PHP verification code

* ** Generate verification code Image * publicfunctionactionVerfiycode () {Header (& amp; quot; Content-type: imagegif & amp; quot;); $ border0; whether border 1 is required: 0 don't $ how4; number of digits of the verification code $ w $ how * 15; image width $ h20 ;... /**

* Generate verification code Image

*/

Public function actionVerfiycode (){

Header ("Content-type: image/gif ");

$ Border = 0; // whether the border is required; 1: 0: not required

$ How = 4; // Number of digits of the verification code

$ W = $ how * 15; // image width

$ H = 20; // Image height

$ Fontsize = 5; // font size

$ Alpha = "abcdefghijkmnopqrstuvwxyz"; // verification code content 1: letter

$ Number = "0123456789"; // verification code content 2: number

$ Randcode = ""; // verification code string initialization

Srand (double) microtime () * 1000000); // initialize the random number seed

$ Im = ImageCreate ($ w, $ h); // Create a verification image

$ Bgcolor = ImageColorAllocate ($ im, 255,255,255); // you can specify the background color.

ImageFill ($ im, 0, 0, $ bgcolor); // fill the background color

If ($ border ){

$ Black = ImageColorAllocate ($ im, 0, 0, 0); // you can specify the border color.

ImageRectangle ($ im, 0, 0, $ w-1, $ h-1, $ black); // draw a border

}

For ($ I = 0; $ I <$ how; $ I ++ ){

$ Alpha_or_number = mt_rand (0, 1); // letters or numbers

$ Str = $ alpha_or_number? $ Alpha: $ number;

$ Which = mt_rand (0, strlen ($ str)-1); // specify the character

$ Code = substr ($ str, $ which, 1); // Obtain the character

$ J =! $ I? 4: $ j + 15; // specifies the position of the painted character.

$ Color3 = ImageColorAllocate ($ im, mt_rand (0,100), mt_rand (0,100), mt_rand (0,100); // character color

ImageChar ($ im, $ fontsize, $ j, 3, $ code, $ color3); // draw characters

$ Randcode. = $ code; // add a verification code string to a bit by bit

}

For ($ I = 0; $ I <5; $ I ++) // draws the background interference line

{

$ Color1 = ImageColorAllocate ($ im, mt_rand (0,255), mt_rand (0,255), mt_rand (0,255); // interference line color

ImageArc ($ im, mt_rand (-5, $ w), mt_rand (-5, $ h), mt_rand (20,300), mt_rand (20,200), 55, 44, $ color1); // interference line

}

For ($ I = 0; $ I <$ how * 40; $ I ++) // draws background interference points

{

$ Color2 = ImageColorAllocate ($ im, mt_rand (0,255), mt_rand (0,255), mt_rand (0,255); // interference point color

ImageSetPixel ($ im, mt_rand (0, $ w), mt_rand (0, $ h), $ color2); // interference point

}

$ Session = new CHttpSession;

$ Session-> open ();

Yii: app ()-> session-> add ('randcode', $ randcode );

/* Drawing ends */

Imagegif ($ im );

ImageDestroy ($ im );

/* Drawing ends */

}