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bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode
From: |
Eli Zaretskii |
Subject: |
bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode |
Date: |
Sat, 18 Feb 2012 10:49:19 +0200 |
> 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?
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Andreas Schwab, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Eli Zaretskii, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Eli Zaretskii, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/17
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode,
Eli Zaretskii <=
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Eli Zaretskii, 2012/02/18
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Chong Yidong, 2012/02/19
- bug#10835: 24.0.93; bidi-paragraph-direction slows down Shell mode, Eli Zaretskii, 2012/02/18