iTextSharp.text.pdf.PdfCopy.PageStamp.AlterContents C# (CSharp) Метод

            public void AlterContents()
            {
                if (over == null && under == null)
                    return;
                PdfArray ar = null;
                PdfObject content = PdfReader.GetPdfObject(pageN.Get(PdfName.CONTENTS), pageN);
                if (content == null) {
                    ar = new PdfArray();
                    pageN.Put(PdfName.CONTENTS, ar);
                }
                else if (content.IsArray()) {
                    ar = (PdfArray)content;
                }
                else if (content.IsStream()) {
                    ar = new PdfArray();
                    ar.Add(pageN.Get(PdfName.CONTENTS));
                    pageN.Put(PdfName.CONTENTS, ar);
                }
                else {
                    ar = new PdfArray();
                    pageN.Put(PdfName.CONTENTS, ar);
                }
                ByteBuffer out_p = new ByteBuffer();
                if (under != null) {
                    out_p.Append(PdfContents.SAVESTATE);
                    ApplyRotation(pageN, out_p);
                    out_p.Append(under.InternalBuffer);
                    out_p.Append(PdfContents.RESTORESTATE);
                }
                if (over != null)
                    out_p.Append(PdfContents.SAVESTATE);
                PdfStream stream = new PdfStream(out_p.ToByteArray());
                stream.FlateCompress(cstp.CompressionLevel);
                PdfIndirectReference ref1 = cstp.AddToBody(stream).IndirectReference;
                ar.AddFirst(ref1);
                out_p.Reset();
                if (over != null) {
                    out_p.Append(' ');
                    out_p.Append(PdfContents.RESTORESTATE);
                    out_p.Append(PdfContents.SAVESTATE);
                    ApplyRotation(pageN, out_p);
                    out_p.Append(over.InternalBuffer);
                    out_p.Append(PdfContents.RESTORESTATE);
                    stream = new PdfStream(out_p.ToByteArray());
                    stream.FlateCompress(cstp.CompressionLevel);
                    ar.Add(cstp.AddToBody(stream).IndirectReference);
                }
                pageN.Put(PdfName.RESOURCES, pageResources.Resources);
            }