如何通过控制节的样式在每个节前添加一条水平线

Question

我想在每个部分之前添加水平线，就像这样

手动的话我可以直接放在\rule{\textwidth}{1pt}每个section前面，但是我想要更灵活的方法，比如通过在序言中放置几段代码来控制section的样式来实现。

Answer 1

您可能不希望该规则位于第一节之前，也不希望该规则位于节从页面顶部开始时。以下代码可实现此目的。

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{titlesec}

\usepackage{lipsum}

\titleformat{\section}
  {\sectionrule\Large\bfseries}
  {\thesection}
  {1em}
  {}

% this command is executed at each \section command
\newcommand{\sectionrule}{%
  % no rule before the first section
  \ifnum\value{section}=0
  \else
    % otherwise, ensure being between paragraphs
    \par
    % add some vertical space
    \addvspace{\bigskipamount}%
    % the rule realized as leaders, so it disappears at a page break
    % see also http://tex.stackexchange.com/a/61643/4427
    \leaders\vrule width \textwidth\vskip0.4pt
    % some other vertical space
    \bigskip
  \fi
}


\begin{document}

\section{First}

\lipsum[1-3]

\section{Second}

\lipsum[2-6]\lipsum[2]\lipsum[2]

\section{Third}

\lipsum

\end{document} 

替代解决方案，在出现分页符的情况下将规则放在页面顶部。

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{titlesec}

\usepackage{lipsum}

\titleformat{\section}
  {\sectionrule\Large\bfseries}
  {\thesection}
  {1em}
  {}

\newcommand{\sectionrule}{%
    \par
    \addvspace{\bigskipamount}%
    \hrule
    \nopagebreak
    \bigskip
}

\begin{document}

\section{First}

\lipsum[1-3]

\section{Second}

\lipsum[2-6]\lipsum[2]\lipsum[2]

\section{Third}

\lipsum

\end{document}

Answer 2

使用 titlesec 很简单：

\documentclass{article}% http://ctan.org/pkg/amsproc

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fourier}
\usepackage{titlesec}

\titleformat{\section}{\vbox{\rule{\linewidth}{0.8pt}}\bigskip\LARGE\bfseries}{\thesection}{1em}{}
\begin{document}
\begin{equation}
  v = \sqrt{2gl(\cos\phi_0 - \cos \phi)}
\end{equation}
\section{Section two}

\end{document}