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Re: Excessive refontification when setting jit-lock-context-unfontify-po
From: |
Stefan Monnier |
Subject: |
Re: Excessive refontification when setting jit-lock-context-unfontify-pos |
Date: |
Fri, 27 Apr 2007 14:54:00 -0400 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.97 (gnu/linux) |
>>> That's what I do. (See `font-latex-fontify-region'.) But the
>>> multiline construct does not get fully highlighted if I don't set
>>> j-l-c-u-p or set the fontified property to nil.
>>
>> Try C-l to make sure that the highlighting is really absent from the buffer,
>> rather than merely being "not yet displayed".
> When typing `C-l' highlighting appears. Is there a possibility to
> enforce such redisplay in an efficient way? I could probably call
> `sit-for' somewhere in the code but I am not sure if this would be the
> right way.
I understand the problem, then. Your code is working fine, it's just that
some part of the text your re-highlight is re-highlighted by jit-lock but
*after* having been rendered by the redisplay engine.
Typically it works like this:
1 - you modify buffer on line starting at position POS
2 - the redisplay engine see that there's nothing to do before POS,
and calls jit-lock starting at POS.
3 - jit-lock calls font-lock, asking it to refontify region POS..POS+N
4 - font-lock decides to extend the region to POS-M1 .. POS+N+M2
5 - after highlighting is done, control returns to the redisplay which goes
on to render POS .. POS+N.
The text between POS-M1 and POS has been refontified but the display does
not (yet) reflect it.
jit-lock has code already to handle similar problems, but the code doesn't
handle this case yet (basically because font-lock currently does not tell
jit-lock that it has extended the region).
The relevant code is in jit-lock-fontify-now:
;; The redisplay engine has already rendered the buffer up-to
;; `orig-start' and won't notice if the above jit-lock-functions
;; changed the appearance of any part of the buffer prior
;; to that. So if `start' is before `orig-start', we need to
;; cause a new redisplay cycle after this one so that any changes
;; are properly reflected on screen.
;; To make such repeated redisplay happen less often, we can
;; eagerly extend the refontified region with
;; jit-lock-after-change-extend-region-functions.
(when (< start orig-start)
(run-with-timer 0 nil 'jit-lock-force-redisplay
(current-buffer) start orig-start))
So in your case you can either use
jit-lock-after-change-extend-region-functions; or you can use a similar
run-with-timer in your font-lock-fontify-region-function. If you look at
jit-lock-force-redisplay, you'll see that it should not cause infinite
looping because it only causes redisplay (like C-l would) but not
re-highlighting.
Of course you can also indeed use jit-lock-context-unfontify-pos, but it has
the disadvantage of causing an unnecessary refontification and requires
extra care to avoid infinite looping. Also it introduces a delay.
In Emacs>22 we should fix the font-lock/jit-lock interface so that jit-lock
can handle this case automatically.
Stefan
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, (continued)
Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Stefan Monnier, 2007/04/24
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/24
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Stefan Monnier, 2007/04/24
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/24
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Stefan Monnier, 2007/04/25
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/25
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Stefan Monnier, 2007/04/25
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/27
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos,
Stefan Monnier <=
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/27
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/28
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Stefan Monnier, 2007/04/29
- Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/30
Re: Excessive refontification when setting jit-lock-context-unfontify-pos, martin rudalics, 2007/04/25
Re: Excessive refontification when setting jit-lock-context-unfontify-pos, Ralf Angeli, 2007/04/27
Re: Excessive refontification when setting jit-lock-context-unfontify-pos, martin rudalics, 2007/04/25