多功能验证码的实现(带详细说明)

功能说明:
1. 可自定义字体
2. 可自定义最大字号
3. 可自定义随机旋转的角度
4. 可自定义前景随机噪色量
5. 可外部生成随机码,由VerifyCode类处理成图片
6. 可自定义数字与英文字母随机出现的比率
7. 可自定义验证码长度
8. 可自定义验证码背景色
9. 可自定义验证码色彩(噪点色同验证码色一致)
10. 可自定义字体
------------------------------
本人觉得用上随机角度就行了,不用前景噪点,因为这个东东会耗一定的资源,(下面代码可直接复制使用)
using System;
using  System.Collections.Generic;
using  System.Web;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;
using  System.IO;
using  System.Drawing;

namespace  CS.Common.Utility
{
        /**////  <summary>
        ///  Chaos验证码
        ///  FileName                        :        VerifyCode.cs      
        ///  Verion                          :              0.20
        ///  Author                          :              zhouyu  http://max.cszi.com
        ///  Update                        :              2007-10-10 51aspx.com
        ///  Description            :              验证码随机旋转一定角度,可使用前景色,背景色效果不大就不用了
        ///  </summary>
        public  class  VerifyCode
        {
                private  int  _length  =  4;                        //验证码长度
                private  int  _fontSize  =  18;              //字体最大尺寸
                private  int  _border  =  0;                      //边框，0时没有连框
                private  Color  _backgroundColor  =  Color.AliceBlue;      //背景色
                private  Color  _fontColor  =  Color.Blue;          //验证码色51aspx
                private  int  _rateNumber  =  10;              //验证码中的数字出现机率  ，越大出现的数字机率越大
                private  string  _randomChars;              //随机生成的验证码
                private  int  _randomAngle  =  40;              //随机码的旋转角度
                private  string  _fontFamily  =  "Verdana";        //字体
                private  int  _chaosNumber  =  0;                //噪点数量  ,0  时不用
                private  Random  random  =  new  Random();    //随机种子51aspx.com，公用
                public  VerifyCode()
                {
                      
                }
                /**////  <summary>
                ///  重载一  ：噪点
                ///  </summary>
                ///  <param  name="chaosNumber"></param>
                public  VerifyCode(int  chaosNumber)
                {
                        _chaosNumber  =  chaosNumber;
                }
                /**////  <summary>
                ///  重载二：长度，噪点
                ///  </summary>
                ///  <param  name="length"></param>
                ///  <param  name="chaosNumber"></param>
                public  VerifyCode(int  length,  int  chaosNumber)
                {
                        _length  =  length;
                        _chaosNumber  =  chaosNumber;
                }
                /**////  <summary>
                ///  重载三：长度，噪点，数字机率
                ///  </summary>
                ///  <param  name="length"></param>
                ///  <param  name="chaosNumber"></param>
                ///  <param  name="rate">越大，生成的随机码中数字占的比例越多</param>
                public  VerifyCode(int  length,  int  chaosNumber,  int  rate)
                {
                        _length  =  length;
                        _chaosNumber  =  chaosNumber;
                        _rateNumber  =  rate;
                }

                .Length  验证码长度(默认4个)#region  .Length  验证码长度(默认4个)
                public  int  Length
                {
                        get  {  return  _length;  }
                        set  {  _length  =  value;  }
                }
                #endregion  
                .FontSize  字体最大尺寸(默认18)#region  .FontSize  字体最大尺寸(默认18)
                public  int  FontSize
                {
                        get  {  return  _fontSize;  }
                        set  {  _fontSize  =  value;  }
                }
                #endregion  
                .Border  边框（默认0  没有连框）#region  .Border  边框（默认0  没有连框）
                public  int  Border
                {
                        get  {  return  _border;  }
                        set  {  _border  =  value;  }
                }
                #endregion
                .BackgroundColor  自定义背景色(默认Color.AliceBlue)#region  .BackgroundColor  自定义背景色(默认Color.AliceBlue)
                public  Color  BackgroundColor
                {
                        get  {  return  _backgroundColor;  }
                        set  {  _backgroundColor  =  value;  }
                }
                #endregion
                .FontColor  验证码色(默认Color.Blue)#region  .FontColor  验证码色(默认Color.Blue)
                public  Color  FontColor
                {
                        get  {  return  _fontColor;  }
                        set  {  _fontColor  =  value;  }
                }
                #endregion
                .RandomCode    随机生成的验证码#region  .RandomCode    随机生成的验证码
                public  string  RandomCode
                {
                        get  {  return  _randomChars;  }
                        set  {  _randomChars  =  value.ToUpper();  }
                }
                #endregion
                .RateNumber  验证码中的数字出现机率,越大出现的数字机率越大(默认10)#region  .RateNumber  验证码中的数字出现机率,越大出现的数字机率越大(默认10)
                public  int  RateNumber
                {
                        get  {  return  _rateNumber;  }
                        set  {  _rateNumber  =  value;  }
                }
                #endregion
                .RandomAngle  随机码的旋转角度(默认40度)#region  .RandomAngle  随机码的旋转角度(默认40度)
                public  int  RandomAngle
                {
                        get  {  return  _randomAngle;  }
                        set  {  _randomAngle  =  value;  }
                }
                #endregion
                .FontFamily  字体#region  .FontFamily  字体
                public  string  FontFamily
                {
                        get  {  return  _fontFamily;  }
                        set  {  _fontFamily  =  value;  }
                }
                #endregion
                .ChaosNumber  噪点数量(默认值为2)#region  .ChaosNumber  噪点数量(默认值为2)
                public  int  ChaosNumber
                {
                        get  {  return  _chaosNumber;  }
                        set  {  _chaosNumber  =  value;  }
                }
                #endregion


                /**////  <summary>
                ///  生成随机验证码
                ///  </summary>
                private  void  CreateCode()
                {
                        //有外部输入验证码时不用产生，否则随机生成
                        if  (!string.IsNullOrEmpty(_randomChars))
                        {  return;  }
                        char  code;
                        for  (int  i  =  0;  i  <  _length;  i++)
                        {
                                int  rand  =  random.Next();
                                if  (rand  %  _rateNumber  ==  0)
                                {  code  =  (char)(''A''  +  (char)(rand  %  26));  }
                                else
                                {  code  =  (char)(''0''  +  (char)(rand  %  10));  }
                                _randomChars  +=  code.ToString();
                        }
                }

                /**////  <summary>
                ///  背景噪点生成
                ///  </summary>
                ///  <param  name="graph"></param>
                private  void    CreateBackgroundChaos(Bitmap  map,Graphics  graph)
                {
                        Pen  blackPen  =  new  Pen(Color.Azure,  0);
                        for  (int  i  =  0;  i  <  map.Width  *  2;  i++)
                        {
                                int  x  =  random.Next(map.Width);
                                int  y  =  random.Next(map.Height);
                                graph.DrawRectangle(blackPen,  x,  y,  1,  1);
                        }
                }
                /**////  <summary>
                ///  前景色噪点
                ///  </summary>
                ///  <param  name="map"></param>
                private  void  CreaetForeChaos(Bitmap  map)
                {
                        for  (int  i  =  0;  i  <  map.Width  *  _chaosNumber;  i++)
                        {
                                int  x  =  random.Next(map.Width);
                                int  y  =  random.Next(map.Height);
                                //map.SetPixel(x,  y,  Color.FromArgb(random.Next(300)));
                                map.SetPixel(x,  y,  _fontColor);
                        }
                }

                /**////  <summary>
                ///  创建随机码图片
                ///  </summary>
                ///  <param  name="context"></param>
                public  void  CreateImage(HttpContext  context)
                {
                        CreateCode();          //创建验证码
                        Bitmap  map  =  new  Bitmap((int)(_randomChars.Length  *  15),  24);                            //创建图片背景
                        Graphics  graph  =  Graphics.FromImage(map);
                        //graph.FillRectangle(new  SolidBrush(Color.Black),  0,  0,  map.Width+1,  map.Height+1);          //填充一个有背景的矩形
                        
                        //if  (_border  >  0)  //画一个边框
                        //{         
                        //        graph.DrawRectangle(new  Pen(Color.Black,  0),  0,  0,  map.Width  -  _border,  map.Height  -  _border);
                        //}
                        //graph.SmoothingMode  =  System.Drawing.Drawing2D.SmoothingMode.AntiAlias;        //模式
                        graph.Clear(_backgroundColor);              //清除画面，填充背景
                        SolidBrush  brush  =  new  SolidBrush(_fontColor);    //画笔
                        Point  dot  =  new  Point(12,  12);
                        //CreateBackgroundChaos(map,graph);              //背景噪点生成
                        CreaetForeChaos(map);              //前景色噪点
                        //文字距中
                        StringFormat  format  =  new  StringFormat(StringFormatFlags.NoClip);
                        format.Alignment  =  StringAlignment.Center;
                        format.LineAlignment  =  StringAlignment.Center;
                        //验证码旋转，防止机器识别
                        char  chars  =  _randomChars.ToCharArray();            //拆散字符串成单字符数组
                        for  (int  i  =  0;  i  <  chars.Length;  i++)
                        {
                                Font  fontstyle  =  new  Font(_fontFamily,  random.Next(_fontSize  -  3,  _fontSize),  FontStyle.Regular);            //字体样式
                                float  angle  =  random.Next(-_randomAngle,  _randomAngle);            //转动的度数
                                graph.TranslateTransform(dot.X,  dot.Y);          //移动光标到指定位置
                                graph.RotateTransform(angle);
                                graph.DrawString(chars[i].ToString(),  fontstyle,  brush,  -2,  2,  format);
                                graph.RotateTransform(-angle);                    //转回去
                                graph.TranslateTransform(2,  -dot.Y);          //移动光标到指定位置
                        }
                      
                        //生成图片
                        MemoryStream  ms  =  new  MemoryStream();
                        map.Save(ms,  System.Drawing.Imaging.ImageFormat.Gif);
                        context.Response.ClearContent();
                        context.Response.ContentType  =  "image/gif";
                        context.Response.BinaryWrite(ms.ToArray());
                        graph.Dispose();
                        map.Dispose();
                }




        }


}
使用方法:


using System;
using  System.Data;
using  System.Configuration;
using  System.Collections;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;
using  CS.Common.Utility;
namespace  Test
{
        public  partial  class  Vcode  :  System.Web.UI.Page
        {
                protected  void  Page_Load(object  sender,  EventArgs  e)
                {
                        VerifyCode  vcode  =  new  VerifyCode();
                        vcode.CreateImage(base.Context);
                        Session["VerifyCode"]  =  vcode.RandomCode;
                    
                }
        }
}