title: Add additional noise to Captcha image?
body: <p>I have this simple captcha script from online. I like it, and I edited it to suit my site, but was wondering if someone could edit it to add some random lines on the captcha itself as it is somewhat too simple.</p>
  
  <p>I did find tutorials on how to do it but it was not working for me.</p>
  
  <p>Here is the simple captcha script; I would love to modify it to have some random lines appear on the captcha:</p>
  
  <pre><code>   $width    = 150;
     $height   = 24;
     $length   = 5;
     $font     = 'caviardreams.ttf';
     $font_size   = 14;
     $bg_color = array(245, 245, 245);
     $chars    = 'ABCDEFGHKMNPQRSTUVWXYZ23456789';
     session_start();
     //putenv('GDFONTPATH=' . realpath('.'));
     $img = imagecreatetruecolor($width, $height);
     $bkgr = imagecolorallocate($img, $bg_color[0], $bg_color[1], $bg_color[2]);
     imagefilledrectangle($img, 0, 0, $width, $height, $bkgr);
  
     $code = '';
     for($i = 0; $i &lt; $length; $i++)
     {
        $code .= $chr = $chars[mt_rand(0, strlen($chars)-1)];
        $r = rand(0, 192);
        $g = rand(0, 192);
        $b = rand(0, 192);
        $color = imagecolorallocate($img, $r, $g, $b);
        $rotation = rand(-35, 35);
        $x = 5+$i*(4/3*$font_size+2);
        $y = rand(4/3*$font_size, $height-(4/3*$font_size)/2);
        imagettftext($img, $font_size, $rotation, $x, $y, $color, $font, $chr);
     }
  
     $_SESSION['random_txt'] = md5($code);
  
     header("Content-type: image/png");
     header("Expires: Mon, 01 Jul 1998 05:00:00 GMT");
     header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
     header("Cache-Control: no-store, no-cache, must-revalidate");
     header("Cache-Control: post-check=0, pre-check=0", false);
     header("Pragma: no-cache");
  
     imagepng($img);
     imagedestroy($img);
  </code></pre>