#167 Offsetted polygons are not very accurate

[Demone]

I was debugging a code that basically creates a "ring" mesh out of 2 concentric polygons (1 is offset of the other), and finally I found why it was not working. Points computed by clipper for a offsetted mesh are not accurate => basically even using doubles any offsetted segment is not longer parallel (unless using a tolerance of just 2/3 decimal digits).

Basically I measured normalized vectors for lines:

I got

0.665 for original segment on X
0.663 for offsetted segment on X.

Also note that I "brute forced" replacing all "integer" references in clipper with "float" (and also remove all roundings), then tried using "doubles" without improving the situation that much.

[Demone]

I would anyway add an option to use "floating Point" coordinates to avoid someone "replace" integers. I'm using the C# version