Section titles, hyphenation, manual line breaks - and how to avoid them

Question

I have several section titles in my document that are getting hyphenated, which is quite ugly.

I am now looking for some way to avoid the hyphenation, which is is somewhat related to this question, but unfortunately my titles have to be centered (so raggedright is not an option), and adding \sloppy to my titlesec definition of the subsection format didn't help:

\newcommand{\trailthesubsection}[1]{\MakeUppercase{#1} (\thesubsection)}
\titleformat{\subsection}
    {\normalfont\fontsize{15pt}{16pt}\bfseries\sffamily\sloppy} % <- "sloppy" didn't help.
    {}
    {0pt}
    {\filcenter\trailthesubsection}

I could, of course, set manual linebreaks - but in order not to destroy the layout of my TOC in the process, I would have to use the optional parameter to the section commands:

\subsection[Could do this but it is not nice]{Could do this\\ but it is not nice}

Isn't there some way to suppress hyphenation for a given text (e.g. by some command in the \titleformat), or to suppress manually-set linebreaks in the TOC?

Answer 1

See this question in the TeX FAQ for a discussion of four different methods for turning off hyphenation. Method three and four consist of adding the instructions

\righthyphenmin62 %% or whatever's large enough ...

and

\hyphenchar\font=-1

respectively. The latter approach is used in the following MWE:

\documentclass{article}
\usepackage{titlesec}
\titleformat*{\section}{\sloppy\bfseries\Large\hyphenchar\font=-1}
\begin{document}
\section{Supercalifragilisticexpialidocious 
   Supercalifragilisticexpialidocious 
   Supercalifragilisticexpialidocious Supercalifragilisticexpialidocious 
   Supercalifragilisticexpialidocious Supercalifragilisticexpialidocious 
   Supercalifragilisticexpialidocious Supercalifragilisticexpialidocious }
\ldots with apologies to Julie Andrews.
\end{document}

Note that the \sloppy command will prevent TeX from creating (seriously!) overfull lines in the section title.

Note (thanks to egreg): the \hyphenchar\font-1 instruction is global, so all other text in the document set in \bfseries\Large will also see hyphenation suppressed -- which may (or may not) be what's desired. Therefore, the \righthyphenmin62 method may be marginally safer to use (pun intended). However, according the TeX FAQ's answer noted earlier, if you're a babel user the method of resetting the \left- and/or \righthyphenmin macros won't work as babel resets them internally.

Addendum: To prevent hyphenation in the optional shortened section title (to be displayed in the table of contents), one would have to insert the instructions

\protect{\hyphenchar\font=-1}\protect\sloppy

at the start of the material in the optional argument of the \section command. (My feeling is that if a section caption is longer than one line, it's probably wise to provide a shortened caption that's short enough not to need a line break at all.)

Answer 2

One way that work is

\newif\ifintoc
\DeclareRobustCommand{\titlebreak}{%
  \ifintoc
    \unskip\space
  \else
    \newline
  \fi}

Then do the Table of Contents by

\begingroup\intoctrue
\tableofcontents
\endgroup

and your title can be input as

\subsection{Could do this\titlebreak but it is not nice}

It's also possible to inject \intoctrue in the code for \tableofcontents.

LaTeX will write \titlebreak in the .toc file, but when this one is read in, \titlebreak will mean "leave a normal space". During normal processing of the document it will mean "break line here". The \unskip\space is to prevent a double space in

 \subsection{Could do this \titlebreak but it is not nice}

or no space in

 \subsection{Could do this\titlebreak but it is not nice}