A Google-like verification code written in. net

Application in B/S structure developmentProgramThe verification code is often used to prevent malicious operations during login. Similar verification codes are found on the internet, but are nothing more than generating a text image. Here, publish a verification code similar to that used by Google.

Effect

CodeAs follows:

Using system;
Using system. text;
Using system. drawing;
Using system. Drawing. drawing2d;
Using system. Drawing. imaging;

Namespace mirainsoft. validatecode
{
/// <Summary>
/// Verification code processing class
/// </Summary>
Public class validatecodefactory
{
/// <Summary>
/// Select the range array for the font
/// </Summary>
Private string [] fonts = {"Times New Roman", "Georgia", "Arial", "Comic Sans MS "};
/// <Summary>
/// Value range array of the Verification Code
/// </Summary>
Private string [] codescopes = {"0", "1", "2", "3", "4", "5", "6", "7 ", "8", "9 "};
///// <Summary>
//// Color value range array
///// </Summary>
// Private color [] colorscopes = {color. crimson, color. palevioletred, color. mediumvioletred, color. purple, color. darkviolet, color. indigo, color. slateblue, color. darkslateblue, color. mediumblue, color. darkblue, color. slateblue, color. darkcyan, color. gold, color. goldenrod, color. orange, color. orangered, color. red, color. darkred };
/// <Summary>
/// Random Number
/// </Summary>
Private random rand;
/// <Summary>
/// Random Seed
/// </Summary>
Private int randseed;
Private string text;
Private int width;
Private int height;
Private string familyname;
Private bitmap image;

/// <Summary>
/// Display text
/// </Summary>
Public String text
{
Get {return this. Text ;}
}
/// <Summary>
/// Generated bitmap
/// </Summary>
Public bitmap image
{
Get {return this. image ;}
}
/// <Summary>
/// Verification Code width
/// </Summary>
Public int width
{
Get {return this. width ;}
}
/// <Summary>
/// Verification Code height
/// </Summary>
Public int height
{
Get {return this. height ;}
}

///

// verification code processing class
///
/// display text length, randomly generated
/// Verification Code width
/// verification Code height
Public validatecodefactory (INT length, int width, int height)
{< br> This. randseed = 111;
for (INT I = 0; I This. TEXT = string. concat (this. text, codescopes [next (codescopes. length)]);
This. setdimensions (width, height);
This. setfamilyname (this. fonts [next (this. fonts. length)]);
This. generateimage ();
}

///

// verification code processing class
///
/// display text
/// Verification Code width
/// Verification Code height
Public validatecodefactory (string s, int width, int height)
{< br> This. randseed = 111;
This. TEXT = s;
This. setdimensions (width, height);
This. setfamilyname (this. fonts [next (this. fonts. length)]);
This. generateimage ();
}

/// <Summary>
/// Verification code processing class
/// </Summary>
/// <Param name = "S"> display text </param>
/// <Param name = "width"> Verification Code width </param>
/// <Param name = "height"> Verification Code height </param>
/// <Param name = "familyname"> font name </param>
Public validatecodefactory (string S, int width, int height, string familyname)
{
This. randseed = 111;
This. Text = s;
This. setdimensions (width, height );
This. setfamilyname (familyname );
This. generateimage ();
}

/// <Summary>
/// Garbage collection
/// </Summary>
~ Validatecodefactory ()
{
Dispose (false );
}

/// <Summary>
/// Release resources
/// </Summary>
Public void dispose ()
{
GC. suppressfinalize (this );
This. Dispose (true );
}

/// <Summary>
/// Release resources
/// </Summary>
/// <Param name = "disposing"> reclaim or not </param>
Protected virtual void dispose (bool disposing)
{
If (disposing)
// Dispose of the bitmap.
This. image. Dispose ();
}

/// <Summary>
/// Set the width and height of the Verification Code
/// </Summary>
/// <Param name = "width"> Verification Code width </param>
/// <Param name = "height"> Verification Code height </param>
Private void setdimensions (INT width, int height)
{
// Check the width and height.
If (width <= 0)
Throw new argumentoutofrangeexception ("width", width, "argument out of range, must be greater than zero .");
If (height <= 0)
Throw new argumentoutofrangeexception ("height", height, "argument out of range, must be greater than zero .");
This. width = width;
This. Height = height;
}

///

// set the font of the displayed text
///
/// font name
private void setfamilyname (string familyname)
{< br> try
{< br> Font font = new font (this. familyname, 12f);
This. familyname = familyname;
font. dispose ();
}< br> catch
{< br> This. familyname = system. drawing. fontfamily. genericserif. name;
}< BR >}

/// <Summary>
/// Generate the verification code
/// </Summary>
Private void generateimage ()
{
// Create a new 32-bit bitmap image.
Bitmap bitmap = new Bitmap (this. Width, this. Height, pixelformat. format32bppargb );

// Create a graphics object for drawing.
Graphics G = graphics. fromimage (Bitmap );
G. smoothingmode = smoothingmode. antialias;
Rectangle rect = new rectangle (0, 0, this. Width, this. Height );

// fill in the background.
hatchbrush = new hatchbrush (hatchstyle. smallconfetti, color. lightgray, color. white);
G. fillrectangle (hatchbrush, rect);

// set up the text font.
sizef size;
float fontsize = rect. height + 1;
Font font;
// adjust the font size until the text fits within the image.
DO
{< br> fontsize --;
font = new font (this. familyname, fontsize, fontstyle. bold);
size = G. measurestring (this. text, font);
}while (size. width/4f) * 3f> rect. width);

// Set up the text format.
Stringformat format = new stringformat ();
Format. Alignment = stringalignment. Center;
Format. linealignment = stringalignment. Center;

// Create a path using the text and warp it randomly.
Graphicspath Path = new graphicspath ();
Path. addstring (this. Text, Font. fontfamily, (INT) font. style, Font. Size, rect, format );
Float v = 4f;
Pointf [] points =
{
New pointf (next (rect. width)/V, next (rect. Height)/V ),
New pointf (rect. Width-next (rect. width)/V, next (rect. Height)/V ),
New pointf (next (rect. width)/V, rect. Height-next (rect. Height)/V ),
New pointf (rect. Width-next (rect. width)/V, rect. Height-next (rect. Height)/V)
};
Matrix matrix = new matrix ();
Matrix. Translate (0f, 0f );
Path. Warp (points, rect, matrix, warpmode. Perspective, 0f );

// Draw the text.
Hatchbrush = new hatchbrush (hatchstyle. largeconfetti, color. Gray, color. Gray );
G. fillpath (hatchbrush, PATH );

// Add some random noise.
Int M = math. Max (rect. Width, rect. Height );
For (INT I = 0; I <(INT) (rect. Width * rect. Height/30f); I ++)
{
Int x = next (rect. width );
Int y = next (rect. Height );
Int W = next (M/50 );
Int H = next (M/50 );
G. fillellipse (hatchbrush, X, Y, W, H );
}

// Clean up.
Font. Dispose ();
Hatchbrush. Dispose ();
G. Dispose ();

// Set the image.
This. Image = bitmap;
}

/// <Summary>
/// Obtain a random number
/// </Summary>
/// <Returns> int </returns>
Private int next ()
{
Rand = new random (unchecked (INT) datetime. Now. ticks) * randseed ++ );

Return Rand. Next ();
}
/// <Summary>
/// Obtain a random number
/// </Summary>
/// <Param name = "maxvalue"> upper bound of a random number </param>
/// <Returns> int </returns>
Private int next (INT maxvalue)
{
Rand = new random (unchecked (INT) datetime. Now. ticks) * Next ());

Return Rand. Next (maxvalue );
}

/// <Summary>
/// Obtain a random number
/// </Summary>
/// <Param name = "minvalue"> lower bound to a random number </param>
/// <Param name = "maxvalue"> upper bound of a random number </param>
/// <Returns> int </returns>
Private int next (INT minvalue, int maxvalue)
{
Rand = new random (unchecked (INT) datetime. Now. ticks) * Next ());

Return Rand. Next (minvalue, maxvalue );
}
}
}