/// <summary>
/// 将孔的点添加到PolygonData
/// Add Points of a Hole to the PolygonData
/// </summary>
/// <param name="points">The Points that define the Hole in the Polygon</param>
internal void AddHole(List <Point> points)
{
// Make Hole Clockwise
if (SweepLinePolygonTriangulator.IsCCW(points))
{
points.Reverse();
}
// The Hole Points
var polyPoints = points.Select(p => new PolygonPoint(p)).ToList();
// If Endpoint equals Startpoint
if (polyPoints[0].Equals(polyPoints[polyPoints.Count - 1]))
{
polyPoints.RemoveAt(polyPoints.Count - 1);
}
mHoles.Add(polyPoints);
var cntBefore = mPoints.Count;
var pointCount = points.Count;
// Add the PolygonPoints for this Polygon Object
mPoints.AddRange(polyPoints);
// Add the Indices
for (int i = cntBefore; i < mPoints.Count; i++)
{
polyPoints[i - cntBefore].Index = i;
}
// Add Edges between the Points (to be able to navigate along the Polygon easily later)
var cnt = mPoints.Count;
for (int i = 0; i < pointCount; i++)
{
var lastIdx = (i + pointCount - 1) % pointCount;
var edge = new PolygonEdge(polyPoints[lastIdx], polyPoints[i]);
polyPoints[lastIdx].EdgeTwo = edge;
polyPoints[i].EdgeOne = edge;
}
}
/// <summary>
/// 使用扫掠线算法对多边形进行三角剖分
/// Triangulate the polygon by using the sweep line algorithm
/// </summary>
/// <returns>An index collection.</returns>
public Int32Collection Triangulate()
{
return(SweepLinePolygonTriangulator.Triangulate(this.points));
}
