Randomly generate 6-bit image verification code

<summary>///PicHandler1 Summary description///</summary> public class Pichandler1:ihttphandler, irequires sessionstate {private String mcheckno = String.        Empty;        protected Imgbuilder _imgbuilder = new Imgbuilder ();        protected Vryimggen _imgbuildernew = new Vryimggen (); private string _text = String.        Empty;        private String _font = "Song Body";        private int _fontsize = 8;        private int _padding = 2;            public void ProcessRequest (HttpContext context) {Mcheckno = Discheckno (); Context.            session["Checkcode"] = Mcheckno;            This._imgbuilder.fontsize = this._fontsize;             this._imgbuilder.padding = this._padding; if (!string.            IsNullOrEmpty (This._font)) {this._imgbuilder.fonts = new string[] {This._font};            } this._imgbuildernew.chaoswight = 40;             This._imgbuildernew.fontsize = 25; this._imgbuildernew.padding = 3;           System.Drawing.Bitmap image = This._imgbuildernew.createimage (mcheckno);            System.IO.MemoryStream ms = new System.IO.MemoryStream (); Image.            Save (MS, System.Drawing.Imaging.ImageFormat.Jpeg); Context.            Response.clearcontent (); Context.            Response.ContentType = "Image/jpeg"; Context. Response.BinaryWrite (Ms.            ToArray ()); Context. session["Checkcode"] = mcheckno.tostring (); If IRequiresSessionState is not implemented, there will be an error here, and the picture context cannot be generated.        Response.End ();            }//Verification code generated protected string Discheckno () {String hash = Hashcode.getnext (); String checkno = String.            Empty;            Random rd = new random (DateTime.Now.Millisecond); for (int i = 0; i < 6; i++) {checkno + = hash. Substring (Rd. Next (1, hash.            Length-1), 1); } Checkno = Checkno.replace ("0", RD.) Next (1, 9).            ToString ()); Checkno = Checkno.replace ("O", RD. Next (1, 9).            ToString ()); Checkno = Checkno.replace ("O", RD. Next (1, 9).            ToString ());        return checkno;            } public bool IsReusable {get {return false; }        }    }

　　

The class that is called

Using system;using system.drawing;using System.Text; <summary>///Vryimggen Summary description///</summary>public class vryimggen{public static string chinesechars = S Tring.     Empty; <summary>//English with Digital string///</summary> protected static readonly string englishornumchars = "0123456     789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ ";    Public Vryimggen () {rnd = new Random (unchecked ((int) DateTime.Now.Ticks));     }//<summary>//Global random number generator///</summary> private random rnd;    int length = 5;  <summary>///Verification code length (default 6 CAPTCHA Length)///</summary> public int Length {get {return length;    } set {length = value;}    } int fontSize = 20; <summary>///Verification Code font size (default 30 pixels for distortion effect, self-modifying)///</summary> public int FontSize {get        {return fontSize;}    set {fontSize = value;}    } int padding = 4; <summary>//frame complement (defaultRecognition 4 pixels)///</summary> public int Padding {get {return Padding;}    set {padding = value;}    } bool Chaos = true;        <summary>//Whether output dryness point (default output)///</summary> public bool Chaos {get {return Chaos;}    set {chaos = value;}    } Color chaoscolor = Color.lightgray; <summary>///output dry point color (default gray)///</summary> public color Chaoscolor {get {return chaos Color;    } set {Chaoscolor = value;}    } int chaoswight = 1;         <summary>///output dry point concentration///</summary> public int Chaoswight {get {return chaoswight;}    set {chaoswight = value;}    } Color backgroundcolor = Color.White; <summary>////Custom background color (default white)///</summary> public color BackgroundColor {get {return B Ackgroundcolor;    } set {backgroundcolor = value;} } color[] colors = {color.black, color.red, Color.darkblue, Color.green, Color.orange, Color.brown, Color.darkcyan, color.purple};        <summary>///custom random color array///</summary> public color[] Colors {get {return Colors;}    set {colors = value;}    } string[] fonts = {"Arial", "Georgia"};        <summary>////Custom font array///</summary> public string[] Fonts {get {return Fonts;}    set {fonts = value;}    } #region produce a waveform filter effect Private Const double PI = 3.1415926535897932384626433832795;     Private Const Double PI2 = 6.283185307179586476925286766559; <summary>//sine wave distorted picture (Edit by 51aspx.com)///</summary>//<param name= "srcbmp" > Picture path </param>//<param name= "Bxdir" > If distortion is selected for true</param>//<param name= "Nmultvalue" > the amplitude multiples of the waveform, the more The greater the degree of distortion, generally 3</param>//<param name= "Dphase" > Waveform starting phase, value range [0-2*PI] </param>//&LT;RETURNS&GT;&L T;/returns> Public System.Drawing.BitmapTwistimage (Bitmap srcbmp, bool Bxdir, double dmultvalue, double dphase) {System.Drawing.Bitmap destbmp = new Bi         TMap (Srcbmp.width, srcbmp.height);        Fills the bitmap background with white 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);                Gets the color of the current point 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 < DESTB Mp.                Height) {destbmp.setpixel (NOLDX, noldy, color);    }}} return destbmp; } #endregion///<summary>///<param Name= "code" > Verification Code </ param>//<returns></returns> public Bitmap createimage (string code) {int fsize = Fontsiz        E         int fwidth = fsize + Padding; int imagewidth = (int) (code.        Length * fwidth) + 4 + Padding * 2;         int imageheight = fsize * 2 + Padding * 2;         System.Drawing.Bitmap image = New System.Drawing.Bitmap (imageWidth-10, imageHeight-10);         Graphics g = graphics.fromimage (image);         G.clear (BackgroundColor); Adds a randomly generated dry point if (this) to the background. Chaos) {             Pen pen = new Pen (chaoscolor, 0);             int c = Chaoswight * 10; for (int i = 0; i < C; i++) {int x = rnd. Next (image.                Width); int y = rnd. 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; Random font and color verification code characters for (int i = 0; i < code. Length; i++) {CIndex = rnd.            Next (colors.length-1); Findex = rnd.             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); }//Draw a border border color of Color.gainsboro g.drawrectangle (new Pen (Color.gainsboro, 0), 0, 0, image. Width-1, image.        HEIGHT-1);         G.dispose ();         Generate Waveform (ADD by 51aspx.com) image = Twistimage (image, True, 8, 4);    return image;    }///<summary>//Generate random character codes///</summary>//<param name= "Codelen" > String length </param> <param name= "Zhcharscount" > Chinese characters </param>//<returns></returns> public string Createve         Rifycode (int codelen, int zhcharscount) {char[] chs = new Char[codelen];        int index; for (int i = 0; i < Zhcharscount; i++) {index = rnd.            Next (0, Codelen);            if (chs[index] = = ' + ') chs[index] = Createzhchar ();        Else-I.;      } for (int i = 0; i < Codelen; i++)  {if (chs[i] = = ' + ') chs[i] = Createenornumchar (); } return new string (CHS, 0, CHS.    Length); }///<summary>//Generate random character codes of default length 5///</summary>//<returns></returns> Public St    Ring Createverifycode () {return Createverifycode (Length, 0); }//<summary>//Generate English or numeric characters///</summary>//<returns></returns> protected Cha R Createenornumchar () {return englishornumchars[rnd.    Next (0, englishornumchars.length)]; }//<summary>//Generate kanji characters///</summary>//<returns></returns> protected char C Reatezhchar () {//If a Chinese character set is provided, the Chinese character set is selected for the kanji if (chinesechars.length > 0) {return Chinesecha Rs[rnd.        Next (0, chinesechars.length)];             }//If the Chinese character set is not provided, then the Chinese character (else {byte[] bytes = new Byte[2] is constructed according to the coding rules of the GB2312 Simplified Chinese encoding table;           The first byte value is between 0xb0, 0xf7 Bytes[0] = (byte) rnd.            Next (0xb0, 0xf8); The second byte value is 0xa1, 0xfe between bytes[1] = (byte) rnd.             Next (0xa1, 0xff); Decodes the Chinese character string str1 = Encoding.GetEncoding ("gb2312") according to the byte array of the Chinese character coding.             GetString (bytes);        return str1[0]; }    } }

　　

Randomly generate 6-bit image verification code