From: Eli Zaretskii <eliz@gnu.org>
To: Chong Yidong <cyd@gnu.org>
Cc: 10835@debbugs.gnu.org
Subject: bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode
Date: Sat, 18 Feb 2012 10:49:19 +0200 [thread overview]
Message-ID: <83y5s0v84w.fsf@gnu.org> (raw)
In-Reply-To: <87y5s0dd6q.fsf@gnu.org>
> From: Chong Yidong <cyd@gnu.org>
> Cc: 10835@debbugs.gnu.org
> Date: Sat, 18 Feb 2012 11:37:33 +0800
>
> Chong Yidong <cyd@gnu.org> writes:
>
> > I just noticed that when I do `ls --color=no' rather than just `ls',
> > insertion and scrolling are very fast. The sluggishness only appears
> > when ls color highlighting is enabled. So the inefficiency of
> > ansi-color.el, and its use of overlays, seems to play a role.
>
> I just confirmed that the sluggishness goes away if I change
> ansi-color.el to make it use text properties.
That figures. bidi.c needs to look up display properties and overlays
with display strings, in order to DTRT with their display (they are
treated as a single neutral character). So having lots of overlays
slows down redisplay a bit more.
> Wish I'd remembered to do that before the pretest began.
If this is a grave problem, we can still do it now, I think. Or we
could use a band-aid, see below.
> Roughly what is happening, I think, is that when overlays are heavily
> used and there are no paragraph breaks (e.g. from the `time' output),
> the bidi code does enough the additional overlay lookups to produce a
> noticeable slowdown.
Yes, the overlays together with the long search for paragraph
beginning probably push the user experience from slightly below the
annoyance threshold to just above it.
> I'm not sure what's the best fix right now, though.
How about setting bidi-paragraph-direction in comint buffers to
left-to-right when the locale indicates that use of bidirectional
scripts is unlikely? We could use locale-language-names and an
additional small database of languages that need bidi, to make that
decision. WDYT?
next prev parent reply other threads:[~2012-02-18 8:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-17 5:41 bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode Chong Yidong
2012-02-17 5:48 ` Chong Yidong
2012-02-17 8:21 ` Andreas Schwab
2012-02-17 13:42 ` Chong Yidong
2012-02-17 16:08 ` Eli Zaretskii
2012-02-17 17:39 ` Chong Yidong
2012-02-17 18:27 ` Eli Zaretskii
2012-02-18 2:28 ` Chong Yidong
2012-02-18 3:37 ` Chong Yidong
2012-02-18 8:49 ` Eli Zaretskii [this message]
2012-02-18 14:14 ` Eli Zaretskii
2012-02-19 14:07 ` Chong Yidong
2012-02-18 8:27 ` Eli Zaretskii
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