private function formatDynamicMetadata(DynamicMetadataInterface $metadata)
    {
        $info = null;
        switch ($metadata::getName()) {
            case SubjectArea::getName():
                $data = [];
                /* @var SubjectArea $metadata */
                foreach (['x', 'y', 'width', 'height'] as $property) {
                    $data[] = $property.':'.$metadata->$property;
                }
                $info = implode('|', $data);

                break;
        }

        return $info;
    }