Vertical Metrics

Layout of vertical text

Two new TrueType tables support vertical text layout. The Vertical Header Table (vhea) provides vertical metric information for the entire font, such as vertical ascent, descent and line gap data. The Vertical Metrics Table (vmtx) supplies two vertical spacing metrics for each glyph, the top sidebearing and the advance height. The formats of these tables are similar to TrueType's hhea and hmtx tables for horizontal metrics.