C# 彩色验证码

using System.Drawing;

 

public partial class VerifyCode : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

                VerifyCode v = new VerifyCode();

                v.Length = this.length;
                v.FontSize = this.fontSize;
                v.Chaos = this.chaos;
                v.BackgroundColor = this.backgroundColor;
                v.ChaosColor = this.chaosColor;
                v.CodeSerial = this.codeSerial;
                v.Colors = this.colors;
                v.Fonts = this.fonts;
                v.Padding = this.padding;
                string code = v.CreateVerifyCode();                //取随机码
                v.CreateImageOnPage(code, this.Context);        // 输出图片

                Response.Cookies.Add(new HttpCookie("CheckCode", code.ToUpper()));// 使用Cookies取验证码的值

        }

        #region 验证码长度(默认6个验证码的长度)
        int length = 6;
        public int Length
        {
            get{ return length; }
            set{ length = value; }
        }
        #endregion

        #region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)
        int fontSize =40;
        public int FontSize
        {
            get{ return fontSize; }
            set{ fontSize = value; }
        }
        #endregion

        #region 边框补(默认1像素)
        int padding = 2;
        public int Padding
        {
            get{ return padding; }
            set{ padding = value; }
        }
        #endregion

        #region 是否输出燥点(默认不输出)
        bool chaos = true;
        public bool Chaos
        {
            get{ return chaos; }
            set{ chaos = value; }
        }
        #endregion

        #region 输出燥点的颜色(默认灰色)
        Color chaosColor = Color.LightGray;
        public Color ChaosColor
        {
            get{ return chaosColor; }
            set{ chaosColor = value; }
        }
        #endregion

        #region 自定义背景色(默认白色)
        Color backgroundColor = Color.White;
        public Color BackgroundColor
        {
            get{ return backgroundColor; }
            set{ backgroundColor = value; }
        }
        #endregion

        #region 自定义随机颜色数组
        Color[] colors = {Color.Black,Color.Red,Color.DarkBlue,Color.Green,Color.Orange,Color.Brown,Color.DarkCyan,Color.Purple};
        public Color[] Colors
        {
            get{ return colors; }
            set{ colors = value; }
        }
        #endregion

        #region 自定义字体数组
        string[] fonts = {"Arial", "Georgia"};
        public string[] Fonts
        {
            get{ return fonts; }
            set{ fonts = value; }
        }
        #endregion

        #region 自定义随机码字符串序列(使用逗号分隔)
        string codeSerial = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
        public string CodeSerial
        {
            get{ return codeSerial; }
            set{ codeSerial = value; }
        }
        #endregion

        #region 产生波形滤镜效果

        private const double PI = 3.1415926535897932384626433832795;
        private const double PI2 = 6.283185307179586476925286766559;

        /// <summary>
        /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
        /// </summary>
        /// <param name="srcBmp">图片路径</param>
        /// <param name="bXDir">如果扭曲则选择为True</param>
        /// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
        /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
        /// <returns></returns>
        public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
        {
            System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

            // 将位图背景填充为白色
            System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
            graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
            graph.Dispose();

            double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

            for (int i = 0; i < destBmp.Width; i++)
            {
                for (int j = 0; j < destBmp.Height; j++)
                {
                    double dx = 0;
                    dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
                    dx += dPhase;
                    double dy = Math.Sin(dx);

                    // 取得当前点的颜色
                    int nOldX = 0, nOldY = 0;
                    nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                    nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                    System.Drawing.Color color = srcBmp.GetPixel(i, j);
                    if (nOldX >= 0 && nOldX < destBmp.Width
                     && nOldY >= 0 && nOldY < destBmp.Height)
                    {
                        destBmp.SetPixel(nOldX, nOldY, color);
                    }
                }
            }

            return destBmp;
        }



        #endregion

        #region 生成校验码图片
        public Bitmap CreateImageCode(string code)
        {
            int fSize    = FontSize;
            int fWidth  = fSize + Padding;

            int imageWidth        = (int)(code.Length * fWidth) + 4 + Padding * 2;
            int imageHeight        = fSize *2 + Padding;

            System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);

            Graphics g = Graphics.FromImage(image);

            g.Clear(BackgroundColor);

            Random rand = new Random();

            //给背景添加随机生成的燥点
            if(this.Chaos)
            {

                Pen pen = new Pen(ChaosColor, 0);
                int c = Length * 10;

                for(int i=0;i<c;i++)
                {
                    int x = rand.Next(image.Width);
                    int y = rand.Next(image.Height);

                    g.DrawRectangle(pen, x, y, 1, 1);
                }
            }

            int left    = 0 , top = 0, top1 = 1, top2 = 1;

            int n1        = (imageHeight - FontSize - Padding * 2);
            int n2        = n1/4;
            top1        = n2;
            top2        = n2 *2;
            
            Font f;
            Brush b;

            int cindex, findex;

            //随机字体和颜色的验证码字符
            for(int i=0; i<code.Length; i++)
            {
                cindex = rand.Next(Colors.Length - 1);
                findex = rand.Next(Fonts.Length - 1);
                
                f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
                b = new System.Drawing.SolidBrush(Colors[cindex]);

                if( i%2 == 1 )
                {
                    top = top2;
                }
                else
                {
                    top = top1;
                }

                left = i * fWidth;

                g.DrawString(code.Substring(i,1), f, b, left, top);
            }

            //画一个边框 边框颜色为Color.Gainsboro
            g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
            g.Dispose();

            //产生波形（Add By 51aspx.com）
            image=TwistImage(image, true, 8, 4);

            return image;
        }
        #endregion

        #region 将创建好的图片输出到页面
        public void CreateImageOnPage(string code, HttpContext context)
        {
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            Bitmap image = this.CreateImageCode(code);

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

            context.Response.ClearContent();
            context.Response.ContentType = "image/Jpeg";
            context.Response.BinaryWrite(ms.GetBuffer());

            ms.Close();
            ms = null;
            image.Dispose();
            image = null;
        }
        #endregion

        #region 生成随机字符码
        public string CreateVerifyCode(int codeLen)
        {
            if(codeLen == 0)
            {
                codeLen = Length;
            }

            string[] arr = CodeSerial.Split(',');

            string code = "";

            int randValue = -1;

            Random rand = new Random(unchecked((int)DateTime.Now.Ticks));

            for(int i=0; i<codeLen; i++)
            {
                randValue = rand.Next(0, arr.Length -1);

                code += arr[randValue];
            }

            return code;
        }
        public string CreateVerifyCode()
        {
            return CreateVerifyCode(0);
        }
        #endregion

    }