Clipper1 to Clipper2: Different fill rules for subject and clip

[EricAtPlanGrid]

In Clipper 1 we have the option of specifying a filltype separately for both subject and clip. Is the expectation that in Clipper 2 we'd need to convert one or the other to match?

[AngusJohnson]

Hi again Eric.
In designing Clipper2, I figured that users would only very rarely require different filling rules for subject and clip (as you seem to require). And supporting only a single fillrule would make the function and method definitions a lot simpler.

[EricAtPlanGrid]

Yes, I'm currently using Clipper to help render PDFs, which have a very … flexible … imaging model. I'd be happy to help contribute to Clipper if some of the building blocks are there to support this! If not, do you have any advice for me in how to achieve my goals?

[AngusJohnson]

do you have any advice for me in how to achieve my goals?

If you want to use Clipper2 then you'd need to make a number of customizations.

Obviously you'll need to store the filling rule with each path so you'd need to include a fillrule parameter to ClipperBase.AddPaths method. You'd also need to add a FillRule member to each LocalMinima struct and assign it in ClipperBase.AddPaths. Then don't use ClipperBase.fillrule_ in IntersectEdges. Instead you'd need to use your new Active.local_min.fillrule member. However, you'll need to be careful which active's fillrule to use where, and comparing Clipper1's IntersectEdges code with Clipper2's would probably get you there.

[EricAtPlanGrid]

If I were to make these changes, adding overrides etc, would this be something you'd be interested in merging?

[AngusJohnson]

Not really. There's a balance between meeting everyone's needs and a really complex library and meeting 99.9% needs and a much simpler library. And you're the only person so far that has requested this.