watercap generator script

gen_cap.php

<?php
// Webmail CAPTCHA Image ganarator
// Generates labelled CAPTCHA images at random
// Can be used to generate a dataset
// README:
// - make sure php5 & php5-gd are installed (can be done via apt)
// - Create a directory to house your dataset
// - put this script in the that directory
// - open a shell and cd into that directory
// - Execute `php gen_cap.php 100` to generate 100 images.
// - Images will ge generated in the same directory
// - Number can be modified as per requirement




   // length of CAPTCHA code in number of characters
   // 
   $captcha_length = 5;


class WaterCap {
 
   var $font = '';

 
   function WaterCap ($code, $width='250', $height='60') {
      

      $this->font = './Vera.ttf';


      /* seed random number gen to produce the same noise pattern time after time */
      mt_srand(crc32($code));   

      

      /* init image */
      $font_size = $height * 0.85;
      $image = @imagecreate($width, $height) or die('Cannot initialize new GD image stream');

     

      /* set the colours */
      $background_color = imagecolorallocate($image, 255, 255, 255);
      $text_color = imagecolorallocate($image, 20, 40, 100);
      $noise_color = imagecolorallocate($image, 100, 120, 180);

    

      /* create textbox and add text */
      $textbox = imagettfbbox($font_size, 0, $this->font, $code) or die('Error in imagettfbbox function');
      $x = ($width - $textbox[4])/2;
      $y = ($height - $textbox[5])/2;
      $d = -1;
      imagettftext($image, $font_size, 0, $x, $y, $text_color, $this->font , $code) or die('Error in imagettftext function');
      imagettftext(
        $image, $font_size, 0, $x + $d, $y + $d, $noise_color, $this->font , $code
      ) or die('Error in imagettftext function');
      imagettftext(
        $image, $font_size, 0, $x + 2 * $d + 1, $y + 2 * $d + 1, $noise_color, $this->font , $code
      ) or die('Error in imagettftext function');
      imagettftext(
        $image, $font_size, 0, $x + 2 * $d, $y + 2 * $d, $background_color, $this->font , $code
      ) or die('Error in imagettftext function');

      /* mix in background dots */
      for( $i=0; $i<($width*$height)/10; $i++ ) { 
            imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $background_color);      
      }

      /* mix in text and noise dots */
      for( $i=0; $i<($width*$height)/25; $i++ ) { 
         imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $noise_color);      
     imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $text_color);       
      }

      /* rotate a bit to add fuzziness */
      $image = imagerotate($image, 1, 16777215);

     

      /* output */
      // header("Content-Type: image/png");
      imagepng($image, $code.".png");
      imagedestroy($image);
   }
}



function generateCode($number_characters) {
      /* list all possible characters, similar looking characters and vowels have been removed */
      // lower case letters such as g, p, q, y get cut off
      //$possible = '23456789bcdfghjkmnpqrstvwxyz';
      $possible = '23456789ABCDEFGHKMNPRSTVWXYZ';


      // sq_mt_randomize();
      $code = '';
      $i = 0;
      while ($i < $number_characters) { 
         $code .= substr($possible, mt_rand(0, strlen($possible)-1), 1);
         $i++;
      }
      return $code;
   }


$count = 0;
while($count < (int)$argv[1]) {

   $captcha_code = generateCode($captcha_length);
   $captcha = new WaterCap($captcha_code);

   $count = $count + 1;

   if($count%1000 == 0 && $count > 0) echo "Finished generating ".$count." CAPTCHAs";

}



?>