/// <summary>
/// 由于多边形创建要求环闭合，需要在调用构造函数前进行检查，故不具备用点数组作为集合的构造函数
/// </summary>
/// <param name="ring">单独外环</param>
public MLPolygon(PolylineD ring)
{
featureType = FeatureType.POLYGON;
mbr[0] = mbr[1] = ring.GetPoint(0).X;
mbr[2] = mbr[3] = ring.GetPoint(0).Y;
for (int i = 1; i < ring.Count; ++i)
{
if (ring.GetPoint(i).X < mbr[0])
{
mbr[0] = ring.GetPoint(i).X;
}
if (ring.GetPoint(i).X > mbr[1])
{
mbr[1] = ring.GetPoint(i).X;
}
if (ring.GetPoint(i).Y < mbr[2])
{
mbr[2] = ring.GetPoint(i).Y;
}
if (ring.GetPoint(i).Y > mbr[3])
{
mbr[3] = ring.GetPoint(i).Y;
}
}
pointNum = ring.Count;
polygon = new PolygonD(new PolylineD[] { ring });
}
public MLPolygon(byte[] feaContent) : base()
{
using (MemoryStream ms = new MemoryStream(feaContent))
{
using (BinaryReader br = new BinaryReader(ms))
{
featureType = FeatureType.POLYGON;
br.BaseStream.Seek(4, SeekOrigin.Current);
mbr[0] = br.ReadDouble();
mbr[2] = br.ReadDouble();
mbr[1] = br.ReadDouble();
mbr[3] = br.ReadDouble();
int partNum = br.ReadInt32();
pointNum = br.ReadInt32();
PolylineD[] rings = new PolylineD[partNum];
//将part数组后面多加一个元素pointNum，方便计算每个part的长度
int[] parts = new int[partNum + 1];
for (int i = 0; i < partNum; ++i)
{
parts[i] = br.ReadInt32();
}
parts[partNum] = pointNum;
double x, y;
PointD[] segPoints;
for (int i = 0; i < partNum; ++i)
{
segPoints = new PointD[parts[i + 1] - parts[i]];
for (int j = 0; j < parts[i + 1] - parts[i]; ++j)
{
x = br.ReadDouble();
y = br.ReadDouble();
segPoints[j] = new PointD(x, y);
}
rings[i] = new PolylineD(segPoints);
}
polygon = new PolygonD(rings);
}
}
}
