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全宽方框方程

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全宽方框方程

我想使用empheq框来将方程式居中对齐，但希望框能够跨越整个页面宽度。

  1. 传递gather/gather*环境会empheq产生中心对齐的方程式，但是框会紧紧包围方程式的内容。

  2. 传递flalign/flalign*环境来empheq产生全宽框但将方程式对齐到中心有点麻烦 - 必须手动完成并且需要一些猜测才能获得正确的对齐（我发现在某些情况下是不可能的）。

请参阅下面的 MWE。

\documentclass{article}
\usepackage[many]{tcolorbox}
\usepackage{empheq}
\usepackage{amsmath}

\newtcbox{\mymath}[1][]{%
    nobeforeafter, width=\textwidth, math upper, enhanced, 
    colframe=gray!10!white, boxrule=0pt, arc=1mm, outer arc=1mm, opacityback=0.5,
    frame hidden, borderline={0.5pt}{0pt}{gray!20!white},
    #1}

\begin{document}
    \begin{enumerate}
        \item Boxed equation using \texttt{empheq} and \texttt{gather*}
        \begin{empheq}[box=\mymath]{gather*}
            \sigma_{xx} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{xx} + \nu(\epsilon_{yy} + \epsilon_{zz})\right] \\ 
            \sigma_{yy} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{yy} + \nu(\epsilon_{xx} + \epsilon_{zz})\right] \\ 
            \sigma_{zz} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{zz} + \nu(\epsilon_{xx} + \epsilon_{yy})\right] \\ 
            \tau_{xy} = G\gamma_{xy} \\ 
            \tau_{yz} = G\gamma_{yz} \\ 
            \tau_{xz} = G\gamma_{xz}
        \end{empheq}
        \item Boxed equation using \texttt{empheq} and \texttt{flalign*}
        \begin{empheq}[box=\mymath]{flalign*}
            \sigma_{xx} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{xx} + \nu(\epsilon_{yy} + \epsilon_{zz})\right] \\ 
            \sigma_{yy} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{yy} + \nu(\epsilon_{xx} + \epsilon_{zz})\right] \\ 
            \sigma_{zz} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{zz} + \nu(\epsilon_{xx} + \epsilon_{yy})\right] \\ 
            \tau_{xy} = G\gamma_{xy} \\ 
            \tau_{yz} = G\gamma_{yz} \\ 
            \tau_{xz} = G\gamma_{xz}
        \end{empheq}
    \end{enumerate}
\end{document}

产生以下输出。 与框的对齐示例。

答案1

需要告知 tcbox 尊重其自己的宽度键tcbox width=forced center（其中一个对齐在此处给出了过度警告，但我认为这是虚假的）

在此处输入图片描述

\documentclass{article}
\usepackage[many]{tcolorbox}
\usepackage{empheq}
\usepackage{amsmath}

\newtcbox{\mymath}[1][]{%
    nobeforeafter, width=\linewidth, math upper, enhanced, 
    colframe=gray!10!white, boxrule=0pt, arc=1mm, outer arc=1mm, opacityback=0.5,
    frame hidden, borderline={0.5pt}{0pt}{gray!20!white},tcbox width=forced center
    #1}

\begin{document}

\noindent X\dotfill X

    \begin{enumerate}
        \item Boxed equation using \texttt{empheq} and \texttt{gather*}
        \begin{empheq}[box=\mymath]{flalign*}
            \sigma_{xx} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{xx} + \nu(\epsilon_{yy} + \epsilon_{zz})\right] \\ 
            \sigma_{yy} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{yy} + \nu(\epsilon_{xx} + \epsilon_{zz})\right] \\ 
            \sigma_{zz} = \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{zz} + \nu(\epsilon_{xx} + \epsilon_{yy})\right] \\ 
            \tau_{xy} = G\gamma_{xy} \\ 
            \tau_{yz} = G\gamma_{yz} \\ 
            \tau_{xz} = G\gamma_{xz}
        \end{empheq}
        \item Boxed equation using \texttt{empheq} and \texttt{gather*}
        \begin{empheq}[box=\mymath]{gather*}
    a=b\\
   c=d
        \end{empheq}
        \item Boxed equation using \texttt{empheq} and \texttt{flalign*}
        \begin{empheq}[box=\mymath]{flalign*}
            \sigma_{xx} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{xx} + \nu(\epsilon_{yy} + \epsilon_{zz})\right] \\ 
            \sigma_{yy} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{yy} + \nu(\epsilon_{xx} + \epsilon_{zz})\right] \\ 
            \sigma_{zz} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{zz} + \nu(\epsilon_{xx} + \epsilon_{yy})\right] \\ 
            \tau_{xy} &= G\gamma_{xy} \\ 
            \tau_{yz} &= G\gamma_{yz} \\ 
            \tau_{xz} &= G\gamma_{xz}
        \end{empheq}
        \item Boxed equation using \texttt{empheq} and \texttt{align*}
        \begin{empheq}[box=\mymath]{align*}
            \sigma_{xx} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{xx} + \nu(\epsilon_{yy} + \epsilon_{zz})\right] \\ 
            \sigma_{yy} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{yy} + \nu(\epsilon_{xx} + \epsilon_{zz})\right] \\ 
            \sigma_{zz} &= \frac{E}{(1+\nu)(1-2\nu)}\left[(1-\nu)\epsilon_{zz} + \nu(\epsilon_{xx} + \epsilon_{yy})\right] \\ 
            \tau_{xy} &= G\gamma_{xy} \\ 
            \tau_{yz} &= G\gamma_{yz} \\ 
            \tau_{xz} &= G\gamma_{xz}
        \end{empheq}
    \end{enumerate}
\end{document}

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