src/png/ANNOUNCE

   1 Libpng 1.5.6 - November 3, 2011
   2
   3 This is a public release of libpng, intended for use in production codes.
   4
   5 Files available for download:
   6
   7 Source files with LF line endings (for Unix/Linux) and with a
   8 "configure" script
   9
  10    libpng-1.5.6.tar.xz (LZMA-compressed, recommended)
  11    libpng-1.5.6.tar.gz
  12    libpng-1.5.6.tar.bz2
  13
  14 Source files with CRLF line endings (for Windows), without the
  15 "configure" script
  16
  17    lpng156.7z  (LZMA-compressed, recommended)
  18    lpng156.zip
  19
  20 Other information:
  21
  22    libpng-1.5.6-README.txt
  23    libpng-1.5.6-LICENSE.txt
  24
  25 Changes since the last public release (1.5.5):
  26
  27   Fixed some 64-bit type conversion warnings in pngrtran.c
  28   Moved row_info from png_struct to a local variable.
  29   The various interlace mask arrays have been made into arrays of
  30     bytes and made PNG_CONST and static (previously some arrays were
  31     marked PNG_CONST and some weren't).
  32   Additional checks have been added to the transform code to validate the
  33     pixel depths after the transforms on both read and write.
  34   Removed some redundant code from pngwrite.c, in png_desgtroy_write_struct().
  35   Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
  36     This removes the need to allocate temporary strings for chunk names on
  37     the stack in the read/write code.  Unknown chunk handling still uses the
  38     string form because this is exposed in the API.
  39   Added a note in the manual the png_read_update_info() must be called only
  40     once with a particular info_ptr.
  41   Revised test-pngtest.sh to report FAIL when pngtest fails.
  42   Added "--strict" option to pngtest, to report FAIL when the failure is
  43     only because the resulting valid files are different.
  44   Revised CMakeLists.txt to work with mingw and removed some material from
  45     CMakeLists.txt that is no longer useful in libpng-1.5.
  46   Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
  47   Speed up png_combine_row() for interlaced images. This reduces the generality
  48     of the code, allowing it to be optimized for Adam7 interlace.  The masks
  49     passed to png_combine_row() are now generated internally, avoiding
  50     some code duplication and localizing the interlace handling somewhat.
  51   Align png_struct::row_buf - previously it was always unaligned, caused by
  52     a bug in the code that attempted to align it; the code needs to subtract
  53     one from the pointer to take account of the filter byte prepended to
  54     each row.
  55   Optimized png_combine_row() when rows are aligned. This gains a small
  56     percentage for 16-bit and 32-bit pixels in the typical case where the
  57     output row buffers are appropriately aligned. The optimization was not
  58     previously possible because the png_struct buffer was always misaligned.
  59   Removed two redundant tests for unitialized row.
  60   Fixed a relatively harmless memory overwrite in compressed text writing
  61     with a 1 byte zlib buffer.
  62   Add ability to call png_read_update_info multiple times to pngvalid.c
  63   Fixes for multiple calls to png_read_update_info. These fixes attend to
  64     most of the errors revealed in pngvalid, however doing the gamma work
  65     twice results in inaccuracies that can't be easily fixed.  There is now
  66     a warning in the code if this is going to happen.
  67   Turned on multiple png_read_update_info in pngvalid transform tests.
  68   Prevent libpng from overwriting unused bits at the end of the image when
  69     it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
  70     overwrite the partial byte at the end of each row if the row width was not
  71     an exact multiple of 8 bits and the image is not interlaced.
  72   Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
  73     (Mans Rullgard).
  74   Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
  75   Added PNG_LSR() and PNG_LSL() macros to defend against buggy compilers that
  76     evaluate non-taken code branches and complain about out-of-range shifts.
  77   Renamed the local variable 'byte' because it appears in a MSYS header
  78     file.
  79   Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
  80
  81 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
  82 (subscription required; visit
  83 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
  84 to subscribe)
  85 or to glennrp at users.sourceforge.net
  86
  87 Glenn R-P