<?php
/**
* Get which version of GD is installed, if any.
*
* Returns the version (1 or 2) of the GD extension.
*/
function gdVersion($user_ver = 0)
{
   if (! extension_loaded('gd')) { return; }
   static $gd_ver = 0;
   // Just accept the specified setting if it's 1.
   if ($user_ver == 1) { $gd_ver = 1; return 1; }
   // Use the static variable if function was called previously.
   if ($user_ver !=2 && $gd_ver > 0 ) { return $gd_ver; }
   // Use the gd_info() function if possible.
   if (function_exists('gd_info')) {
       $ver_info = gd_info();
       preg_match('/\d/', $ver_info['GD Version'], $match);
       $gd_ver = $match[0];
       return $match[0];
   }
   // If phpinfo() is disabled use a specified / fail-safe choice...
   if (preg_match('/phpinfo/', ini_get('disable_functions'))) {
       if ($user_ver == 2) {
           $gd_ver = 2;
           return 2;
       } else {
           $gd_ver = 1;
           return 1;
       }
   }
   // ...otherwise use phpinfo().
   ob_start();
   phpinfo(8);
   $info = ob_get_contents();
   ob_end_clean();
   $info = stristr($info, 'gd version');
   preg_match('/\d/', $info, $match);
   $gd_ver = $match[0];
   return $match[0];
} // End gdVersion()

// Usage:

if ($gdv = gdVersion()) {
   if ($gdv >=2) {
       echo 'TrueColor functions may be used.';
   } else {
       echo 'GD version is 1.  Avoid the TrueColor functions.';
   }
} else {
   echo "The GD extension isn't loaded.";
}
?>