bug#6140: 24.0.50; Redisplay problem with the Lao script

bug#6140: 24.0.50; Redisplay problem with the Lao script

[Eli Zaretskii]

This bug report will be sent to the Free Software Foundation,
not to your local site managers!
Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the bug-gnu-emacs@gnu.org mailing list,
and to the gnu.emacs.bug news group.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug.  If you can, give
a recipe starting from `emacs -Q':

 emacs -Q
 C-h H
 C-u 1 5 6 4 C-f

This will place you on the character in the Lao greeting whose buffer
position is 1565.  This is the 2nd character to the left of the slash.

Now type "M-x" and observe the character to the right of the cursor.  It
is a composed character.  Once you type "M-x", it is "decomposed": its
upper part (and everything in that line to the right of it) shifts to
the right.

I see the same in Emacs 23.2, so this has nothing to do with bidi
reordering code.

If this is a problem with the Lao font used for displaying Lao, then
please tell which Lao font is better.  For the record, "C-u C-x ="
says that the font used is this:

 -outline-DejaVu Sans Mono-normal-normal-normal-mono-13-*-*-*-c-*-iso10646-1

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
d:/gnu/bzr/emacs/test/etc/DEBUG.


In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2010-05-08 on HOME-C4E4A596F7
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --no-opt'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  value of $XMODIFIERS: nil
  locale-coding-system: cp1255
  default enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  scroll-bar-mode: right
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  view-mode: t

Recent input:
C-h H <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> M-x r e d r a <tab> <return> <right> <right> 
<right> <left> <right> <left> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <double-down-mouse-1> <double-mouse-1> <triple-down-mouse-1> 
<triple-mouse-1> <triple-down-mouse-1> <triple-mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <double-down-mouse-1> 
<double-mouse-1> <right> <right> <right> <right> <right> 
<left> <right> <left> M-x C-g <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <double-down-mouse-1> <double-mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <wheel-down> <wheel-down> <double-wheel-down> 
<triple-wheel-down> <wheel-up> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <wheel-up> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <left> <left> <left> <next> <prior> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> M-x 
C-g <down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> 
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <right> 
M-x C-g <right> <left> <left> M-x C-g <right> C-x = 
M-x r e p o p <backspace> r t <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading vc-bzr...done
View mode: type C-h for help, h for commands, q to quit.
Quit [4 times]
Char: ຍ (3725, #o7215, #xe8d, file ...) point=1565 of 3163 (49%) column=36

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr message rfc822 mml easymenu mml-sec
mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mailabbrev mail-utils gmm-utils mailheader
emacsbug thai-util thai-word mule-util lao-util regexp-opt vc-bzr sha1
hex-util view tooltip ediff-hook vc-hooks lisp-float-type mwheel dos-w32
disp-table ls-lisp w32-win w32-vars tool-bar dnd fontset image fringe
lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar
mldrag mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev button minibuffer faces cus-face files text-properties overlay
md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process multi-tty emacs)

bug#6140: 24.0.50; Redisplay problem with the Lao script

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

>  emacs -Q
>  C-h H
>  C-u 1 5 6 4 C-f
>
> This will place you on the character in the Lao greeting whose buffer
> position is 1565.  This is the 2nd character to the left of the slash.
>
> Now type "M-x" and observe the character to the right of the cursor.  It
> is a composed character.  Once you type "M-x", it is "decomposed": its
> upper part (and everything in that line to the right of it) shifts to
> the right.

I tried reproducing this in Emacs 27, but used `C-u 1 8 9 3 C-f' instead
to get to that place in the Lao greeting.

But nothing in particular seems to happen when I `M-x' anywhere from
within the greeting, as far as I can see.

> I see the same in Emacs 23.2, so this has nothing to do with bidi
> reordering code.
>
> If this is a problem with the Lao font used for displaying Lao, then
> please tell which Lao font is better.  For the record, "C-u C-x ="
> says that the font used is this:
>
>  -outline-DejaVu Sans Mono-normal-normal-normal-mono-13-*-*-*-c-*-iso10646-1

I have:

    xfthb:-PfEd-DejaVu Sans Mono-normal-normal-normal-*-17-*-*-*-m-0-iso10646-1 (#x4B9)

which is pretty similar...

Are you still seeing this problem or has it gone away in the nine years
since this was reported?

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

bug#6140: 24.0.50; Redisplay problem with the Lao script

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 6140@debbugs.gnu.org
> Date: Wed, 21 Aug 2019 16:53:11 -0700
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >  emacs -Q
> >  C-h H
> >  C-u 1 5 6 4 C-f
> >
> > This will place you on the character in the Lao greeting whose buffer
> > position is 1565.  This is the 2nd character to the left of the slash.
> >
> > Now type "M-x" and observe the character to the right of the cursor.  It
> > is a composed character.  Once you type "M-x", it is "decomposed": its
> > upper part (and everything in that line to the right of it) shifts to
> > the right.
> 
> I tried reproducing this in Emacs 27, but used `C-u 1 8 9 3 C-f' instead
> to get to that place in the Lao greeting.
> 
> But nothing in particular seems to happen when I `M-x' anywhere from
> within the greeting, as far as I can see.

I verified that the problem is still reproducible in Emacs 23, but not
in Emacs 26.  So I'm closing the bug.