Double?

[seghier]

Hi
Is Clipper2 support double now?

[philstopford]

Yes, via ClipperD

[seghier]

Is there an example how to create offset with ClipperD in c#?
This is from the documentation:

[AngusJohnson]

Is there an example how to create offset with ClipperD in c#?

Why not use the wrapper function instead:

Clipper2/CSharp/Clipper2Lib/Clipper.cs

Lines 150 to 151 in f9a40f0

	public static PathsD InflatePaths(PathsD paths, double delta, JoinType joinType,
	EndType endType, double miterLimit = 2.0, int precision = 2)

[seghier]

Thanks @AngusJohnson
I try this but the result is not precise as Grasshopper offset.
I use the precision = 1000

holeCurves.Clear();
outCurves.Clear();

PathsD pathsD = ConvertPolylineD(curves); // converted from Rhino curves
PathsD solutionD = new PathsD();
solutionD = Clipper.InflatePaths(pathsD, distance, JoinTypes[jointype], EndTypes[endtype], 1000);

foreach (PathD path in solutionD)
{
    Polyline polyline = new Polyline(path.Select(p => new Point3d(p.x, p.y, 0)));
    polyline.Add(polyline[0]);
    if (Clipper.IsPositive(path))
        outCurves.Add(polyline.ToNurbsCurve());
    else
        holeCurves.Add(polyline.ToNurbsCurve());
}


PathsD ConvertPolylineD(List<Curve> curves)
{
    PathsD pathsD = new PathsD();
    foreach (Curve curve in curves)
    {
        Polyline polyline;
        curve.TryGetPolyline(out polyline);
        PathD path = new PathD();
        foreach (Point3d point in polyline)
        {
            path.Add(new PointD(point.X, point.Y));
        }
        pathsD.Add(path);
    }
    return pathsD;
}

[AngusJohnson]

I use the precision = 1000

Rounding precisions of > 8 should be throwing an error,

[seghier]

I get the same result with precision = 2 or 7

[AngusJohnson]

Please post a small sample of your polygon data.

[seghier]

I use Rhino , this is the list of the points of the polygon

{12.516166, 11.34008, 0}
{11.402324, 11.972632, 0}
{10.329735, 11.450089, 0}
{10.357238, 10.363749, 0}
{11.539835, 10.267492, 0}
{11.36107, 10.831288, 0}
{12.502415, 10.886293, 0}

[AngusJohnson]

I use Rhino , this is the list of the points of the polygon

How much are you offsetting, what join and end types are you using?
And what results are you expecting that you aren't getting?

[seghier]

distance: 0.26
jointype: mitter
endtype: butt
miterlimit: 2

I want the same result as Rhino offset: 0.26 or any other distance in all direction, you can see a little deformation in this scale and in any other scale i got the same

[AngusJohnson]

It looks fine to me.
I'm pretty sure there's something wrong with your own code or with Grasshopper's code.

    public static void Main()
    {
      PathsD subject = new();
      subject.Add(Clipper.MakePath(new double[] { 12.516166, 11.34008, 11.402324, 11.972632, 
        10.329735, 11.450089, 10.357238, 10.363749, 11.539835, 10.267492, 11.36107, 10.831288, 
        12.502415, 10.886293 }));

      PathsD solution = Clipper.InflatePaths(subject, 0.26, JoinType.Miter, EndType.Butt);

      SvgWriter svg = new SvgWriter();
      SvgUtils.AddOpenSubject(svg, subject);
      SvgUtils.AddSolution(svg, solution, true);
      string filename = @"..\..\..\tmp.svg";
      SvgUtils.SaveToFile(svg, filename, FillRule.NonZero, 600, 400, 60);
      ClipperFileIO.OpenFileWithDefaultApp(filename);
    }

[seghier]

I import your svg in Rhino ,you can see the difference

[AngusJohnson]

OK, thanks, I understand the problem now and I'll investigate,

[AngusJohnson]

If you increase decimal precision to 4 (instead of the default 2), then you will get much more precise coordinates in your solutions:

      subject.Add(Clipper.MakePath(new double[] { 12.516166, 11.34008, 11.402324, 11.972632, 
        10.329735, 11.450089, 10.357238, 10.363749, 11.539835, 10.267492, 11.36107, 10.831288, 
        12.502415, 10.886293 }));

      // note: decimal precision = 4
      PathsD solution = Clipper.InflatePaths(subject, 0.26, JoinType.Miter, EndType.Butt, 2, 4);

      double dist1 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][5], solution[0][11], solution[0][12]));
      double dist2 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][6], solution[0][11], solution[0][12]));
      Console.WriteLine(dist1);
      Console.WriteLine(dist2);
      Console.WriteLine("");

      dist1 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][6], solution[0][10], solution[0][11]));
      dist2 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][7], solution[0][10], solution[0][11]));
      Console.WriteLine(dist1);
      Console.WriteLine(dist2);
      Console.WriteLine("");

      dist1 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][7], solution[0][9], solution[0][10]));
      dist2 = Math.Sqrt(Clipper.PerpendicDistFromLineSqrd(solution[0][8], solution[0][9], solution[0][10]));
      Console.WriteLine(dist1);
      Console.WriteLine(dist2);
      Console.WriteLine("");

0.2600018419969803
0.26004789498548786

0.26008413786029844
0.26009812880015465

0.2600231448041895
0.2599279847035176

[seghier]

Thank you , yes the result much better