Function resolve_origin 

pub fn resolve_origin(
    params: &Transform3d,
    size: Vec2,
    scale_factor: f32,
) -> (Vec2, bool)

The resolved pivot as an offset from the border-box min, in physical px, plus whether an unsupported unit fell back to center (caller reports — this stays pure for tests). Percent resolves against the border box, not the outset-inflated capture rect: a blur outset must not move the pivot.