FW: [mpeg-OTspec] RE: font media types

[Levantovsky, Vladimir]

Forwarding to the AHG list on behalf of Chris Lilley


-----Original Message-----
From: Chris Lilley [mailto:chris at w3.org] 
Sent: Tuesday, April 05, 2011 4:56 PM
To: David Singer
Cc: Levantovsky, Vladimir; David Lemon; OTspec; Tab Atkins; Karsten Luecke
Subject: Re: [mpeg-OTspec] RE: font media types

On Tuesday, April 5, 2011, 7:52:35 PM, David wrote:

DS> Just a question;  would the details of the contents be better
DS> expressed as an optimal paramater?

DS> e.g.

DS> application/font-off;glyphtype="ttf" to indicate that ttf kinds of outlines are inside?

Right. One difference between TrueType and OpenType is that two different types of glyph definitions are allowed, TrueType quadratic Beziéers and PostScript type 1 cubic Beziéers.

Another difference is that OpenType allows some glyph shaping tables (GSUB, GPOS) and language-dependent formatting which the original TrueType format did not.

A complication is that the choice of filename extension (.ttf, .otf) is to some extent the decision of the user as how many OpenType features they used and how different platforms handle which features and which filename extensions.

I can say based on my experience as a participant in the ietf-types mailing list (since 1994) that the main factors they will consider are

a) did you exactly follow the template from RFC 2048[1]
b) is there a defined and publicly-readable specification (ok there)
c) for registrations in the standards tree, previously the ietf tree, is the organization an accredited SDO (ok there)
d) where there are multiple registrations, is the mapping from filename extension to media type straightforward and unique

Its point d) where some work may need to be done. Not ehtat for the audience which will be reviewing the registration,the details of file internals are opaque; its purely a mapping of filename extension to internet media type (previously MIME type) that matters.



[1] http://www.ietf.org/rfc/rfc2048.txt

-- 
 Chris Lilley   Technical Director, Interaction Domain                 
 W3C Graphics Activity Lead, Fonts Activity Lead
 Co-Chair, W3C Hypertext CG
 Member, CSS, WebFonts, SVG Working Groups