Re: RTL PUA?

2011/8/20 Ken Whistler <kenw_at_sybase.com>:
> There are 131,068 private use code points in the standard. That is all there
> ever will be.

I also fully agree (sorry then to Michael Everson support for such new
RTL PUA assignments).

All that can be done is to fix the softwares. Notably the font formats
where you'll be able to define the necessary overrides for
directionality mirroring mappings (for RTL conscripts), and other
reordering properties that may be needed to support Indic conscripts
(such as prepended letters).

Adding new RTL PUAs will require any way modification of
renderers/layout engines to support it. These same engines can as well
be modified to support external character properties table needed to
override the existing PUAs, so that they can be rendered correctly.

May be it's the desire of OpenType designers to not use any such
overrides, but this was only intended for normal non-PUA characters.
An revised OpenType specification can perfectly integrate the
possibility of some new extension table, and assert that these custom
properties stored in fonts will ONLY by valid and usable for PUA
characters only, as a font validation constraint.
Received on Sun Aug 21 2011 - 03:15:52 CDT