private static List <List <Point2d> > clipGeometries(
            List <List <Point2d> > geoms
            , GeomType geomType
            , long extent
            , uint bufferSize
            )
        {
            List <List <Point2d> > retVal = new List <List <Point2d> >();

            //points: simply remove them if one part of the coordinate pair is out of bounds:
            // <0 || >extent
            if (geomType == GeomType.POINT)
            {
                foreach (var geomPart in geoms)
                {
                    List <Point2d> outGeom = new List <Point2d>();
                    foreach (var geom in geomPart)
                    {
                        if (
                            geom.X < (0L - bufferSize) ||
                            geom.Y < (0L - bufferSize) ||
                            geom.X > (extent + bufferSize) ||
                            geom.Y > (extent + bufferSize)
                            )
                        {
                            continue;
                        }
                        outGeom.Add(geom);
                    }

                    if (outGeom.Count > 0)
                    {
                        retVal.Add(outGeom);
                    }
                }

                return(retVal);
            }

            //use clipper for lines and polygons
            bool closed = true;

            if (geomType == GeomType.LINESTRING)
            {
                closed = false;
            }


            Polygons subjects = new Polygons();
            Polygons clip     = new Polygons(1);
            Polygons solution = new Polygons();

            clip.Add(new Polygon(4));
            clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, 0L - bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, 0L - bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, extent + bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, extent + bufferSize));

            foreach (var geompart in geoms)
            {
                Polygon part = new Polygon();

                foreach (var geom in geompart)
                {
                    part.Add(new InternalClipper.IntPoint(geom.X, geom.Y));
                }
                subjects.Add(part);
            }

            InternalClipper.Clipper c = new InternalClipper.Clipper();
            c.AddPaths(subjects, InternalClipper.PolyType.ptSubject, closed);
            c.AddPaths(clip, InternalClipper.PolyType.ptClip, true);

            bool succeeded = false;

            if (geomType == GeomType.LINESTRING)
            {
                InternalClipper.PolyTree lineSolution = new InternalClipper.PolyTree();
                succeeded = c.Execute(
                    InternalClipper.ClipType.ctIntersection
                    , lineSolution
                    , InternalClipper.PolyFillType.pftNonZero
                    , InternalClipper.PolyFillType.pftNonZero
                    );
                if (succeeded)
                {
                    solution = InternalClipper.Clipper.PolyTreeToPaths(lineSolution);
                }
            }
            else
            {
                succeeded = c.Execute(
                    InternalClipper.ClipType.ctIntersection
                    , solution
                    , InternalClipper.PolyFillType.pftNonZero
                    , InternalClipper.PolyFillType.pftNonZero
                    );
            }

            if (succeeded)
            {
                retVal = new List <List <Point2d> >();
                foreach (var part in solution)
                {
                    List <Point2d> geompart = new List <Point2d>();
                    foreach (var geom in part)
                    {
                        geompart.Add(new Point2d()
                        {
                            X = geom.X, Y = geom.Y
                        });
                    }
                    retVal.Add(geompart);
                }

                return(retVal);
            }
            else
            {
                //if clipper was not successfull return original geometries
                return(geoms);
            }
        }
Exemple #2
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        /// <summary>
        /// TO BE REMOVED!!! Processing geometries is out of scope.
        /// Clip geometries extending beyond the tile border.
        /// </summary>
        /// <param name="geoms">Raw tile geometries of the feature</param>
        /// <param name="geomType">Geometry type of the feature</param>
        /// <param name="extent">Extent of the layer </param>
        /// <param name="bufferSize">Units (in internal tile coordinates) to go beyond the tile border. Pass '0' to clip exactly at the tile border</param>
        /// <param name="scale">Factor for scaling the geometries</param>
        /// <returns></returns>
        public static List <List <Point2d <long> > > ClipGeometries(
            List <List <Point2d <long> > > geoms
            , GeomType geomType
            , long extent
            , uint bufferSize
            , float scale
            )
        {
            List <List <Point2d <long> > > retVal = new List <List <Point2d <long> > >();

            //points: simply remove them if one part of the coordinate pair is out of bounds:
            // <0 || >extent
            if (geomType == GeomType.POINT)
            {
                foreach (var geomPart in geoms)
                {
                    List <Point2d <long> > outGeom = new List <Point2d <long> >();
                    foreach (var geom in geomPart)
                    {
                        if (
                            geom.X < (0L - bufferSize) ||
                            geom.Y < (0L - bufferSize) ||
                            geom.X > (extent + bufferSize) ||
                            geom.Y > (extent + bufferSize)
                            )
                        {
                            continue;
                        }
                        outGeom.Add(geom);
                    }

                    if (outGeom.Count > 0)
                    {
                        retVal.Add(outGeom);
                    }
                }

                return(retVal);
            }

            //use clipper for lines and polygons
            bool closed = true;

            if (geomType == GeomType.LINESTRING)
            {
                closed = false;
            }


            Polygons subjects = new Polygons();
            Polygons clip     = new Polygons(1);
            Polygons solution = new Polygons();

            clip.Add(new Polygon(4));
            clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, 0L - bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, 0L - bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, extent + bufferSize));
            clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, extent + bufferSize));

            foreach (var geompart in geoms)
            {
                Polygon part = new Polygon();

                foreach (var geom in geompart)
                {
                    part.Add(new InternalClipper.IntPoint(geom.X, geom.Y));
                }
                subjects.Add(part);
            }

            InternalClipper.Clipper c = new InternalClipper.Clipper();
            c.AddPaths(subjects, InternalClipper.PolyType.ptSubject, closed);
            c.AddPaths(clip, InternalClipper.PolyType.ptClip, true);

            bool succeeded = false;

            if (geomType == GeomType.LINESTRING)
            {
                InternalClipper.PolyTree lineSolution = new InternalClipper.PolyTree();
                succeeded = c.Execute(
                    InternalClipper.ClipType.ctIntersection
                    , lineSolution
                    , InternalClipper.PolyFillType.pftNonZero
                    , InternalClipper.PolyFillType.pftNonZero
                    );
                if (succeeded)
                {
                    solution = InternalClipper.Clipper.PolyTreeToPaths(lineSolution);
                }
            }
            else
            {
                succeeded = c.Execute(
                    InternalClipper.ClipType.ctIntersection
                    , solution
                    , InternalClipper.PolyFillType.pftNonZero
                    , InternalClipper.PolyFillType.pftNonZero
                    );
            }

            if (succeeded)
            {
                retVal = new List <List <Point2d <long> > >();
                foreach (var part in solution)
                {
                    List <Point2d <long> > geompart = new List <Point2d <long> >();
                    // HACK:
                    // 1. clipper may or may not reverse order of vertices of LineStrings
                    // 2. clipper semms to drop the first vertex of a Polygon
                    // * We don't care about 1.
                    // * Added a check for 2 and insert a copy of last vertex as first
                    foreach (var geom in part)
                    {
                        geompart.Add(new Point2d <long>()
                        {
                            X = geom.X, Y = geom.Y
                        });
                    }
                    if (geomType == GeomType.POLYGON)
                    {
                        if (!geompart[0].Equals(geompart[geompart.Count - 1]))
                        {
                            geompart.Insert(0, geompart[geompart.Count - 1]);
                        }
                    }
                    retVal.Add(geompart);
                }

                return(retVal);
            }
            else
            {
                //if clipper was not successfull return original geometries
                return(geoms);
            }
        }