如何为每个章节的第一段设置特定的字体

Question

我需要在每个章节的第一段使用不同的字体排版，并且我不希望这会影响\lstlisting。我尝试使用，\everypar但如果\lstlisting有，它会中断。我该怎么做？

Answer 1

以下适用于标准类（article、report、book）。它利用了最近版本的 LaTeX 中引入的新钩子。

您可能需要自己处理异常，至少对于像下面示例中那样的简单事情，一切都会顺利。

\documentclass[]{book}

\usepackage{listings}

% change this for your setup, restoreparformat should revert all the changes you
% introduce with firstparformat
\newcommand*\firstparformat  {\sffamily\large}
\newcommand*\restoreparformat{\rmfamily\normalsize}

% this injects the code into the hooks
% ------------------------------------
% changes should be global (just to make sure), hence we don't use `\newif`
\let\iffirstparformat\iffalse
\protected\def\firstparformatfalse{\global\let\iffirstparformat\iffalse}
\protected\def\firstparformattrue {\global\let\iffirstparformat\iftrue}
% sections are a hard thing, there are subsections and stuff all using the same
% internals
\protected\def\startsectionsaveform
  {%
    \global\let\startsectionsaveformTMP\iffirstparformat
    \firstparformatfalse
  }
\protected\def\startsectionrestoreform
  {\global\let\iffirstparformat\startsectionsaveformTMP}
\AddToHook{cmd/section/before}       {\firstparformattrue}
\AddToHook{cmd/@startsection/before} {\startsectionsaveform}
\AddToHook{cmd/@xsect/after}         {\startsectionrestoreform}
% chapters are way easier
\AddToHook{cmd/chapter/before}       {\firstparformatfalse}
\AddToHook{cmd/@chapter/after}       {\firstparformattrue}
\AddToHook{cmd/@schapter/after}      {\firstparformattrue}
% the paragraphs check whether they are the first and if so use the format
\AddToHook{para/begin}
  {%
    \iffirstparformat
      \expandafter\firstparformat
    \fi
  }
% at the end of the paragraph we might need to revert these changes
\AddToHook{para/after}
  {%
    \iffirstparformat
      \firstparformatfalse
      \expandafter\restoreparformat
    \fi
  }

% exceptions
\AddToHook{env/lstlisting/before}{\firstparformatfalse}

\usepackage{duckuments}

\begin{document}
\chapter{Chapter}
\blindduck[1-2]
\section{Section}
\blindduck[1-2]
\subsection{Subsection}
\blindduck[1-2]

\chapter{Chapter}
\section{Section}
\blindduck[1-2]
\chapter{Chapter}
\begin{lstlisting}
listing
listing
\listing
\end{lstlisting}
\end{document}