Re: Pango Unicode coverage

[Owen Taylor <otaylor redhat com>]

Roozbeh Pournader <roozbeh sharif edu> writes:

> On 24 Dec 2001, Owen Taylor wrote:
> 
> > Forget of Deseret is BMP or not.
> 
> It's out of BMP. But what is the reason for not supporting it? 
> Not-yet-agreed font format?

 * The unicode character property code in Glib needs some
   work to handle properties for characters not in the 
   BMP. (The interfaces are fine, but the internal data
   structures are limited.)

 * For X font support, you'd either need to write a custom 
   shaper module, or add support for unicode-encoded fonts
   covering non-BMP portions to the basic shaper. (There
   have been long discussions for what XLFD's to use  -
   I don't know if there was ever an agreement)   

 * For Xft/FT2 support, you'd either need to write a custom
   shaper module or figure out some way of handling non
   BMP encodings generically. (Can the TTF format handle
   Unicode charmaps with characters outside the BMP? I don't
   think so...)

If possible, a standard way of handing non-BMP fonts would be better
than custom font encodings for every non-BMP character set, though for
core X fonts, there are certainly problems with the inefficiency of
the core protocol for sparse encodings.

Regards,
                                        Owen