fix(layout): strip default-ignorable characters instead of rendering fallback glyphs - #3456
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…fallback glyphs Bidi controls and other Unicode Default_Ignorable_Code_Points (e.g. U+202A LRE, U+202C PDF, U+200F RLM, zero-width chars, BOM) were not in the small IGNORABLE_CODEPOINTS list, so they reached glyph mapping, missed the font's cmap and were drawn as fallback .notdef glyphs (visible garbage, often overprinted on an adjacent letter). Strip characters the font cannot render using the Unicode default-ignorable set (mirroring fontkit's isDefaultIgnorable), while preserving the previously handled U+2028/U+2029 separators. Characters the font does provide a glyph for are left untouched.
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Fixes rendering of Unicode Default_Ignorable_Code_Points (bidi controls, zero-width chars, BOM, variation selectors, …) which currently show up as visible fallback
.notdefglyphs in generated PDFs.Problem
Characters like
U+202A(LRE),U+202C(PDF),U+200F(RLM), zero-width spaces/joiners, and the BOM are default-ignorable — browsers render nothing for them. In react-pdf they appear as garbage, typically a stray glyph overprinted on the first letter of the following text (plus a swallowed adjacent space).This is common with text (e.g. names) for RTL locales, which often arrive wrapped in bidi embedding controls. Example:
"\u202aExample Name\u202c\u200f"renders with a stray glyph stacked on the first letter.Root cause
packages/layout/src/text/ignoreChars.tsonly stripped a 3-entry list (U+2028,U+2029,U+2060). All other default-ignorables reached font substitution, missed the font cmap, and were drawn as fallback glyphs. fontkit already handles these correctly viaisDefaultIgnorable/hideDefaultIgnorables, but that path is not reached because react-pdf performs its own per-codepoint font substitution first.Changes
isDefaultIgnorableranges.U+2028/U+2029separator stripping (kept via an explicit extra set) to avoid a regression.packages/layout/tests/text/ignoreChars.test.tsand a changeset.Testing
yarn vitest run packages/layout— all 417 layout tests pass (incl. 6 new). Lint + typecheck clean.