Re: Scrolling commands and skipping redisplay, was: Re: emacs rendering comparisson between emacs23 and emacs26.3

[Eli Zaretskii]

> From: Stefan Monnier <address@hidden>
> Cc: Dmitry Gutov <address@hidden>,  address@hidden,  address@hidden,
>   address@hidden,  address@hidden,  address@hidden
> Date: Fri, 10 Apr 2020 09:00:04 -0400
> 
> > Depends on what you mean by "precision".  They might very well miss
> > some parts of the buffer entirely, i.e. never see them on display.
> 
> But that happens regardless of whether the scroll is computed correctly,
> because redisplay itself is skipped.

It isn't skipped here if I use jit-lock-defer-time.  Maybe your
keyboard auto-repeat rate is too high?  Mine is set to about 50/sec.

> > This may or may not be important, depending on the use case.  An
> > editor is not supposed to skip portions of the buffer when scrolling
> > continuously.
> 
> If we can arrange for the "skip jit-lock during scroll" to ensure that
> the subsequent redisplay also skips jit-lock (or is itself skipped),
> then this should not happen, right?
> E.g. in the case where jit-lock-defer-time > 0.

Indeed, it doesn't here.

> > Here, it behaves much better.  So maybe some other factors are at work
> > in your configuration.
> 
> I think different definitions of "better" are at play here as well.

In the context of the above, "better" means "without flickering".