About "RectClipLines", May be this is a bug???

[jim-jiang-github]

C# project, Use nuget Clipper2 1.3.0, net6.0

S1:
Code:

 static void Main(string[] args)
 {
     List<PointD> ps = new List<PointD>();
     ps.Add(new PointD(200, 1000));
     ps.Add(new PointD(3300, 1000));
     ps.Add(new PointD(3300, 600));
     ps.Add(new PointD(200, 600));
     ps.Add(new PointD(200, 1000));
     PathsD psd = new PathsD();
     psd.Add(new PathD(ps));
     double width = 15000;
     double height = 1520;
     int split = 500;
     SvgWriter svg = new(FillRule.NonZero);

     for (int i = 0; i < (int)(width / split); i++)
     {
         var startX = i * split;
         var endX = split * i + split;
         RectD clipRect = new RectD(Math.Max(0, startX - 2), 0, endX, height);
         PathsD paths = Clipper.RectClipLines(clipRect, psd, 0);
         SvgUtils.AddOpenSubject(svg, paths);
     }
     svg.SaveToFile("rectclip.svg");
 }

result:

S2:
Code:

static void Main(string[] args)
{
    List<PointD> ps = new List<PointD>();
    ps.Add(new PointD(200, 1000));
    for (int i = 1; i < 32; i++)
    {
        ps.Add(new PointD(i * 100 + 200, 1000));
    }
    ps.Add(new PointD(3300, 1000));
    ps.Add(new PointD(3300, 600));
    for (int i = 1; i < 32; i++)
    {
        ps.Add(new PointD(3300 - i * 100, 600));
    }
    ps.Add(new PointD(200, 600));
    ps.Add(new PointD(200, 1000));
    PathsD psd = new PathsD();
    psd.Add(new PathD(ps));
    double width = 15000;
    double height = 1520;
    int split = 500;
    SvgWriter svg = new(FillRule.NonZero);

    for (int i = 0; i < (int)(width / split); i++)
    {
        var startX = i * split;
        var endX = split * i + split;
        RectD clipRect = new RectD(Math.Max(0, startX - 2), 0, endX, height);
        PathsD paths = Clipper.RectClipLines(clipRect, psd, 0);
        SvgUtils.AddOpenSubject(svg, paths);
    }
    svg.SaveToFile("rectclip.svg");
}

result:

Demo:
Clipper2Lib.Test.zip

I wanted to implement polygon cutting. I constructed a rectangle as a special polygon, and then I found that the result of code 1 was not what I wanted. What I wanted was the result of code 2.

The difference between the two codes is that the number of points describing the rectangle is different, but the result of the two codes describing the polygon is the same, but the code 2 fits more meaningless point data.

What is causing the two results to be different? Or am I doing it the wrong way? I want to cut any polygon, and it seems that most polygons are cut fine, except this rectangle.

[AngusJohnson]

No, AFAICS this isn't a bug.
If you're cutting a polygon, then presumably you're expecting polygons in your solutions.
Assuming that's the case then SvgUtils.AddOpenSubject(svg, paths); should be replaced with SvgUtils.AddSubject(svg, paths);.