Fwd: UAX#50 conformance: Is it possible to update existing fonts without causing damage to existing non-CSS applications?

---------- Forwarded message ---------
From: Taro Yamamoto <tyamamot@adobe.com>
Date: 2019年11月25日(月) 14:21
Subject: Re: UAX#50 conformance: Is it possible to update existing fonts
without causing damage to existing non-CSS applications?
To: fantasai <fantasai@inkedblade.net>, MURATA Makoto <
eb2m-mrt@asahi-net.or.jp>, Nat McCully <nmccully@adobe.com>
Cc: Florian Rivoal <florian@rivoal.net>


2019/11/25 13:53 に、"fantasai" <fantasai@inkedblade.net> を書き込みました:

    On 11/25/19 5:35 AM, MURATA Makoto wrote:
    >
    > I have discussed with Yamamoto-san of Adobe.  He
    > strongly feels that it is impossible to update
    > existing fonts without causing damage to existing
    > non-CSS applications.  I assume that his opinion is
    > based on discussions internal to Adobe.

    Can Yamamoto-san give an example of an update to an existing font that
would
    cause breakage in non-CSS applications?

    ~fantasai

To say more precisely, the concern that I had was NOT about the possible
(?) incompatibility between what's in fonts and what's written in UAX#50,
but about the possible incompatibility between the glyph postures composed
by today's layout software using any fonts (old or new) and the postures
defined in and assumed by UAX#50.

Nat, help me clarify this point better. Thanks.

Regards,

--Taro






-- 
Regards,
Makoto