Apparently incorrect output using ParallelOffsetIslands

[esuig]

Hello,

first of all, great work. Your library is impressive.

I'm starting using it to understand the potentialities.

I'm looking at the ParallelOffsetIslands. I created a small test in which I have three profiles (one outer profile and two islands). The coordinates of the profiles are as follows:

island 1:
(20,20)
(20,40)
(40,40)
(40,20)
IsClosed() = true;

island 2:
(60,30)
(60,80)
(80,80)
(80,30)
IsClosed() = true;

outer contour:
(0,0)
(100,0)
(100,100)
(0,100)
IsClosed() = true;

Then I followed exaclty the steps reported here:
https://github.com/jbuckmccready/CavalierContours/blob/master/examples/polylineoffsetislands.cpp

to perform the offset of the input profiles. However, I get a strange result that is (the blue profiles are the input ones, while the green are the output ones):

In the output I get 2 profiles (the smaller one and the bigger that includes both the offset of the bigger island and the offset of the outer contour), but I would expect 3 profiles if the coincident segments are not discarded.
Or, I would expect something like:

Maybe I am missing something? or it is a bug?

[jbuckmccready]

It's a known limitation right now in the simultaneous/island offsetting where overlapping/coincident offset segments are not removed. I had planned to look into it more when I implement the simultaneous offset algorithm in the Rust project where I'm continuing development here.