Accord.Imaging.Filters.FeaturesMarker.ProcessFilter C# (CSharp) Method

        protected override void ProcessFilter(UnmanagedImage sourceData, UnmanagedImage destinationData)
        {
            if (sourceData.PixelFormat == PixelFormat.Format8bppIndexed)
                sourceData = toRGB.Apply(sourceData);

            // Copy image contents
            sourceData.Copy(destinationData);

            Bitmap managedImage = destinationData.ToManagedImage(makeCopy: false);

            using (Graphics g = Graphics.FromImage(managedImage))
            using (Pen positive = new Pen(Color.Red))
            using (Pen negative = new Pen(Color.Blue))
            using (Pen line = new Pen(Color.FromArgb(0, 255, 0)))
            {
                // mark all points
                foreach (SpeededUpRobustFeaturePoint p in points)
                {
                    int S = (int)(scale * p.Scale);
                    int R = (int)(S / 2f);

                    Point pt = new Point((int)p.X, (int)p.Y);
                    Point ptR = new Point((int)(R * System.Math.Cos(p.Orientation)),
                                          (int)(R * System.Math.Sin(p.Orientation)));

                    Pen myPen = (p.Laplacian > 0 ? negative : positive);

                    g.DrawEllipse(myPen, pt.X - R, pt.Y - R, S, S);
                    g.DrawLine(line, new Point(pt.X, pt.Y), new Point(pt.X + ptR.X, pt.Y + ptR.Y));
                }
            }

        }
    }