private function createWriter($file = null)
{
if ($file || $this->_useTemporaryFile) {
if (!$this->_writer instanceof PHPRtfLite_StreamOutput) {
$this->_writer = new PHPRtfLite_StreamOutput();
}
if (is_null($file)) {
$file = sys_get_temp_dir() . '/' . md5(microtime(true)) . '.rtf';
}
$this->_writer->setFilename($file);
} else {
if (!$this->_writer instanceof PHPRtfLite_Writer_String) {
$this->_writer = new PHPRtfLite_Writer_String();
}
}
}