tikzpicture 環境使 \noindent 無效

Question

請參閱此 MWE：

\documentclass[a4paper]{article}
\usepackage{tikz}
\usepackage[showframe]{geometry}
\usepackage{ulem}
\setlength\fboxsep{0pt}
\begin{document}

% \begin{tikzpicture}[remember picture, overlay]
%   \node[inner sep=0pt] at (current page.center) {\includegraphics[width=\textwidth]{example-image.pdf}};
% \end{tikzpicture}
\ExplSyntaxOn
\noindent
\fbox{\begin{minipage}{\textwidth}
  \mode_leave_vertical:
  \hbox_to_wd:nn { 2cm } { Classification }
  \uline { \hbox_to_wd:nn { 2.4cm } { \hfill 1234 \hfill } }
  \hfill
  \hbox_to_wd:nn { 1.67cm } { Secret-level }
  \uline { \hbox_to_wd:nn { 2.4cm } { \hfill AAAA \hfill } }
\end{minipage}}
\ExplSyntaxOff

\noindent\begin{minipage}{\textwidth}
  Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
\end{minipage}

\end{document}

如果我取消註釋該tikzpicture部分，則第一個小頁會縮進，即使\noindent它之前有。

Answer 1

開頭tikzpicture是一個段落，因此\noindent沒有任何效果。

將其移到之前\begin{tikzpicture}（我添加\ignorespaces以避免在之前出現不需要的空格minipage，但您也可以使用註釋字元%）。

\documentclass[a4paper]{article}
\usepackage{tikz}
\usepackage[showframe]{geometry}
\usepackage{ulem}
\setlength\fboxsep{0pt}
\begin{document}

\noindent
\begin{tikzpicture}[remember picture, overlay]
  \node[inner sep=0pt] at (current page.center) {\includegraphics[width=\textwidth]{example-image.pdf}};
\end{tikzpicture}\ignorespaces
\ExplSyntaxOn
\fbox{\begin{minipage}{\textwidth}
  \mode_leave_vertical:
  \hbox_to_wd:nn { 2cm } { Classification }
  \uline { \hbox_to_wd:nn { 2.4cm } { \hfill 1234 \hfill } }
  \hfill
  \hbox_to_wd:nn { 1.67cm } { Secret-level }
  \uline { \hbox_to_wd:nn { 2.4cm } { \hfill AAAA \hfill } }
\end{minipage}}
\ExplSyntaxOff

\noindent\begin{minipage}{\textwidth}
  Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
\end{minipage}

\end{document}

Answer 2

我不確定expl3在這種情況下使用您會獲得多少收益。更直接地說，你只是把事情變得太複雜了，因為 LaTeX 已經有了所需的工具。

minipage嵌套在的頂部\fbox應該是\framebox.也要小心端線。

\documentclass[a4paper]{article}
\usepackage{tikz}
%\usepackage[showframe]{geometry}
\usepackage{ulem}

\begin{document}

\noindent
\begin{tikzpicture}[remember picture, overlay]
  \node[inner sep=0pt] at (current page.center) {%
    \includegraphics[width=\textwidth]{example-image.pdf}%
  };
\end{tikzpicture}% <--- important
\begingroup\setlength{\fboxsep}{0pt}%
\framebox[\dimeval{\textwidth-2\fboxrule}][s]{%
  \strut
  \,Classification
  \uline{\makebox[2.4cm][c]{1234}}%
  \hfill
  Secret-level
  \uline{\makebox[2.4cm][c]{AAAA}}%
}
\endgroup

\bigskip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod 
tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim 
veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex 
ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate 
velit esse cillum dolore eu fugiat nulla pariatur.

\end{document}

的寬度\framebox由 修正\fboxrule，因此不會過滿。

應\noindent位於 之前tikzpicture。

\documentclass[a4paper]{article}
\usepackage{tikz}
%\usepackage[showframe]{geometry}
\usepackage{ulem}

\begin{document}

\noindent
\begin{tikzpicture}[remember picture, overlay]
  \node[inner sep=0pt] at (current page.center) {%
    \includegraphics[width=\textwidth]{example-image.pdf}%
  };
\end{tikzpicture}% <--- important
\begingroup\setlength{\fboxsep}{0pt}%
\framebox[\dimeval{\textwidth-2\fboxrule}][s]{%
  \strut
  \,Classification
  \uline{\makebox[2.4cm][c]{1234}}%
  \hfill
  Secret-level
  \uline{\makebox[2.4cm][c]{AAAA}}%
}
\endgroup

\bigskip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod 
tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim 
veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex 
ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate 
velit esse cillum dolore eu fugiat nulla pariatur.

\end{document}