jpeg_simple_progression() public method

Generates a default scan script for writing a progressive-JPEG file.
This is the recommended method of creating a progressive file, unless you want to make a custom scan sequence. You must ensure that the JPEG color space is set correctly before calling this routine.
public jpeg_simple_progression ( ) : void
return void
Example #1
0
        public void TestCompressorWithContextRows()
        {
            using (MemoryStream stream = new MemoryStream())
            {
                jpeg_compress_struct compressor = new jpeg_compress_struct(new jpeg_error_mgr());
                compressor.Image_height = 100;
                compressor.Image_width = 100;
                compressor.In_color_space = J_COLOR_SPACE.JCS_GRAYSCALE;
                compressor.Input_components = 1;
                compressor.jpeg_set_defaults();

                compressor.Dct_method = J_DCT_METHOD.JDCT_IFAST;
                compressor.Smoothing_factor = 94;
                compressor.jpeg_set_quality(75, true);
                compressor.jpeg_simple_progression();

                compressor.Density_unit = DensityUnit.Unknown;
                compressor.X_density = (short)96;
                compressor.Y_density = (short)96;

                compressor.jpeg_stdio_dest(stream);
                compressor.jpeg_start_compress(true);

                byte[][] rowForDecompressor = new byte[1][];
                int bytesPerPixel = 1;
                while (compressor.Next_scanline < compressor.Image_height)
                {
                    byte[] row = new byte[100 * bytesPerPixel]; // wasteful, but gets you 0 bytes every time - content is immaterial.
                    rowForDecompressor[0] = row;
                    compressor.jpeg_write_scanlines(rowForDecompressor, 1);
                }
                compressor.jpeg_finish_compress();

                byte[] bytes = stream.ToArray();

                string filename = "TestCompressorWithContextRows.jpg";
                File.WriteAllBytes(Tester.MapOutputPath(filename), bytes);
                FileAssert.AreEqual(Tester.MapExpectedPath(filename), Tester.MapOutputPath(filename));
            }
        }
        private static bool applyOptions(jpeg_compress_struct compressor, CompressOptions options)
        {
            compressor.jpeg_set_quality(options.Quality, options.ForceBaseline);
            compressor.Dct_method = options.DCTMethod;

            if (options.Debug)
                compressor.Err.Trace_level = 1;

            if (options.Grayscale)
                compressor.jpeg_set_colorspace(J_COLOR_SPACE.JCS_GRAYSCALE);

            if (options.Optimize)
                compressor.Optimize_coding = true;

            compressor.Restart_interval = options.RestartInterval;
            compressor.Restart_in_rows = options.RestartInRows;

            compressor.Smoothing_factor = options.SmoothingFactor;

            int q_scale_factor = 100;
            if (options.Quality != 75)
                q_scale_factor = jpeg_compress_struct.jpeg_quality_scaling(options.Quality);

            /* Set quantization tables for selected quality. */
            /* Some or all may be overridden if -qtables is present. */
            if (options.Qtables != "") /* process -qtables if it was present */
            {
                if (!read_quant_tables(compressor, options.Qtables, q_scale_factor, options.ForceBaseline))
                    return false;
            }

            if (options.Qslots != "")  /* process -qslots if it was present */
            {
                if (!set_quant_slots(compressor, options.Qslots))
                    return false;
            }

            if (options.Sample != "")  /* process -sample if it was present */
            {
                if (!set_sample_factors(compressor, options.Sample))
                    return false;
            }

            if (options.Progressive) /* process -progressive; -scans can override */
                compressor.jpeg_simple_progression();

            return true;
        }
Example #3
0
        /// <summary>
        /// Parse optional switches.
        /// Returns true if switches were parsed successfully; false otherwise.
        /// fileIndex receives index of first file-name argument (== -1 if none).
        /// for_real is false on the first (dummy) pass; we may skip any expensive
        /// processing.
        /// </summary>
        static bool parse_switches(jpeg_compress_struct cinfo, string[] argv, bool for_real, out int fileIndex)
        {
            /* Set up default JPEG parameters. */
            /* Note that default -quality level need not, and does not,
             * match the default scaling for an explicit -qtables argument.
             */
            int quality = 75;           /* default -quality value */
            int q_scale_factor = 100;       /* default to no scaling for -qtables */
            bool force_baseline = false; /* by default, allow 16-bit quantizers */
            bool simple_progressive = false;

            string qtablefile = null;    /* saves -qtables filename if any */
            string qslotsarg = null; /* saves -qslots parm if any */
            string samplearg = null; /* saves -sample parm if any */

            outfilename = null;
            fileIndex = -1;
            cinfo.Err.Trace_level = 0;

            /* Scan command line options, adjust parameters */
            int argn = 0;
            for ( ; argn < argv.Length; argn++)
            {
                string arg = argv[argn];
                if (string.IsNullOrEmpty(arg) || arg[0] != '-')
                {
                    /* Not a switch, must be a file name argument */
                    fileIndex = argn;
                    break;
                }

                arg = arg.Substring(1);

                if (cdjpeg_utils.keymatch(arg, "baseline", 1))
                {
                    /* Force baseline-compatible output (8-bit quantizer values). */
                    force_baseline = true;
                }
                else if (cdjpeg_utils.keymatch(arg, "dct", 2))
                {
                    /* Select DCT algorithm. */
                    argn++; /* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    if (cdjpeg_utils.keymatch(argv[argn], "int", 1))
                        cinfo.Dct_method = J_DCT_METHOD.JDCT_ISLOW;
                    else if (cdjpeg_utils.keymatch(argv[argn], "fast", 2))
                        cinfo.Dct_method = J_DCT_METHOD.JDCT_IFAST;
                    else if (cdjpeg_utils.keymatch(argv[argn], "float", 2))
                        cinfo.Dct_method = J_DCT_METHOD.JDCT_FLOAT;
                    else
                        return false;
                }
                else if (cdjpeg_utils.keymatch(arg, "debug", 1) || cdjpeg_utils.keymatch(arg, "verbose", 1))
                {
                    /* Enable debug printouts. */
                    /* On first -d, print version identification */
                    if (!printed_version)
                    {
                        Console.Write(string.Format("Bit Miracle's CJPEG, version {0}\n{1}\n", jpeg_common_struct.Version, jpeg_common_struct.Copyright));
                        printed_version = true;
                    }
                    cinfo.Err.Trace_level++;
                }
                else if (cdjpeg_utils.keymatch(arg, "grayscale", 2) || cdjpeg_utils.keymatch(arg, "greyscale", 2))
                {
                    /* Force a monochrome JPEG file to be generated. */
                    cinfo.jpeg_set_colorspace(J_COLOR_SPACE.JCS_GRAYSCALE);
                }
                else if (cdjpeg_utils.keymatch(arg, "optimize", 1) || cdjpeg_utils.keymatch(arg, "optimise", 1))
                {
                    /* Enable entropy parm optimization. */
                    cinfo.Optimize_coding = true;
                }
                else if (cdjpeg_utils.keymatch(arg, "outfile", 4))
                {
                    /* Set output file name. */
                    argn++;/* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    outfilename = argv[argn];   /* save it away for later use */
                }
                else if (cdjpeg_utils.keymatch(arg, "progressive", 1))
                {
                    /* Select simple progressive mode. */
                    simple_progressive = true;
                    /* We must postpone execution until num_components is known. */
                }
                else if (cdjpeg_utils.keymatch(arg, "quality", 1))
                {
                    /* Quality factor (quantization table scaling factor). */
                    argn++;/* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    try
                    {
                        quality = int.Parse(argv[argn]);
                        /* Change scale factor in case -qtables is present. */
                        q_scale_factor = jpeg_compress_struct.jpeg_quality_scaling(quality);
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine(e.Message);
                        return false;
                    }
                }
                else if (cdjpeg_utils.keymatch(arg, "qslots", 2))
                {
                    /* Quantization table slot numbers. */
                    argn++; /* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    qslotsarg = argv[argn];
                    /* Must delay setting qslots until after we have processed any
                     * colorspace-determining switches, since jpeg_set_colorspace sets
                     * default quant table numbers.
                     */
                }
                else if (cdjpeg_utils.keymatch(arg, "qtables", 2))
                {
                    /* Quantization tables fetched from file. */
                    argn++; /* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    qtablefile = argv[argn];
                    /* We postpone actually reading the file in case -quality comes later. */
                }
                else if (cdjpeg_utils.keymatch(arg, "restart", 1))
                {
                    /* Restart interval in MCU rows (or in MCUs with 'b'). */
                    argn++; /* advance to next argument */

                    if (argn >= argv.Length)
                        return false;

                    bool inBlocks = false;
                    if (argv[argn].EndsWith("b") || argv[argn].EndsWith("B"))
                        inBlocks = true;

                    string parsee = argv[argn];
                    if (inBlocks)
                        parsee = parsee.Remove(parsee.Length - 1);

                    try
                    {
                        int val = int.Parse(parsee);
                        if (val < 0 || val > 65535)
                            return false;

                        if (inBlocks)
                        {
                            cinfo.Restart_interval = val;
                            cinfo.Restart_in_rows = 0; /* else prior '-restart n' overrides me */
                        }
                        else
                        {
                            cinfo.Restart_in_rows = val;
                            /* restart_interval will be computed during startup */
                        }
                    }
                    catch (Exception e)
                    {
                    	Console.WriteLine(e.Message);
                        return false;
                    }
                }
                else if (cdjpeg_utils.keymatch(arg, "sample", 2))
                {
                    /* Set sampling factors. */
                    argn++; /* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    samplearg = argv[argn];
                    /* Must delay setting sample factors until after we have processed any
                     * colorspace-determining switches, since jpeg_set_colorspace sets
                     * default sampling factors.
                     */
                }
                else if (cdjpeg_utils.keymatch(arg, "smooth", 2))
                {
                    /* Set input smoothing factor. */

                    argn++; /* advance to next argument */
                    if (argn >= argv.Length)
                        return false;

                    try
                    {
                        int val = int.Parse(argv[argn]);
                        if (val < 0 || val > 100)
                            return false;

                        cinfo.Smoothing_factor = val;
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine(e.Message);
                        return false;
                    }
                }
                else
                {
                    /* bogus switch */
                    return false;
                }
            }

            /* Post-switch-scanning cleanup */

            if (for_real)
            {
                /* Set quantization tables for selected quality. */
                /* Some or all may be overridden if -qtables is present. */
                cinfo.jpeg_set_quality(quality, force_baseline);

                if (qtablefile != null) /* process -qtables if it was present */
                {
                    if (!read_quant_tables(cinfo, qtablefile, q_scale_factor, force_baseline))
                        return false;
                }

                if (qslotsarg != null)  /* process -qslots if it was present */
                {
                    if (!set_quant_slots(cinfo, qslotsarg))
                        return false;
                }

                if (samplearg != null)  /* process -sample if it was present */
                {
                    if (!set_sample_factors(cinfo, samplearg))
                        return false;
                }

                if (simple_progressive) /* process -progressive; -scans can override */
                    cinfo.jpeg_simple_progression();
            }

            return true;
        }