Function outline_glyph_em 

pub fn outline_glyph_em(
    ch: char,
    style: FaceStyle,
    role: ScriptRole,
) -> (Option<Shape>, f64)

Outline one character in em space (+Y up), optionally as a fake script.

Scripts: scale by SCRIPT_SCALE, then buffer so stem weight stays close to the full-size glyph. Results are memoized.