Math Equation Rendering (OMML → MathML)

[caio-pizzol]

SuperDoc converts Office Math (OMML) from Word documents into browser-native MathML. No KaTeX. No MathJax. No external dependencies. The browser renders the math directly.

How it works

.docx → OMML XML → ProseMirror → Layout Engine → DomPainter → <math> DOM

The importer extracts m:oMath elements and stores the full OMML tree as a JSON attribute on atomic ProseMirror nodes. At render time, the DomPainter walks the tree and converts each OMML element to its MathML equivalent via a converter registry. The browser does the rest.

Export round-trips cleanly — the original XML is preserved via carbonCopy.

What's built

• Import pipeline — m:oMath (inline) and m:oMathPara (display) both import as proper PM nodes
• ProseMirror schema — mathInline and mathBlock atomic nodes
• Layout engine — MathRun type, measured as atomic units like images
• DomPainter rendering — converter registry, renderMathRun(), cursor positioning
• Leaf nodes — m:r / m:t text classification (<mi>, <mo>, <mn>)
• Fraction — m:f → <mfrac>, working proof of concept
• 47 unit tests across the pipeline

What's left: 14 converters

Each converter is one function. ~20 lines of TypeScript. One file, two one-line registrations, a test. No schema changes. No adapter changes. No exporter changes.

Contribution guide: CONTRIBUTING.md

Done

• Math: implement m:sSup superscript converter (community) #2595 — m:sSup superscript → <msup>
• Math: implement m:sSub subscript converter (community) #2596 — m:sSub subscript → <msub>
• Math: implement m:bar overbar/underbar converter (community) #2610 — m:bar overbar/underbar → <mover> / <munder>

Easy

• Math: implement m:sSubSup sub-superscript converter (community) #2597 — m:sSubSup sub+superscript → <msubsup>
• Math: implement m:rad radical/sqrt converter (community) #2598 — m:rad radical/sqrt → <msqrt> / <mroot>
• Math: implement m:limLow lower limit converter (community) #2599 — m:limLow lower limit → <munder>
• Math: implement m:limUpp upper limit converter (community) #2600 — m:limUpp upper limit → <mover>
• Math: implement m:box and m:borderBox converters (community) #2605 — m:box + m:borderBox → <mrow> / <menclose>
• Math: implement m:phant phantom converter (community) #2608 — m:phant phantom → <mphantom>

Medium

• Math: implement m:d delimiter converter (community) #2611 — m:d delimiter → <mrow> + <mo>
• Math: implement m:nary n-ary operator converter (community) #2602 — m:nary n-ary (∫, ∑, ∏) → <munderover>
• Math: implement m:acc accent converter (community) #2604 — m:acc accent → <mover accent="true">
• Math: implement m:groupChr group character converter (community) #2606 — m:groupChr group character → <munder> / <mover>
• Math: implement m:func function apply converter (community) #2603 — m:func function apply → <mrow>
• Math: implement m:sPre pre-sub-superscript converter (community) #2609 — m:sPre pre-sub-superscript → <mmultiscripts>

Hard

• Math: implement m:m matrix converter (community) #2601 — m:m matrix → <mtable>
• Math: implement m:eqArr equation array converter (community) #2607 — m:eqArr equation array → <mtable>

How to pick one up

1. Grab an issue from the list above
2. Read the contribution guide
3. Follow the pattern in converters/fraction.ts
4. Each issue has a .docx test file attached — upload it to the dev app to verify your converter works
5. Open a PR

Related

• feat(math): add OMML rendering infrastructure and community contribution scaffolding (SD-2369) #2585 — infrastructure PR (merged)
• ECMA-376 §22.1 — Office Math spec