Function reverse_arc_ring

pub fn reverse_arc_ring(ring: &ArcRing) -> ArcRing

Reverse a ring’s orientation, preserving its geometry.

Bulges are stored per departing edge, so reversing the vertex order alone would attach each bulge to the wrong edge. The bulge list must shift by one and negate: the edge that left vertex i toward i + 1 becomes the edge leaving i + 1 toward i, curving the other way.