2 

     3 

     4 Version 8  10-Jan-2010

     5 ----------------------

     6 

     7 jpegtran now supports the same -scale option as djpeg for "lossless" resize.

     8 An implementation of the JPEG SmartScale extension is required for this

     9 feature.  A (draft) specification of the JPEG SmartScale extension is

    10 available as a contributed document at ITU and ISO.  Revision 2 or later

    11 of the document is required (latest document version is Revision 3).

    12 The SmartScale extension will enable more features beside lossless resize

    13 in future implementations, as described in the document (new compression

    14 options).

    15 

    16 Add sanity check in BMP reader module to avoid cjpeg crash for empty input

    17 image (thank to Isaev Ildar of ISP RAS, Moscow, RU for reporting this error).

    18 

    19 Add data source and destination managers for read from and write to

    20 memory buffers.  New API functions jpeg_mem_src and jpeg_mem_dest.

    21 Thank to Roberto Boni from Italy for the suggestion.

    22 

    23 

    24 Version 7  27-Jun-2009

    25 ----------------------

    26 

    27 New scaled DCTs implemented.

    28 djpeg now supports scalings N/8 with all N from 1 to 16.

    29 cjpeg now supports scalings 8/N with all N from 1 to 16.

    30 Scaled DCTs with size larger than 8 are now also used for resolving the

    31 common 2x2 chroma subsampling case without additional spatial resampling.

    32 Separate spatial resampling for those kind of files is now only necessary

    33 for N>8 scaling cases.

    34 Furthermore, separate scaled DCT functions are provided for direct resolving

    35 of the common asymmetric subsampling cases (2x1 and 1x2) without additional

    36 spatial resampling.

    37 

    38 cjpeg -quality option has been extended for support of separate quality

    39 settings for luminance and chrominance (or in general, for every provided

    40 quantization table slot).

    41 New API function jpeg_default_qtables() and q_scale_factor array in library.

    42 

    43 Added -nosmooth option to cjpeg, complementary to djpeg.

    44 New variable "do_fancy_downsampling" in library, complement to fancy

    45 upsampling.  Fancy upsampling now uses direct DCT scaling with sizes

    46 larger than 8.  The old method is not reversible and has been removed.

    47 

    48 Support arithmetic entropy encoding and decoding.

    49 Added files jaricom.c, jcarith.c, jdarith.c.

    50 

    51 Straighten the file structure:

    52 Removed files jidctred.c, jcphuff.c, jchuff.h, jdphuff.c, jdhuff.h.

    53 

    54 jpegtran has a new "lossless" cropping feature.

    55 

    56 Implement -perfect option in jpegtran, new API function

    57 jtransform_perfect_transform() in transupp. (DP 204_perfect.dpatch)

    58 

    59 Better error messages for jpegtran fopen failure.

    60 (DP 203_jpegtran_errmsg.dpatch)

    61 

    62 Fix byte order issue with 16bit PPM/PGM files in rdppm.c/wrppm.c:

    63 according to Netpbm, the de facto standard implementation of the PNM formats,

    64 the most significant byte is first. (DP 203_rdppm.dpatch)

    65 

    66 Add -raw option to rdjpgcom not to mangle the output.

    67 (DP 205_rdjpgcom_raw.dpatch)

    68 

    69 Make rdjpgcom locale aware. (DP 201_rdjpgcom_locale.dpatch)

    70 

    71 Add extern "C" to jpeglib.h.

    72 This avoids the need to put extern "C" { ... } around #include "jpeglib.h"

    73 in your C++ application.  Defining the symbol DONT_USE_EXTERN_C in the

    74 configuration prevents this. (DP 202_jpeglib.h_c++.dpatch)