Extends below descender
Audit code: extends-below-descender
Definition
The glyph's bbox extends below the OS/2 descender. Some renderers will clip the bottom stroke.
How Patens surfaces this
The Patens audit module checks for extends-below-descender 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 extends-below-descender firing on real
glyphs, or check your own work from the CLI:
npx patens audit your-project.font.jsonCanonical 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· § OS/2 — usWinDescent
Glyphs extending below usWinDescent clip on Windows applications using legacy line-height metrics.