Re: first time post with some questions

[Owen Taylor <otaylor redhat com>]

Roozbeh Pournader <roozbeh sharif edu> writes:

> On 22 Nov 2000, Owen Taylor wrote:
> 
> > (I actually think that explicit embeddings and overrides are going
> > to be fairly rare, but would like to see the support there.)
> 
> They are rare simply because they are not supported everywhere. Bidi
> text processing software writers will have a much simpler life if they are
> allowed to emit explicit codes.
> 
> > So, the only sense I could imagine it being complex is that it might
> > be slow compared to a simpler algorithm.... but compared to shaping,
> > determination of bidirectional level isn't a significant bottleneck
> > in Pango. And I know of several more optimizations that could speed up
> > FriBidi further.
> 
> It seems that pango uses a complex Arabic shaping algorithm. Has it been
> that much necessary? As an Arabic programmer I always consider shaping
> much simpler than bidi.

It is somewhat simpler, but also slower, because you have to get font
information, calculate the metrics and so forth. Also, by "shaping" I
meant such things as line breaks, and the rest of the process of
laying out text.
 
> And about FriBidi, what are you going to do? Are you branching from the
> original version? This seems good and important to us, since the updating
> cycle in the original FriBidi is not short enough.

What I did was to include a copy of the parts of FriBidi that 
Pango needs in Pango, with some fixes that haven't been applied
to the original code. You can compile Pango to either use this
included version, or to use a separate version.

I don't really want to maintain a separate version of this code -
I certainly plan on sending any changes I make to the version
of Pango back to Dov. I exchanged a couple of mails with Dov a few
months ago and he indicated that he didn't have much time to
work on FriBidi these days, but was planning to make an updated
release. 

Omer Zak <omerz actcom co il> has also been compiling his own
version of FriBidi with various improvements. 

> BTW, is there a mailing list or irc channel for pango discussion?

gtk-i18n-list gnome org is the mailing list for Pango discussion.

#gtk+ on irc.gimp.org would probably be the best place to discuss
Pango; both Robert Brady and myself are there fairly often. 
But I am also _not_ there fairly often. ;-)

Regards,
                                        Owen