Help with this (almost working) code to draw arbitrary rounded polygons? ie. From a series of corner points and rounding radius?

[PavelBoytchev]

If it is OK to have the rounding not perfectly circular, a much shorter solution is to use shapes and quadratic curves at each vertex.

In the snapshot, blue has radius=0 (i.e. no rounding), red radius = 2 (small rounding), yellow radius = 4