jpeg_downsampler

type jpeg_downsampler = record

  start_pass: procedure(

  cinfo: j_compress_ptr

);

  downsample: procedure(

  cinfo: j_compress_ptr;

  input_buf: JSAMPIMAGE;

  in_row_index: JDIMENSION;

  output_buf: JSAMPIMAGE;

  out_row_group_index: JDIMENSION

);

  need_context_rows: Boolean;

end;