[MPEG-OTSPEC] Hints, TT and CFF (was: Re: Proposal to make OFF complete)

[Eric Muller]

On 8/18/2020 9:58 PM, Behdad Esfahbod wrote:
> The claim-to-superiority of CFF format is: 1. better hinting, and 2. 
> better compression. Re better-hinting, the interpretation of CFF hints 
> is NOT specified anywhere.

In fairness, and without taking side on the proposal to remove CFF/CFF2:

Although there is a spec for TT hints, it's hardly complete and requires 
quite a bit of reverse engineering if you want something that works. And 
there is more black magic if you want something that behaves like 
Microsoft's implementation(s).

CFF leaves the interpretation of the hints to the rasterizer, with the 
intent that rasterizers can be improved without having to rework the 
fonts. So the specification is complete if font designers know what to 
do. I'd be interested to hear from font designers: do you think you 
understand how to set hints in CFF fonts? Are there things missing from 
the Type 1 Book + Type 2 technical note?

Eric.