C# C/S 图片验证码功能源码

         /// <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();
        }

// -----------------------------------------------------------------
// 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
    }
}

C# C/S 图片验证码功能源码

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