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cdsc_tex/README
Benjamin Mako Hill b94d69f6a3 README: document what makes the tagging work, and what defeats it
Records that tagging=on is the key doing the work and pdfstandard=ua-2
only writes the claim, since setting the second without the first is
the failure this series fixes and is easy to reintroduce.

Adds the TeX Live 2025 requirement to Dependencies, including that
Debian trixie ships 2024 and that Overleaf projects choose their TeX
Live version in the settings menu and do not always default high
enough.

Adds sections on writing an accessible document (headings, alt text,
table header rows), on customizing the styles, and on verifying that a
PDF really carries structure. The customizing section names titlesec
and titling specifically: they are the obvious tools for the job the
two style files do, and they break tagging silently.

Notes that the poster is not accessible and makes no claim.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-13 18:16:01 -07:00

222 lines
7.8 KiB
Plaintext

================================
=== CDSC LaTeX Templates =======
================================
Copyright (c) 2009-2026 Benjamin Mako Hill <mako@atdot.cc> / <makohill@uw.edu>
This repository contains LaTeX configuration files and templates used to
format papers, memos, letters, and posters. All files are released under
the GNU GPL version 3 or later.
The latest version can be found in git at:
https://gitea.communitydata.science/collective/cdsc_tex
You can check out the latest version with:
git clone https://gitea.communitydata.science/collective/cdsc_tex.git
Bug reports, comments, questions, and patches can be directed to:
Benjamin Mako Hill <makohill@uw.edu> [work]
Benjamin Mako Hill <mako@atdot.cc> [personal]
To submit a patch, clone the repository, make your changes, and use
git format-patch to generate patch files to send by email:
git format-patch origin/master
git send-email *.patch
================================
=== Dependencies ===============
================================
On Debian or Ubuntu, install the following packages:
* latexmk
* texlive-luatex
* texlive-latex-recommended
* texlive-fonts-extra
* texlive-fonts-recommended
* texlive-bibtex-extra
apt install latexmk texlive-luatex texlive-latex-recommended \
texlive-fonts-extra texlive-fonts-recommended \
texlive-bibtex-extra
On other systems, installing a full TeX Live distribution should provide
everything needed.
All four templates build with LuaLaTeX (via latexmk -lualatex). The text
fonts are Libertinus Serif and TeX Gyre Heros, both provided by
texlive-fonts-extra.
The paper, memo, and letter templates need TeX Live 2025 or later. The
tagging code they rely on is not in TeX Live 2024, where the build
stops with "the key 'document/metadata/tagging' is unknown". Debian
trixie ships TeX Live 2024, so a trixie machine needs a newer TeX Live
from elsewhere in the archive. On Overleaf, choose the TeX Live
version under Menu > Settings > TeX Live version; 2025 or later is
required and is not always the default for an older project.
================================
=== Accessibility ==============
================================
The paper, memo, and letter templates produce tagged PDFs that declare
PDF/UA-2 (ISO 14289-2). The poster template does not; see below.
Tagging is switched on by the tagging=on key in the \DocumentMetadata
block at the top of each template. That key is what does the work: it
loads the kernel code that puts headings, paragraphs, lists, tables,
and figures into the PDF's structure tree, which is what a screen
reader walks. The neighbouring pdfstandard=ua-2 key only writes the
conformance claim into the file's metadata. Setting the standard
without setting tagging=on yields a PDF that announces itself as
accessible and contains nothing for assistive software to read, so
keep the two together.
The paper and memo templates were originally built on the memoir
class, which is incompatible with the LaTeX tagged-PDF code. They now
use the standard article class with custom styling (cdsc-paper.sty
and cdsc-memo.sty) to keep their previous look while supporting full
tagging.
Writing an accessible document
------------------------------
Tagging gets you the structure; the content is still up to the author.
Three things matter most, and the paper template carries a worked
example of each:
* Use \section and \subsection for headings rather than setting type
in bold by hand. Screen reader users navigate by the heading tree,
and hand-formatted text is invisible to it.
* Give every figure an alt= description on \includegraphics, saying
what the reader is meant to take from it. A decorative image takes
\includegraphics[artifact]{...} instead, keeping it out of the
reading order.
* Mark header rows on data tables with \tagpdfsetup{table/header-rows
={1}} so their cells become TH rather than TD. Without it a table
reads as an undifferentiated grid of values.
Customizing the styles
----------------------
Some common packages defeat tagging, and the failure is usually
silent: the document compiles without complaint and the tags are
simply missing. Before adding a package, check its status against the
LaTeX Tagging Project's list:
https://latex3.github.io/tagging-project/tagging-status/
titlesec and titling are the two to know about here, because they are
the obvious tools for the job cdsc-paper.sty and cdsc-memo.sty do.
titlesec replaces the \@startsection hook that the tagging code uses
to emit heading tags, so loading it produces a PDF with no headings in
the structure tree and no error to say so. Both style files therefore
build their headings and title blocks from the article class's own
\@startsection and \@maketitle hooks.
Verifying
---------
To see whether a PDF really carries structure, open the tag tree in a
PDF reader that shows one, or check for the tags directly:
python3 -c "import pikepdf,sys; d=pikepdf.open(sys.argv[1]); \
print(d.Root.get('/StructTreeRoot') and 'tagged' or 'UNTAGGED')" file.pdf
That confirms structure exists but not that the file conforms to
PDF/UA-2. Full conformance checking needs veraPDF
(https://verapdf.org/), which is not packaged in Debian.
Posters
-------
The poster template is not accessible and makes no accessibility
claim. The beamer class rejects \DocumentMetadata outright, and the
LaTeX Tagging Project lists beamer and beamerposter as no-support,
meaning incompatible and not expected to change. When a poster needs
an accessible version, build a companion document from the paper or
memo template.
================================
=== Branches ===================
================================
This repository has two main branches:
master Standard LaTeX templates (paper, memo, letter, poster)
knitr Knitr/R template for reproducible research documents
================================
=== Scripts ====================
================================
new_tex_document
----------------
Creates a new document directory from a template. Takes a document type
and destination directory as arguments:
new_tex_document <type> <directory>
Available types:
paper LaTeX paper template (master branch)
memo LaTeX memo template (master branch)
knitr Knitr/R paper template (knitr branch)
letter LaTeX letter template (master branch)
Example:
new_tex_document paper my-new-paper
This creates my-new-paper/ populated with the template files, with the
main source file renamed to my-new-paper.tex (or .Rtex for knitr).
rename_tex_to_dirname
---------------------
Renames the single .tex file in the current directory to match the
directory name. Useful for cleaning up a template that was set up
manually:
cd my-paper && rename_tex_to_dirname
================================
=== Shell Aliases ==============
================================
The file cdsc_tex_aliases.sh provides aliases for the old individual
script names, for convenience or backwards compatibility. Add the
following to your .bashrc or .zshrc:
[[ -f ~/tex/cdsc_tex/cdsc_tex_aliases.sh ]] && \
source ~/tex/cdsc_tex/cdsc_tex_aliases.sh
This defines the following aliases (only if new_tex_document is in PATH):
new_tex_memo → new_tex_document memo
new_knitr_document → new_tex_document knitr
new_tex_letter → new_tex_document letter
================================
=== Migration ==================
================================
The individual scripts new_knitr_document and new_tex_letter have
been consolidated into new_tex_document. The old scripts remain in
the repository but are superseded.
To migrate, replace calls to the old scripts with new_tex_document:
Old: new_knitr_document mydir
New: new_tex_document knitr mydir
Old: new_tex_letter mydir
New: new_tex_document letter mydir
Alternatively, source cdsc_tex_aliases.sh (see above) to keep using the
old names without changing your workflow.