[ft-devel] Slightly off-spec opentype CFF fonts shipped in os X Yosemite

[Hin-Tak Leung]

Two fonts in OS X Yosemite (maybe other versions also), YuppySC-Regular.otf and 
YuppyTC was apparently made in 1996 (according to the copyright notice) and 
have not been updated, and uses the obsolete 'ForceBoldThreshold' key in the 
private dictionary inside the CID font dict array. The key was removed in 2000, 
16 years ago, mentioned in changelog in the appendix in the CFF spec. I had to 
go fishing in fonttools's look up table to find the actual value, as it is no 
longer listed in table 23 of the CFF spec :-).

The out-soon CFF update to font validator catches that...  Should be in a few 
days. CFF table is just a lot to check...

It is mostly harmless, just an extra key which no longer mean anything and has 
not for 16 years, but then unknown keys needs to be decoded correctly with the 
corresponding number of operands, to get at the rest of the dictionary so it 
affects the integrity of the dictionary itself, and should be fixed.

Michael please tell the relevant apple colleagues, and Behdad please consider 
throwing an error in fonttools if such is specified in inputs to assembling 
fonts.