jpeg_copy_critical_parameters() public method

Initializes the compression object with default parameters, then copy from the source object all parameters needed for lossless transcoding.
Parameters that can be varied without loss (such as scan script and Huffman optimization) are left in their default states.
public jpeg_copy_critical_parameters ( jpeg_compress_struct dstinfo ) : void
dstinfo jpeg_compress_struct Target JPEG compression object.
return void
jpeg_decompress_struct Class Documentation
Esempio n. 1
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 public static string IncImageDCT(string fullPath)
 {
     string suffix = "testDCT";
     var img = new Bitmap(fullPath);
     var width = img.Width;
     var height = img.Height;
     int hd = height / 8;
     int wd = width / 8;
     img.Dispose();
     BitMiracle.LibJpeg.Classic.jpeg_decompress_struct oJpegDecompress = new BitMiracle.LibJpeg.Classic.jpeg_decompress_struct();
     System.IO.FileStream oFileStreamImage = new System.IO.FileStream(fullPath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
     oJpegDecompress.jpeg_stdio_src(oFileStreamImage);
     oJpegDecompress.jpeg_read_header(true);
     BitMiracle.LibJpeg.Classic.jvirt_array<BitMiracle.LibJpeg.Classic.JBLOCK>[] JBlock = oJpegDecompress.jpeg_read_coefficients();
     var block = JBlock[0].Access(0, hd); // accessing the element
     for (int i = 0; i < hd; i++)
     {
         for (int j = 0; j < wd; j++)
         {
             short t = block[i][j].data[0];
             if ((t >= 0 && t % 2 == 1) || (t < 0 && t % 2 == 0))
             {
                 t--;
             }
             else if ((t >= 0 && t % 2 == 0) || (t < 0 && t % 2 == 1))
             {
                 t++;
             }
             block[i][j].data[0] = t;
         }
     }
     oJpegDecompress.jpeg_finish_decompress();
     oFileStreamImage.Close();
     ////
     string filenameNew = MyHelper.AppendFileName(fullPath, suffix);
     System.IO.FileStream objFileStreamMegaMap = System.IO.File.Create(filenameNew);
     BitMiracle.LibJpeg.Classic.jpeg_compress_struct oJpegCompress = new BitMiracle.LibJpeg.Classic.jpeg_compress_struct();
     oJpegCompress.jpeg_stdio_dest(objFileStreamMegaMap);
     oJpegDecompress.jpeg_copy_critical_parameters(oJpegCompress);
     oJpegCompress.Image_height = height;
     oJpegCompress.Image_width = width;
     oJpegCompress.jpeg_write_coefficients(JBlock);
     oJpegCompress.jpeg_finish_compress();
     objFileStreamMegaMap.Close();
     oJpegDecompress.jpeg_abort_decompress();
     return filenameNew;
 }