Re: How to debug emacs repaint problems?

[Eli Zaretskii <eliz@gnu.org>]

> From: joakim@verona.se
> Date: Sat, 14 Oct 2023 20:09:31 +0200
> 
> Hello,
> 
> I have a long standing problem where it appears that my build of emacs
> seems to invalidate a lot of regions on screen, which leads to flicker
> in my setup of vnc. 
> 
> This flicker problem doesnt appear so much in the emacs that is
> installed by my distro, which is fedora, emacs 28.
> 
> It would be easier to debug this if emacs could be persuaded to give
> some visual hints of which regions its invalidating. Is this possible?

Not AFAIU, since Emacs doesn't invalidate any regions.  It decides by
itself which parts of the screen need to be redrawn, and then does
that.

> I use these settings in turbovnc:
> Tight+Low quality jpeg(WAN)
> /opt/TurboVNC/bin/tvncconfig -set ALR=1
> /opt/TurboVNC/bin/tvncconfig -set ALRAll=true
> 
> The idea is that a low quality codec should be used to refresh
> invalidated rects, and then after a while be losslessly refreshed.
> This works well in applications that dont invalidate the entire window,
> when only small parts of the window needs to be changed.

I don't know anything about turbovnc, but what you say is not how
Emacs display works.

Btw, does the flickering happen with text-mode frames or GUI frames?
And which part(s) of the Emacs display flicker?