# Get two short subtitles out of a too long title

Is there a way to get n shorter strings out of a long one in Latex? Let's say I have something like \title{A very long title} and I want it to be broken into two pieces such that I can later use colorbox{red}{A very} and \color{blue}{long title}. The break point should be calculated through a distance provided by the user.

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Out of \title, yes, but you'll have to store the content first/before \maketitle since most document classes remove \@title - the placeholder macro. By distance, you mean characters? –  Werner Oct 22 '12 at 14:11
@Werner by distance, I mean "if it is longer than 8cm break the title". Here the use of the \title{} command was just an example. What I have in mind is related to the \chapter{} command. –  pluton Oct 22 '12 at 14:57
I don't think that, even if feasible in general, such an automatic procedure is good: breaking a title requires semantic considerations. For instance The story of\\my life would probably be better split as The story\\of my life. –  egreg Oct 22 '12 at 21:04
ok, so the user could indicated where the title should be broken but the two (sub-)strings are still desired. –  pluton Oct 23 '12 at 0:00
in which case a new command \chapter[optional]{substring1}{substring2} should be designed? –  pluton Oct 23 '12 at 0:11

I don't think you need anything special for the \chapter command:

\chapter[The real long title]
{\textcolor{red}{The real}\\
\textcolor{green}{long title}}


is all you need. You can abstract it with new commands:

\documentclass{book}
\usepackage{xcolor}
\usepackage{xparse}
\newcommand{\firstchapline}[1]{\textcolor{red}{#1}}
\newcommand{\secondchapline}[1]{\textcolor{green}{#1}}

\makeatletter
\NewDocumentCommand{\coloredchapter}{som}
{\IfBooleanTF{#1}
{\chapter*{#3}}
{\IfNoValueTF{#2}
{\make@coloredchapter{#3}}
{\chapter[#2]{#3}}%
}%
}
\newcommand{\make@coloredchapter}[1]{%
\begingroup
\let\firstchapline\@firstofone
\let\secondchapline\@firstofone
\let\\\space
\protected@edef\x{\endgroup\noexpand\chapter[#1]}%
\x{#1}}
\makeatletter

\begin{document}
\frontmatter
\tableofcontents
\mainmatter
\coloredchapter{\firstchapline{A really}\\\secondchapline{long title}}
\coloredchapter[Short title]{\firstchapline{A really}\\\secondchapline{long title}}
\coloredchapter*{\firstchapline{A really}\\\secondchapline{long title}}
\end{document}


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