;
Font font = new Font(@"宋体", 8, FontStyle.Regular);
Rectangle rcTmp = new Rectangle(30, this.Height - timeHeight, 30, timeHeight);
g.DrawString("2013-12", font, brush, rcTmp, fmC);