Layout

Units

Internal: micrometers (int). Conversions with specified rounding:

• 1 pt = 352.777µm, 1 twip = 17.638µm, 1 EMU = 0.0277µm, 1 px@96dpi = 264.58µm
• ptToUm, umToPt, pxToUm, twipToUm, emuToUm in src/export/layout/units.ts

Text

getFontMetrics approximates avg char width/line height from fontSizePt. breakLines is greedy, respects spaces/tabs/\n, hard breaks, fallback inside long words, deterministic.

Blocks & tables

Margins collapsed per own rules, keep-with-next for headings, row split diagnostics, header repeat. Images flagged if w/h > usable. columns measure nested paragraphs/images per slot and emit one box with the max height. PDF drawing (contiguous table rows, image align) lives in src/export/pdf/, not in this pagination layer.

Pagination

paginateDocument(doc, {widows:2, orphans:2}) does vertical flow, forced breaks, widows/orphans, image constraints. Deterministic: same input + fixed IDs/clock → same hash and pages[].boxes.

Diagnostics

image-too-large, row-too-tall, missing-glyph, unknown-block.

Pagination feeds export. Page preview in the editor uses the same document.page box and does not mutate the AST.

See src/export/layout/*.