[ft-devel] twilight zone and engine compensation; and v 2.7.1 schedule?

[Hin-Tak Leung]

While comparing b66 and the older MS rasterer's backend, I found a rather 
interesting issue - the _undocumented_ behavior of a few hinting instructions 
while in twilight zone only agrees between freetype and MS rasterer (or the 
older version of it shipped with the 2003 FontVal), when the engine 
compensation distance is black.

This is somewhat surprising as I'd think they should agree when engine 
compensation distance is gray, since the distance type is essentially undefined 
when in twilight zone, or rather dodgy in any case, when contours are not 
'real'...

Any thoughts/hints about the subtlety of hinting between twilight zone and 
engine compensation?

So in this case, the undocumented behavior of Freetype seems to be wrong - or 
incomplete (not adapting to engine compensation).

Sorry the fonts which prompted this discussion are all proprietary ones, listed 
in https://github.com/HinTak/Font-Validator/issues/20 . Some of them are from 
Apple, so not too rare.


Also, I found a few 'XXX undocumented' which are actually documented in Apple's 
version of the truetype reference. There are small differences between the 
apple one and MS one, in these cases, rather important/interesting. I try not 
to read the apple one, mostly because I don't like reading "specs" in a 
'drifting' format that can change without notice. (esp when the apple web 
master decides to apply a different template layout, or do breadcrumbs 
differently...). I kept some inline comments in my local freetype clone and 
they probably should be upstreamed at some point.


A while go there were some words about 2.7.1 coming soon - what happened to 
that? I guess the impact is just whether to back-port some of the post-2.7.0 
changes or just wait and rebase later.