Function label_weight_grow_px 

pub fn label_weight_grow_px(weight: f64) -> f64

Outward glyph buffer (px) so absolute ink stems grow past Regular.

grow = 0.5 × FONT_STEM_EM × FONT_PX × (ink - 1) where ink is diagram_weight; zero at WEIGHT_MIN.

Panics

Panics if weight is invalid (see diagram_weight).