string str="hello";  Graphics g = Graphics.FromImage(new Bitmap(1, 1));  Font font=new Font("宋体", 9);  SizeF sizeF = g.MeasureString(str, font); //测量出字体的高度和宽度  Brush brush; //笔刷，颜色  brush = Brushes.Lime;  PointF pf = new PointF(0, 0);  Bitmap img = new Bitmap(Convert.ToInt32(sizeF.Width), Convert.ToInt32(sizeF.Height));  g = Graphics.FromImage(img);  g.DrawString(str, font, brush, pf);  //输出图片  MemoryStream ms = new MemoryStream();  img.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);  Response.BinaryWrite(ms.ToArray());