convert Text To Image

 public byte[] ChangeStringToImage(string pic)
        {
            try
            {
                //判断字符串不等于空和null
                if (pic == null || pic.Trim() == String.Empty)
                {
                    return null;
                }
                //创建一个位图对象
                Bitmap image = new Bitmap((int)Math.Ceiling((pic.Length * 20.0)), 20);
                //创建Graphics
                Graphics g = Graphics.FromImage(image);
                try
                {
                    //清空图片背景颜色
                    g.Clear(Color.White);
                    Font font = new Font("Arial", 8f, (FontStyle.Regular));
                    System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Black, Color.DarkRed, 1.2f, true);
                    g.DrawString(pic, font, brush, 2, 2);
                    //画图片的边框线
                   // g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    //image.Save("d:/001.jpg");
                    ImageFormat format = image.RawFormat;
                    using (MemoryStream ms = new MemoryStream())
                    {
                        image.Save(ms, ImageFormat.Png);
                        byte[] buffer = new byte[ms.Length];
                        //Image.Save()会改变MemoryStream的Position，需要重新Seek到Begin  
                        ms.Seek(0, SeekOrigin.Begin);
                        ms.Read(buffer, 0, buffer.Length);
                        return buffer;
                    }
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
            }
            catch (Exception)
            {
                return null;
            }
        }