Port Clipper1 OffsetPolygons() method to Clipper2 ClipperOffset class

[Ixorus]

First of all, thank you for this amazing library, Angus! I really appreciate the effort you've put into this.

I am having some difficulty porting some (working great) Clipper1 code over to Clipper2. The code needs to turn a solid shape into an outline.

This is done by creating an offset (inset, in this case), which becomes a hole in the original solid shape.

Here is the original solid shape:

Here is the shape with the offset hole from Clipper1:

And here is the shape with the offset hole from Clipper2:

It is unusual to discover such a beautiful mistake! I love the output from Clipper2, but it is not what is needed.

To isolate the issue, I renamed the original Clipper class to "Clipper1", so I could go back and forth between the libraries by just changing the "1" to a "2" and back. However, there isn't an exact 1:1 correspondence with the libraries.

The C# OffsetPolygons method from Clipper1 is:

        public static Polygons OffsetPolygons(Polygons poly, double delta,
                                              JoinType jointype, double MiterLimit)
        {
            var result = new Polygons(poly.Count);
            new PolyOffsetBuilder(poly, result, delta, jointype, MiterLimit);
            return result;
        }

The attempted port to Clipper2 is:

        public static Polygons OffsetPolygons(Polygons poly, double delta,
                                              JoinType joinType, double miterLimit)
        {
            ClipperOffset co = new ClipperOffset(miterLimit);
            co.AddPaths(poly, joinType, EndType.Square);
            Polygons result = co.Execute(delta);

            return result;
        }

I can post other code, if it helps.

Am I missing something somewhere? How can I create an exact port of that Clipper1 code?

[AngusJohnson]

Am I missing something

EndType.Polygon 😉.

Lovely post and I'd say more except it's 3.30am and I'm back to sleep.

[Ixorus]

That worked!

I can't believe it was that simple.

Thank you so much!

[Ixorus]

That worked perfectly! I can't believe it was that simple. 🤦 Thank you!

…

On Sat, Aug 6, 2022 at 1:23 PM Angus Johnson ***@***.***> wrote: Am I missing something EndType.Polygon 😉. Lovely post and I'd say more except it's 3.30am and I'm back to sleep. — Reply to this email directly, view it on GitHub <#154 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AXJ2NPBQ2G4AWJNQME2JAVDVX2NRBANCNFSM55Y7G2LA> . You are receiving this because you authored the thread.Message ID: ***@***.***>