Drops vertices where the outline barely turns (less than angle radians), and repeated points.
tags (one per edge, edge i = p[i]→p[i+1]) are kept in step; an edge merged into its predecessor
keeps the predecessor's tag, but only vertices between edges with equal tags are dropped.
Drops vertices where the outline barely turns (less than
angleradians), and repeated points.tags(one per edge, edge i = p[i]→p[i+1]) are kept in step; an edge merged into its predecessor keeps the predecessor's tag, but only vertices between edges with equal tags are dropped.