Table of Contents chapter number width

Question

I am using the tocloft package to design my table of contents. I know how to set the width of the chapter numbers in the toc using

\setlength{\cftchapnumwidth}{2em}

However this sets a fixed width of 2em for all chapter numbers. Some chapter numbers need more space than others - .e.g. XVII vs V. Is there a way to set the width to dynamically include the width of the chapter number followed by one space?

Answer 1

In this instance you're most likely interested in adjusting the number widths of all sectional units in the ToC, since they are usually set hierarchically. As such, a simple redefinition of the \numberline macro suffices:

\usepackage{tocloft}% http://ctan.org/pkg/tocloft
\makeatletter
\renewcommand{\numberline}[1]{%
  \@cftbsnum #1\@cftasnum~\@cftasnumb%
}
\makeatother

The above removes the former \hb@xt@\@tempdima{...} construction, which sets the number inside a fixed-width box, left-aligned. In fact, the original definition made by tocloft is:

\renewcommand{\numberline}[1]{%
  \hb@xt@\@tempdima{\@cftbsnum #1\@cftasnum\hfil}\@cftasnumb}

Here's a minimal working example showing the result:

\documentclass{report}
\usepackage{tocloft}% http://ctan.org/pkg/tocloft
\makeatletter
\renewcommand{\numberline}[1]{%
  \@cftbsnum #1\@cftasnum~\@cftasnumb%
}
\makeatother
\begin{document}
\tableofcontents
\chapter{A chapter}\section{A section}
\setcounter{chapter}{11}
\chapter{A chapter}\section{A section}
\setcounter{chapter}{122}
\chapter{A chapter}\section{A section}
\setcounter{chapter}{1233}
\chapter{A chapter}\section{A section}
\setcounter{chapter}{12344}
\chapter{A chapter}\section{A section}
\end{document}

Since the original definition left a "dynamic" gap between the number and the title, I've forced it to be ~ in my example. You can modify that to whatever length you're interested in (\quad, \hspace*{2em}, ...).

Note that this modification has to be inserted before calling \tableofcontents.