我想得到 polyline2d 的质心。我有一条来自 TraceBoundary 的折线,如下所示:
DBObjectCollection objs = Application.DocumentManager.MdiActiveDocument.Editor.TraceBoundary(Point, false);
Polyline polyline = (Polyline)objs[0];
Point2d centroid = ***The missing part i need any way to get center of gravity of the above polyline as point2d***
我以前用 autolisp 这样做过:
(setq arob (entlast))
(setq enpol (vlax-ename->vla-object arob))
(setq cgpoint (vlax-get-property enpol 'Centroid))
我有一个数学解决方案,但是当折线带有一些曲线时它是无效的。
我不会使用这个功能:
public static Point2d GetPolyLineCentroid(Polyline polyline)
{
double area = polyline.Area;
double cx = 0.0;
double cy = 0.0;
double X0 = 0.0;
double Y0 = 0.0;
double X1 = 0.0;
double Y1 = 0.0;
for (int i = 0; i < polyline.NumberOfVertices - 1; i++)
{
X0 = polyline.GetPoint2dAt(i).X;
Y0 = polyline.GetPoint2dAt(i).Y;
X1 = polyline.GetPoint2dAt(i + 1).X;
Y1 = polyline.GetPoint2dAt(i + 1).Y;
cx += (X0 + X1) * (X0 * Y1 - X1 * Y0);
cy += (Y0 + Y1) * (X0 * Y1 - X1 * Y0);
}
// last Point
int Lv = polyline.NumberOfVertices - 1;
X0 = polyline.GetPoint2dAt(Lv).X;
Y0 = polyline.GetPoint2dAt(Lv).Y;
X1 = polyline.GetPoint2dAt(0).X;
Y1 = polyline.GetPoint2dAt(0).Y;
cx += (X0 + X1) * (X0 * Y1 - X1 * Y0);
cy += (Y0 + Y1) * (X0 * Y1 - X1 * Y0);
cx /= 6 * area;
cy /= 6 * area;
return new Point2d(cx, cy);
}
我不想使用 AutoLisp。有没有办法在.NET中做到这一点?