生成随机验证码图片程序

 

ashx代码

Imports  System
Imports  System.Web
Imports  System.Drawing
Imports  System.IO
Imports  System.Web.UI

Public   Class  login_validatecode :  Implements  IHttpHandler
    
#Region  "验证码的长度(默认6个)"
     Private  m_codeLenght  As   Integer   =   6

     Public   Property  CodeLenght()  As   Integer
         Get
             Return  m_codeLenght
         End   Get
         Set ( ByVal  value  As   Integer )
            m_codeLenght  =  value
         End   Set
     End Property
#End Region
#Region  "验证码的字体大小（默认13相素）"
     Private  m_fontSize  As   Integer   =   13
     Public   Property  FontSize()  As   Integer
         Get
             Return  m_fontSize
         End   Get
         Set ( ByVal  value  As   Integer )
            m_fontSize  =  value
         End   Set
     End Property
#End Region
#Region  "验证码的字体样式（默认Roman）"
     Private  m_fontFamily  As   String   =   " Roman "
     Public   Property  FontFamily()  As   String
         Get
             Return  m_fontFamily
         End   Get
         Set ( ByVal  value  As   String )
            m_fontFamily  =  value
         End   Set
     End Property
#End Region
#Region  "是否输出燥点"
     Private  m_point  As   Boolean   =   True
     Public   Property  Point()  As   Boolean
         Get
             Return  m_point
         End   Get
         Set ( ByVal  value  As   Boolean )
            m_point  =  value
         End   Set
     End Property
#End Region
#Region  "输出燥点的颜色(默认海洋蓝)"
     Private  m_pointColor  As  Color  =  Color.LightSeaGreen
     Public   Property  PointColor()  As  Color
         Get
             Return  m_pointColor
         End   Get
         Set ( ByVal  value  As  Color)
            m_pointColor  =  value
         End   Set
     End Property
#End Region
    
#Region  "图片背景噪音线数量（默认5条）"
     Private  m_lineNumber  As   Integer   =   5
     Public   Property  LineNumber()  As   Integer
         Get
             Return  m_lineNumber
         End   Get
         Set ( ByVal  value  As   Integer )
            m_lineNumber  =  value
         End   Set
     End Property
#End Region
#Region  "图片背景噪音线颜色(默认灰色)"
     Private  m_lineColor  As  Color  =  Color.LightGray
     Public   Property  LineColor()  As  Color
         Get
             Return  m_lineColor
         End   Get
         Set ( ByVal  value  As  Color)
            m_lineColor  =  value
         End   Set
     End Property
#End Region
#Region  "图片的背景颜色(默认白色)"
     Private  m_backgroundColor  As  Color  =  Color.White
     Public   Property  BackgroundColor()  As  Color
         Get
             Return  m_backgroundColor
         End   Get
         Set ( ByVal  value  As  Color)
            m_backgroundColor  =  value
         End   Set
     End Property
#End Region
    
#Region  "图片边框颜色(默认灰色)"
     Private  m_rectangleColor  As  Color  =  Color.LightGray
     Public   Property  RectangleColor()  As  Color
         Get
             Return  m_rectangleColor
         End   Get
         Set ( ByVal  value  As  Color)
            m_rectangleColor  =  value
         End   Set
     End Property
#End Region
    
#Region  "随即颜色数组"
     Private  m_colors  As  Color()  =  {Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, _
    Color.DarkCyan, Color.Purple}
     Public   Property  Colors()  As  Color()
         Get
             Return  m_colors
         End   Get
         Set ( ByVal  value  As  Color())
            m_colors  =  value
         End   Set
     End Property
#End Region
#Region  "随即字符串"
     Private  m_randomCode  As   String   =   " 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,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z "
     Public   Property  RandomCode()  As   String
         Get
             Return  m_randomCode
         End   Get
         Set ( ByVal  value  As   String )
            m_randomCode  =  value
         End   Set
     End Property
#End Region
#Region  "生成验证码图片"
     Public   Function  CreateImage( ByVal  code  As   String )  As  Bitmap
         ' 设置字体大小 
         Dim  FSize  As   Integer   =   Me .FontSize
         Dim  FWidth  As   Integer   =  FSize   '  FSize + 2
         ' 设置图片大小 
         Dim  ImgWidth  As   Integer   =   CInt ((code.Length  *  FWidth))  +  code.Length  *   2   '  CInt((code.Length * FWidth)) + 4
         Dim  ImaHeight  As   Integer   =  FSize  + 6  ‘ FSize  *   2
         ' 创建图片和画笔 
         Dim  iamge  As   New  Bitmap(ImgWidth, ImaHeight)
         Dim  gh  As  Graphics  =  Graphics.FromImage(iamge)
        gh.Clear(m_backgroundColor)
        
         ' 绘制图片的背景噪音线
         Dim  rand  As   New  Random()
         For  i  As   Integer   =   1   To  m_lineNumber
             Dim  x1  As   Integer   =  rand.Next(ImgWidth)
             Dim  x2  As   Integer   =  rand.Next(ImgWidth)
             Dim  y1  As   Integer   =  rand.Next(ImaHeight)
             Dim  y2  As   Integer   =  rand.Next(ImaHeight)
            gh.DrawLine( New  Pen(m_lineColor), x1, y1, x2, y2)
         Next
        
         ' 绘制图片边框线
        gh.DrawRectangle( New  Pen(m_rectangleColor,  1 ),  0 ,  0 , ImgWidth  -   1 , (ImaHeight  -   1 ))
         ' 绘制图片的前景噪音点
         If  m_point  Then
             For  i  As   Integer   =   0   To  m_codeLenght  *   2   -   1
                 Dim  x  As   Integer   =  rand.Next(ImgWidth)
                 Dim  y  As   Integer   =  rand.Next(ImaHeight)
                iamge.SetPixel(x, y, Color.FromArgb(rand.Next()))
             Next
             ' Me.MakePoint(gh, ImgWidth, ImaHeight)
         End   If
         ' 绘制字符串随即颜色 
        MakeFontColor(gh, code, ImaHeight, FSize)

         Return  iamge
     End Function
#End Region
#Region  "产生随即字符串"
     '''   <summary>  
     '''  返回产成的随即字符串 
     '''   </summary>  
     '''   <param name="codeLenght"> 字符串的长度 </param>  
     '''   <returns> 返回产成的随即字符串 </returns>  
     Public   Function  MakeCode( ByVal  codeLenght  As   Integer )  As   String
         Dim  splitStr  As   String ()  =  m_randomCode.Split( " , " )
         Dim  newCode  As   String   =   Nothing
         Dim  rand  As   New  Random( CType (DateTime.Now.Ticks  Mod  System.Int32.MaxValue,  Integer ))
         For  i  As   Integer   =   0   To  codeLenght  -   1
            newCode  &=  splitStr(rand.Next( 0 , splitStr.Length  -   1 ))
         Next
         Return  newCode
     End Function
#End Region
#Region  "产成字符串的随即颜色"
     Public   Sub  MakeFontColor( ByVal  g  As  Graphics,  ByVal   str   As   String ,  ByVal  imgHeight  As   Integer ,  ByVal  fontSize  As   Integer )
         Dim  b  As  Brush
         Dim  colorIndex  As   Integer
         Dim  rand  As   New  Random()
         Dim   left   As   Integer   =   0 , top  As   Integer   =   0 , top1  As   Integer   =   1 , top2  As   Integer   =   1
         Dim  n1  As   Integer   =  imgHeight  -  fontSize  -   4
         Dim  n2  As   Integer   =  n1  /   4
        top1  =  n2
        top2  =  n2  *   2
         For  i  As   Integer   =   0   To  m_codeLenght  -   1
            colorIndex  =  rand.[ Next ](m_colors.Length  -   1 )
            b  =   New  System.Drawing.SolidBrush(m_colors(colorIndex))
             If  i  Mod   2   =   1   Then
                top  =  top2
             Else
                top  =  top1
             End   If
             left   =  i  *  (fontSize)
             Dim  f  As   New  Font( Me .FontFamily,  Me .FontSize)
            g.DrawString( str .Substring(i,  1 ), f, b,  left , top)
         Next
     End Sub
#End Region
#Region  "随即产生燥点"
     '''   <summary>  
     '''  随即产生燥点 
     '''   </summary>  
     '''   <param name="g"> 画笔 </param>  
     '''   <param name="imgWidth"> 绘制的宽度 </param>  
     '''   <param name="imgHeight"> 绘制的高度 </param>  
     Public   Sub  MakePoint( ByVal  g  As  Graphics,  ByVal  imgWidth  As   Integer ,  ByVal  imgHeight  As   Integer )
         Dim  rand  As   New  Random()
         Dim  p  As   New  Pen(m_pointColor,  0 )
         For  i  As   Integer   =   0   To  m_codeLenght  *   2   -   1
             Dim  x  As   Integer   =  rand.Next(imgWidth)
             Dim  y  As   Integer   =  rand.Next(imgHeight)
            g.DrawRectangle(p, x, y,  1 ,  1 )
         Next
     End Sub
#End Region

#Region  "将绘制的图片输出到页面"
     Public   Sub  CreateImageOnPage( ByVal  code  As   String ,  ByVal  text  As  HttpContext)

         Dim  ms  As   New  MemoryStream()
         Dim  img  As  Bitmap  =  CreateImage(code)
        img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)
        text.Response.ClearContent()
        text.Response.ContentType  =   " image/Jpeg "
        text.Response.BinaryWrite(ms.GetBuffer())
        ms.Close()
        ms  =   Nothing
        img.Dispose()
        img  =   Nothing
     End Sub
#End Region
    
    
    
     Public   Sub  ProcessRequest( ByVal  context  As  HttpContext)  Implements  IHttpHandler.ProcessRequest
         Dim  gvc  As   New  login_validatecode()
        gvc.CodeLenght  =   4
        gvc.FontSize  =   13
        gvc.Point  =   False
         Dim  code  As   String   =  gvc.MakeCode(gvc.CodeLenght)  ' 获取随即字符串
        HttpContext.Current.Response.Cookies.Add( New  HttpCookie( " BBS_LOGIN_VALIDATECODE " , code))
        gvc.CreateImageOnPage(code, context)
        context.Response.End()
     End Sub
 
     Public   ReadOnly   Property  IsReusable()  As   Boolean   Implements  IHttpHandler.IsReusable
         Get
             Return   False
         End   Get
     End Property
End Class