John Bowler 01ff090760 API reduction, PNG compression level
PNG compression level setting API: this allows the various compression settings
controlling deflate, fitlering, and so on to be set via a single setting with
six values.  This is currently documented in png.h ("Write compression
settings").

Internally the compression settings have been tuned both for the overall setting
and for any specific settings made by the original APIs.

APIs to control iCCP chunk compression separately have been added.

contrib/examples/pngcp.c has been modified to accomodate the new compression
setting and to include options for separate control of iCCP chunk compression.

The new ABI, png_setting, has been modified to accomodate a wider range of
settings and most of the old compression control ABIs have been replaced by
function-like macros with the same API which call png_setting.  This is an API
check in 1.7.0 for png_setting (alone).  png_setting now handles all of
png_set_option.  This eliminates 19 ABIs at the cost of adding 1 (png_setting).

CRC and benign error checking has been updated internally to use bit-fields and
the CRC calculation skip when the CRC is not used has been improved slightly to
avoid the initialization of the CRC.  A new png_setting based API allows more
detailed control of benign error/warning messages (this may change, the internal
error handling seems too complex.)  The ERROR_NUMBERS support has been removed
with the intent of implementing proper i18n.

The memcpy-size-0 issue in png_push_fill_buffer has been fixed, with an
appropriate debug() assert if a fill for 0 bytes occurs.

Most PNG_FLAG_ values for png_struct::flags have been eliminated (as a result of
the benign error handling changes).  Only one remains.

Signed-off-by: John Bowler <jbowler@acm.org>
2016-06-07 06:48:52 -07:00
..
2016-06-07 06:48:52 -07:00
2015-09-14 17:57:40 -07:00
2015-11-26 09:55:37 -08:00

This directory (contrib/examples) contains examples of libpng usage.

NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.

To the extent possible under law, the authors have waived all copyright and
related or neighboring rights to this work.  This work is published from:
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The files may be used freely in any way.  The intention is that appropriate
parts of the files be used in other libpng-using programs without any need for
the authors of the using code to seek copyright or license from the original
authors.

The source code and comments in this directory are the original work of the
people named below.  No other person or organization has made contributions to
the work in this directory.

ORIGINAL AUTHORS
    The following people have contributed to the code in this directory.  None
    of the people below claim any rights with regard to the contents of this
    directory.

    John Bowler <jbowler@acm.org>