bug#11822: 24.1; emacsclient terminal mode captures escape characters as text

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Unfortunately Fclear_face_cache (and global variables like face_change_count
> or windows_or_buffers_changed) isn’t frame-specific. So — I expect but
> haven’t tested — changing screenGamma on an existing frame will probably
> also force faces to be recomputed on every frame.

As explained in my other message, while windows_or_buffers_changed is
a global var, this part of the system can be more discriminating (using
[wfb]set_redisplay), thanks to the `redisplay' field of
relevant structures.

Those `redisplay' fields could completely replace the
windows_or_buffers_changed variable, but when I introduced those fields,
I kept the global var to ease the change.

I used the redisplay--*-cause variables (arrays where element I gets
incremented every time the corresponding global var was found to have
value I upon redisplay) to find which assignment to
windows_or_buffers_changed caused a particular global redisplay and
tried to figure out how to replace that global assignment by appropriate
calls to [wfb]set_redisplay.

We could similarly move face_change_count to the frame structure (or add such
a field in the frame structure).

> I think that’s probably true, and if most people are using local displays
> most of the time, they may not be much of a bottleneck. I did a couple
> experiments with a local X server and got about half a millisecond
> round-trip time to the server to answer some queries. Even multiplying by
> 160 queries, that’s still under a tenth of a second of wasted time (though
> I think there are other wasted round-trips in the color queries
> too). I think you’d have to get off the local network neighborhood to even
> notice; maybe in such cases people just chalk it up to slow networks, when
> actually Emacs could be doing better.

Hmm... what if you have 20-100 frames (which I often do).
I do find the frame creation to be slow (and I always display locally).


        Stefan