public static Dictionary <string, object> GetAnnotationsFromPDF(string filepath, int page = 1)
        {
            if (!System.IO.File.Exists(filepath))
            {
                throw new Exception(Properties.Resources.FileNotFoundError);
            }

            List <Content.Annotation> elements = new List <Content.Annotation>();

            Rectangle pagesize = null;

            // Open a new memory stream
            using (var ms = new System.IO.MemoryStream())
            {
                // Create a new pdf reader and get the first page
                PdfReader myPdfReader = new PdfReader(filepath);

                if (page < 1 || page > myPdfReader.NumberOfPages)
                {
                    throw new Exception(Properties.Resources.WrongPageNumber);
                }

                PdfDictionary pageDict   = myPdfReader.GetPageN(page);
                PdfArray      annotArray = pageDict.GetAsArray(PdfName.ANNOTS);
                pagesize = myPdfReader.GetPageSizeWithRotation(page).ToDSRectangle();

                if (annotArray == null)
                {
                    throw new Exception(Properties.Resources.NoAnnotations);
                }

                // Walk through the annotation element array
                for (int i = 0; i < annotArray.Size; i++)
                {
                    // Get the elements type and subject to filter by
                    PdfDictionary annotationElement = annotArray.GetAsDict(i);
                    PdfName       subtype           = annotationElement.GetAsName(PdfName.SUBTYPE);
                    if (subtype != null)
                    {
                        if (subtype == PdfName.LINE)
                        {
                            elements.Add(annotationElement.ToLine());
                        }
                        else if (subtype == PdfName.POLYGON)
                        {
                            elements.Add(annotationElement.ToPolyCurve(true));
                        }
                        else if (subtype == PdfName.POLYLINE)
                        {
                            elements.Add(annotationElement.ToPolyCurve(false));
                        }
                        else if (subtype == PdfName.INK)
                        {
                            elements.Add(annotationElement.InkToPolyCurve());
                        }
                        else if (subtype == PdfName.SQUARE)
                        {
                            elements.Add(annotationElement.ToRectangle());
                        }
                        else if (subtype == PdfName.FREETEXT)
                        {
                            elements.Add(annotationElement.ToRectangle());
                        }
                        else if (subtype == PdfName.CIRCLE)
                        {
                            elements.Add(annotationElement.ToCircle());
                        }
                    }
                }

                string content = PdfTextExtractor.GetTextFromPage(myPdfReader, page, new SimpleTextExtractionStrategy());
            }

            return(new Dictionary <string, object>()
            {
                { "Annotations", elements },
                { "Rectangle", pagesize }
            });
        }