BitMiracle.LibJpeg.Classic.jpeg_compress_struct.jpeg_write_scanlines C# (CSharp) Method

        public int jpeg_write_scanlines(byte[][] scanlines, int num_lines)
        {
            if (m_global_state != JpegState.CSTATE_SCANNING)
                ERREXIT(J_MESSAGE_CODE.JERR_BAD_STATE, (int)m_global_state);

            if (m_next_scanline >= m_image_height)
                WARNMS(J_MESSAGE_CODE.JWRN_TOO_MUCH_DATA);

            /* Call progress monitor hook if present */
            if (m_progress != null)
            {
                m_progress.Pass_counter = m_next_scanline;
                m_progress.Pass_limit = m_image_height;
                m_progress.Updated();
            }

            /* Give master control module another chance if this is first call to
            * jpeg_write_scanlines.  This lets output of the frame/scan headers be
            * delayed so that application can write COM, etc, markers between
            * jpeg_start_compress and jpeg_write_scanlines.
            */
            if (m_master.MustCallPassStartup())
                m_master.pass_startup();

            /* Ignore any extra scanlines at bottom of image. */
            int rows_left = m_image_height - m_next_scanline;
            if (num_lines > rows_left)
                num_lines = rows_left;

            int row_ctr = 0;
            m_main.process_data(scanlines, ref row_ctr, num_lines);
            m_next_scanline += row_ctr;
            return row_ctr;
        }

        private static void compress(Stream input, CompressOptions options, Stream output)
        {
            Debug.Assert(input != null);
            Debug.Assert(options != null);
            Debug.Assert(output != null);

            jpeg_compress_struct cinfo = new jpeg_compress_struct(new cd_jpeg_error_mgr());

            /* Initialize JPEG parameters.
             * Much of this may be overridden later.
             * In particular, we don't yet know the input file's color space,
             * but we need to provide some value for jpeg_set_defaults() to work.
             */
            cinfo.In_color_space = J_COLOR_SPACE.JCS_RGB; /* arbitrary guess */
            cinfo.jpeg_set_defaults();

            /* Figure out the input file format, and set up to read it. */
            cjpeg_source_struct src_mgr = new bmp_source_struct(cinfo);
            src_mgr.input_file = input;

            /* Read the input file header to obtain file size & colorspace. */
            src_mgr.start_input();

            /* Now that we know input colorspace, fix colorspace-dependent defaults */
            cinfo.jpeg_default_colorspace();

            /* Adjust default compression parameters */
            if (!applyOptions(cinfo, options))
                return;

            /* Specify data destination for compression */
            cinfo.jpeg_stdio_dest(output);

            /* Start compressor */
            cinfo.jpeg_start_compress(true);

            /* Process data */
            while (cinfo.Next_scanline < cinfo.Image_height)
            {
                int num_scanlines = src_mgr.get_pixel_rows();
                cinfo.jpeg_write_scanlines(src_mgr.buffer, num_scanlines);
            }

            /* Finish compression and release memory */
            src_mgr.finish_input();
            cinfo.jpeg_finish_compress();

            /* All done. */
            if (cinfo.Err.Num_warnings != 0)
                Console.WriteLine("Corrupt-data warning count is not zero");
        }