bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Gregor Zattler]

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Dear Emacs developers,

with this (see below) recently build emacs -Q -nw in an xterm /
urxvt (this does not happen in a graphical frame) enter this
Text:


Zwangsräumung von HG♿M99


The symbol between "HG" and "M99" is the unicode wheelchair symbol.

With point at the wheelchair symbol hit C-f: The cursor moves not to the
"M" but to the left "9".  This gives problems in the rest of the line
when one for instance swaps characters with C-t.  When doing so a few
times it's hard to tell if it's a display problem or if the letters are
swapped around.

The problem is also visible at the line between windows (see attached
screen shot).  This happens when hitting C-l.


Is this an emacs bug, a terminal emulators bug or a bug of the font used?


Thanks for looking into this, Gregor

P.S.: Totally unrelated to this emacs problem: HG is a person who needs to use
a wheelchair, M99 is a shop in Berlin/Kreuzberg HG runs and in which he
also lives.  His forcefull eviction is scheduled for 9th of August.





In GNU Emacs 25.0.95.1 (x86_64-pc-linux-gnu, GTK+ Version 3.20.6)
 of 2016-07-24 built on len
Repository revision: 0e646c73f57fc50de36ef659ead9a94968f8cba7
System Description:	Debian GNU/Linux testing (stretch)

Configured using:
 'configure --prefix=/usr/local/stow/emacs-snapshot
 --with-file-notification=inotify --enable-checking
 --without-toolkit-scroll-bars --with-x-toolkit=gtk3'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
GTK3 X11

Important settings:
  value of $LC_COLLATE: de_DE.utf8
  value of $LC_CTYPE: de_DE.utf8
  value of $LC_MESSAGES: POSIX
  value of $LC_MONETARY: de_DE.utf8
  value of $LC_NUMERIC: de_DE.utf8
  value of $LC_TIME: de_DE.utf8
  value of $LANG: de_DE.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
kill-line: End of buffer [2 times]
Mark set [2 times]
Undo! [26 times]
scroll-down-command: Beginning of buffer [5 times]
Mark set [2 times]
Type C-x 1 to delete the help window.
next-line: End of buffer
Making completion list...

Load-path shadows:
None found.

Features:
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time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel x-win term/common-win x-dnd tool-bar dnd fontset
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prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
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hashtable-print-readable backquote dbusbind inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 93560 5294)
 (symbols 48 20054 0)
 (miscs 40 51 171)
 (strings 32 15184 4315)
 (string-bytes 1 431177)
 (vectors 16 9893)
 (vector-slots 8 387568 16181)
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 (intervals 56 409 13)
 (buffers 976 22)
 (heap 1024 24251 706))

[-- Attachment #2: ragged-line-between-emacs-windows.jpg --]
[-- Type: image/jpeg, Size: 171097 bytes --]

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Eli Zaretskii]

> Date: Wed, 27 Jul 2016 18:32:11 +0200
> From: Gregor Zattler <telegraph@gmx.net>
> 
> with this (see below) recently build emacs -Q -nw in an xterm /
> urxvt (this does not happen in a graphical frame) enter this
> Text:
> 
> 
> Zwangsräumung von HG♿M99
> 
> 
> The symbol between "HG" and "M99" is the unicode wheelchair symbol.
> 
> With point at the wheelchair symbol hit C-f: The cursor moves not to the
> "M" but to the left "9".  This gives problems in the rest of the line
> when one for instance swaps characters with C-t.  When doing so a few
> times it's hard to tell if it's a display problem or if the letters are
> swapped around.
> 
> The problem is also visible at the line between windows (see attached
> screen shot).  This happens when hitting C-l.
> 
> 
> Is this an emacs bug, a terminal emulators bug or a bug of the font used?

This character is marked as "wide" in the Unicode database, so Emacs
thinks it takes up 2 columns.

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Eli Zaretskii]

> Date: Wed, 27 Jul 2016 20:34:23 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 24088@debbugs.gnu.org
> 
> > Date: Wed, 27 Jul 2016 18:32:11 +0200
> > From: Gregor Zattler <telegraph@gmx.net>
> > 
> > with this (see below) recently build emacs -Q -nw in an xterm /
> > urxvt (this does not happen in a graphical frame) enter this
> > Text:
> > 
> > 
> > Zwangsräumung von HG♿M99
> > 
> > 
> > The symbol between "HG" and "M99" is the unicode wheelchair symbol.
> > 
> > With point at the wheelchair symbol hit C-f: The cursor moves not to the
> > "M" but to the left "9".  This gives problems in the rest of the line
> > when one for instance swaps characters with C-t.  When doing so a few
> > times it's hard to tell if it's a display problem or if the letters are
> > swapped around.
> > 
> > The problem is also visible at the line between windows (see attached
> > screen shot).  This happens when hitting C-l.
> > 
> > 
> > Is this an emacs bug, a terminal emulators bug or a bug of the font used?
> 
> This character is marked as "wide" in the Unicode database, so Emacs
> thinks it takes up 2 columns.

Perhaps Handa-san (CC'ed) could look into this issue.  AFAICT, Emacs
correctly marks the character as wide, but then I'm not sure how this
indication should be taken into account while writing the text to the
TTY.

Thanks.

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Lars Ingebrigtsen]

Gregor Zattler <telegraph@gmx.net> writes:

> with this (see below) recently build emacs -Q -nw in an xterm /
> urxvt (this does not happen in a graphical frame) enter this
> Text:
>
> Zwangsräumung von HG♿M99
>
> The symbol between "HG" and "M99" is the unicode wheelchair symbol.
>
> With point at the wheelchair symbol hit C-f: The cursor moves not to the
> "M" but to the left "9". 

I'm unable to reproduce this issue on Debian/bullseye with Emacs 25.1
(or Emacs 28).  Are you still seeing this problem?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Gregor Zattler]

Hi Lars,
* Lars Ingebrigtsen <larsi@gnus.org> [2021-07-06; 19:41]:
> Gregor Zattler <telegraph@gmx.net> writes:
>> with this (see below) recently build emacs -Q -nw in an xterm /
>> urxvt (this does not happen in a graphical frame) enter this
>> Text:
>>
>> Zwangsräumung von HG♿M99
>>
>> The symbol between "HG" and "M99" is the unicode wheelchair symbol.
>>
>> With point at the wheelchair symbol hit C-f: The cursor moves not to the
>> "M" but to the left "9". 
>
> I'm unable to reproduce this issue on Debian/bullseye with Emacs 25.1
> (or Emacs 28).  Are you still seeing this problem?

No I do not see this behavior anymore with Debian Buster
10.10 and emacs 28.50 nore emacs 26.1.  I Tested with urxvt
and xterm (which does not show a wheelchair but behaves ok).
Interestingly in urxvt it looks different from my screenshot
for the bug report: Now it's a Widersprüche character and
there is more empty space left and right of the wheelchair.
Cursor movements are OK.

Thanks for looking into this.
Please close this bug report.


Ciao; Gregor
-- 
 -... --- .-. . -.. ..--.. ...-.-

bug#24088: emacs 25.0.95; display problems in terminal emulator after unicode wheelcair symbol

[Lars Ingebrigtsen]

Gregor Zattler <telegraph@gmx.net> writes:

> Thanks for looking into this.
> Please close this bug report.

Thanks for checking; I'm closing the report then.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no