Re: gtk_tree_model_iter_previous()

[Jonathan Blandford <jrb redhat com>]

Owen Taylor <otaylor redhat com> writes:

> On Wed, 2004-01-21 at 13:44, Murray Cumming Comneon com wrote:
> > As mentioned here:
> > http://bugzilla.gnome.org/show_bug.cgi?id=128058
> > 
> > It would be nice to have a gtk_tree_model_iter_previous() as well as the
> > current gtk_tree_model_iter_next(). Totem has an implementation, though I
> > guess it's significantly slower than gtk_tree_model_iter_next():
> > http://cvs.gnome.org/lxr/source/totem/src/totem-playlist.c#146
> 
> I've written that function before, and think it would be useful to
> have in GTK+. Would need a warning in the docs about performance. We
> could potentially add a vtable member to GtkTreeModel in the future to
> allow models to accelerate it when possible with the model's data
> structures.
> 
> I've discussed this with Jonathan before, forget what his response
> was.

The current GtkTreeModel interface is the minimum needed for the
GtkTreeView/GtkSortModel to work.  People have previously requested this
and other model interface changes, and like Owen said, we can certainly
add them.  A concern is that it's not needed for the vast majority of
cases, and I am not going to add the back-pointers to make it 'fast' in
either of the store models.  That means that it'll really only be fast
in custom models -- which can add their own prev call anyway.

> But post-2.4.

Definitely.

-Jonathan