Piwik\SettingsServer::isGdExtensionEnabled PHP Method

    public static function isGdExtensionEnabled()
    {
        static $gd = null;
        if (is_null($gd)) {
            $gd = false;
            $extensions = @get_loaded_extensions();
            if (is_array($extensions)) {
                $gd = in_array('gd', $extensions) && function_exists('imageftbbox');
            }
        }
        return $gd;
    }

 public function execute()
 {
     $label = $this->translator->translate('Installation_SystemCheckGDFreeType');
     if (SettingsServer::isGdExtensionEnabled()) {
         return array(DiagnosticResult::singleResult($label, DiagnosticResult::STATUS_OK));
     }
     $comment = sprintf('%s<br />%s', $this->translator->translate('Installation_SystemCheckGDFreeType'), $this->translator->translate('Installation_SystemCheckGDHelp'));
     return array(DiagnosticResult::singleResult($label, DiagnosticResult::STATUS_WARNING, $comment));
 }