fix(font): align fallback styling and glyph sizing with Ghostty#6
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Three glyph-rendering divergences from Ghostty, reported via a side-by-side comparison of a faint+italic mixed CJK/Latin line and each verified against Ghostty's source: - Synthetic bold/italic was applied to shared fallback faces (CJK/emoji/Nerd Font). A left-flush full-width glyph such as ） resolved under an italic style got a faux shear that pushed its ink out of its own cell into the neighbor. Ghostty synthesizes styles only for the primary family's regular face and renders fallback faces upright (CodepointResolver.zig getIndex relaxes to regular; completeStyles synthesizes primary-only), so is_native_style_face now treats fallback faces as native and synthesis_for skips them. - Ordinary text glyphs were downscaled kitty-style to fit their cell span, shrinking East-Asian-Ambiguous symbols such as ※ and ① that wide-metric macOS fallback fonts cover (12x12 instead of 20x20 at 24px). Ghostty never fits ordinary text — only its generated Nerd Font/Powerline icon table is cell-constrained (nerd_font_attributes.zig) — so fit_width is now passed only for Nerd Font fallback faces and everything else rasterizes at natural size, overflowing its cell like Ghostty does. - Menlo's native italic face was never detected: font-kit 0.14.3's CoreText backend reports byte-identical Font::properties() for every static face of some families (verified for Menlo and Helvetica), so italic text rendered as regular outlines plus a synthetic shear while Ghostty uses the real Menlo Italic. resolve_required_style now detects the unreliable-properties case (two distinctly-named faces with identical properties) and resolves the style by PostScript name suffix instead. Repro tests were written red-first and turn green with this change. The old narrow_fallback_glyph_fits_within_its_cell_span pin asserted the non-parity fit behavior for ① and is inverted accordingly.
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Summary
Side-by-side comparison with Ghostty on a faint+italic mixed CJK/Latin line showed three glyph-rendering divergences: full-width
）shifted out of its cell after an italic run,※rendered at ~60% of its proper size, and italic Latin drawn with a synthesized slant instead of the real italic face. Each root cause was verified against Ghostty's source and fixed innoa-font.Changes
CodepointResolver.zigrelaxes style to regular;completeStylesis primary-only), sois_native_style_facenow short-circuits for fallback faces andsynthesis_forskips them.※/①and friends rasterize at natural size and may overflow their cell, exactly like Ghostty. (U+203B correctly stays 1 column: Ghostty's width tables treat East-Asian-Ambiguous as narrow, soprint_widthwas already parity-correct.)Font::properties()for every static face of a family (verified for Menlo and Helvetica; Courier New / Hiragino Sans are unaffected). Italic text now uses the real Menlo Italic instead of regular outlines + synthetic shear.Test plan
noa-font(written and confirmed failing before the fix, green after): fallback shear/embolden suppression, upright/italic raster identity for）, natural-size raster for※/①, Menlo native-italic detection.cargo test --workspacegreen (noa-pty/noa-ipc failures under the sandbox are pre-existing device/socket permission artifacts, green when run unsandboxed);cargo clippy -p noa-font --all-targetsclean;cargo fmt --all -- --checkclean.cargo run -p noawith italic + full-width punctuation content).Risk
Medium-low. Behavior-only change contained to
noa-font(no public signature, frozen-contract, or cache-key changes;noa-renderuntouched — verified by grep and diff). Rollback is a single-commit revert. On-screen visual parity is not yet confirmed, and font environments differ across machines (tests self-skip when a required font is absent).