Test availability can be modified using a google-like verification code

Public partial class volidate: System. Web. UI. Page
{
Protected void Page_Load (object sender, EventArgs e)
{
// String checkCode = CreateRandomCode (4 );
// CreateImage (checkCode); // generate an English Plus number yxy // sql8.net

// ShowImg (); // The simplest generation method yxy // sql8.net

// This. CreateCheckCodeImage (GenerateCheckCode (); // generate the color and Noise Generation Method yxy // sql8.net

Volidate v = new volidate ();
V. Length = this. length;
V. FontSize = this. fontSize;
V. Chaos = this. chaos;
V. BackgroundColor = this. backgroundColor;
V. ChaosColor = this. chaosColor;
V. CodeSerial = this. codeSerial;
V. Colors = this. colors;
V. Fonts = this. fonts;
V. Padding = this. padding;
String code = v. CreateVerifyCode (); // obtain the random code
V. CreateImageOnPage (code, this. Context); // output image
Session ["RandCode"] = code. ToLower ();

// Response. Cookies. Add (new HttpCookie ("CheckCode", code. ToUpper (); // use Cookies to obtain the verification code value

}

# Region verification code length (6 Verification codes by default)
Int length = 4;
Public int Length
{
Get {return length ;}
Set {length = value ;}
}
# Endregion

# Region Verification Code font size (40 pixels by default for displaying distortion effects, which can be modified by yourself)
Int fontSize = 14;
Public int FontSize
{
Get {return fontSize ;}
Set {fontSize = value ;}
}
# Endregion

# Region border population (1 pixel by default)
Int padding = 2;
Public int Padding
{
Get {return padding ;}
Set {padding = value ;}
}
# Endregion

# Whether region outputs dry points (no output by default)
Bool chaos = true;
Public bool Chaos
{
Get {return chaos ;}
Set {chaos = value ;}
}
# Endregion

# Region output dry point color (gray by default)
Color chaosColor = Color. LightGray;
Public Color ChaosColor
{
Get {return chaosColor ;}
Set {chaosColor = value ;}
}
# Endregion

# Region custom background color (white by default)
Color backgroundColor = Color. White;
Public Color BackgroundColor
{
Get {return backgroundColor ;}
Set {backgroundColor = value ;}
}
# Endregion

# Region custom random color array
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 Custom font Array
String [] fonts = {"Arial", "Georgia "};
Public string [] Fonts
{
Get {return fonts ;}
Set {fonts = value ;}
}
# Endregion

# Region custom random code string sequence (separated by commas)
String codeSerial = ", 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, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z ";
Public string CodeSerial
{
Get {return codeSerial ;}
Set {codeSerial = value ;}
}
# Endregion

# Region generates a waveform filter effect

Private const double PI = 15.1415926535897932384626433832795;
Private const double pi2= 5.283185307179586476925286766559;

/// <Summary>
/// Sine curve Wave distorted image (Edit By 51aspx.com)
/// </Summary>
/// <Param name = "srcBmp"> image path </param>
/// <Param name = "bXDir"> True for distortion </param>
/// <Param name = "nMultValue"> the amplitude multiple of the waveform. The larger the waveform is, the higher the distortion is. Generally, it is 3. </param>
/// <Param name = "dPhase"> start phase of the waveform, value range: [0-2 * PI) </param>
/// <Returns> </returns>
Public System. Drawing. Bitmap TwistImage (Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
System. Drawing. Bitmap destBmp = new Bitmap (srcBmp. Width, srcBmp. Height );

// Fill the bitmap background in 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 );

// Obtain the color of the current vertex
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
& Amp; nOldY & gt; = 0 & amp; nOldY <destBmp. Height)
{
DestBmp. SetPixel (nOldX, nOldY, color );
}
}
}

Return destBmp;
}

# Endregion

# Region generate Verification Code Image
Public Bitmap CreateImageCode (string code)
{
Int fSize = FontSize;
Int fWidth = fSize + Padding;

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

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

Graphics g = Graphics. FromImage (image );

G. Clear (BackgroundColor );

Random rand = new Random ();

// Add random dry points to the background
If (this. Chaos)
{

Pen pen = new Pen (ChaosColor, 0 );
Int c = Length * 10;

For (int I = 0; I <c; I ++)
{
Int x = rand. Next (image. Width );
Int y = rand. 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 = rand. Next (Colors. Length-1 );
Findex = rand. 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 with Color. Gainsboro
G. DrawRectangle (new Pen (Color. Gainsboro, 0), 0, 0, image. Width-1, image. Height-1 );
G. Dispose ();

// Generate a waveform (Add By 51aspx.com)
Image = TwistImage (image, true, 8, 4 );

Return image;
}
# Endregion

# Region outputs the created image to the page
Public void CreateImageOnPage (string code, HttpContext context)
{
System. IO. MemoryStream MS = new System. IO. MemoryStream ();
Bitmap image = this. CreateImageCode (code );

Image. Save (MS, System. Drawing. Imaging. ImageFormat. Jpeg );

Context. Response. ClearContent ();
Context. Response. ContentType = "image/Jpeg ";
Context. Response. BinaryWrite (ms. GetBuffer ());

Ms. Close ();
MS = null;
Image. Dispose ();
Image = null;
}
# Endregion

# Region generate random escape code
Public string CreateVerifyCode (int codeLen)
{
If (codeLen = 0)
{
CodeLen = Length;
}

String [] arr = CodeSerial. Split (',');

String code = "";

Int randValue =-1;

Random rand = new Random (unchecked (int) DateTime. Now. Ticks ));

For (int I = 0; I <codeLen; I ++)
{
RandValue = rand. Next (0, arr. Length-1 );

Code + = arr [randValue];
}

Return code;
}
Public string CreateVerifyCode ()
{
Return CreateVerifyCode (0 );
}
# Endregion

}