Re: Dependency libraries and ABI

[Owen Taylor <otaylor redhat com>]

Christopher Blizzard <blizzard redhat com> writes:

> James Henstridge wrote:
> > Is it possible to build Xft2 outside of the X source tree?  If so,
> > then maybe it would be okay to tell people that they needed to
> > update their Xft in order to get AA text.  Telling everyone to
> > upgrade their X libs (which may involve building the whole X tree)
> > sounds less likely to happen.
> 
> Yes, it is possible with relatively minor pain.  I would suggest that
> if people here are really worried about Xft2 portability because it's
> not going to be on systems for a while, ship Xft2 with Gtk2.  It
> doesn't require any server side changes and is relatively self
> contained.  It's a relatively simple solution that's going to make
> life for Gtk2 users much easier in the future.
> 
> It solves the pkg-config problems, because we don't have to include it
> in the link line (it's already in the library) and when it does make
> it onto the system, pkg-config can just start spitting out the
> dependency for developers.  Current apps won't be affected either
> since the gtk2 library can pull in the dependency directly.  It's a
> real win-win there.

Well, it would be nice, but:

 - We're releasing GTK+-2.0.0 on Monday. (And yes, that's a firm date
   barring emergencies. We need to get it out and move on.)

 - Switching over to Xft2 is a major change, much more code churn
   than I'm willing to do at this point.

 - I think Xft2 and fontconfig need a few more months to mature
   before I'd want to base a stable release on them. (Just out
   of general principle.)

 - I don't want to be in the position of "shipping" Xft2 code outselves --
   all sorts of problems to have a copy of the library, so we'd
   need to have people get another external library.

 - Xft2 brings in other new external dependencies (expat, fontconfig)
   expat is especially problematical because people tend to use
   their own versions of it in apps, so unless it is symbol-renamed,
   it is going to be a problem.

 - We're releasing GTK+-2.0.0 on Monday.

Not to beat on Chris about this :-) . But unless we want to drop Xft
support entirely for 2.0.0 (highly unattractive), we have to go
with Xft1 and figure out how to manage that the best we can.

[...]

> FYI, this is what I've been working on for Mozilla.  As a side note I
> would _strongly_ recommend that you guys consider doing this for Gtk2
> for completely selfish reasons.  One of the big problems that I'm
> about to run into is that Mozilla needs Xft2 and if Gtk2 uses Xft1
> then you will have AA fonts in Mozilla with Gtk1.2 but not with Gtk2.
> Ironic, eh?

Well, "Ironic" wasn't the term that comes to mind. But the terms that
came to mind weren't suitable for this mailing list.

Regards,
                                        Owen