googlefonts__vertical_metrics

Check font follows the Google Fonts vertical metric schema

googlefonts/vertical_metrics

• Applies to: TTF
• Fontspector can hotfix?: no
• Fontspector can fix sources?: no

Rationale

This check generally enforces Google Fonts’ vertical metrics specifications. In particular:

• lineGap must be 0
• Sum of hhea ascender + abs(descender) + linegap must be between 120% and 200% of UPM
• Warning if sum is over 150% of UPM

The threshold levels 150% (WARN) and 200% (FAIL) are somewhat arbitrarily chosen and may hint at a glaring mistake in the metrics calculations or UPM settings.

Our documentation includes further information: https://github.com/googlefonts/gf-docs/tree/main/VerticalMetrics

Proposal

• https://github.com/fonttools/fontbakery/pull/3762 and https://github.com/fonttools/fontbakery/pull/3921

Profiles

• googlefonts (in section 'Font File Checks')