 Mathematical glyph variant

A mathematical glyph variant is an alternative ready-made glyph supplied for a mathematical shape at a different extent. In an OpenType MATH table, each MathGlyphVariantRecord pairs a glyph index with its advanceMeasurement along the extension direction.^[ref]

Consider an invented set of vertical variants with construction measurements 900, 1300 and 1800 font units. A selection policy seeking the smallest variant at least 1200 units tall chooses 1300; a target of 1700 chooses 1800. A target of 2000 exceeds the set and may need a mathematical glyph assembly if the font supplies suitable parts.

This discrete choice is useful for growing mathematical delimiters around tall expressions. The numbers are an explanatory selection example, not measurements of an installed computer font. A separately drawn taller glyph can change proportions without requiring every stroke to undergo the same uniform enlargement.