Asp.net生成的 带燥点、滤镜效果的验证码

学习示例如下：

using System;using System.Collections.Generic;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Drawing;namespace HeFuSystem.Sys_Admin{    public partial class CheckCode : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {            Initialization();        }        private void Initialization()        {            CheckCode v = new CheckCode();            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            //Session保存验证码（此处已转化为小写）            Session["CheckCode"] = code.ToLower();        }        #region how to use the code        //aspx page        //<img id="imgVerify" src="VerifyCode.aspx?" alt="看不清？点击更换" style="cursor:pointer" onclick="this.src=this.src+'?'" /><br />        /// <summary>        /// 验证输入        /// </summary>        /// <param name="code">验证码</param>        /// <returns>是否正确</returns>        private bool Checkcode(String code)        {            if (Request.Cookies["CheckCode"] == null)                return false;//cookie不存在            if (String.Compare(Request.Cookies["CheckCode"].Value, code.Trim().ToUpper(), true) != 0)                return false;//对不起，验证码错误！            else                return true;//恭喜，验证码输入正确        }        #endregion        #region 验证码长度(默认5个验证码的长度)        int length = 5;        private 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 = 45;        private int FontSize        {            get { return fontSize; }            set { fontSize = value; }        }        #endregion        #region 边框补(默认1像素)        int padding = 0;        private int Padding        {            get { return padding; }            set { padding = value; }        }        #endregion        #region 是否输出燥点(默认输出)        bool chaos = true;        private 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;        Color chaosColor = Color.Cyan;        private Color ChaosColor        {            get { return chaosColor; }            set { chaosColor = value; }        }        #endregion        #region 自定义背景色(默认白色)        Color backgroundColor = Color.White;        private 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 };        private Color[] Colors        {            get { return colors; }            set { colors = value; }        }        #endregion        #region 自定义字体数组        string[] fonts = { "Arial", "Georgia" };        private 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 = "1,2,3,4,5,6,7,8,a,b,c,d,e,f,h,i,j,k,m,n,p,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";        private 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>        private 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        private 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        private 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        private 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;        }        private string CreateVerifyCode()        {            return CreateVerifyCode(0);        }        #endregion    }}

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