Beamer Check

Beamer Slide Deck Audit and Fix

Overview

This skill implements a compile → inspect → fix → verify loop for Beamer slide decks. The goal is to catch and fix all issues before the user has to open the PDF themselves.

Run the full audit protocol below. Do not skip the visual inspection phase — compilation warnings alone do not catch all layout problems.

Phase 1: Automated Compilation Check

Run the diagnostic script:

python {baseDir}/scripts/beamer_check.py <path-to-tex-file> --output-dir <work-dir>/beamer-check-output

This will:

1. Compile the .tex file twice with pdfLaTeX
2. Parse the log for errors, warnings, overfull/underfull boxes, and missing files
3. Render every slide to a PNG image for visual inspection
4. Write a diagnostics.json summary

Read the script output and the diagnostics.json file. Categorise every issue found:

• Compilation errors — the PDF was not produced or is incomplete
• Missing files — images, packages, or fonts that could not be found
• Overfull hbox — content wider than the text area (text running off the right edge)
• Overfull vbox — content taller than the slide area (text running off the bottom)
• Warnings — package conflicts, deprecated commands, missing references

Phase 2: Visual Inspection

This is the most important phase. Many layout problems produce no warnings at all.

Open and examine EVERY rendered slide image in beamer-check-output/slides/. For each slide, check for:

Text issues

• Text running off the right edge of the slide
• Text running off the bottom of the slide
• Text overlapping with other elements (headers, footers, images)
• Font size too small to read (below \footnotesize on a 16:9 slide)
• Orphaned words or lines that look awkward
• Verbatim/code blocks that exceed the text width

Layout issues

• Itemize/enumerate lists that overflow the frame
• Tables wider than the slide
• Columns that are misaligned or overlapping
• Excessive white space on one side, crowded on the other
• Content obscured by the Beamer theme elements (navigation bar, footer)

Image issues

• Missing images (blank spaces or error markers)
• Images that are distorted (wrong aspect ratio)
• Images that are too small to be useful
• Images that overflow the frame boundary

Structure issues

• Empty slides (no content rendered)
• Duplicate slide titles
• Table of contents that doesn't match actual section structure
• Frame titles that are cut off

Phase 3: Fix

For every issue identified in Phases 1 and 2, apply the appropriate fix. Ask the user before editing their file.

Common fixes reference

Text running off the right edge (overfull hbox):

% Option 1: Allow slightly loose spacing
\begin{frame}[fragile]{Title}
\sloppy
Content here...
\end{frame}

% Option 2: Reduce font size for that frame
\begin{frame}{Title}
\small  % or \footnotesize for more reduction
Content here...
\end{frame}

% Option 3: Break long lines manually
Very long text that needs to be broken\\
across multiple lines.

% Option 4: For URLs
\url{https://very-long-url.com/that/overflows}
% Replace with:
{\small\url{https://very-long-url.com/that/overflows}}

Content overflowing the bottom (overfull vbox):

% Option 1: Reduce font size
\begin{frame}{Title}
\small
Too much content...
\end{frame}

% Option 2: Use allowframebreaks to auto-split
\begin{frame}[allowframebreaks]{Title}
Lots of content that will auto-split across slides...
\end{frame}

% Option 3: Shrink the whole frame (use sparingly)
\begin{frame}[shrink=10]{Title}
Content...
\end{frame}

% Option 4 (best): Split into two slides manually
% This is usually the right answer for teaching slides

Verbatim/code blocks overflowing:

% Use fragile option on the frame
\begin{frame}[fragile]{Title}
\begin{verbatim}
code here
\end{verbatim}
\end{frame}

% For long code, reduce font size
\begin{frame}[fragile]{Title}
\begin{verbatim}
\small
code here
\end{verbatim}
\end{frame}

Tables too wide:

% Option 1: Use \resizebox
\resizebox{\textwidth}{!}{%
\begin{tabular}{lccccc}
...
\end{tabular}
}

% Option 2: Use \small or \footnotesize
{\footnotesize
\begin{tabular}{lccccc}
...
\end{tabular}
}

% Option 3: Use tabularx for automatic column width
\usepackage{tabularx}
\begin{tabularx}{\textwidth}{lXXX}
...
\end{tabularx}

Missing images:

% Add a fallback so compilation doesn't fail
\IfFileExists{image.png}{%
  \includegraphics[width=0.8\textwidth]{image.png}
}{%
  \textit{[Image not found: image.png]}
}

Column alignment issues:

% Make sure column widths sum to \textwidth
\begin{columns}[T]  % T = top-aligned
\begin{column}{0.48\textwidth}
Left content
\end{column}
\begin{column}{0.48\textwidth}
Right content
\end{column}
\end{columns}
% Leave ~0.04\textwidth for the gap between columns

Phase 4: Verify

After applying fixes:

1. Run the diagnostic script again on the modified file:

   python {baseDir}/scripts/beamer_check.py <path-to-tex-file> --output-dir <work-dir>/beamer-check-verify
   

2. Confirm that:

   • All previous compilation errors are resolved
   • No new errors or warnings were introduced
   • Overfull box count has decreased (ideally to zero)

3. Visually inspect the re-rendered slides again, focusing on the slides that were modified. Confirm the fixes worked and didn't introduce new layout problems.

4. If new issues are found, repeat Phases 3-4 until clean.

Phase 5: Report

Present a summary to the user:

Beamer Audit Complete
=====================
Slides checked: [N]
Issues found: [N]
Issues fixed: [N]
Remaining issues: [N] (with explanation if any)

Changes made:
- Slide 3: Reduced font size to \small (text overflow)
- Slide 7: Split into two slides (content exceeded frame)
- Slide 12: Added [fragile] option (verbatim block)
- ...

Important notes

• Always ask the user before editing their .tex file
• Prefer splitting content across slides over shrinking text — readability matters more than slide count
• The [shrink] option is a last resort — it makes everything smaller, which is usually worse than splitting
• [allowframebreaks] is acceptable for reference/bibliography slides but looks bad for regular content — prefer manual splits
• When in doubt, err on the side of more slides with less content