ItalicModifier

Renders italic by slanting glyphs. Without a parameter (auto) the pipeline prefers a real italic face (family cut, variable ital/slnt axis, or OS fallback) and shears synthetically only when none exists. Parameters override that: a number sets an explicit synthetic slant (<i=20>), f (<i=f>) synthesizes from the run font's own ItalicStyle, and r (<i=r>) uses a real italic face only — never synthesizes, leaving the text upright when none is available.