- update to 1.6.22:
Added a png_image_write_to_memory() API and a number of assist macros
to allow an application that uses the simplified API write to bypass
stdio and write directly to memory.
Relaxed limit checks on gamma values in pngrtran.c. As suggested in
the comments gamma values outside the range currently permitted
by png_set_alpha_mode are useful for HDR data encoding. These values
are already permitted by png_set_gamma so it is reasonable caution to
extend the png_set_alpha_mode range as HDR imaging systems are starting
to emerge.
Restored "& 0xff" in png_save_uint_16() and png_save_uint_32() that
were accidentally removed from libpng-1.6.17.
Changed PNG_INFO_cHNK and PNG_FREE_cHNK from 0xnnnn to 0xnnnnU in png.h
(Robert C. Seacord).
Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
SSE filter speed improvements for bpp=3:
memcpy-free implementations of load3() / store3().
Added PNG_FAST_FILTERS macro (defined as
PNG_FILTER_NONE|PNG_FILTER_SUB|PNG_FILTER_UP).