C#验证码

    /// <summary>
    ///验证码
    /// </summary>
    public class VerifyCode
    {
        /// <summary>
        /// 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 )
        /// </summary>
        int FontSize = 40;

        /// <summary>
        /// 文字间距
        /// </summary>
        int Padding = 3;

        /// <summary>
        /// 自定义背景色 ( 默认白色 )
        /// </summary>
        Color BackgroundColor = Color.White;

        /// <summary>
        /// 自定义随机颜色数组
        /// </summary>
        Color[] Colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
        /// <summary>
        /// 自定义字体数组
        /// </summary>
        string[] Fonts = { "Arial", "Georgia", "courier new" };


        /// <summary>
        /// 自定义随机码字符串序列 ( 使用逗号分隔 )
        /// </summary>
        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";

        #region 产生波形滤镜效果
        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="dMultValue"> 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 byte[] TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
        {
            using (Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height))
            {
                // 将位图背景填充为白色
                using (Graphics graph = Graphics.FromImage(destBmp))
                {
                    graph.FillRectangle(new SolidBrush(Color.White), 0, 0, destBmp.Width, destBmp.Height);
                    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 = (bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen) + dPhase;
                            double dy = Math.Sin(dx);
                            // 取得当前点的颜色 
                            int nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                            int nOldY = bXDir ? j : j + (int)(dy * dMultValue);
                            Color color = srcBmp.GetPixel(i, j);
                            if (nOldX >= 0 && nOldX < destBmp.Width && nOldY >= 0 && nOldY < destBmp.Height)
                            {
                                destBmp.SetPixel(nOldX, nOldY, color);
                            }
                        }
                    }
                }
                using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
                {
                    destBmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                    return ms.GetBuffer();
                }
            }
        }
        #endregion
        #region 生成校验码图片
        public byte[] CreateImageCode(int codeLen = 6)
        {
            string code = CreateVerifyCode(codeLen);
            int fSize = FontSize;
            int fWidth = fSize + Padding;
            int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
            int imageHeight = fSize * 2 + Padding;
            using (Bitmap image = new Bitmap(imageWidth, imageHeight))
            {
                using (Graphics g = Graphics.FromImage(image))
                {
                    g.Clear(BackgroundColor);
                    Random rand = new Random();
                    int left = 0, top = 0;
                    int n1 = (imageHeight - FontSize - Padding * 2);
                    int n2 = n1 / 4;
                    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 Font(Fonts[findex], fSize, FontStyle.Bold);
                        b = new SolidBrush(Colors[cindex]);
                        if (i % 2 == 1)
                        {
                            top = n2 * 2;
                        }
                        else
                        {
                            top = n2;
                        }
                        left = i * fWidth;
                        g.DrawString(code.Substring(i, 1), f, b, left, top);
                    }
                }
                // 产生波形
                return TwistImage(image, true, 8, 4);
            }
        }
        #endregion 
        #region 生成随机字符码
        public string CreateVerifyCode(int codeLen)
        {
            string[] arr = CodeSerial.Split(',');
            string code = "";
            Random rand = new Random(unchecked((int)DateTime.Now.Ticks));
            for (int i = 0; i < codeLen; i++)
            {
                code += arr[rand.Next(0, arr.Length - 1)];
            }
            return code;
        }
        #endregion
    }