- From: Jonathan Kew <jonathan@jfkew.plus.com>
- Date: Tue, 18 Aug 2009 22:21:28 +0100
- To: Laurence Penney <lorp@lorp.org>
- Cc: John Hudson <tiro@tiro.com>, "www-font@w3.org" <www-font@w3.org>
On 18 Aug 2009, at 22:00, Laurence Penney wrote: >> JH: >>> [By the way, since the OT and OFF specs are not formally identical >>> and with no guarantee against them diverging at some stage, I >>> wonder if there is a benefit to the web font format in choosing >>> one of these as the formal definition of the fontdata format?] >> > JK: >> I'm not sure there's any real benefit there. WebOTF or WOFF or >> whatever we call it is really a repackaging of sfnt data, and is >> independent of the details of what's inside the sfnt tables. It's >> true that if OpenType and OFF were to diverge, implementers would >> have to choose what to support, but that's equally true for "raw" >> sfnt data as for sfnt-repackaged-in-EOT/EOTL/WOFF/whatever, and >> doesn't directly affect the actual web-repackaging formats. > > There might also be good reasons for allowing WebOTFs which don't > expand to fully working fonts at all. > > For example, one might conceive of web pages linking to a web font > that contains only the glyphs required to render that page. > Successive page views on the same site would request only the > additional glyphs needed to render the new page, via a WebOTF that > contained the new glyphs - just a loca and glyf table - which would > be inserted into the correct place in a font being gradually built > up by the browser. That sounds like a nightmarishly complex scenario. You don't just need the glyph data (loca + glyf, or CFF). What about metrics and hints -- the "global" stuff as well as the instructions on the individual glyphs? And kerning -- not just between glyphs in such a subset, but also between the older glyphs and the newcomers? And then there are GSUB and GPOS layout tables, with all those lookups that operate in terms of glyph indices; you'd have to constantly readjust those as new glyphs arrive. Perhaps someone will design a protocol and format suitable for this kind of use, but WebOTF (or anything that is simply designed as a mechanism to deliver OpenType fonts) isn't the answer. JK
Received on Tuesday, 18 August 2009 21:22:18 UTC