Wrong intersection depending on minor difference in coordinates

[purplecomet1]

You can view the issue here: https://codepen.io/purplecomet1/pen/WqOZRB

The polygons are defined on lines 9-12 and 21-25 respectively.

If you select 'Intersection' and run it, only a portion of it is highlighted instead of the whole shape.

If you edit certain coordinates slightly, however, it will produce the correct intersection. For example, adding '.0001' to either the x or y coordinate on line 10 will produce the correct intersection. The same is true for removing the last 3 decimal places of the y-coordinate on line 23.

[purplecomet1]

You can get even more bizarre intersections if you delete the decimal places from lines 21 and 25 (so that the coordinates become [27, 74]).

This intersection selects a portion of the polygon that is outside of the bounding polygon and a random line from across the polygon.

[bluenote10]

Another check against polybooljs. It also seems to avoid the problem:

Input:

Output:

I'll stop making these comparisons now. What I wanted to find out is whether looking into polybooljs may help to fix some of the open issues -- which seems to be the case. After all, there might be even a single cause of all the issues, e.g., just a missing edge case check.

[w8r]

It's the precision model, I suspect.

[rowanwins]

Resolved in v0.6.0 by #111

[rowanwins]

Turns out the demo site I used to check the ouput was doing some funky things and this isn't resolved :(

[rowanwins]

The intersection operation appears to be working 0.7.3, although the difference operations seem to be generating a few stray segments