仅在按下键时显示超链接按钮

Question

我有一个 Beamer 演示文稿，其中每张幻灯片上都有一些超链接。这些超链接允许跳转到 PDF 中的不同部分。

有时这些按钮会干扰幻灯片中的文本、公式和图形。有没有办法让它们仅在按下某个键时才可见？

代码：

\documentclass{beamer}

\AtBeginSection[]{\label{sec:\thesection}}
\newcounter{prevsec}

\title{Some Title}

\setbeamertemplate{navigation symbols}{}

\setbeamertemplate{footline}{%
        \setcounter{prevsec}{\thesection}
        \ifnum\theprevsec>1
            \addtocounter{prevsec}{-1}
        \fi
    \quad\hyperlinkpresentationstart{\beamerreturnbutton{Back to start}}%
    \quad\hyperlinksectionstart{\beamerreturnbutton{Back to section start}}%
    \quad\hyperlink{Detailed_Analysis}{\beamergotobutton{Detailed Analysis}}%
    \quad\hyperlinksectionstartnext{\beamerskipbutton{Next section}}%
    \quad\hyperlink{sec:\theprevsec}{\beamerskipbutton{previous section}}%
    \vspace*{0.2cm}%
}


\begin{document}

   \section{sec1}
    \begin{frame}%{ss}
    1st section/ page 1 out of 1
    \end{frame}

    \begin{frame}
    1st section/ page 2 out of 2
    \end{frame}

    \begin{frame}[label=Detailed_Analysis]
        Detailed Analysis
    \end{frame}

    \section{sec2}
    \begin{frame}
    2nd section
    \end{frame}

    \section{sec3}
    \begin{frame}
    3rd section
    \end{frame}

    \begin{frame}
    More content on the 3rd section
    \end{frame}

    \begin{frame}
    Even More content on the 3rd section
    \end{frame}


\end{document}

Answer 1

这是基于 OCG（即 PDF 层）的解决方案，可在 Acrobat Reader 中运行。

无需按下任何键，只需通过将鼠标指针靠近滑动脚来切换导航控件的可见性：

\documentclass{beamer}

\usepackage{ocgx2}

%patch hyperref to make PDF Annotations PDF-Layer-(OCG)-aware
\makeatletter
  \let\Hy@setpdfborderOrig\Hy@setpdfborder
  \def\Hy@setpdfborder{\ocgbase@insert@oc\Hy@setpdfborderOrig}%
\makeatother

\AtBeginSection[]{\label{sec:\thesection}}
\newcounter{prevsec}

\title{Some Title}

\setbeamertemplate{navigation symbols}{}

\setbeamertemplate{footline}{%
  \setcounter{prevsec}{\thesection}%
  \ifnum\theprevsec>1
    \addtocounter{prevsec}{-1}%
  \fi%
  \parbox{\paperwidth}{%
    \toggleocgs[triggerocg=onmouseenter]{navLayer}{\phantom{\rule{\paperwidth}{.2cm}}}\\
    \begin{ocg}{navLayer}{navLayer}{off}
    % dumb PDF annotation to work-around an AR bug  
    \immediate\pdfannot width 3pt height 3pt depth 0pt{/Ff 65537/FT/Btn/Subtype/Widget}%   
    \quad\hyperlinkpresentationstart{\beamerreturnbutton{Back to start}}%
    \quad\hyperlinksectionstart{\beamerreturnbutton{Back to section start}}%
    \quad\hyperlink{Detailed_Analysis}{\beamergotobutton{Detailed Analysis}}%
    \quad\hyperlinksectionstartnext{\beamerskipbutton{Next section}}%
    \quad\hyperlink{sec:\theprevsec}{\beamerskipbutton{previous section}}%
    \end{ocg}\\%
    \toggleocgs[triggerocg=onmouseenter]{navLayer}{\phantom{\rule{\paperwidth}{.2cm}}}%
  }% 
}

\begin{document}

   \section{sec1}
    \begin{frame}%{ss}
    1st section/ page 1 out of 1
    \end{frame}

    \begin{frame}
    1st section/ page 2 out of 2
    \end{frame}

    \begin{frame}[label=Detailed_Analysis]
        Detailed Analysis
    \end{frame}

    \section{sec2}
    \begin{frame}
    2nd section
    \end{frame}

    \section{sec3}
    \begin{frame}
    3rd section
    \end{frame}

    \begin{frame}
    More content on the 3rd section
    \end{frame}

    \begin{frame}
    Even More content on the 3rd section
    \end{frame}

\end{document}