updates.txt

JPEG2000的C++实现代码

Changes from version 2.2.2 to version 2.2.3
-------------------------------------------
* Extremely minor changes to avoid mixed use of formatted and
  unformatted calls to "ostream" objects.  These appear to
  excite a bug in GCC version 3.0.  The only file affected is
  "params.cpp" in "coresys/parameters".

Changes from version 2.2.1 to version 2.2.2
-------------------------------------------
  Note: none of these have any impact whatsoever on executable code
  or DLL's.
* Renamed the "core" directory as "coresys".  A trivial change
  and my appologies for those whom this might adversely affect.
  However, the use of the name "core" was causing some people
  difficulties, since it is identical to the name of a Unix core
  dump file.
* Made the Linux MMX-optimized functions "extern C" instead of
  "extern", so as to avoid problems caused by different name
  mangling conventions between various versions of gcc.
* Eliminated multi-line comments from assembler files so as to
  avoid problems created by earlier versions of the gnu assembler.

Changes from version 2.2 to version 2.2.1
-----------------------------------------
* Replaced the C++ I/O routines used for image and compressed data
  transfers with ANSI C I/O functions.  This was motivated by the
  fact that the new-style ANSI C++ I/O package is unbelievably slow,
  at least as implemented in Microsoft's Visual C++ compiler.
  The change has no impact whatsoever on the Kakadu core system;
  it affects only the implementation of a few application level
  objects -- the core system abstracts all such I/O considerations
  through interface classes which are implemented by applications.
  Everything now runs a little faster than it did in version 2.1 and
  quite a bit faster than it did in the first release of version 2.2.
* Made provision for compiling under versions of GCC prior to version 3.0.
  To use this, you should define GCC_VERSION_LESS_THAN_3.

Changes from version 2.1 to version 2.2
---------------------------------------
* Extensive support for ROI (Region of Interest) specification
  at encode time (see "kakadu.pdf" for more on this).
* Migrated from the old-style C++ iostream package to the new standard
  iostream package -- minimal use of "using namespace std" and never used
  in common header files, so this should enhance namespace protection
  and portability.
* Added AT&T style versions of the small amount of  Pentium assembly code
  to enable compilation of a high speed version under GCC as well as
  MSVC.
* Some minor bug fixes.

Changes from version 2.0.2 to version 2.1
-----------------------------------------
* Extensive support for working with the JP2 file format.  The "kdu_show"
  application demonstrates the capabilities required of a conformant
  JP2 reader: palette mapping; interpolation of components to a common
  resolution; application of registration offsets in the CRG marker
  segment; and colour conversion to an appropriate rendering space (sRGB
  here).  The "kdu_region_decompressor" object provides extensive support
  for general purpose interactive rendering applications, performing all
  of the above tasks in a platform independent manner.
* It is now possible to directly control rate-distortion slope thresholds
  used in the construction of quality layers.  This capability may also
  be used to significantly increase compression speed, if a suitable
  threshold is known, since the encoder then incrementally predicts
  the point at which there is no point in coding further coding passes.
* A number of improvements to the "kdu_show" application, including
  the ability to arbitrarily zoom into images.
* A number of minor bug fixes, including one important bug reported by
  Aaron Deever of Kodak, and a bug which occasionally manifested itself
  in the incremental rate prediction heuristic (reported by Jim Andrew
  of CISRA).
* Improved documentation.

Changes from version 2.0.1 to version 2.02
------------------------------------------
* A PDF document (documentation.pdf) has been prepared to guide the new
  user into some of the more important aspects of the Kakadu system.  The
  first draft is included here.
* A very simple compression example and a very simple decompression example
  have been added to assist developers in familiarizing themselves with
  the Kakadu system -- the existing demo apps provide perhaps too much
  functionality to be quickly understood.
* A full BIBO (Bounded Input Bounded Output) numerical analysis of
  the DWT and other processing steps is used to establish the best
  utilization of limited precision sample data representations.
  The new version should not be able to fall prey to numerical
  overflow or underflow difficulties under any circumstances (this
  could just have been possible with the last version).  It also
  provides slightly higher accuracy.
* The automatic heuristic for generating quality layer rate
  targets has been substantially improved.
* A number of minor bugs/limitations were corrected, although these
  had not manifested themselves in any real examples.


Changes from version 2.0 to version 2.01
----------------------------------------
* One line change in each of "kdu_expand.cpp" and "kdu_compress.cpp" to
  correct a minor rare bug in these demo applications.
* Minor changes in "kdu_show.cpp" to correct a rare bug and improve the
  user interface in regard to image rotation.
* Four lines added to each of "encoder.cpp" and "decoder.cpp" to fix
  a minor memory leak.