bug#15339: 24.3.50; Control characters are displayed as square in describe-char

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Xue Fuqiao]

To reproduce:

  emacs -Q
  C-q C-l
  C-u C-x =

In the *Help* buffer, the ‘decomposition’ property of this character
(should be itself, I believe) is displayed as a square, but the
character is displayed right (^L) in the *scratch* buffer.  I also tried
^M, ^G, ^H, ^V, and ^[; the results are the same.


In GNU Emacs 24.3.50.1 (x86_64-apple-darwin12.4.0, NS apple-appkit-1187.39)
 of 2013-09-07 on xfq.local
Bzr revision: 114163 eggert@cs.ucla.edu-20130907002056-0jom28xr5402rpm9
Windowing system distributor `Apple', version 10.3.1187
Configured using:
 `configure --with-ns --enable-checking --disable-silent-rules'

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Help

Minor modes in effect:
  tooltip-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
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-q C-l C-b C-u C-x = C-x o SPC <escape> x r e - e
m - b u <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Type C-x 1 to delete the help window, C-M-v to scroll help.
Char: C-l (12, #o14, #xc) point=192 of 192 (99%) column=0

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils pp wid-edit cl-loaddefs cl-lib descr-text
help-mode easymenu time-date tooltip ediff-hook vc-hooks lisp-float-type
mwheel ns-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mode prog-mode register page menu-bar
rfn-eshadow timer select scroll-bar 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 minibuffer nadvice loaddefs button
faces cus-face macroexp files text-properties overlay sha1 md5 base64
format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process ns multi-tty emacs)


-- 
Best regards, Xue Fuqiao.
http://www.gnu.org/software/emacs/

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Jan Djärv]

Hi. 

11 sep 2013 kl. 15:28 skrev Xue Fuqiao <xfq.free@gmail.com>:

> To reproduce:
> 
>  emacs -Q
>  C-q C-l
>  C-u C-x =

I'm assuming you go back one character before C-u C-X =. 

I can't reproduce this on a current trunk build. I get "C-l (displayed as C-l)".
That is not correct either, it should be "displayed as ^L".  But it is like that on all platforms. 

Can you try on 24.3 and an updated trunk?  Also try with -nw. 

Thanks,

    Jan D.

> 
> In the *Help* buffer, the ‘decomposition’ property of this character
> (should be itself, I believe) is displayed as a square, but the
> character is displayed right (^L) in the *scratch* buffer.  I also tried
> ^M, ^G, ^H, ^V, and ^[; the results are the same.
> 
> 
> In GNU Emacs 24.3.50.1 (x86_64-apple-darwin12.4.0, NS apple-appkit-1187.39)
> of 2013-09-07 on xfq.local
> Bzr revision: 114163 eggert@cs.ucla.edu-20130907002056-0jom28xr5402rpm9
> Windowing system distributor `Apple', version 10.3.1187
> Configured using:
> `configure --with-ns --enable-checking --disable-silent-rules'
> 
> Important settings:
>  value of $LANG: en_US.UTF-8
>  locale-coding-system: utf-8-unix
>  default enable-multibyte-characters: t
> 
> Major mode: Help
> 
> Minor modes in effect:
>  tooltip-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
>  blink-cursor-mode: t
>  auto-composition-mode: t
>  auto-encryption-mode: t
>  auto-compression-mode: t
>  buffer-read-only: t
>  line-number-mode: t
>  transient-mark-mode: t
> 
> Recent input:
> C-q C-l C-b C-u C-x = C-x o SPC <escape> x r e - e
> m - b u <tab> <return>
> 
> Recent messages:
> For information about GNU Emacs and the GNU system, type C-h C-a.
> Type C-x 1 to delete the help window, C-M-v to scroll help.
> Char: C-l (12, #o14, #xc) point=192 of 192 (99%) column=0
> 
> Load-path shadows:
> None found.
> 
> Features:
> (shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
> mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
> gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
> mail-prsvr mail-utils pp wid-edit cl-loaddefs cl-lib descr-text
> help-mode easymenu time-date tooltip ediff-hook vc-hooks lisp-float-type
> mwheel ns-win tool-bar dnd fontset image regexp-opt fringe
> tabulated-list newcomment lisp-mode prog-mode register page menu-bar
> rfn-eshadow timer select scroll-bar 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 minibuffer nadvice loaddefs button
> faces cus-face macroexp files text-properties overlay sha1 md5 base64
> format env code-pages mule custom widget hashtable-print-readable
> backquote make-network-process ns multi-tty emacs)
> 
> 
> -- 
> Best regards, Xue Fuqiao.
> http://www.gnu.org/software/emacs/
> 
> 

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Xue Fuqiao]

On Thu, Sep 12, 2013 at 2:35 PM, Jan Djärv <jan.h.d@swipnet.se> wrote:
> Hi.

Hi Jan,

> 11 sep 2013 kl. 15:28 skrev Xue Fuqiao <xfq.free@gmail.com>:
>
>> To reproduce:
>>
>>  emacs -Q
>>  C-q C-l
>>  C-u C-x =
>
> I'm assuming you go back one character before C-u C-X =.

Yes, sorry.

> I can't reproduce this on a current trunk build. I get "C-l (displayed
> as C-l)".

I mean the ‘decomposition’ character property (see the OP).

> That is not correct either, it should be "displayed as ^L".  But it is like that on all platforms.
>
> Can you try on 24.3 and an updated trunk?

Sorry, I can't try them in the near future.

> Also try with -nw.

I tried it, but I can't see even a square.  It is like this:

  decomposition: (12) ('')

-- 
Best regards, Xue Fuqiao.
http://www.gnu.org/software/emacs/

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Eli Zaretskii]

> Date: Thu, 12 Sep 2013 16:42:20 +0800
> From: Xue Fuqiao <xfq.free@gmail.com>
> Cc: "15339@debbugs.gnu.org" <15339@debbugs.gnu.org>
> 
> I mean the ‘decomposition’ character property (see the OP).

That portion of the display shows (in this case, since there's no
decomposition) how the raw character in question would be displayed.
And since no available font has a glyph for ^L, you see an empty
square.  That looks correct to me.  You expected to see ^L, but that
comes from a display table, which is bypassed in this case, and for
good reason, as explained above.

So I don't think this is a bug, just something that might not be
expected.

> I tried it, but I can't see even a square.  It is like this:
> 
>   decomposition: (12) ('')

That's not what I see, I see the TTY graphics for Form Feed (FF)
character, which is also correct.  This is on MS-Windows, where the
console font has a glyph for FF, which looks like ♀.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Andreas Schwab]

Eli Zaretskii <eliz@gnu.org> writes:

> That's not what I see, I see the TTY graphics for Form Feed (FF)
> character, which is also correct.  This is on MS-Windows, where the
> console font has a glyph for FF, which looks like ♀.

On a text terminal, the character is written literally, which messes up
the display (FF has the effect of moving the cursor down).

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Eli Zaretskii]

> From: Andreas Schwab <schwab@suse.de>
> Cc: Xue Fuqiao <xfq.free@gmail.com>, 15339@debbugs.gnu.org
> Date: Thu, 12 Sep 2013 17:51:05 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > That's not what I see, I see the TTY graphics for Form Feed (FF)
> > character, which is also correct.  This is on MS-Windows, where the
> > console font has a glyph for FF, which looks like ♀.
> 
> On a text terminal, the character is written literally, which messes up
> the display (FF has the effect of moving the cursor down).

Yes, I saw that also.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Jan Djärv]

Hi.

12 sep 2013 kl. 17:51 skrev Andreas Schwab <schwab@suse.de>:

> Eli Zaretskii <eliz@gnu.org> writes:
> 
>> That's not what I see, I see the TTY graphics for Form Feed (FF)
>> character, which is also correct.  This is on MS-Windows, where the
>> console font has a glyph for FF, which looks like ♀.
> 
> On a text terminal, the character is written literally, which messes up
> the display (FF has the effect of moving the cursor down).
> 
> Andreas.
> 

Yes, that happens on OSX also.

	Jan D.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Eli Zaretskii]

> From: Jan Djärv <jan.h.d@swipnet.se>
> Date: Thu, 12 Sep 2013 19:24:24 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>,
>  Xue Fuqiao <xfq.free@gmail.com>,
>  15339@debbugs.gnu.org
> 
> > On a text terminal, the character is written literally, which messes up
> > the display (FF has the effect of moving the cursor down).
> > 
> > Andreas.
> 
> Yes, that happens on OSX also.

Perhaps for control characters, the default should be not to show the
decomposition.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[npostavs]

tags 15339 fixed
close 15339 25.1
quit

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Jan Djärv <jan.h.d@swipnet.se>
>> Date: Thu, 12 Sep 2013 19:24:24 +0200
>> Cc: Eli Zaretskii <eliz@gnu.org>,
>>  Xue Fuqiao <xfq.free@gmail.com>,
>>  15339@debbugs.gnu.org
>> 
>> > On a text terminal, the character is written literally, which messes up
>> > the display (FF has the effect of moving the cursor down).
>> > 
>> > Andreas.
>> 
>> Yes, that happens on OSX also.
>
> Perhaps for control characters, the default should be not to show the
> decomposition.

This seems to have been done in Emacs 25.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Jan Djärv]

Hello.

12 sep 2013 kl. 10:42 skrev Xue Fuqiao <xfq.free@gmail.com>:

> On Thu, Sep 12, 2013 at 2:35 PM, Jan Djärv <jan.h.d@swipnet.se> wrote:
>> Hi.
> 
> Hi Jan,
> 
>> 11 sep 2013 kl. 15:28 skrev Xue Fuqiao <xfq.free@gmail.com>:
>> 
>>> To reproduce:
>>> 
>>> emacs -Q
>>> C-q C-l
>>> C-u C-x =
>> 
>> I'm assuming you go back one character before C-u C-X =.
> 
> Yes, sorry.
> 
>> I can't reproduce this on a current trunk build. I get "C-l (displayed
>> as C-l)".
> 
> I mean the ‘decomposition’ character property (see the OP).

Ah, missed that.  There is indeed a square.  There is a square there for GNU/Linux also, so it may be intentional.

	Jan D.

bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Andreas Schwab]

Jan Djärv <jan.h.d@swipnet.se> writes:

> I can't reproduce this on a current trunk build. I get "C-l (displayed as C-l)".

Please look further down, in the character code properties (you may have
to customize it to include the decomposition).

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."