Question about coordinate value in PathD

[enuinc]

Hi

I am using the float point version of the boolean code in Clipper2 and would like to confirm something.

I am using the C++ version of code.

basically, when I prepare the PathsD objects, I specify the polygon coordinates with float point, then use Execute() to get the boolean results (I used the PolyTreeD version of code, as the results may contain holes). However, when I tried to extract the boolean results, I find the coordiantes of the resultant polygons all scaled by 100. I think the code internally scale the input coordinates by 100 (or up to 8 decimal point), then perform the boolean using integer code.

this is fine, but I would suggest to scale the coordinates back when output. Otherwise I have to keep track the scaling factor. I did found the ClipperD's private member variable scale_, but can not figure out how to get this value.

Thanks
enuinc

[AngusJohnson]

  PathsD subjects, clips, solution;
  subjects.push_back(MakePathD("10,10, 100,10, 100,100, 10,100"));
  clips.push_back(MakePathD("20,20, 110,20, 110,110, 20,110"));
  solution = Intersect(subjects, clips, FillRule::NonZero);
  std::cout << solution << std::endl;

Output:
100,100, 20,100, 20,20, 100,20

[enuinc]

I am including my code example as follows. Can you please check to see what I did wrong?

Thanks
enunic

   Clipper2Lib::PathsD subjects, clips;
    subjects.push_back(Clipper2Lib::MakePathD("10,10, 100,10, 100,100, 10,100"));
    clips.push_back(Clipper2Lib::MakePathD("20,20, 110,20, 110,110, 20,110"));
    
    Clipper2Lib::ClipperD clipper;
    clipper.AddSubject(subjects);
    clipper.AddClip(clips);

    Clipper2Lib::PolyTreeD solution1;
    clipper.Execute(Clipper2Lib::ClipType::Union, Clipper2Lib::FillRule::EvenOdd, solution1);
    
    for (int i=0; i<solution1.Count(); i++) {
        Clipper2Lib::PolyPathD* pCurrentPolygon = solution1[i];
        
        Clipper2Lib::PathD CurrentPathD = pCurrentPolygon->Polygon();
    
        for (size_t j=0; j<CurrentPathD.size(); j++) {
            std::cout << CurrentPathD[j].x << "  " << CurrentPathD[j].y << std::endl;
        }
    }

Output:
10000 2000
11000 2000
11000 11000
2000 11000
2000 10000
1000 10000
1000 1000
10000 1000

[enuinc]

BTW, I am using the PolyTreeD as my result may contain holes。

[sergey-239]

@AngusJohnson both
ClipperD::Execute(ClipType clip_type, FillRule fill_rule, PolyTreeD& polytree) and
ClipperD::Execute::(ClipType clip_type, FillRule fill_rule, PolyTreeD& polytree, Paths64& open_paths)
do not call ScalePaths on outputs. Obviously it's a bug.
Regards,
Sergey.

[AngusJohnson]

In the latest commit, the C++ Polytree class has had a major rewrite, so I'm hoping this issue has now been fixed.

[rs0xFFFF]

Clipper2 just keeps getting better! Thanks! I tried Delphi Tokyo 32 bit but it doesn't work because the DLL is probably 64 bit. Since I'm not very familiar with Visual Studio, would it be possible to put a clipper2_32.dll into Git?

[reunanen]

I would say ideally not to git itself, but rather publish one as a Github Actions artifact!