winAscent below typoAscender (top clip risk)

Audit code: metrics-win-clip-top

Definition

OS/2 winAscent is below typoAscender — top edges of glyphs may clip on Windows. winAscent is Windows' clipping boundary; if it sits below the typoAscender, ascenders that reach typoAscender will be cropped. Bump winAscent up.

How Patens surfaces this

The Patens audit module checks for metrics-win-clip-top across five teaching surfaces: the edit-panel inline issue list, the project-wide audit page, the release pre-flight check, the family hub, and the home-page project tile. Every surface shows the same plain-English explanation and links back to this page. This rule is detection-only — there's no automatic fix because the correction is design-dependent (it requires a judgment call about the glyph's intended shape or the font's intended behaviour). The audit message links to the specific glyph or field that needs attention.

Run this check yourself

Patens runs every audit rule live as you draw — including this one. The editor (in private alpha) shows metrics-win-clip-top firing on real glyphs, or check your own work from the CLI:

npx patens audit your-project.font.json

Canonical references

Primary literature where this rule is established or explained. Drawn from the open-licensed corpus — browse the full 42-source canonical library or read the research artifact.

OpenType Specification 1.9.1 ↗
Microsoft Typography · 1997 · Microsoft Corporation· § usWinAscent

usWinAscent defines the Windows clipping bounds; ascenders above it clip in Windows applications using legacy metrics.

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