On 2016-02-21 20:04, Alan Mackenzie <acm@muc.de> writes:

>> The problem: if jit-lock-mode it t, then using set-text-properties to
>> change the face does not work.
>
>> To reproduce: start emacs with -Q. In the scratch buffer, type "foo".
>> Then evaluate:
>> (set-text-properties 192 195 (list 'face 'italic))
>
>> Nothing changes, and when I do a `describe-char' on one letter of "foo"
>> I don't see the face.
>
> At a guess, what's happening here is this: your `set-text-properties'
> does indeed work.  But setting text properties is a buffer change.  So
> `before-change-functions' and `after-change-functions' will both be
> executed.  `a-c-f' contains `jit-lock-after-change', which helpfully
> refontifies the line for you.  All this happens before the screen is
> redisplayed.
>
> If you bind these hooks to nil around your call, I think it will work:
>
> (let (before-change-functions after-change-functions)
>   (set-text-properties 192 195 (list 'face 'italic)))

Thanks a lot for the suggestion, but unfortunately it does not work. I
guess some other function must be re-fontifying the text.

Alan

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