Re: Is there something like `on-display-functions'?

[Stefan Monnier]

> Is this nothing-to-do-with-ness documented anywhere?  In the elisp
> manual, jit-lock is found twice, both occurrences in "Other Font Lock
> Variables".  Without reading the source code in great detail, you'd be
> hard pressed to find out that the jit-lock mechanism is operative when
> font-lock mode is disabled.

Yes, that's inherited from jit-lock's origin as a "font-lock support mode".
It deserves to be better documented.

>> The docstring doesn't mention font-lock.

> It mentions "fontification".  Isn't that a synonym for font-lock?  Or is
> it the part of redisplay that converts characters into glyphs and pixels,
> regardless of whether font-lock is enabled?

"fontification" usually refers to the act of adding `face' properties
(and similar things) to enhance the visual appearance of the text.
Font-lock is the canonical package that does fontification, hilit19 was
another one.  Some major modes do/did it without using font-lock.

> jit-lock-register says that FUN is "registered as a fontification
> function".  I think Somebody (tm) could usefully separate out jit-lock
> from font-lock in the doc strings and manual.

Agreed.

> Just as a matter of interest, how does jit-lock know the END parameter
> which it passes to FUN?  Or is this just a random value, a few hundred
> bytes after BEG?

It's a somewhat arbitrary value, computed based on jit-lock-chunk-size.


        Stefan