RE: WOFF2 [WOFF3?] and variable fonts

Hi John,

Thank you for bringing up a good question. The major revision of the font format spec definitely warrants a thorough review but I am also quite confident that the WOFF2 format is sufficiently future-proof to accommodate new optimizations (if any) using existing signaling mechanisms for new table transforms.

I believe that the WOFF2 (as is) is already capable of encoding and delivering new font variation data, and the WOFF2 table directory structure has already incorporated all previously known variation tables. There are no empty code points left anyway so any new tables (including those that were recently added to the mix) would have to be encoded using custom table flag and their tags. As far as content aware optimizations are concerned - the main question that needs to be answered if there is significant redundancy that's been introduced as part of the new variations data. All previously defined content-aware preprocessing steps exploit the known redundancy to eliminate it prior to entropy coding but we deliberately eliminated certain processing steps where complexity of preprocessing wasn't justified due to small gains in compression ratios. Whether the new data contains significantly redundant information or not is definitely going to be the subject of additional research, and if such redundant data is identified we would need to see if the process of eliminating such redundancy produces enough gains to justify the increase in processing complexity.

Thank you,
Vlad


-----Original Message-----
From: John Hudson [mailto:john@tiro.ca] 
Sent: Friday, September 16, 2016 4:04 PM
To: public-webfonts-wg@w3.org
Subject: WOFF2 [WOFF3?] and variable fonts

Something for the agenda in upcoming webfonts dicussions: potential optimisation of new OT Font Variations data in the 'content-aware preprocessing' step. Is this something that could be incorporated into
WOFF2 as a compatible update, or does it imply WOFF3?

JH


-- 

John Hudson
Tiro Typeworks Ltd    www.tiro.com
Salish Sea, BC        tiro@tiro.com

Getting Spiekermann to not like Helvetica is like training
a cat to stay out of water. But I'm impressed that people
know who to ask when they want to ask someone to not like
Helvetica. That's progress. -- David Berlow

Received on Friday, 16 September 2016 22:16:56 UTC