RE: [External] : Partly deferred font-locking?

[Drew Adams]

> Is it somehow possible to defer (only) the more expensive parts of
> font-lock using a timer?  A use case would be the symlink-target
> checking fontification rules in dired: the need to check the target file
> properties makes scrolling large dired buffers sluggish.
> 
> It seems there are only global settings available that also always
> influence font-locking completely as a whole (`jit-lock-stealth-time',
> `jit-lock-defer-time').
> 
> Are there other ways?  Or would it be worth to implement?

There's option `font-lock-maximum-decoration'.
However, it's up to a major mode whether to
provide multiple levels, and how many to provide.

Beyond levels, we could imagine being able to
specify a list of particular kinds of fontifying
per mode.  That's not possible with this option
today.  No doubt there's room for improvement.

But AFAIK, hardly any major modes, even those
from vanilla Emacs itself, provide multiple
levels.  So it's not clear whether improvement
in the possibilities would actually be put to
use by modes, to give users more control.