如何向（hyperref）pdf 表单 TextField 添加换行符？

Question

请考虑以下玩具反馈表：

\documentclass{article}
\usepackage{hyperref}
  \renewcommand*{\DefaultHeightofTextMultiline}{20\baselineskip}

\begin{document}
  \centering
  \begin{Form}
    \TextField[multiline,width=\textwidth,
    value={%
      You should write your feedback in a readable way, for example using bullet points:
      * Insert at least 1 positive comment (mandatory)
      * Insert at least 1 critical comment or question (mandatory)
      \newline
      Use multiple paragraphs.
      \newline
      Some examples of concrete, actionable feedback:
      * The first figure does not have a caption; please add it.
      * The derivation of Equation (7) became unclear around Equation (5). I think this is because you did not make the substitution of x explicit and feel doing so would make the argument clearer.%
  },
  name=mytextfield]{}%
  \end{Form}
\end{document}

使用 pdflatex 编译此文件会出现以下警告（两次，每次一次\newline）：

Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding):
(hyperref)                removing `\newline' on input line 20.

这并不让我感到惊讶，因为对于通过 hyperref 创建和填充的大多数 pdf 字段来说，换行是没有意义的，而且可能不支持。然而，通过编辑表单并保存生成的文件（在我的情况下使用 Okular），我能添加换行符。使用PyPDF2的PdfFileReader.getFields方法，我得到：

'You should write your feedback in a readable way, for example using bullet points:\n* Insert at least 1 positive comment (mandatory)\n* Insert at least 1 critical comment or question (mandatory)\n\nUse multiple paragraphs.\n\nSome examples of concrete, actionable feedback:\n* The first figure does not have a caption; please add it.\n* The derivation of Equation (7) became unclear around Equation (5). I think this is because you did not make the substitution of x explicit and feel doing so would make the argument clearer.'

注意换行符\n。所以这似乎是可能的。我想在我的 LaTeX 文件中添加这些换行符。这可能吗？我该怎么做？

我天真地尝试添加文字\n为\textbackslash{n}，但失败了：

'You should write your feedback in a readable way, for example using bullet points:\\n * Insert at least 1 positive comment (mandatory)\\n * Insert at least 1 critical comment or question (mandatory)\\n \\n Use multiple paragraphs.\\n \\n Some examples of concrete, actionable feedback:\\n * The first figure does not have a caption; please add it.\\n * The derivation of Equation (7) became unclear around Equation (5). I think this is because you did not make the substitution of x explicit and feel doing so would make the argument clearer.'

Answer 1

更新：实际上最好使用\textCR或\textLF。如果编码发生变化，它们也会起作用。

\string\n对我有用：

\documentclass{article}
\usepackage{hyperref}
  \renewcommand*{\DefaultHeightofTextMultiline}{20\baselineskip}

\begin{document}
  \centering
  \begin{Form}
    \TextField[multiline,width=\textwidth,
    value={%
      You should write your feedback in a readable way, for example using bullet points:\string\n
      * Insert at least 1 positive comment (mandatory)\string\n
      * Insert at least 1 critical comment or question (mandatory)\string\n
      Use multiple paragraphs.
      \string\n
      Some examples of concrete, actionable feedback:\string\n
      * The first figure does not have a caption; please add it.\string\n
      * The derivation of Equation (7) became unclear around Equation (5). I think this is because you did not make the substitution of x explicit and feel doing so would make the argument clearer.\string\n%
  },
  name=mytextfield]{}%
  \end{Form}
\end{document}