/// <summary>
/// increase of decrease polygon points offseting
/// </summary>
public static IEnumerable <Vector3D> Offset(this IReadOnlyList <Vector3D> pts, double tol, double offset)
{
var intmap = new Int64Map(tol, pts.SelectMany(x => x.Coordinates));
var clipper = new ClipperOffset();
{
var path = pts.Select(p => new IntPoint(intmap.ToInt64(p.X), intmap.ToInt64(p.Y))).ToList();
// http://www.angusj.com/delphi/clipper.php
clipper.AddPath(path, JoinType.jtMiter, EndType.etClosedPolygon);
}
var intoffset = intmap.ToInt64(intmap.Origin + offset) - intmap.ToInt64(intmap.Origin);
var sol = new List <List <IntPoint> >();
clipper.Execute(ref sol, intoffset);
return(sol.SelectMany(s => s.Select(si => new Vector3D(intmap.FromInt64(si.X), intmap.FromInt64(si.Y), 0))));
}
/// <summary>
/// can generate a Int64MapExceptionRange exception if double values can't fit into a In64 representation.
/// In that case try with tolerances not too small.
/// It is suggested to use a lenTol/10 to avoid lost of precision during domain conversions.
/// </summary>
public static IEnumerable <IEnumerable <Vector3D> > Boolean(this IEnumerable <Vector3D> polyA, double tol, IEnumerable <Vector3D> polyB, ClipType type, bool selfCheckInt64MapTolerance = true)
{
var intmap = new Int64Map(tol, polyA.SelectMany(x => x.Coordinates).Union(polyB.SelectMany(x => x.Coordinates)), selfCheckInt64MapTolerance);
var clipper = new Clipper();
{
var path = polyA.Select(p => new IntPoint(intmap.ToInt64(p.X), intmap.ToInt64(p.Y))).ToList();
clipper.AddPath(path, PolyType.ptSubject, true);
}
{
var path = polyB.Select(p => new IntPoint(intmap.ToInt64(p.X), intmap.ToInt64(p.Y))).ToList();
clipper.AddPath(path, PolyType.ptClip, true);
}
var sol = new List <List <IntPoint> >();
clipper.Execute(type, sol);
var res = sol.Select(s => s.Select(si => new Vector3D(intmap.FromInt64(si.X), intmap.FromInt64(si.Y), 0)));
return(res);
}