Re: Emacs and Gnome Canvas

[Jan Djärv]

2010-07-15 17:20, Eli Zaretskii skrev:
> > Date: Thu, 15 Jul 2010 17:16:31 +0200
> > From: Jan Djärv<address@hidden>
> > CC: address@hidden, address@hidden
> >
> > 2010-07-15 16:35, Eli Zaretskii skrev:
> > > > Date: Thu, 15 Jul 2010 16:24:27 +0200
> > > > From: Jan Djärv<address@hidden>
> > > > Cc: address@hidden, address@hidden
> > > >
> > > > No, they need to be done anyway sometime, it is no waste.  If the text isn't
> > > > displayed, the attributes are nvertheless set up correctly for the time when
> > > > the text is to be displayed later (by scrolling for example).
> > >
> > > By which time those attributes could have recomputed many times, for
> > > just one display!
> >
> > That may be so.  But there is nothing actually displayed, you just do a update
> > of the attributes.
>
> This "just" is the hottest bottleneck of the current display engine.
> That's why we try so hard to avoid it.

I would have thought that the actual drawing would be the bottleneck.  Not 
that I benchmarked or anything.


> > I'm sure one could hook in to the scroll bars and just update the
> > visible portion if that is needed.
>
> I don't think updating the scroll bar is an important CPU user in
> today's redisplay.

I meant that you can update the portion that is visible and postpone update of 
the other parts until they become visible.

        Jan D.