根据宽度改变 \texheight

Question

你好。我想定义一个环境，根据宽度改变文本高度

\documentclass[a4paper]{book}
\usepackage{lipsum}

\begin{document}
\the\textwidth---\the\textheight

\newenvironment{whtext}[1]{%
\newpage\begingroup
\hsize=#1 
\vsize=\dimexpr\textheight*\numexpr\hsize/\textwidth\relax  
\textwidth=\hsize
\textheight=\vsize}%
{\endgroup\newpage}


\lipsum[1-10]

\begin{whtext}{15cm}
\the\textwidth---\the\textheight
\lipsum[1-20]
\the\textwidth---\the\textheight
\end{whtext}

\end{document}

我该做什么？

Answer 1

直接操纵等不是一个好主意textheight。该geometry软件包提供了使用 执行此操作的方法\newgeometry，但价格是\clearpage\newpage

\documentclass[a4paper]{book}
\usepackage{geometry}
\usepackage{lipsum}

\begin{document}
\the\textwidth---\the\textheight

\newenvironment{whtext}[1]{%
\newpage\begingroup
\hsize=#1 
\vsize=\dimexpr\textheight*\numexpr\hsize/\textwidth\relax  
\newgeometry{textheight=\vsize,textwidth=\hsize}
 }%
{\endgroup\newpage}


\lipsum[1-10]

\begin{whtext}{15cm}
\the\textwidth---\the\textheight

\lipsum[1-20]
\the\textwidth---\the\textheight
\end{whtext}

\begin{whtext}{10cm}
\the\textwidth---\the\textheight

\lipsum[1-20]
\the\textwidth---\the\textheight
\end{whtext}

\end{document}

Answer 2

我认为我有答案

\documentclass[a4paper]{book}
\usepackage{lipsum}

\begin{document}
\the\textwidth---\the\textheight

\makeatletter
\newenvironment{whtext}[1]{%
\newpage\begingroup
\hsize=#1 
\vsize=\dimexpr\textheight*\hsize/\textwidth\relax  
\textwidth=\hsize
\textheight=\vsize}%
{\endgroup\newpage}
\makeatother

\lipsum[1-10]

\begin{whtext}{15cm}
\the\textwidth---\the\textheight
\lipsum[1-20]
\the\textwidth---\the\textheight
\end{whtext}

\end{document}