update-fonts

name	update-fonts
description	Update Eigendeck's bundled MathJax math fonts to the latest builds from the dgleich/mathjax-fonts repo. Use when the user says to update the fonts / font packs, points at a new mathjax-fonts commit, or wants to add a new font. mathjax-fonts now ships PREBUILT -nosre bundles, so the eigendeck side is just pull (or clone at the pinned commit) + npm run setup — no local rebuild.

Update the math font packs

Eigendeck's math rendering uses one MathJax bundle per font, from the sibling dgleich/mathjax-fonts repo. That repo now commits the prebuilt -nosre bundles at its repo root, so on the eigendeck side there is no build step — just pull + copy. (Rebuilding lives in the mathjax-fonts repo now; see the bottom section, only needed when you change a font's sources.) The user-facing version is docs/updating-fonts.md.

TL;DR (eigendeck side)

1. git pull mathjax-fonts (or let npm run setup clone it at the pinned commit)
2. npm run setup — copies the prebuilt -nosre bundles → public/mathjax/
3. verify (npm run build + a visual screenshot)

0. Where things live

• Source repo: /work/mathjax-fonts (sibling clone; gitignored in eigendeck).
• 10 packages: ptsans lato libertinus libertinus-sans lm-sans noto-sans source-sans source-code shantell concrete-euler.
• mathjax-fonts commits the prebuilt -nosre bundles at its repo root (tex-mml-svg-mathjax-<id>-nosre.js; older checkouts also keep per-package copies under mathjax-<id>/). tools/setup-fonts.mjs reads from the root (falls back to the subdir) and pins a fresh clone to MATHJAX_FONTS_COMMIT.
• In eigendeck, public/mathjax/ is gitignored → a font update commits nothing here except registry / setup / doc / new-TTF changes. The font bytes don't travel via eigendeck git.
• ~/.cargo not needed. Use export HOME=/tmp for git in /work.

1. Get the fonts (pull, or let setup clone at the pin)

cd /work/mathjax-fonts && git pull --ff-only    # brings the updated prebuilt bundles

If there's no sibling clone, npm run setup clones it at MATHJAX_FONTS_COMMIT. To move to a newer build: pull, then bump MATHJAX_FONTS_COMMIT in tools/setup-fonts.mjs to the new SHA. (An existing clone is used as-is; setup warns if its HEAD differs from the pin.)

Each release should ship the latest fonts — refresh the pin (pull + bump MATHJAX_FONTS_COMMIT + npm run setup) as part of cutting a release. See the release skill.

2. Copy into the app

cd /work && npm run setup        # copies -nosre.js → public/mathjax/ (no build)

3. Verify

• Build: npm run build (tsc + vite) passes.
• Visual (best — math is SVG, so headless screenshots work): build a deck with one slide per font (set slide.bodyFont / slide.titleFont to the id) containing math like $\lambda=\sum_{i=1}^n \alpha_i x_i^2$ $\mathrm{\alpha},\beta$ $\int_0^1 f$ $\sqrt{\frac{a}{b}}$, via eigendeck-cli <deck> import json <json>. Open the REAL app through the eigendeck-e2e rig (tauri-driver + WebKitWebDriver + xvfb), selectSlide(i) through the window.__eigendeck seam (dist built with VITE_EIGENDECK_SEAM=1), wait for the SVG to render, and GET /session/<id>/screenshot. Eyeball the font.

Adding a NEW font

1. In mathjax-fonts: add it (mathjax-<id>/ with a build/webpack-nosre.config.cjs), add <id> to build-all-nosre.cjs's packages list, rebuild, and commit the prebuilt -nosre bundle (see below).
2. Add its id to MATHJAX_FONTS_PACKAGES in tools/setup-fonts.mjs.
3. Add a FONT_PACKAGES entry in src/lib/fontRegistry.mjs (mathjaxBundle: 'tex-mml-svg-mathjax-<id>-nosre.js', files = its text-font TTF names; mirror an existing kind: 'static'/'variable' entry), and a label.
4. Put the text-font TTFs in public/fonts/<id>/ (these ARE committed). For an OFL/Google font: curl -fsSL github.com/google/fonts/raw/main/ofl/<id>/<Family>-Regular.ttf → regular.ttf (+ bold/italic/bold-italic + OFL.txt).
5. npm run setup, npm run build, screenshot-verify.

Rebuilding in mathjax-fonts (only when you change a font's sources)

This is not an eigendeck-side step — only do it when you edit a font's cjs/ / sources in the mathjax-fonts repo, then commit the rebuilt bundle there.

export HOME=/tmp
cd /work/mathjax-fonts
# every package needs its own node_modules; symlink any that lack one:
for p in mathjax-*/; do [ -d "${p}node_modules" ] || ln -sfn ../mathjax-shantell/node_modules "${p}node_modules"; done
node mathjax-shantell/build/build-all-nosre.cjs    # applies the lcGreek patch, webpacks all
git add tex-mml-svg-mathjax-*-nosre.js && git commit -m "rebuild nosre bundles"

• -nosre only — the full SRE build hangs Tauri's restricted WebKit Worker.
• lcGreek patch is mandatory (build-all-nosre applies it, idempotent). Without it \mathrm{\alpha} renders italic instead of upright Greek.

Gotchas

• No build on the eigendeck side — npm run setup only copies the prebuilt bundles. Don't run webpack here.
• PT Sans is the default, sourced from mathjax-fonts/mathjax-ptsans (migrated off the old in-tree mathjax-ptsans-bundle/).
• The full …js (non-nosre) bundles are unused by the app; only -nosre loads.

Commit (eigendeck side)

Only registry / setup / doc / new-TTF changes are committable (public/mathjax/ bundles are gitignored). Work on a fonts/... branch, commit, fast-forward into main, push. Rebuilt bundles + build-script changes are committed in the mathjax-fonts repo itself (separate repo).