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[Followup] Compose canonical decompositions (NFC) in the default shaper - #403
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- Compose each base + combining-mark cluster into the font's precomposed glyph via font-aware NFC before GSUB, matching HarfBuzz: decomposed input (i + U+0300, or Arabic alef + fathatan + hamza-above) shapes to the precomposed glyph instead of separate marks - Only apply the result when it changes the glyph count (composition or its decompose fallback); leave pure canonical reordering alone so it can't disturb downstream GSUB (e.g. Arabic shadda + vowel calt) - Decompose back any composed codepoint the font has no glyph for, so its marks stay available for GPOS mark positioning - Scope to the default shaper and the Arabic/Hebrew/Thai shapers that inherit it; Indic/Hangul/Universal keep their own composition - Add 6 canonical-composition shaping tests (FiraSans Latin, Amiri Arabic incl. the reorder regression)
This was referenced Oct 18, 2026
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Follow up to #380