John Bowler aa725a375c [libpng16] Corrected estimate of error in libpng png_set_rgb_to_gray API.
The API is extremely inaccurate for sRGB conversions because it uses an 8-bit
intermediate linear value and it does not use the sRGB transform, so it
suffers from the known instability in gamma transforms for values close
to 0 (see Poynton).  The net result is that the calculation has a maximum
error of 14.99/255; 0.5/255^(1/2.2).  pngstest now uses 15 for the
permitted 8-bit error. This may still not be enough because of arithmetic
error.
2012-02-04 15:11:16 -06:00
..
2011-11-16 13:35:16 -06:00

This "contrib" directory contains contributions which are not necessarily under
the libpng license, although all are open source.  They are not part of
libpng proper and are not used for building the library.