[Tex/LaTex] Extendible equals sign

amsmathmacrossymbols

I have a command that has been floating around in my standard preamble for a while:

\newcommand{\xeq}[1]{\stackrel{\;#1}{\cleaders\hbox{=\!}\hfill}\:}

It is meant to mimic the AMS-LaTeX extendible arrow symbols \xleftarrow and \xrightarrow.

It's not perfect for two reasons:

It does not take the optional lower argument like the AMS \xrightarrow[down]{up}
The overlap of the constituent equals signs is slightly visible.

Does anyone have a better command or know of a package with such a command?

Best Answer

I think you can more or less copy the definitions from amsmath.sty:

\documentclass{minimal}

\usepackage{amsmath}

\makeatletter
\newcommand*{\Relbarfill@}{\arrowfill@\Relbar\Relbar\Relbar}
\newcommand*{\xeq}[2][]{\ext@arrow 0055\Relbarfill@{#1}{#2}}
\makeatother

\begin{document}

$a \xeq[uuuuu]{vvv} b$

\end{document}

Related Solutions

[Tex/LaTex] Extendible \cong congruence sign

One could always use \resizebox to stretch the symbol.

\documentclass{article}
\usepackage{amsmath,graphicx}
\makeatletter
\newcommand*\morph[1]{%
    \setbox0=\hbox{\scriptsize#1}%
    \setbox2=\hbox{$\m@th{\cong}$}%
    \stackrel{\copy0}{%
        \ifdim\wd2<\wd0
            \resizebox{\wd0}{\ht2}{$\m@th{\cong}$}%
        \else
            \cong
        \fi
    }%
}
\begin{document}
\[X\morph{long text}Y\morph{i}Z\]
\end{document}

[Tex/LaTex] Short equals sign

graphicx allows for resizing things through \resizebox{<width>}{<height>}{<stuff>}. Here's what you could do:

enter image description here

\documentclass{article}
\usepackage{graphicx}% http://ctan.org/pkg/graphicx
\makeatletter
\newcommand{\shorteq}{%
  \settowidth{\@tempdima}{-}% Width of hyphen
  \resizebox{\@tempdima}{\height}{=}%
}
\makeatother
\begin{document}
Here is a~-~hyphen, here is a~\shorteq~sign.\par
Here is a~-~hyphen, here is a~=~sign.
\end{document}

The above MWE provides \shorteq that squishes a = into the width of - of the prevailing font.

textcomp also provides \textdblhyphen which is similar, but different:

enter image description here

\documentclass{article}
\usepackage{textcomp}% http://ctan.org/pkg/textcomp
\begin{document}
Here is a~-~hyphen, here is a~\textdblhyphen~sign.\par
Here is a~-~hyphen, here is a~=~sign.
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Extendible \cong congruence sign

[Tex/LaTex] Short equals sign

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