#183 Horizontal line segments in a open subject path are reversed in the solution

[Anonymous]

using ClipperLib;

using Path = List<IntPoint>;
using Paths = List<List<IntPoint>>;

            Path subj = new Path();
            subj.Add(new IntPoint(64332, 43978));
            subj.Add(new IntPoint(63972, 43978));
            //subj.Add(new IntPoint(63972, 43979)); change previous point? Not horizontal anymore
            subj.Add(new IntPoint(63887, 43954));
            subj.Add(new IntPoint(63887, 47093));
            subj.Add(new IntPoint(63887, 47986));

            Paths clip = new Paths(1);
            clip.Add(new Path(4));
            clip[0].Add(new IntPoint(60000, 47831));
            clip[0].Add(new IntPoint(70000, 47831));
            clip[0].Add(new IntPoint(70000, 40000));
            clip[0].Add(new IntPoint(60000, 40000));

            PolyTree solution = new PolyTree();

            Clipper c = new Clipper();
            c.AddPath(subj, PolyType.ptSubject, false);
            c.AddPaths(clip, PolyType.ptClip, true);
            c.Execute(ClipType.ctIntersection, solution);

            Paths insidePath = Clipper.OpenPathsFromPolyTree(solution);

Hello Angus,

I discovered a bug when clipping open subject paths that contain a horizontal line segment. In the included example, the horizontal segment is reversed in the solution path. By changing the horizontal segment to a almost horizontal segment (Y+1), the order of the points in the solution becomes correct. Can you please have a look at this bug?

[Anonymous]

Im using the C# version of ClipperLib version 6.4.2

[Anonymous]

A (non-practical) workaround for the issue is to invert all Ys of all polygons, also of the results.

[Angus Johnson]

Thanks for the feedback, and I'm sorry it's taken me so long to reply.
Yes, there's a bug here that I hope to fix in the next few days. Cheers.