C＃的彩色验证码

private void CreateImage(string checkCode)



        {

            int iwidth = (int)(checkCode.Length * 15);

            System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 25);

            Graphics g = Graphics.FromImage(image);

            g.Clear(Color.White);

//定义颜色

            Color[] c = {Color.Black,Color.Red,Color.DarkBlue,Color.Green,Color.Orange,Color.Brown,Color.DarkCyan,Color.Purple};

//定义字体

            string[] font = {"Verdana","Microsoft Sans Serif","Comic Sans MS","Arial","宋体"};

            Random rand = new Random();

//随机输出噪点

            for(int i=0;i<50;i++)

            {

                int x = rand.Next(image.Width);

                int y = rand.Next(image.Height);

                g.DrawRectangle(new Pen(Color.LightGray, 0),x,y,1,1);

            }



//输出不同字体和颜色的验证码字符

            for(int i=0;i<checkCode.Length;i++)

            {

                int cindex = rand.Next(7);

                int findex = rand.Next(5);

                

                Font f = new System.Drawing.Font(font[findex], 10, System.Drawing.FontStyle.Bold);

                Brush b = new System.Drawing.SolidBrush(c[cindex]);

                int ii=4;

                if((i+1)%2==0)

                {

                    ii=2;

                }

                g.DrawString(checkCode.Substring(i,1), f, b, 3+(i*12), ii);

            }

//画一个边框

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



//输出到浏览器

            System.IO.MemoryStream ms = new System.IO.MemoryStream();

            image.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);

            Response.ClearContent();

            Response.ContentType = "image/Jpeg";

            Response.BinaryWrite(ms.ToArray());

            g.Dispose();

            image.Dispose();

        }