Using etoolbox to Adjust Vertical Space

Oct 13, 2025 by miodeya.com 31 views

Introduction

When working with long documents, it's essential to have a well-organized Table of Contents (TOC) that provides a clear overview of the content. However, the default vertical space between parts in the TOC might not always be suitable for your needs. In this article, we'll explore how to adjust the vertical space between parts in the TOC using LaTeX.

Understanding the Problem

By default, LaTeX uses a fixed vertical space between parts in the TOC. This can lead to an uneven layout, especially when dealing with multiple parts or sections. To address this issue, we can use the etoolbox package to customize the TOC.

Using etoolbox to Adjust Vertical Space

The etoolbox package provides a range of tools for customizing LaTeX documents. To adjust the vertical space between parts in the TOC, we can use the \pretocmd command to add a custom command to the \part command.

\usepackage{etoolbox}
\makeatletter
\pretocmd{\part}{\addtocontents{toc}{\protect\addvspace{-...}}{}}
\makeatother

In the above code, \pretocmd is used to add a custom command to the \part command. The \addtocontents command is used to add a custom line to the TOC. The \addvspace command is used to add a vertical space of a specified size.

Customizing the Vertical Space

To customize the vertical space between parts in the TOC, we need to specify the size of the vertical space using the \addvspace command. The size of the vertical space can be specified in points (pt), inches (in), or other units.

\usepackage{etoolbox}
\makeatletter
\pretocmd{\part}{\addtocontents{toc}{\protect\addvspace{-10pt}}{}}
\makeatother

In the above code, the vertical space between parts in the TOC is set to -10pt. This will reduce the vertical space between parts in the TOC.

Adjusting the Vertical Space for Different Parts

If you want to adjust the vertical space between parts in the TOC differently for different parts, you can use the \addtocontents command with a conditional statement.

\usepackage{etoolbox}
\makeatletter
\pretocmd{\part}{\ifnum\value{part}=1\relax
  \addtocontents{toc}{\protect\addvspace{-10pt}}
\else
  \addtocontents{toc}{\protect\addvspace{-20pt}}
\fi}{}}
\makeatother

In the above code, the vertical space between parts in the TOC is set to -10pt for the first part and -20pt for subsequent parts.

Conclusion

Customizing the vertical space between parts in the TOC is an essential aspect of document design. Using the etoolbox package, we can easily adjust the vertical space between parts in the TOC to suit our needs. By following the steps outlined in this article, you can create a well-organized TOC that provides a clear overview of your document's content.

Example Use Case

Here's an example use case that demonstrates how to adjust the vertical space between parts in the TOC:

\documentclass{book}
\usepackage{etoolbox}
\makeatletter
\pretocmd{\part}{\addtocontents{toc}{\protect\addvspace{-10pt}}{}}
\makeatother
\begin{document}
\tableofcontents
\part{Part 1}
\chapter{Chapter 1}
\chapter{Chapter 2}
\part{Part 2}
\chapter{Chapter 3}
\chapter{Chapter 4}
\end{document}

In this example, the vertical space between parts in the TOC is set to -10pt. This will reduce the vertical space between parts in the TOC.

Tips and Variations

To increase the vertical space between parts in the TOC, use a positive value with the \addvspace command.
To remove the vertical space between parts in the TOC, use the \addvspace command with a value of 0pt.
To customize the vertical space between chapters in the TOC, use the \pretocmd command with the \chapter command instead of the \part command.
Frequently Asked Questions: Customizing the Table of Contents ====================================================================

Q: What is the purpose of customizing the Table of Contents?

A: Customizing the Table of Contents (TOC) is essential for creating a well-organized and visually appealing document. By adjusting the vertical space between parts in the TOC, you can improve the overall layout and make it easier for readers to navigate your document.

Q: How do I adjust the vertical space between parts in the TOC?

A: To adjust the vertical space between parts in the TOC, you can use the etoolbox package and the \pretocmd command to add a custom command to the \part command. You can then use the \addtocontents command to add a custom line to the TOC and the \addvspace command to specify the size of the vertical space.

Q: What units can I use to specify the size of the vertical space?

A: You can use points (pt), inches (in), or other units to specify the size of the vertical space. For example, you can use \addvspace{-10pt} to reduce the vertical space between parts in the TOC by 10 points.

Q: Can I customize the vertical space between chapters in the TOC?

A: Yes, you can customize the vertical space between chapters in the TOC by using the \pretocmd command with the \chapter command instead of the \part command.

Q: How do I remove the vertical space between parts in the TOC?

A: To remove the vertical space between parts in the TOC, you can use the \addvspace command with a value of 0pt. For example, you can use \addtocontents{toc}{\protect\addvspace{0pt}} to remove the vertical space between parts in the TOC.

Q: Can I adjust the vertical space between parts in the TOC differently for different parts?

A: Yes, you can adjust the vertical space between parts in the TOC differently for different parts by using the \addtocontents command with a conditional statement. For example, you can use \ifnum\value{part}=1\relax to check if it's the first part and then use \addtocontents{toc}{\protect\addvspace{-10pt}} to reduce the vertical space between parts in the TOC.

Q: What are some common mistakes to avoid when customizing the TOC?

A: Some common mistakes to avoid when customizing the TOC include:

Using the wrong units to specify the size of the vertical space
Not using the \protect command to protect the \addvspace command
Not using the \addtocontents command to add a custom line to the TOC
Not using the \pretocmd command to add a custom command to the \part command

Q: How do I troubleshoot issues with the TOC?

A: To troubleshoot issues with the TOC, you can try the following:

Check the LaTeX log file for errors
Use the \showthe command to display the value of a variable
Use the \typeout command to print a message to the console
Use the \tracingall command to enable tracing for the TOC

Q: Can I customize the TOC using other packages?

A: Yes, you can customize the TOC using other packages such as tocloft or tocstyle. However, the etoolbox package is a popular and widely-used package for customizing the TOC.

Q: How do I update the TOC after making changes to the document?

A: To update the TOC after making changes to the document, you can use the \tableofcontents command to regenerate the TOC. You can also use the \clearpage command to clear the page and then use the \tableofcontents command to regenerate the TOC.