Arabic text, direction and imported typography
A detailed reference for imported text controls, supported composition rules, font requirements and explicit compatibility limitations.
Applies to Design 0.8.0 on doc.et.
These are composition and import notes, not a claim of identical InDesign typography. Some controls are retained in files without being fully reproduced.
Understand the imported layout#
Paragraph direction, story column flow and table direction are separate choices. An imported right-to-left publication can use all three, so inspect the whole page rather than assuming that changing paragraph alignment fixes its reading order.
Supported composition rules#
| Area | Behavior |
|---|---|
| Mixed scripts | Separate Hebrew/Arabic script runs, resolved shaping direction, language tags and OpenType joining features |
| Style boundaries | Pre/post shaping context preserves joining when a character style changes within an Arabic word |
| Font fallback | Combining marks and join controls stay with the preceding base face |
| Bidirectional layout | Full paragraph context, cluster contents and Unicode controls survive line breaking; per-line UAX #9 ordering keeps marks attached, including lines with tab leaders |
| Character direction | Imported default/LTR/RTL overrides participate in bidi resolution; single-character punctuation mirroring is corrected against final paragraph levels |
| Digits | European, Arabic-Indic and Persian conversion in both directions, contextual defaults, language-sensitive native digits, original UTF-8 source ranges retained |
| Diacritics | Font GDEF classification and OpenType mark anchors; explicit X/Y offsets affect marks only, in thousandths of an em |
| Positional forms | Explicit isolated/initial/medial/final OpenType feature selection; automatic forms remain the default |
| Kashidas | Paragraph and character switches, actual font coverage, shaper-approved insertion boundaries, nonjoiner protection, whole-cluster movement to keep marks attached |
| Story direction | Independent right-to-left column flow, including span-column bounds |
| Table direction | Right-to-left cell placement, merged spans, physical edge styles/borders, hit testing and left/right column insertion |
| Serialization | Character controls, paragraph policy/width values, story/table directions survive native data and IDML round trips |
Compatibility boundaries#
- Vendor-specific Arabic/Naskh justification policies and Paragraph Kashida Width presets are preserved but not reproduced. Preflight reports their use. Automatic elongation still uses bounded, scaled tatweel insertion rather than full line reshaping or a vendor allocation algorithm.
- Loose/Medium/Tight/OpenType-from-baseline diacritic presets are preserved and reported. Composition uses font anchors and explicit offsets instead.
- Script-specific stretched alternates, contextual swash policies, complete RTL tab-stop semantics and re-shaping at emergency intra-word line breaks require further compatibility work. Tracking and arbitrary metric changes within a cursive word can still open joining gaps.
- A font must contain the required glyphs and appropriate OpenType tables. This change neither embeds proprietary fonts nor makes missing-font errors disappear.
- CJK compatibility boundaries remain documented in
cjk-typography.md.
Review a publication before exporting#
- Check that the required fonts are available and that combining marks remain attached to their base characters.
- Inspect line starts, line ends and narrow columns at a readable zoom.
- Review the preflight findings, including unsupported composition rules as well as missing fonts, links and overset text.
- Compare an exported proof with the intended layout and keep the editable source.
A clean-looking first page is not enough to validate a long publication. Examine pages with mixed scripts, tables, unusual punctuation and style changes as well.
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Sources and edition notes
Adapted for the browser edition from the pinned Designcraft 0.8.0 source. Upstream documentation may also describe desktop workflows.
- docs/arabic-typography.md — Adapted from the upstream documentation for this pinned release.
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