How to draw dot in center of detected circles underlying drawn line

Image

image

image

something

private void Firstpointbtn_Click(object sender, EventArgs e)
{
    // code to set the first point for "MANUAL" mode goes here
    MessageBox.Show("Fp click");
            
    if (img_path != null)
    {
        Image<Bgr, byte> imgin = new Image<Bgr, byte>(img_path);
        DisplayWindow2.Image = imgin.Bitmap;
        Drawshape = 1;
    }
    else
    {
        MessageBox.Show("Please Select Image");
    }
}

private void Secondpointbtn_Click(object sender, EventArgs e)
{
    // code to set the second point for "MANUAL" mode goes here
    MessageBox.Show("Sp click");
            
    if (img_path != null)
    {
        Drawshape = 2;
    }
    else
    {
        MessageBox.Show("Please Select Image");
    }           
}

private void DisplayWindow2_MouseDown(object sender, MouseEventArgs e)
{
    try
    {
        if (Drawshape == 1 || Drawshape == 2)
        {
            if (e.Button == MouseButtons.Left)
            {
                Graphics g = Graphics.FromImage(DisplayWindow2.Image);
                Pen p = new Pen(Color.Yellow, 1);
                var cursorPosition = DisplayWindow2.PointToClient(Cursor.Position);
                g.DrawEllipse(p, cursorPosition.X, cursorPosition.Y, 2, 2);
                MyCircles.Add(cursorPosition);
                DisplayWindow2.Refresh();

                // Save the center point of the circle
                if (Drawshape == 1)
                {
                    firstPoint = cursorPosition;
                }
                else if (Drawshape == 2)
                {
                    secondPoint = cursorPosition;
                }
            }
            if (p1.X == 0)
            {
                p1.X = e.X;
                p1.Y = e.Y;
            }
            else
            {
                p2.X = e.X;
                p2.Y = e.Y;
                p1List.Add(p1);
                p2List.Add(p2);
                //  p1.X = 0;
                DisplayWindow2.Invalidate();
            }
        }
    }
    catch (Exception exx)
    {
        MessageBox.Show(exx.Message);
    }
// } missing here

private void DisplayWindow2_Paint(object sender, PaintEventArgs e)
{
    if (DisplayWindow2.Image != null)
    {
        using (var p = new Pen(Color.Yellow, 1))
        {
            for (int x = 0; x < p1List.Count; x++)
            {
                e.Graphics.DrawLine(p, p1List[x], p2List[x]);
            }
            p.Dispose();
        }
    }
}

private void ManualCalculatebtn_Click(object sender, EventArgs e)
{
    MessageBox.Show("selected Manual and click on calculate");
            
    if (img_path != null)
    {
        try
        {
            Image<Bgr, byte> imgInput = new Image<Bgr, byte>(img_path);

            var temp = imgInput.Not().SmoothGaussian(5).Convert<Gray, byte>().ThresholdBinary(new Gray(220), new Gray(150));
            VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
            Mat hierarchy = new Mat();
            CvInvoke.FindContours(temp, contours, hierarchy, Emgu.CV.CvEnum.RetrType.External, Emgu.CV.CvEnum.ChainApproxMethod.ChainApproxSimple);
            Point startPoint = new Point(p1.X, p1.Y);
            Point endPoint = new Point(p2.X, p2.Y);
            double slope = (double)(endPoint.Y - startPoint.Y) / (double)(endPoint.X - startPoint.X);
            for (int i = 0; i < contours.Size; i++)
            {
                double area = CvInvoke.ContourArea(contours[i]);
                if (5 > area && area >= 30) continue;
                MCvMoments moments = CvInvoke.Moments(contours[i]);
                Point center = new Point((int)(moments.M10 / moments.M00), (int)(moments.M01 / moments.M00));
                       
                int radius = 3; // the radius of the object to be drawn
                // initialize the object's position to the center point
                double t = ((double)(center.X - p1.X) / (double)(p2.X - p1.X));// the angle at which the object moves (in degrees)
                int newX = (int)(p1.X + t * (p2.X - p1.X));
                int newY = (int)(p1.Y + t * (p2.Y - p1.Y));
                Point newCenter = new Point(newX, newY);
                      
                int angle = newX;
                double x = center.X + radius * Math.Cos(angle * Math.PI / 180); // calculate the x coordinate of the object's new position
                double y = center.Y + radius * Math.Sin(angle * Math.PI / 180); // calculate the y coordinate of the object's new position
                newCenter = new Point((int)x, (int)y); // update the object's position
                if (center.Y > startPoint.Y - slope * (center.Y - startPoint.X) && center.X > startPoint.X && center.X < endPoint.X)
                {
                    CvInvoke.Circle(imgInput, newCenter, 2, new MCvScalar(0, 0, 250), -1);
                }
            }
            DisplayWindow2.Image = imgInput.Bitmap;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
}