iTextSharp.text.pdf.PdfStamperImp.AlterContents C# (CSharp) Метод

        protected internal void AlterContents()
        {
            foreach (PageStamp ps in pagesToContent.Values) {
                PdfDictionary pageN = ps.pageN;
                MarkUsed(pageN);
                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;
                    MarkUsed(ar);
                }
                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 (ps.under != null) {
                    out_p.Append(PdfContents.SAVESTATE);
                    ApplyRotation(pageN, out_p);
                    out_p.Append(ps.under.InternalBuffer);
                    out_p.Append(PdfContents.RESTORESTATE);
                }
                if (ps.over != null)
                    out_p.Append(PdfContents.SAVESTATE);
                PdfStream stream = new PdfStream(out_p.ToByteArray());
                stream.FlateCompress(compressionLevel);
                ar.AddFirst(AddToBody(stream).IndirectReference);
                out_p.Reset();
                if (ps.over != null) {
                    out_p.Append(' ');
                    out_p.Append(PdfContents.RESTORESTATE);
                    ByteBuffer buf = ps.over.InternalBuffer;
                    out_p.Append(buf.Buffer, 0, ps.replacePoint);
                    out_p.Append(PdfContents.SAVESTATE);
                    ApplyRotation(pageN, out_p);
                    out_p.Append(buf.Buffer, ps.replacePoint, buf.Size - ps.replacePoint);
                    out_p.Append(PdfContents.RESTORESTATE);
                    stream = new PdfStream(out_p.ToByteArray());
                    stream.FlateCompress(compressionLevel);
                    ar.Add(AddToBody(stream).IndirectReference);
                }
                AlterResources(ps);
            }
        }