Equations: Word (OMML) import, layout and save, plus an equation editor like Word's

[gledguri]

Closes #24.

What's in it

Word equations (commit 1). OMML is read into a math tree (fractions, scripts, radicals, n-ary operators, delimiters, functions, limits, accents, bars, boxes, equation arrays, matrices, phantoms), laid out with the OpenType MATH table (Cambria Math when installed, otherwise STIX Two Math or another open math font), drawn on screen and in PDF, and written back as OMML. Display equations sit on their own centred line. Previously equations were flattened to plain text.

An equation editor modelled on Word's (commit 2).

• Insert › Equation edits in place, with an Equation tab: ready-made equations, Unicode/LaTeX input and professional ↔ linear conversion, Normal Text, eight symbol sets, and structure galleries (fraction, script, radical, integral, large operator, bracket, function, accent, limit and log, operator, matrix) with tiles rendered by the math engine.
• Typing builds up like Word (a/b, x^2, √, ∑… then space); Math AutoCorrect turns \alpha, \sqrt… into symbols; Tab moves between empty slots; arrows and Backspace work through structures.
• The right-click menu has structure commands (fraction type, radical degree, limit position, matrix rows/columns, remove brackets…).
• A trailing #(n) numbers a display equation at the right margin; # alone numbers it automatically. DOCX output keeps numbers Word-compatible.

Testing

• cargo xtask ci passes (fmt, clippy, tests, assets, layers, wasm).
• DOCX round-trip tests for OMML, and used on macOS with Word documents containing equations.

🤖 Generated with Claude Code

[echelon]

Merged — thank you for the contribution, @gledguri! 🎉 Equations with OMML import/save, layout from the OpenType MATH table, and an in-place editor with its own tab is a huge piece of work. While merging main into your branch I:

• gave the built-in equation gallery our own descriptive names and grouping (the formulas are maths facts, but we keep the clean-room line by not mirroring another product's gallery names/order);
• made the equations row in ROADMAP.md consistent;
• added the Equation strings to the Brazilian Portuguese, Spanish and Ukrainian catalogs;
• made Equation one of main's contextual tabs (with Table and Picture Format) and reconciled it with LaTeX (.tex) import and export (#7) #11's LaTeX Inline::Equation in the flow model (an empty math now means "parse linear").
  A follow-up worth doing someday: formats::latex and your doc::math_latex both convert LaTeX and could share code.

If you haven't already, come join us on Discord: https://discord.gg/artcraft — we'd love to have you there.

[Neeraj-Parekh]

Subscribing — validating releases on Ubuntu 26.04 (posted #1971). Interested in live TeX-math preview on top of the OMML work here; happy to test .tex round-trips and equation edge cases when there's something to try.