Re: Redisplay problems?

[Eli Zaretskii]

> From: Stefan <address@hidden>
> Cc: address@hidden, address@hidden, address@hidden, address@hidden,
>         address@hidden
> Date: Sat, 22 Mar 2014 14:43:21 -0400
> 
> > When frames that were iconified get the expose event, and the frame's
> > garbaged flag is not set, we will redraw them using outdated matrices,
> > because expose_frame uses the current glyph matrices without
> > recomputing them.
> 
> If the current matrices are outdated, then indeed we may expose the
> outdated content.  But of course, the next redisplay will fix it, so
> it's not terrible.

You will momentarily show incorrect contents.

> If the garbaged flag is set, the behavior is not much better: instead of
> exposing outdated content we don't expose anything (i.e. it stays
> blank), and again the next redisplay should fix.

It is slightly better, because you never show incorrect contents.

> This said, I think that the more common case of deiconifying/deobscuring
> is that the matrices are still up-to-date because nothing has changed in
> the mean time.  In that case we're better off not setting the "garbaged"
> flag, so we immediately get the right content exposed rather then first
> exposing blank.

I actually don't think we should be bothered about this at all.  Why
does it make sense to optimize the use case where a frame is
deiconified?