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Re: Format name proposals

From: Jonathan Kew <jonathan@jfkew.plus.com>
Date: Tue, 18 Aug 2009 22:21:28 +0100
Cc: John Hudson <tiro@tiro.com>, "www-font@w3.org" <www-font@w3.org>
Message-Id: <0953501F-9183-4C7D-8391-0F67A9CA6A72@jfkew.plus.com>
To: Laurence Penney <lorp@lorp.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.

Received on Tuesday, 18 August 2009 21:22:18 UTC

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