Subject: Re: bug#62780: 30.0.50; Redisplay gets slow when using Org tables + show-trailing-whitespace

From: Ihor Radchenko <[email-masked]>
Date: Fri, 14 Apr 2023 12:52:32 +0000

Eli Zaretskii <[email-masked]> writes:

> Btw, it is not true that we are looking all the way to point-max in
> this case: you will see in composition_compute_stop_pos that it limits
> the search to the next 500 buffer positions:

Sure. Though 500 is clearly not small enough threshold.

Also, I am a bit confused about the purpose of

      /* Make sure the above arbitrary limit position is not in the
	 middle of composable text, so we don't break compositions by
	 submitting the composable text to the shaper in separate
	 chunks.  We play safe here by assuming that only SPC, TAB,
	 FF, and NL cannot be in some composition; in particular, most
	 ASCII punctuation characters could be composed into ligatures.  */

in compute_stop_pos

AFAIU, it tries hard to not stop in the middle of composed region. Then,
why need to fall back to 500 in the composition_compute_stop_pos call?

-- 
Ihor Radchenko // yantar92,
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