有验证码的登陆界面（ajax,ashx技术制作）(3)

            // 随机线条
            Pen linePen = new Pen(Color.Gray, 0);
            Random rand = new Random();
            for (int i = 0; i < 5; i++)
            {
                int x1 = rand.Next(image.Width);
                int y1 = rand.Next(image.Height);
                int x2 = rand.Next(image.Width);
                int y2 = rand.Next(image.Height);
                g.DrawLine(linePen, x1, y1, x2, y2);
            }

            // 随机点
            for (int i = 0; i < 30; i++)
            {
                int x = rand.Next(image.Width);
                int y = rand.Next(image.Height);
                image.SetPixel(x, y, Color.Gray);
            }

            // 边框
            g.DrawRectangle(new Pen(Color.Gray), 0, 0, image.Width - 1, image.Height - 1);

            // 输出图片
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            context.Response.ClearContent();
            context.Response.ContentType = "image/Jpeg";
            context.Response.BinaryWrite(ms.ToArray());
            g.Dispose();
            image.Dispose();
        }