code: public function htmlFromPdfFile($filename, $saveToFile = null)
      {
          $command = $this->prepareCommand($filename, $saveToFile);
          $command->setAsHtml(true);
          return $this->execute($command);
      }
docs: /* (non-PHPdoc)
  @see SGH\PdfBox.PdfConverter::htmlFromPdfFile()