CentralizedControl/Veldrid.Common/Clipper2/Clipper.Minkowski.cs


#nullable enable
using System;

namespace Clipper2Lib
{
    public class Minkowski
    {
        private static Paths64 MinkowskiInternal(Path64 pattern, Path64 path, bool isSum, bool isClosed)
        {
            int delta = isClosed ? 0 : 1;
            int patLen = pattern.Count, pathLen = path.Count;
            Paths64 tmp = new Paths64(pathLen);

            foreach (Point64 pathPt in path)
            {
                Path64 path2 = new Path64(patLen);
                if (isSum)
                {
                    foreach (Point64 basePt in pattern)
                    {
                        path2.Add(pathPt + basePt);
                    }
                }
                else
                {
                    foreach (Point64 basePt in pattern)
                    {
                        path2.Add(pathPt - basePt);
                    }
                }
                tmp.Add(path2);
            }

            Paths64 result = new Paths64((pathLen - delta) * patLen);
            int g = isClosed ? pathLen - 1 : 0;

            int h = patLen - 1;
            for (int i = delta; i < pathLen; i++)
            {
                for (int j = 0; j < patLen; j++)
                {
                    Path64 quad = new Path64(4)
                    {
                        tmp[g][h], tmp[i][h], tmp[i][j], tmp[g][j]
                    };
                    if (!Clipper.IsPositive(quad))
                    {
                        result.Add(Clipper.ReversePath(quad));
                    }
                    else
                    {
                        result.Add(quad);
                    }

                    h = j;
                }
                g = i;
            }
            return result;
        }

        public static Paths64 Sum(Path64 pattern, Path64 path, bool isClosed)
        {
            return Clipper.Union(MinkowskiInternal(pattern, path, true, isClosed), FillRule.NonZero);
        }

        public static PathsD Sum(PathD pattern, PathD path, bool isClosed, int decimalPlaces = 2)
        {
            double scale = Math.Pow(10, decimalPlaces);
            Paths64 tmp = Clipper.Union(MinkowskiInternal(Clipper.ScalePath64(pattern, scale),
              Clipper.ScalePath64(path, scale), true, isClosed), FillRule.NonZero);
            return Clipper.ScalePathsD(tmp, 1 / scale);
        }

        public static Paths64 Diff(Path64 pattern, Path64 path, bool isClosed)
        {
            return Clipper.Union(MinkowskiInternal(pattern, path, false, isClosed), FillRule.NonZero);
        }

        public static PathsD Diff(PathD pattern, PathD path, bool isClosed, int decimalPlaces = 2)
        {
            double scale = Math.Pow(10, decimalPlaces);
            Paths64 tmp = Clipper.Union(MinkowskiInternal(Clipper.ScalePath64(pattern, scale),
              Clipper.ScalePath64(path, scale), false, isClosed), FillRule.NonZero);
            return Clipper.ScalePathsD(tmp, 1 / scale);
        }

    }

} // namespace