Re: Redisplay problems?

[Eli Zaretskii]

> From: Stefan <address@hidden>
> Cc: address@hidden, address@hidden, address@hidden, address@hidden,
>         address@hidden
> Date: Mon, 24 Mar 2014 14:07:34 -0400
> 
> > If the redisplay flag of an obscured/iconified frame _is_ set, then it
> > looks like you cannot win anyway, because the entire frame needs to be
> > completely redisplayed, and comparing against the current matrices is
> > meaningless (since nothing is on the glass, so a full redraw is the
> > only alternative).  So I think setting the garbaged flag in this case
> > is TRT.
> 
> No: setting the garbaged flag has the side-effect of disabling all
> optimizations while computing the new matrices.  And in this case, we
> don't need to disable those optimizations, AFAIK.

Without anything on the screen that reflects the current matrices,
what would be the point of these optimizations?  These optimizations
only make sense when portions of the frame are already on the glass,
because we can then avoid both recomputing and redrawing those
portions, or some of them.  But when nothing is on the glass, these
optimizations will not help, because you must redraw everything, and
AFAIK we don't currently have a redisplay mode where the portions of
matrices that were not recomputed are nevertheless redrawn.