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In the following MWE I have a centred piece of unbreakable text. Problem is that this causes an extra bit of vertical space, so that visually the centred text is not vertically centred between the two paragraphs. What is the best way to deal with this?
\documentclass{article}
\usepackage{lipsum}
\begin{document}
\lipsum[2]
\begin{center}
\texttt{a~sentence~that~is~long~and~continues~with~the~reason~so~that~it~sticks~out~a~bit}
\end{center}
\lipsum[3]
\end{document}
Don't use center (which is internally a list):
\documentclass{article}
\usepackage{lipsum}
\begin{document}
\lipsum[2]
{\par\bigskip\centering
\texttt{a~sentence~that~is~long~and~continues~with~the~reason~so~that~it~sticks~out~a~bit}
\par\bigskip}
\lipsum[3]
\end{document}
center is not the best choice (and similar flushleft and flushright). The idea to use a list structure to change the justification of a paragraph doesn't seems right. Generally I find it more natural to use commands like \raggedright or \centering.
– Ulrike Fischer
Jan 30 '13 at 16:47
\renewenvironment{center}{\par\bigskip\centering}{\par\bigskip} are there any catastrophic consequences? I mean, I have always used center as if it acted like this and am somewhat surprised that something I thought was obvious is in fact not the case.
– Geoff
Feb 1 '13 at 19:18
You're wondering why there's more vertical space before than after the unbreakable text, right?
Ulrike told you a good way to deal with it, I'd like to explain a bit why this happens. The problem is indeed the somewhat unfortunate definition of the center environment. This starts with \trivlist\centering\item\relax, so it uses the \centering command inside a trivial list. Now \item places an (empty) label as the first object to be centered, and your unbreakable text doesn't fit on the line, so TeX decides to put it on the next line. You can visualize this by redefining \trivlist so that the label isn't empty anymore:
Note that the LABEL isn't centered since I defined it so that it sticks out to the left.
\documentclass{article}
\makeatletter
\def\trivlist{%
\parsep\parskip
\@nmbrlistfalse
\@trivlist
\labelwidth\z@
\leftmargin\z@
\itemindent\z@
%\let\@itemlabel\@empty
\def\@itemlabel{\llap{LABEL}}
\def\makelabel##1{##1}}
\makeatother
\begin{document}
\noindent left \hfill right
\begin{center}
\texttt{a~sentence~that~is~not~so~long}
\end{center}
\noindent left \hfill right
\begin{center}
\texttt{a~sentence~that~is~long~and~continues~with~the~reason~so~that~it~sticks~out~a~bit}
\end{center}
\noindent left \hfill right
\end{document}
I think you're safe if you redefine the center environment to use Ulrike's suggestion. Note the \begingroup and \endgroup!
\renewenvironment{center}{\begingroup\par\bigskip\centering}{\par\bigskip\endgroup}
:-) As long as you only have short enough lines, the environment is quite satisfactory, at least in my opinion.
– Hendrik Vogt
Feb 1 '13 at 22:31
\renewenvironment{center}{\par\bigskip\centering}{\par\bigskip} and then I don't need to worry about it. Unless there is something that can happen that I don't know about.
– Geoff
Feb 2 '13 at 8:56
centeris one) add space before and after them. – Martin Schröder Jan 30 '13 at 17:08centerenvironment (which of course also occurs without long unbreakable text). The question is why there's additional space only before the environment! (So no, it's not a duplicate of that other question.) – Hendrik Vogt Jan 31 '13 at 21:53