Re: [apps-discuss] font/* (and draft-freed-media-type-regs)

"Levantovsky, Vladimir" <Vladimir.Levantovsky@MonotypeImaging.com> Fri, 18 November 2011 15:17 UTC

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From: "Levantovsky, Vladimir" <Vladimir.Levantovsky@MonotypeImaging.com>
To: =?utf-8?B?Ik1hcnRpbiBKLiBEw7xyc3Qi?= <duerst@it.aoyama.ac.jp>
Date: Fri, 18 Nov 2011 10:17:04 -0500
Thread-Topic: [apps-discuss] font/* (and draft-freed-media-type-regs)
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Cc: "gadams@xfsi.com Adams" <gadams@xfsi.com>, Ned Freed <ned.freed@mrochek.com>, David Singer <singer@apple.com>, "apps-discuss@ietf.org" <apps-discuss@ietf.org>
Subject: Re: [apps-discuss] font/* (and draft-freed-media-type-regs)
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On Friday, November 18, 2011 2:52 AM Martin J. Dürst wrote:
> 
> On 2011/11/16 8:22, Levantovsky, Vladimir wrote:
> 
> > In fact, SC29/WG11 is in the process of finalizing a new application
> (as part of the ISO/IEC 14496-22:2009/Amd.2 work) where we decided to
> apply for a new "application/font-sfnt" type using additional optional
> parameters to specify types of outlines and advanced layout mechanisms
> supported by a font. Doing so allows creating a flexible and extensible
> (albeit slightly cumbersome) mechanism to identify any SFNT-based font
> using same MIME type definition for a number of font flavors combining
> either TTF or CFF outlines with any currently known layout engine
> support (e.g. OpenType, AAT or SIL). Under the circumstances, this
> seemed to be a pragmatic way to compensate for the lack of "font" type.
> 
> I have no idea about the details involved, but what you say here about
> optional parameters sounds rather dangerous to me.
> 
> Setting parameters correctly on Web servers, while in theory not too
> complicated, turns out to be quite brittle and impractical in many
> scenarios. Even the base media type often isn't correct.
> 
> What you call a "flexible and extensible (albeit slightly cumbersome)
> mechanism" may turn out, in actual practice, to be highly cumbersome,
> confusing, and rarely used.
> 
> Again, I have to admit that I'm not familiar with the details, so if for
> example these parameters are only advisory and in practice things work
> perfectly well even if they are not used, then it might be less big of
> a deal.
> 
> Can you give use a bit more information to help understand the
> trade-offs involved?
> 

The SC29/WG11 planned to register the "application/font-sfnt" type with the following two optional parameters:
1) 	Name: 	Outlines
	Value: 	TTF, CFF
2) 	Name: 	Layout
	Value: 	OTF, AAT, SIL 

This would allow to identify fonts of multiple flavors, e.g.:
TrueType - application/font-sfnt (Outlines=TTF);
OpenType with TTF outlines - application/font-sfnt (Outlines=TTF, Layout=OTF);
OpenType with CFF outlines - application/font-sfnt (Outlines=CFF, Layout=OTF);
AAT fonts - application/font-sfnt (Outlines=TTF, Layout=AAT); etc.

I understand that the alternative would be to register a number of separate subtypes for each font flavor, and it would probably be the way we will go if font/* is available.

Thank you,
Vlad