272 lines
9.2 KiB
C#
272 lines
9.2 KiB
C#
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/* Poly2Tri
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* Copyright (c) 2009-2010, Poly2Tri Contributors
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* http://code.google.com/p/poly2tri/
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* * Neither the name of Poly2Tri nor the names of its contributors may be
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* used to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// Changes from the Java version
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// Polygon constructors sprused up, checks for 3+ polys
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// Naming of everything
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// getTriangulationMode() -> TriangulationMode { get; }
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// Exceptions replaced
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// Future possibilities
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// We have a lot of Add/Clear methods -- we may prefer to just expose the container
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// Some self-explanitory methods may deserve commenting anyways
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using Poly2Tri.Triangulation.Delaunay;
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namespace Poly2Tri.Triangulation.Polygon
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{
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public class Polygon : Triangulatable
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{
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protected List<Polygon> _holes;
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protected PolygonPoint _last;
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protected List<TriangulationPoint> _points = new List<TriangulationPoint>();
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protected List<TriangulationPoint> _steinerPoints;
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protected List<DelaunayTriangle> _triangles;
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/// <summary>
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/// Create a polygon from a list of at least 3 points with no duplicates.
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/// </summary>
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/// <param name="points">A list of unique points</param>
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public Polygon(IList<PolygonPoint> points)
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{
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if (points.Count < 3) throw new ArgumentException("List has fewer than 3 points", "points");
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// Lets do one sanity check that first and last point hasn't got same position
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// Its something that often happen when importing polygon data from other formats
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if (points[0].Equals(points[points.Count - 1])) points.RemoveAt(points.Count - 1);
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_points.AddRange(points.Cast<TriangulationPoint>());
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}
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/// <summary>
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/// Create a polygon from a list of at least 3 points with no duplicates.
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/// </summary>
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/// <param name="points">A list of unique points.</param>
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public Polygon(IEnumerable<PolygonPoint> points) : this((points as IList<PolygonPoint>) ?? points.ToArray())
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{
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}
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public Polygon()
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{
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}
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public IList<Polygon> Holes
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{
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get { return _holes; }
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}
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#region Triangulatable Members
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public TriangulationMode TriangulationMode
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{
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get { return TriangulationMode.Polygon; }
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}
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public IList<TriangulationPoint> Points
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{
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get { return _points; }
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}
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public IList<DelaunayTriangle> Triangles
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{
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get { return _triangles; }
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}
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public void AddTriangle(DelaunayTriangle t)
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{
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_triangles.Add(t);
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}
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public void AddTriangles(IEnumerable<DelaunayTriangle> list)
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{
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_triangles.AddRange(list);
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}
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public void ClearTriangles()
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{
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if (_triangles != null) _triangles.Clear();
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}
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/// <summary>
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/// Creates constraints and populates the context with points
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/// </summary>
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/// <param name="tcx">The context</param>
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public void PrepareTriangulation(TriangulationContext tcx)
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{
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if (_triangles == null)
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{
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_triangles = new List<DelaunayTriangle>(_points.Count);
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}
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else
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{
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_triangles.Clear();
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}
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// Outer constraints
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for (int i = 0; i < _points.Count - 1; i++)
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{
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tcx.NewConstraint(_points[i], _points[i + 1]);
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}
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tcx.NewConstraint(_points[0], _points[_points.Count - 1]);
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tcx.Points.AddRange(_points);
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// Hole constraints
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if (_holes != null)
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{
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foreach (Polygon p in _holes)
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{
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for (int i = 0; i < p._points.Count - 1; i++)
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{
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tcx.NewConstraint(p._points[i], p._points[i + 1]);
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}
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tcx.NewConstraint(p._points[0], p._points[p._points.Count - 1]);
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tcx.Points.AddRange(p._points);
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}
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}
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if (_steinerPoints != null)
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{
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tcx.Points.AddRange(_steinerPoints);
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}
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}
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#endregion
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public void AddSteinerPoint(TriangulationPoint point)
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{
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if (_steinerPoints == null)
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{
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_steinerPoints = new List<TriangulationPoint>();
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}
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_steinerPoints.Add(point);
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}
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public void AddSteinerPoints(List<TriangulationPoint> points)
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{
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if (_steinerPoints == null)
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{
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_steinerPoints = new List<TriangulationPoint>();
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}
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_steinerPoints.AddRange(points);
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}
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public void ClearSteinerPoints()
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{
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if (_steinerPoints != null)
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{
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_steinerPoints.Clear();
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}
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}
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/// <summary>
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/// Add a hole to the polygon.
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/// </summary>
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/// <param name="poly">A subtraction polygon fully contained inside this polygon.</param>
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public void AddHole(Polygon poly)
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{
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if (_holes == null) _holes = new List<Polygon>();
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_holes.Add(poly);
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// XXX: tests could be made here to be sure it is fully inside
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// addSubtraction( poly.getPoints() );
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}
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/// <summary>
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/// Inserts newPoint after point.
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/// </summary>
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/// <param name="point">The point to insert after in the polygon</param>
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/// <param name="newPoint">The point to insert into the polygon</param>
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public void InsertPointAfter(PolygonPoint point, PolygonPoint newPoint)
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{
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// Validate that
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int index = _points.IndexOf(point);
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if (index == -1)
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throw new ArgumentException(
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"Tried to insert a point into a Polygon after a point not belonging to the Polygon", "point");
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newPoint.Next = point.Next;
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newPoint.Previous = point;
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point.Next.Previous = newPoint;
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point.Next = newPoint;
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_points.Insert(index + 1, newPoint);
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}
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/// <summary>
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/// Inserts list (after last point in polygon?)
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/// </summary>
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/// <param name="list"></param>
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public void AddPoints(IEnumerable<PolygonPoint> list)
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{
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PolygonPoint first;
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foreach (PolygonPoint p in list)
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{
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p.Previous = _last;
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if (_last != null)
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{
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p.Next = _last.Next;
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_last.Next = p;
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}
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_last = p;
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_points.Add(p);
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}
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first = (PolygonPoint) _points[0];
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_last.Next = first;
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first.Previous = _last;
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}
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/// <summary>
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/// Adds a point after the last in the polygon.
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/// </summary>
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/// <param name="p">The point to add</param>
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public void AddPoint(PolygonPoint p)
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{
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p.Previous = _last;
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p.Next = _last.Next;
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_last.Next = p;
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_points.Add(p);
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}
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/// <summary>
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/// Removes a point from the polygon.
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/// </summary>
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/// <param name="p"></param>
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public void RemovePoint(PolygonPoint p)
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{
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PolygonPoint next, prev;
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next = p.Next;
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prev = p.Previous;
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prev.Next = next;
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next.Previous = prev;
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_points.Remove(p);
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}
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}
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}
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