Re: Selections in TreeViewS and efficiency issues

[Matthias Kaeppler <nospam digitalraid com>]

Murray Cumming wrote:
> On Sat, 2005-04-09 at 18:56 +0200, Matthias Kaeppler wrote:
>
> > Matthias Kaeppler wrote:
> >
> > > 1.  How can I avoid this seemingly inefficient behavior? How can I keep 
> > > it from reiterating over all rows again, if I add more items to the 
> > > selection?
> >
> > Looks like I'm the only one who's bothered by this.
> > Okay, look again:
> >
> > Consider a TreeView with 1000 entries.  Now select the first entry, hold 
> > shift and press the down-key to expand the selection downwards till you 
> > reach the bottom.
> > After hitting 'down' for the n-th time, the signal handler has been 
> > called (n * (n+1)) / 2 times (1 + 2 + 3 + ... + n).  That means, after 
> > selecting 1000 entries this way, the signal handler has been called 
> > (1000 * 1001)/2 times, that is 500500 times.  In words: Over half a 
> > /million/ times!
>
>
> This is more appropriate for gtk-list gnome org  They would probably
> like a real example rather than a theory.

Well, I'm using gtkmm and the libsig++ callbacks.  I have no idea if 
this will apply to Gtk+ programs written in C.
Or are the gtkmm developers in that mailing list, too?

If you need an example, I can send you the source code of my widget, 
it's not much. Just set a counter in the selected_foreach_iter callback 
and you'll see.

--
Matthias Kaeppler