PHP Generate Image Verification code

/** *  verification code class for generating various verification codes  */class captcha{    /**      *  Generate verification Code      *  @param  int  $length   code character length       *  @param  int  $width   width      *  @param   int  $height   Length      *  @param  string  $type   type       *  @return       */    public  Static function getcode ($length =4, $width =50, $height =22, $type = ' png ')      {         //session_start ();          $randval  = self::randstring ($length);         //$_ session[' captcha ']=  $randval;                  $width  =  ($length *9+10) > $width? $length *9+10: $width;        if  (  $type! = ' gif '  && function_exists (' Imagecreatetruecolor '))  {              $im  =  @imagecreatetruecolor ($width, $height);         }else {              $im  =  @imagecreate ($width, $height);         }         $r  = array (225,255,255,223);          $g  = array (225,236,237,255);          $b  = array (225,236,166,125);         $key  = mt_rand (0,3);         $backColor  =  Imagecolorallocate ($im,  $r [$key], $g [$kEY], $b [$key]);     //background color (random)          $borderColor  = imagecolorallocate ($im,  100, 100, 100);                     //Border Color           $pointColor  = imagecolorallocate ($im, Mt_rand (0,255), Mt_rand (0,255), Mt_rand ( 0,255))             //point color           @imagefilledrectangle ($im, 0, 0,  $width  - 1,  $height  - 1,  $backColor);         @imagerectangle ($im,  0,  0,  $width -1,  $height -1,  $borderColor);         $ Stringcolor = imagecolorallocate ($im, Mt_rand (0,200), Mt_rand (0,120), Mt_rand (0,120));         //  interference         for ($i =0; $i <10; $i + +) {              $fontcolor =imagecolorallocate ($im, Mt_rand (0,255), Mt_rand (0,255), Mt_rand (0,255));             imagearc ($im, Mt_rand ( -10, $width), Mt_rand ( -10, $height), Mt_rand (30,300), Mt_rand (20,200), 55,44, $fontcolor);         }        for ($i =0; $i <25; $i + +) {              $fontcolor =imagecolorallocate ($im, Mt_rand ( 0,255), Mt_rand (0,255), Mt_rand (0,255));             Imagesetpixel ($im, Mt_rand (0, $width), Mt_rand (0, $height), $pointColor);         }         @imagestring ($im,  10, 20, 10, $ randval,  $stringColor);            header ("content-type: image/". $type );         $ImageFun = ' Image '. $type;          $ImageFun ($im),         imagedestroy ($im);          return  $randval;     }}

The above is the complete method to generate a picture verification code, the following is the use of this method to generate a verification code:

Include ". /lib/captcha.class.php "; $captcha = new Captcha (); $checkCode = $captcha->getcode (4,75,32); Echo $checkCode;

Finally, the effect of the page display is this, refresh one at a time:

PHP Generate Image Verification code