iTextSharp.text.pdf.FilterHandlers.Filter_CCITTFAXDECODE.Decode C# (CSharp) Метод

            public byte[] Decode(byte[] b, PdfName filterName, PdfObject decodeParams, PdfDictionary streamDictionary)
            {
                PdfNumber wn = (PdfNumber)PdfReader.GetPdfObjectRelease(streamDictionary.Get(PdfName.WIDTH));
                PdfNumber hn = (PdfNumber)PdfReader.GetPdfObjectRelease(streamDictionary.Get(PdfName.HEIGHT));
                if (wn == null || hn == null)
                    throw new UnsupportedPdfException(MessageLocalization.GetComposedMessage("filter.ccittfaxdecode.is.only.supported.for.images"));
                int width = wn.IntValue;
                int height = hn.IntValue;

                PdfDictionary param = decodeParams is PdfDictionary ? (PdfDictionary)decodeParams : null;
                int k = 0;
                bool blackIs1 = false;
                bool byteAlign = false;
                if (param != null) {
                    PdfNumber kn = param.GetAsNumber(PdfName.K);
                    if (kn != null)
                        k = kn.IntValue;
                    PdfBoolean bo = param.GetAsBoolean(PdfName.BLACKIS1);
                    if (bo != null)
                        blackIs1 = bo.BooleanValue;
                    bo = param.GetAsBoolean(PdfName.ENCODEDBYTEALIGN);
                    if (bo != null)
                        byteAlign = bo.BooleanValue;
                }
                byte[] outBuf = new byte[(width + 7) / 8 * height];
                TIFFFaxDecompressor decoder = new TIFFFaxDecompressor();
                if (k == 0 || k > 0) {
                    int tiffT4Options = k > 0 ? TIFFConstants.GROUP3OPT_2DENCODING : 0;
                    tiffT4Options |= byteAlign ? TIFFConstants.GROUP3OPT_FILLBITS : 0;
                    decoder.SetOptions(1, TIFFConstants.COMPRESSION_CCITTFAX3, tiffT4Options, 0);
                    decoder.DecodeRaw(outBuf, b, width, height);
                    if (decoder.fails > 0) {
                        byte[] outBuf2 = new byte[(width + 7) / 8 * height];
                        int oldFails = decoder.fails;
                        decoder.SetOptions(1, TIFFConstants.COMPRESSION_CCITTRLE, tiffT4Options, 0);
                        decoder.DecodeRaw(outBuf2, b, width, height);
                        if (decoder.fails < oldFails) {
                            outBuf = outBuf2;
                        }
                    }
                }
                else {
                    TIFFFaxDecoder deca = new TIFFFaxDecoder(1, width, height);
                    deca.DecodeT6(outBuf, b, 0, height, 0);
                }
                if (!blackIs1) {
                    int len = outBuf.Length;
                    for (int t = 0; t < len; ++t) {
                        outBuf[t] ^= 0xff;
                    }
                }
                b = outBuf;
                return b;
            }