theseus/bundled-addons/docx-editor
Local Dev 2f8eaa62ff feat(docx-editor): the page fills the window, and two fonts ship with it
The page sat marooned in the middle of a wide window with dark space either
side of it. It is now drawn at the size the document actually claims — A4
stays A4, margins come from its own sectPr — and CSS `zoom` scales that to
fit, defaulting to Fit width with a control in the footer and Ctrl +/-/0.

Scaling rather than widening is deliberate. A page stretched to the window
would break every line somewhere different from where the printed page
breaks it, and an editor whose whole claim is that it shows you the document
should not lie about where the lines end. `zoom` also beats a transform
here: it affects layout, so the board scrolls correctly and ProseMirror's
coordinate maths keeps working.

Ubuntu and Fraunces now ship in fonts/, because Windows has neither and a
font offered in the ribbon that the machine lacks is a font the user picks
and then cannot see. Fetched once by `npm run fonts` and committed, never at
runtime: an extension in a browser built around not phoning home should not
ask a font CDN what a document looks like every time one is opened.

Two things had to be worked around. On file:// Chromium registers @font-face
rules and then refuses to fetch the files — the family appears in
document.fonts and every glyph still renders in the fallback — so the add-on
reads the woff2 and hands the page a stylesheet with them inlined as data
URLs. The PDF export needed the same treatment for a different reason: its
print window runs from a temp folder, where a relative url() resolves to
nothing, which would have quietly undone the one-stylesheet-for-both promise
that lib/doc-css.js exists to keep. If either path fails, the ribbon labels
those families "(not available)" rather than implying otherwise.

About 700 KB, most of it Ubuntu's Cyrillic and Greek — kept because the
documents this is used on are not all English. Licences ship alongside.
2026-09-22 19:12:56 +02:00
..
fonts feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
lib feat(docx-editor): ship it in the build, updated over the first-party channel 2026-09-21 22:47:13 +02:00
vendor feat(docx-editor): ship it in the build, updated over the first-party channel 2026-09-21 22:47:13 +02:00
addon.json feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
editor.css feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
editor.html feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
editor.js feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
fonts.css feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
icon-16.png feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
icon-32.png feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
icon-48.png feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
icon-128.png feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
icon-256.png feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
icon.svg feat(docx-editor): the blue DOC badge, kept as the generated source 2026-09-22 00:10:56 +02:00
index.js feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
panel.html feat(docx-editor): ship it in the build, updated over the first-party channel 2026-09-21 22:47:13 +02:00
README.md feat(docx-editor): the page fills the window, and two fonts ship with it 2026-09-22 19:12:56 +02:00
ROUND-TRIP.md feat(docx-editor): ship it in the build, updated over the first-party channel 2026-09-21 22:47:13 +02:00

Word editor — a Theseus extension

Opens, edits and saves Word documents (.docx) in a full Theseus tab, and exports them as PDF.

Saving comes in three shapes. Save drops a copy in your downloads until the document has a home; Save as… opens a real file dialog where the extension you type — .docx or .pdf — decides the format, and from then on Save writes straight to that file; PDF is the one-click export. PDFs are rendered by Chromium's own print pipeline from lib/doc-css.js, the same stylesheet the editor displays, on the paper size the document itself specifies — so the export matches the preview rather than being a second opinion about it.

It is a first-party extension: written here, signed with the Silent Mode operator key, and updated over the channel at theseus.x/extensions/docx-editor/ like every other add-on Theseus ships. It does not go through the community catalogue, which is for extensions published by whoever owns a BNS name.

It ships inside Theseus, so a fresh install already has it and Settings lists it under Built into Theseus; the channel above then updates it between releases without waiting for one. That is the same arrangement as screenshot, aegis and pdf-editor, and it is what gives a user their first copy at all — Settings can only install from the community catalogue, so an extension that is neither bundled nor catalogued has a working update channel and no way in.

The cost is about 400 KB compressed in the installer, most of it the vendored editor libraries.

The page, and the fonts

The sheet is drawn at the size the document says it is — A4 stays A4, margins come from its own sectPr — and CSS zoom scales the whole thing to fit the window. Scaling rather than widening is the point: a page stretched to the window would break every line somewhere different from where the printed page breaks it. The footer carries the control, and Fit width is the default because a page marooned in the middle of a wide window wastes the screen. The choice is remembered per editor, not per document.

Ubuntu and Fraunces ship with the add-on, in fonts/, because Windows has neither and a font offered in the ribbon that the machine lacks is a font the user picks and then cannot see. Regenerate with npm run fonts; licences are in fonts/LICENSES.txt. They cost about 700 KB, most of it Ubuntu's Cyrillic and Greek coverage — dropping those subsets would roughly halve it.

Two wrinkles worth knowing. The editor is on file://, where Chromium registers @font-face rules but refuses to fetch the font files, so the add-on reads them and hands the page a stylesheet with the woff2 inlined as data URLs; the same inlined copy goes into the PDF export, whose print window runs from a temp folder where a relative url() would resolve to nothing. If either path fails the ribbon labels those two families "(not available)" rather than pretending.

The icon

icon.svg is the one drawing. npm run icons rasterises it to icon-16/32/48/128/256.png and writes a minified copy into addon.json's icon field, which is what the dock button and the catalogue card read — so there is never a second version to keep in step.

It is a blue document badge, paired with pdf-editor's red one so the two editors read as a set in the dock — a solid fill stays legible at the 1618px the dock actually renders, which an outlined page does not.

Deliberately not Microsoft's Word icon: their mark is a blue sheet carrying a white W, and dressing our extension up as theirs would be both a legal problem and a dishonest one. A folded-corner page is the universal document glyph, and "DOC" is the file format rather than anyone's trademark.

Building

The vendored libraries (mammoth, ProseMirror, docx, JSZip) are bundled by a build step that lives outside this folder, because mammoth needs local patches before it can carry everything the editor edits:

cd ../../addon-build/docx-editor
npm install
npm run build        # writes vendor/docx-vendor.js here
npm run icons        # re-rasterises icon.svg after editing it

vendor/docx-vendor.js is committed, so the extension is installable straight from a checkout; re-run npm run build after touching anything under addon-build/.

Publishing

The full recipe is in docs/ADDON-UPDATES.md; the short version, signed with the operator key and always from a clean copy of the commit rather than the working tree:

git archive HEAD TheseusNavigator/extensions/docx-editor | tar -x -C <clean>
node scripts/sign-addon-update.mjs         <clean>/TheseusNavigator/extensions/docx-editor         https://navigate.st/bns/theseus.x/extensions/docx-editor         "$USERPROFILE/.silentmode/ops/addon-update-key.pem" --out out/

node ../Argus/src/lib/sia-upload.js out/docx-editor-<version>.tar.gz bns/theseus/extensions/docx-editor
node ../Argus/src/lib/sia-upload.js out/updates.json                 bns/theseus/extensions/docx-editor

The channel lives on Sia only — nothing goes to the VPS filesystem — and is served through the gateway at https://navigate.st/bns/theseus.x/extensions/. A first release has no updates.json to prepend to, so it ships one holding just its own entry. Versions must increase.

Testing

Three levels, all re-runnable, all from ../../addon-build/docx-editor:

node test/roundtrip.mjs                  # the built-in fixture
node test/corpus.mjs <folder of .docx>   # real documents
node ../../../scratchpad/verify-docx-editor/drive.mjs   # a real Theseus, over CDP

The last one installs this folder into a throwaway profile the way the community channel would, and is the only one that catches browser-only breakage.

What survives a round trip, and what doesn't, is written up in ROUND-TRIP.md. Read that before promising anyone a Word feature.