PDF Mosaic: How to add ink annotation to PDF documents

using PDFMosaic;
using System;
using System.Drawing;
 
namespace PDFInkAnnotationSample
{
    class PDFInkAnnotationSample
    {
        static void Main()
        {
            PDFDocument pdf = new PDFDocument();
            pdf.Pages.Add(new PDFPage(PDFPaperFormat.A4));
 
            Random rnd = new Random();
            PDFInkList list = new PDFInkList();
            PointF[] f = new PointF[5];
            for (int j = 0; j < 5; ++j)
            {
                int min = rnd.Next(100);
                int max = rnd.Next(100, 600);
                for (int i = 0; i < f.Length; ++i)
                {
                    f[i].X = rnd.Next(min, max);
                    f[i].Y = rnd.Next(min, max);
 
                }
                list.AddArray(new PDFPointsArray(f));
            }
            PDFInkAnnotation annot = new PDFInkAnnotation(list);
            annot.Contents = "PDF ink annotation";
            annot.Color = new PDFColorRGB(80, 80, 50);
 
            pdf.Pages[0].Annotations.Add(annot);
            pdf.Save("TestInkAnnotation.pdf", true);
        }
    }
}