C# C/S 图片验证码功能源码

运行效果如图

用法如下:

        /// <summary>
        /// 显示验证码
        /// </summary>
        /// <returns>验证码</returns>
        private void GetVerifyCode()
        {
            VerifyCodeImage verifyCodeImage = new VerifyCodeImage();
            // 取随机码
            string code = verifyCodeImage.CreateVerifyCode().ToUpper();
            // 输出图片
            this.picVerifyCode.Image = verifyCodeImage.CreateImage(code, 3);
            this.picVerifyCode.Tag = code;
        }

 

        private void picVerifyCode_DoubleClick(object sender, EventArgs e)
        {
            this.GetVerifyCode();
            // this.txtVerifyCode.Clear();
            this.txtVerifyCode.SelectAll();
            this.txtVerifyCode.Focus();
        }

 

源码如下:

//-----------------------------------------------------------------
// All Rights Reserved , Copyright (C) 2011 , Hairihan TECH, Ltd. 
//-----------------------------------------------------------------

using System;
using System.Drawing;
using System.Web;

namespace DotNet.Utilities
{
    public class VerifyCodeImage
    {
        public VerifyCodeImage()
        {
        }

        #region 验证码长度(默认4个验证码的长度)
        int length = 4;
        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 = 50;
        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)
        //  去除 0,1,i,l,o,I,L,O
        string codeSerial = "2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,J,K,M,N,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 bitmap = new Bitmap(srcBmp.Width, srcBmp.Height);

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

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

            for (int i = 0; i < bitmap.Width; i++)
            {
                for (int j = 0; j < bitmap.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 < bitmap.Width
                     && nOldY >= 0 && nOldY < bitmap.Height)
                    {
                        bitmap.SetPixel(nOldX, nOldY, color);
                    }
                }
            }
            return bitmap;
        }
        #endregion

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

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

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

            Graphics graphics = Graphics.FromImage(bitmap);

            graphics.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(bitmap.Width);
                    int y = rand.Next(bitmap.Height);

                    graphics.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 font;
            Brush brush;

            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);

                font = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
                brush = new System.Drawing.SolidBrush(Colors[cindex]);

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

                left = i * fWidth;

                graphics.DrawString(code.Substring(i, 1), font, brush, left, top);
            }

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

            // 产生波形
            bitmap = TwistImage(bitmap, true, multValue, 4);

            return bitmap;
        }
        #endregion

        #region 生成随机字符码
        public string CreateVerifyCode(int codeLength)
        {
            if (codeLength == 0)
            {
                codeLength = Length;
            }
            string[] arr = CodeSerial.Split(',');
            string code = "";
            int randValue = -1;
            Random random = new Random(unchecked((int)DateTime.Now.Ticks));
            for (int i = 0; i < codeLength; i++)
            {
                randValue = random.Next(0, arr.Length - 1);
                code += arr[randValue];
            }
            return code;
        }

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


        #region 将创建好的图片输出到页面
        /// <summary>
        /// 将创建好的图片输出到页面
        /// </summary>
        /// <param name="code">验证码</param>
        /// <param name="multValue">扭曲度(越大越扭曲)</param>
        /// <param name="httpContext">上下文</param>
        public void CreateImageOnPage(string code, double multValue, HttpContext httpContext)
        {
            System.IO.MemoryStream memoryStream = new System.IO.MemoryStream();
            Bitmap bitmap = this.CreateImage(code, multValue);
            bitmap.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            httpContext.Response.ClearContent();
            httpContext.Response.ContentType = "image/Jpeg";
            httpContext.Response.BinaryWrite(memoryStream.GetBuffer());

            memoryStream.Close();
            memoryStream = null;
            bitmap.Dispose();
            bitmap = null;
        }
        #endregion
    }
}