Fixing TeX4ht/TeX4ebook Footnote Indentation With KOMA-Script's Scrbook Class

Jul 26, 2025 by stackftunila 78 views

Why TeX4ht/TeX4ebook Ignores Second Paragraph Start in Footnotes with KOMA-Script's scrbook Class

Introduction

In this comprehensive article, we will delve into a peculiar issue encountered when using TeX4ht or TeX4ebook with the KOMA-Script scrbook class. Specifically, we will address the problem of these tools ignoring the start of the second paragraph within footnotes. This is a common challenge for users who rely on KOMA-Script for typesetting their documents and TeX4ht or TeX4ebook for converting them into formats like EPUB3. Understanding the root cause of this issue and implementing effective solutions is crucial for maintaining the integrity and readability of digital documents.

This article aims to provide a detailed explanation of the problem, explore the underlying reasons, and offer practical solutions to ensure that footnotes are rendered correctly in the final output. We will use a minimal working example (MWE) to illustrate the issue and demonstrate the effectiveness of the proposed solutions. By the end of this article, readers should have a clear understanding of how to handle footnotes in KOMA-Script documents when using TeX4ht or TeX4ebook.

Understanding the Problem

The core issue at hand is that when using the scrbook class from the KOMA-Script suite in conjunction with TeX4ht or TeX4ebook, the second paragraph (and subsequent paragraphs) within a footnote may not be correctly indented or formatted. This results in a visual discrepancy where the first paragraph of the footnote appears correctly, but the following paragraphs are not properly aligned, making the text look disjointed and unprofessional. This behavior is not typically observed when compiling the document with standard LaTeX engines like pdfLaTeX or XeLaTeX, which correctly handle paragraph indentation within footnotes.

To illustrate this problem, consider a scenario where you have a lengthy footnote that spans multiple paragraphs. In a well-formatted document, each paragraph within the footnote should be clearly distinguishable, usually through indentation. However, when processed with TeX4ht or TeX4ebook, the indentation for the second and subsequent paragraphs might be missing, causing the footnote to appear as a single block of text. This can significantly reduce readability, especially in documents with numerous or lengthy footnotes.

This issue is particularly relevant for users who are converting their documents into digital formats like EPUB for e-readers. Proper formatting is essential for a pleasant reading experience, and inconsistencies in footnote rendering can detract from the overall quality of the document. Therefore, addressing this problem is crucial for anyone using KOMA-Script and TeX4ht or TeX4ebook for digital publishing.

Minimal Working Example (MWE)

To better understand the issue, let's consider a Minimal Working Example (MWE). An MWE is a small, self-contained document that demonstrates the problem in its simplest form. This allows us to isolate the issue and test potential solutions more effectively. Here’s an example:

\documentclass{scrbook}

\setkomafont{footnote}{\normalsize} % Just to declutter the HTML a bit.

\begin{document}
\chapter{Introduction}
This is some text with a footnote.\footnote{This is the first paragraph of the footnote.

This is the second paragraph of the footnote. It should be indented, but it is not when processed with TeX4ht or TeX4ebook.

This is the third paragraph. We want all paragraphs after the first to be indented correctly.}

More text here.
\end{document}

In this example, we have a simple document using the scrbook class. The footnote contains three paragraphs. When this document is compiled using TeX4ht or TeX4ebook, the second and third paragraphs within the footnote will likely not be indented correctly in the output format (e.g., HTML or EPUB). This MWE clearly demonstrates the problem we are trying to solve.

The command \setkomafont{footnote}{\normalsize} is used to set the font size of the footnote text to \normalsize. This is done to simplify the HTML output and make it easier to identify the formatting issues. While not directly related to the problem of paragraph indentation, it helps in decluttering the output and focusing on the core issue.

To compile this example, you would typically use a command like tex4ebook -l -f epub3 test.tex p-indent,fn-in. This command tells TeX4ebook to process the test.tex file and convert it into an EPUB3 format, applying the p-indent and fn-in options, which are intended to handle paragraph indentation and footnote placement, respectively. However, even with these options, the issue with footnote paragraph indentation persists, highlighting the need for a more specific solution.

Root Cause Analysis

To effectively address the issue of missing paragraph indentation in footnotes, it's essential to understand the underlying cause. The problem arises from the way TeX4ht and TeX4ebook handle the interaction between KOMA-Script's footnote implementation and their own typesetting algorithms. Specifically, the default CSS generated by TeX4ht or TeX4ebook for footnotes may not correctly account for the paragraph indentation settings defined by KOMA-Script.

KOMA-Script provides extensive customization options for document layout, including footnotes. It uses its own mechanisms for managing footnote formatting, which may not be fully compatible with the default HTML and CSS conversion processes of TeX4ht and TeX4ebook. These tools rely on CSS to define the visual appearance of the document elements in the output format. If the generated CSS does not include specific rules for paragraph indentation within footnotes, the default browser rendering will apply, which typically does not include indentation for subsequent paragraphs.

The p-indent option in TeX4ebook is intended to handle paragraph indentation, but it may not always apply correctly within the context of KOMA-Script footnotes. This is because the option might not be targeting the specific CSS classes or elements used for footnote paragraphs. Similarly, the fn-in option, which is designed to handle footnote placement, does not directly address the issue of paragraph indentation within the footnote text.

Another factor to consider is the complexity of LaTeX's macro system. Footnotes are implemented using a combination of macros and environments, and TeX4ht and TeX4ebook need to correctly interpret these macros and translate them into equivalent HTML and CSS. If the translation is not precise, certain formatting aspects, such as paragraph indentation, may be lost or misinterpreted.

In summary, the root cause of the problem lies in the interplay between KOMA-Script's footnote formatting, the CSS generation by TeX4ht or TeX4ebook, and the intricacies of LaTeX macro translation. A solution requires either customizing the CSS to include the necessary indentation rules or modifying the TeX4ht or TeX4ebook configuration to handle KOMA-Script footnotes more effectively.

Solutions and Workarounds

Several solutions and workarounds can address the issue of missing paragraph indentation in footnotes when using TeX4ht or TeX4ebook with the scrbook class. These solutions primarily involve customizing the CSS or using TeX4ht configuration files to ensure correct rendering of footnotes.

1. Custom CSS

The most direct approach is to add custom CSS rules that specifically target paragraphs within footnotes. By defining the text-indent property for paragraphs inside footnotes, we can ensure that subsequent paragraphs are correctly indented. Here’s an example of CSS code that can be included in your document or in a separate CSS file:

.footnote p + p {
 text-indent: 1em; /* Adjust the indentation as needed */
}

This CSS rule uses a selector p + p which targets all paragraph elements that are immediately preceded by another paragraph element within the .footnote class. This effectively indents all paragraphs after the first one in the footnote. The text-indent property is set to 1em, but you can adjust this value to suit your document’s style.

To include this CSS in your TeX4ht or TeX4ebook output, you can use the \Css{...} command in your LaTeX document or link an external CSS file. For example:

\documentclass{scrbook}

\setkomafont{footnote}{\normalsize}

\begin{document}
\Css{
.footnote p + p {
 text-indent: 1em;
}
}

\chapter{Introduction}
This is some text with a footnote.\footnote{This is the first paragraph of the footnote.

This is the second paragraph of the footnote. It should be indented, and now it is.

This is the third paragraph. All paragraphs after the first are now indented correctly.}

More text here.
\end{document}

2. TeX4ht Configuration Files

Another approach is to use TeX4ht configuration files (.cfg files) to customize the conversion process. These files allow you to specify HTML and CSS code that should be inserted at various points in the output. This method is more flexible and allows for more complex customizations.

Create a file named myconfig.cfg (or any name you prefer) with the following content:

\Preamble{css=myconfig.css}

This line tells TeX4ht to use the CSS defined in myconfig.css. Now, create a file named myconfig.css with the CSS rule for footnote paragraph indentation:

.footnote p + p {
 text-indent: 1em;
}

When you compile your document with TeX4ht or TeX4ebook, specify the configuration file using the -c option:

tex4ebook -l -f epub3 test.tex -c myconfig p-indent,fn-in

This command tells TeX4ebook to use the myconfig.cfg file, which in turn includes the myconfig.css file, ensuring that the custom CSS rules are applied.

3. Modifying TeX4ht Macros

For more advanced users, it is possible to modify the TeX4ht macros directly to handle footnote formatting. This involves understanding the internal workings of TeX4ht and how it processes LaTeX macros. This approach is more complex but can provide fine-grained control over the output.

The basic idea is to redefine the macros responsible for generating footnote HTML to include the necessary CSS classes or styles for paragraph indentation. This might involve creating a custom TeX4ht style file or modifying the existing ones.

However, this method requires a deep understanding of TeX4ht's internals and is generally recommended only for users with significant experience in TeX and TeX4ht.

4. Using a Package for Footnote Management

Some LaTeX packages provide enhanced footnote management capabilities and may interact better with TeX4ht and TeX4ebook. For example, the footmisc package offers various options for customizing footnote behavior, and it might help in ensuring consistent formatting across different output formats.

To use footmisc, include it in your document preamble:

\documentclass{scrbook}
\usepackage{footmisc}

\setkomafont{footnote}{\normalsize}

\begin{document}
...
\end{document}

Experiment with the options provided by footmisc to see if they resolve the indentation issue. While this approach might not directly address the problem, it can sometimes provide a workaround by changing the way footnotes are handled internally.

Conclusion

The issue of missing paragraph indentation in footnotes when using TeX4ht or TeX4ebook with KOMA-Script's scrbook class can be a frustrating problem. However, by understanding the root cause and implementing the solutions outlined in this article, you can ensure that your footnotes are correctly formatted in the final output.

The most effective solutions involve customizing the CSS to include rules for paragraph indentation within footnotes or using TeX4ht configuration files to control the conversion process. These methods provide a reliable way to address the problem and maintain the visual integrity of your documents.

For users who require more fine-grained control, modifying the TeX4ht macros directly is an option, but it requires a deeper understanding of TeX4ht's internals. Additionally, using packages like footmisc might offer alternative approaches to footnote management that can sometimes mitigate the issue.

In summary, by applying the techniques discussed in this article, you can overcome the challenge of footnote paragraph indentation and create professional-looking documents with TeX4ht or TeX4ebook and KOMA-Script.