vmtx: Vertical Metrics

The 'vmtx' table provides Advance Heights and Top Side Bearings for each glyph in the font, to describe the spacing of the glyphs when they are written vertically. GDI will use the vertical metrics data when an application requests a vertical writing font.

Requirements

A font with vertical metrics must have both a 'vhea' and a 'vmtx' table.

Recommendations

None additional to TTF spec.