示例开始和结束前的一行

Question

我有这个示例风格：

\newtheoremstyle{example}{}{}{}{}{\bfseries}{\smallskip}{\newline}{}
\theoremstyle{example}
\newtheorem{example}{Example}

我想在“示例”标题之前和示例结束之后添加一条细小而粗的浅绿色线条。可以这样做吗？

Answer 1

这是有可能的。比如

\documentclass{article}
\usepackage{amsthm}
\newtheoremstyle{example}{}{}{}{}{\bfseries}{\smallskip}{\newline}{}
\theoremstyle{example}
\newtheorem{example}{Example}
%%
\usepackage[nopar]{lipsum}
\usepackage{xcolor}
%%
\newenvironment{greenexample}{%
  \par\noindent{\color{green}\hrule height 1pt}\hfill\vspace*{-\baselineskip}
  \begin{example}%
  }{%
    \strut{\color{green}\hrule height 1pt\hfill}
  \end{example}
}
\begin{document}
\lipsum[2]

\begin{example}[Test]
  As an example \textit{e.g.} can be used.
\end{example}

\lipsum[2]

\begin{greenexample}[Test]
  As an example \textit{e.g.} can be used.  
\end{greenexample}

\lipsum[2]
\end{document}

Answer 2

一个简单的解决方案thmtools，它与配合使用amsthm：

\documentclass{article}
\usepackage{amsthm, thmtools}

\newtheoremstyle{example}{}{}{}{}{\bfseries}{\smallskip}{\newline}{}
%
\declaretheorem[%
style=example,%
preheadhook={\bigskip{\color{DarkSeaGreen3}\hrule height 0.8pt\vspace{-1ex}}},%
postfoothook={\vspace{-0.8ex}{\color{DarkSeaGreen3}\hrule height 0.8pt}\bigskip}]%
{Example}%
\usepackage{lipsum, graphicx}
\usepackage[x11names]{xcolor}

\begin{document}

\lipsum[2]
%
\begin{Example}[Test]
  As an example \textit{e.g.} can be used by Latin lovers ; o)
  \begin{center}
    \includegraphics[scale=0.5]{pepe-le-pew2}
  \end{center}
\end{Example}
%
\lipsum[11]

\end{document}