opencvsharp的指定连通区域最小外接矩形获取

using OpenCvSharp;

Mat source = new Mat(@"D:\code-cs\FormsApplication5\aaaa\snap7.png", ImreadModes.Grayscale);
Cv2.ImShow("Demo", source);
Cv2.WaitKey(0);

Mat labels = new Mat();
int num_labels = Cv2.ConnectedComponents(source, labels, PixelConnectivity.Connectivity4);

Point[][] contours;
HierarchyIndex[] hierarchly;
Cv2.FindContours(source, out contours, out hierarchly, RetrievalModes.Tree, ContourApproximationModes.ApproxSimple, new Point(0, 0));


//将结果画出并返回结果
Mat dst_Image = Mat.Zeros(source.Size(), source.Type());
Random rnd = new Random();
for (int i = 0; i < contours.Length; i++)
{
    Scalar color = new Scalar(255, 255, 255);//白色
    //Cv2.DrawContours(dst_Image, contours, i, color, 1, LineTypes.Link8, hierarchly);
}

//查找指定
Point2f pt = new Point2f(1, 40);
var ret = Cv2.PointPolygonTest(contours[0], pt, false);

RotatedRect rect = Cv2.MinAreaRect(contours[0]);
Point2f[] P = rect.Points();
for (int j = 0; j <= 3; j++)
{
    Cv2.Line(dst_Image, (Point)P[j], (Point)P[(j + 1) % 4], new Scalar(255, 0, 0), 1);
}


Cv2.ImShow("dst_Image:", dst_Image);
Cv2.WaitKey(0);