From: Shriramana Sharma <>
Date: Mon, 22 Aug 2011 10:42:05 +0530

On 08/22/2011 08:24 AM, Peter Constable wrote:
> I'm not saying that there shouldn't be_some_ software that can do
> what you expect. But there will likely be some different views on
> what ought to be included within that "some".

Peter, given that both AAT and Graphite have provisions for assigning
custom properties including BC to PUA characters, it seems Uniscribe is
the only one missing out. Those advocating RTL PUA areas seem to reject
AAT and Graphite as "hacks" or "wow *one* application" [*].

[* = LibreOffice is the *only* multipurpose application running on
/Windows/ to support Graphite and I'm not counting SIL WorldPad. On *nix
platforms, *any* number of applications that use HB-NG for rendering
will be able to handle Graphite in the near future because HB-Graphite
integration is already done. That is to say, once GTK and Qt fully
switch to HB-NG.]

Anyhow, if you Microsoft guys added support in Uniscribe for ascribing
custom properties including BC to PUA characters (or have you already
done it) it would be what would satisfy these PUA RTL users and convince
them that no RTL PUA zones are needed, it seems.

The suggestion has been made that fonts should be able to carry some
additional custom tables specifying custom properties for PUA
characters, which seems reasonable. I'm not sure if the OT GDEF table or
the AAT PROP table completely satisfies this requirement. People
interesting in using custom properties for the PUA (which includes me
for Indic script) should then sit up and formulate the syntax for such

If Uniscribe, AAT, and Harfbuzz then provided generic support for
parsing such tables and rendering PUA characters accordingly, it would
be an all-around solution both for RTL PUA as well as Indic PUA, I
suppose. (But I'm not sure how such a custom table would interact with
the innate ability of Graphite to handle custom properties. It should
probably be either the new proposed custom table or Graphite.)


Shriramana Sharma
Received on Mon Aug 22 2011 - 00:15:37 CDT

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