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Is there a TeX command that returns the width of a given text as length value, so that I can use the result directly as a length argument of another command?

I mean, I would like to have a command \getWidth{my text} and want to use the result directly as the first argument of \parbox:

\parbox{\getWidth{my text}}{my foo\\bar text}
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4 Answers 4

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169

Use the calc package (\usepackage{calc}):

\parbox{\widthof{my text}}{...}

An “only primitives” approach would be

\newdimen\mywidth
\setbox0=\hbox{<text to measure>}
\mywidth=\wd0

and then use \mywidth.

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11
  • 2
    @M.Reza mu can be used only in math and only for \mkern or \mskip.
    – egreg
    Nov 22, 2013 at 10:04
  • 2
    @zyy \widthof returns a suitable result only in some places, one of which is the argument to \parbox. Unfortunately textpos cannot use it, as far as I know.
    – egreg
    May 1, 2020 at 19:58
  • 2
    @zyy One usually does something like \settowidth{\dimen0}{<text>} and then passes \dimen0 to the macro that has to use the width.
    – egreg
    May 1, 2020 at 20:26
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    @egreg I found out why, textblock takes in a relative value with no units while \widthof returns with a unit, this is explained in the documentation of textpos where it talks about troubleshooting Missing number, treated as zero.
    – zyy
    May 2, 2020 at 4:09
  • 1
    @zyy Oh, yes. I tried textblock quite a long time ago; there is textpos* that accepts lengths, AFAIR.
    – egreg
    May 2, 2020 at 8:26
160

I like to answer the question in a more general way, so that it is useful to a wider group of people.

There are the following macros which allow to store the width, height (the material above the baseline) and depth (the material below the baseline) of a given content.

\settowidth{\somelength}{<content>}
\settodepth{\somelength}{<content>}
\settoheight{\somelength}{<content>}

The calc package also provides one for the total height (height + depth):

\settototalheight{\somelength}{<content>}

as well as

\widthof{<content>}
\heightof{<content>}
\depthof{<content>}
\totalheightof{<content>}

which can be used directly inside \setlength or \addtolength.

If you need multiple dimension of the same content you can also store it in a box register and use its dimension directly (the above macros do this as well internally). These are dimension expressions and can be prefixed with a factor, e.g. .5\wd\mybox is half the width.

\newsavebox\mybox
\sbox{\mybox}{<content>}
\wd\mybox % width
\ht\mybox % height
\dp\mybox % depth

For the totalheight you need to add \ht\mybox and \dp\mybox together.

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3
113

This can be done without the calc package

\documentclass{article}

\begin{document}
  \newlength{\myl}
  \settowidth{\myl}{test text}
  \the\myl
\end{document}

\the\myl will print out the value ~37pt.

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0
6

Here is an option with pgf

% !Mode:: "TeX:UTF-8"
\documentclass{article}
\usepackage{pgf}

\begin{document}
\noindent
\pgfmathwidth{"length you wanted"}
\parbox{\pgfmathresult pt}{the text you want to print out}
\end{document}

where \pgfmathwidth returns width of the text contained in the double quotes to \pgfmathresult, notice the result of \pgfmathwidth is always in points and only the numeric value is provided

parbox

By the way, \pgfmathwidth works for Chinese characters as well.

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