Re: Scrolling commands and skipping redisplay

[Eli Zaretskii]

> Date: Sat, 11 Apr 2020 17:04:04 +0000
> Cc: address@hidden, address@hidden, address@hidden, address@hidden,
>   address@hidden
> From: Alan Mackenzie <address@hidden>
> 
> > I dislike (i)b and (ii)b because they are jerky, and because when I
> > stop leaning on C-v, I have a lot of screen to watch scrolling, until
> > Emacs starts executing new commands.  I guess my auto-repeat rate is
> > higher than Alan's. or maybe it's because I'm trying this in a GUI
> > frame, not a TTY frame.
> 
> It sounds like your time for scrolling a screen, even without
> fontification, is close to your auto-repeat time.

_Only_ without fontification.  With fontifications, at least in CC
Mode, Emacs gets stuck after several screenfuls in -O0 and -Og builds,
which means the time to scroll is longer than the auto-repeat
interval.

> My repeat rate is 30 characters/second.

It's about 50 here.

>     As an alternative to setting `fast-but-imprecise-scrolling' you
>     might prefer to enable jit-lock deferred fontification (See Font
>     Lock).  To do this, customize `jit-lock-defer-time' to a small
>     positive number such as 0.1.  This gives you less jerky scrolling,
>     but the buffer contents on any scroll operation into a fresh portion
>     of the buffer will at first be unfontified,

No objections.