bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Drew Adams]

emacs -Q
M-x customize-variable inverse-video
Toggle the value to choose inverse video.  Set for current session.
 
It has no effect, either on existing frames or on new ones.

But doing this has the desired effect:
M-x customize-face default
Turn on attribute `inverse-video'.  Set for current session.

Setting user option `inverse-video' should have the same effect: it
should affect the current session.

In GNU Emacs 24.0.96.1 (i386-mingw-nt5.1.2600)
 of 2012-04-28 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.6) --no-opt --enable-checking --cflags
 -ID:/devel/emacs/libs/libXpm-3.5.8/include
 -ID:/devel/emacs/libs/libXpm-3.5.8/src
 -ID:/devel/emacs/libs/libpng-dev_1.4.3-1/include
 -ID:/devel/emacs/libs/zlib-dev_1.2.5-2/include
 -ID:/devel/emacs/libs/giflib-4.1.4-1/include
 -ID:/devel/emacs/libs/jpeg-6b-4/include
 -ID:/devel/emacs/libs/tiff-3.8.2-1/include
 -ID:/devel/emacs/libs/gnutls-3.0.9/include'
 

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Drew Adams]

ping

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Lars Ingebrigtsen]

"Drew Adams" <drew.adams@oracle.com> writes:

> emacs -Q
> M-x customize-variable inverse-video
> Toggle the value to choose inverse video.  Set for current session.
>
> It has no effect, either on existing frames or on new ones.

Hm.  Is this a deprecated variable or something?  Or is it only used on
startup?  In any case, the doc string should probably mention this,
whatever is going on...

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

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> "Drew Adams" <drew.adams@oracle.com> writes:
>
>> emacs -Q
>> M-x customize-variable inverse-video
>> Toggle the value to choose inverse video.  Set for current session.
>>
>> It has no effect, either on existing frames or on new ones.
>
> Hm.  Is this a deprecated variable or something?  Or is it only used on
> startup?  In any case, the doc string should probably mention this,
> whatever is going on...

Not sure what it is.  It seems to be orthogonal to "emacs
--reverse-video", and has no effect when I try setting it manually in a
running session, nor when I run "emacs --eval='(setq inverse-video t)'
-Q -nw".

It was removed from the manual here:
b4a1a8b278 2010-03-02 Chong Yidong * frames.texi (Mouse Avoidance): Mention make-pointer-invisible.

I also found the following:

./src/ChangeLog.9:

> 2001-10-20  Miles Bader  <miles@gnu.org>
[...]
> 	The following changes remove inverse-video support for terminals
> 	that use a `magic cookie' standout mode.  Due to changes in the
> 	way mode-lines are displayed, such support no longer works
> 	anyway, and it's probable that almost no one uses such terminals
> 	anymore:
[...]
> 2001-04-25  Gerd Moellmann  <gerd@gnu.org>
> 
> 	* faces.el (tty-handle-reverse-video): Don't set inverse-video.

So I have the same question as Lars: is this just some old obsolete
variable that should be removed?

Best regards,
Stefan Kangas

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Drew Adams]

> >> emacs -Q
> >> M-x customize-variable inverse-video
> >> Toggle the value to choose inverse video.  Set for current session.
> >>
> >> It has no effect, either on existing frames or on new ones.
> >
> > Hm.  Is this a deprecated variable or something?  Or is it only used
> on
> > startup?  In any case, the doc string should probably mention this,
> > whatever is going on...
> 
> Not sure what it is.  It seems to be orthogonal to "emacs
> --reverse-video", and has no effect when I try setting it manually in a
> running session, nor when I run "emacs --eval='(setq inverse-video t)'
> -Q -nw".
> 
> It was removed from the manual here:
> b4a1a8b278 2010-03-02 Chong Yidong * frames.texi (Mouse Avoidance):
> Mention make-pointer-invisible.
> 
> I also found the following:
> 
> ./src/ChangeLog.9:
> 
> > 2001-10-20  Miles Bader  <miles@gnu.org>
> [...]
> > 	The following changes remove inverse-video support for terminals
> > 	that use a `magic cookie' standout mode.  Due to changes in the
> > 	way mode-lines are displayed, such support no longer works
> > 	anyway, and it's probable that almost no one uses such terminals
> > 	anymore:
> [...]
> > 2001-04-25  Gerd Moellmann  <gerd@gnu.org>
> >
> > 	* faces.el (tty-handle-reverse-video): Don't set inverse-video.
> 
> So I have the same question as Lars: is this just some old obsolete
> variable that should be removed?

Why would it be obsolete?  Anyway, it's in the C source code still.

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Stefan Kangas]

[-- Attachment #1: Type: text/plain, Size: 1447 bytes --]

Drew Adams <drew.adams@oracle.com> writes:

>> Not sure what it is.  It seems to be orthogonal to "emacs
>> --reverse-video", and has no effect when I try setting it manually in a
>> running session, nor when I run "emacs --eval='(setq inverse-video t)'
>> -Q -nw".
>> 
>> It was removed from the manual here:
>> b4a1a8b278 2010-03-02 Chong Yidong * frames.texi (Mouse Avoidance):
>> Mention make-pointer-invisible.
>> 
>> I also found the following:
>> 
>> ./src/ChangeLog.9:
>> 
>> > 2001-10-20  Miles Bader  <miles@gnu.org>
>> [...]
>> > 	The following changes remove inverse-video support for terminals
>> > 	that use a `magic cookie' standout mode.  Due to changes in the
>> > 	way mode-lines are displayed, such support no longer works
>> > 	anyway, and it's probable that almost no one uses such terminals
>> > 	anymore:
>> [...]
>> > 2001-04-25  Gerd Moellmann  <gerd@gnu.org>
>> >
>> > 	* faces.el (tty-handle-reverse-video): Don't set inverse-video.
>> 
>> So I have the same question as Lars: is this just some old obsolete
>> variable that should be removed?
>
> Why would it be obsolete?  Anyway, it's in the C source code still.

As I said, I can't discern any visible effects from setting it to t.

By the way, the attached patch removes the variable.  I'm not suggesting
to install it as is, but perhaps it could be useful in figuring out what
the inverse-video variable does and what to do about it.

Best regards,
Stefan Kangas


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: inverse-video.diff --]
[-- Type: text/x-diff, Size: 2931 bytes --]

diff --git a/src/dispnew.c b/src/dispnew.c
index 4cdc76f5bc..6cea3b8de6 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -6234,7 +6234,6 @@ init_display_interactive (void)
   SET_CHAR_GLYPH (space_glyph, ' ', DEFAULT_FACE_ID, 0);
   space_glyph.charpos = -1;
 
-  inverse_video = 0;
   cursor_in_echo_area = false;
 
   /* Now is the time to initialize this; it's used by init_sys_modes
@@ -6497,10 +6496,6 @@ syms_of_display (void)
 On most systems, changing this value will affect the amount of padding
 and the other strategic decisions made during redisplay.  */);
 
-  DEFVAR_BOOL ("inverse-video", inverse_video,
-	       doc: /* Non-nil means invert the entire frame display.
-This means everything is in inverse video which otherwise would not be.  */);
-
   DEFVAR_BOOL ("visible-bell", visible_bell,
 	       doc: /* Non-nil means try to flash the frame to represent a bell.
 
diff --git a/src/msdos.c b/src/msdos.c
index 1192b37a0d..e1ba6d0813 100644
--- a/src/msdos.c
+++ b/src/msdos.c
@@ -838,14 +838,6 @@ IT_set_face (int face)
       fg = bg;
       bg = tem;
     }
-  /* If the user requested inverse video, obey.  */
-  if (inverse_video)
-    {
-      unsigned long tem2 = fg;
-
-      fg = bg;
-      bg = tem2;
-    }
   if (tty->termscript)
     fprintf (tty->termscript, "<FACE %d: %lu/%lu[FG:%lu/BG:%lu]>", face,
 	     fp->foreground, fp->background, fg, bg);
diff --git a/src/term.c b/src/term.c
index 642010549b..9407385540 100644
--- a/src/term.c
+++ b/src/term.c
@@ -356,16 +356,12 @@ tty_show_cursor (struct tty_display_info *tty)
 
 
 /* Set standout mode to the state it should be in for
-   empty space inside windows.  What this is,
-   depends on the user option inverse-video.  */
+   empty space inside windows.  */
 
 static void
 tty_background_highlight (struct tty_display_info *tty)
 {
-  if (inverse_video)
-    tty_turn_on_highlight (tty);
-  else
-    tty_turn_off_highlight (tty);
+  tty_turn_off_highlight (tty);
 }
 
 /* Set standout mode to the mode specified for the text to be output.  */
@@ -373,10 +369,7 @@ tty_background_highlight (struct tty_display_info *tty)
 static void
 tty_highlight_if_desired (struct tty_display_info *tty)
 {
-  if (inverse_video)
-    tty_turn_on_highlight (tty);
-  else
-    tty_turn_off_highlight (tty);
+  tty_turn_off_highlight (tty);
 }
 \f
 
@@ -1909,9 +1902,7 @@ turn_on_face (struct frame *f, int face_id)
      Do this first because TS_end_standout_mode may be the same
      as TS_exit_attribute_mode, which turns all appearances off. */
   if (MAY_USE_WITH_COLORS_P (tty, NC_REVERSE)
-      && (inverse_video
-	  ? fg == FACE_TTY_DEFAULT_FG_COLOR || bg == FACE_TTY_DEFAULT_BG_COLOR
-	  : fg == FACE_TTY_DEFAULT_BG_COLOR || bg == FACE_TTY_DEFAULT_FG_COLOR))
+      && (fg == FACE_TTY_DEFAULT_BG_COLOR || bg == FACE_TTY_DEFAULT_FG_COLOR))
     tty_toggle_highlight (tty);
 
   if (face->tty_bold_p && MAY_USE_WITH_COLORS_P (tty, NC_BOLD))

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Drew Adams]

> > Why would it be obsolete?  Anyway, it's in the C source code still.
> 
> As I said, I can't discern any visible effects from setting it to t.
> 
> By the way, the attached patch removes the variable.  I'm not
> suggesting to install it as is, but perhaps it could be useful
> in figuring out what the inverse-video variable does and what
> to do about it.

OK by me. 

I was hoping someone might know what this is about,
but I guess it's too late for that.

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Fri, 01 Nov 2019 20:58:18 +0100
> Cc: 11430@debbugs.gnu.org, Lars Ingebrigtsen <larsi@gnus.org>,
>  Stefan Kangas <stefan@marxist.se>
> 
> > Why would it be obsolete?  Anyway, it's in the C source code still.
> 
> As I said, I can't discern any visible effects from setting it to t.

It's a bug, plain and simple, that setting that variable doesn't
affect the display.

Fixing the bug may not be easy, and isn't high priority, but it
nevertheless is a bug.

FWIW, I see no reason to remove the variable just because we don't
seem to know how to fix this.

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:
> It's a bug, plain and simple, that setting that variable doesn't
> affect the display.
>
> Fixing the bug may not be easy, and isn't high priority, but it
> nevertheless is a bug.
>
> FWIW, I see no reason to remove the variable just because we don't
> seem to know how to fix this.

I'd argue it's not an important feature.  It seems like it's been
broken for a long time without anyone complaining.  We could remove it
and refer any existing users to "emacs -rv" instead.

Just my two cents, but I don't feel strongly either way.

Best regards,
Stefan Kangas

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> It's a bug, plain and simple, that setting that variable doesn't
> affect the display.
>
> Fixing the bug may not be easy, and isn't high priority, but it
> nevertheless is a bug.
>
> FWIW, I see no reason to remove the variable just because we don't
> seem to know how to fix this.

The variable hasn't worked for 20 years (apparently), and this is the
only bug report about it, which is perhaps a hint that we should just
remove it.

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

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Drew Adams]

> The variable hasn't worked for 20 years (apparently), and this is the
> only bug report about it, which is perhaps a hint that we should just
> remove it.

It doesn't follow that we should remove it.
A bug is a bug.  Better to keep this bug open.
Someday, perhaps, Someone(TM) will be motivated
and find a way to fix it.  And if not, so what?

What harm does it do to keep a report open for
a recognized bug?  When it comes to free software
and its volunteers, no one's career is boosted by
just reducing a bug count as an end in itself.
Or am I missing something?

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Stefan Kangas <stefan@marxist.se>,  11430@debbugs.gnu.org,
>   drew.adams@oracle.com
> Date: Mon, 21 Sep 2020 17:03:36 +0200
> 
> > FWIW, I see no reason to remove the variable just because we don't
> > seem to know how to fix this.
> 
> The variable hasn't worked for 20 years (apparently), and this is the
> only bug report about it, which is perhaps a hint that we should just
> remove it.

I'm asking not to remove it yet.  Maybe one of these days I will find
time to work on this.  It bugs me (pun intended) that this veteran
feature stopped working on TTY frames.

bug#11430: 24.0.96; Customizing `inverse-video' has no effect on session

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> I'm asking not to remove it yet.  Maybe one of these days I will find
> time to work on this.  It bugs me (pun intended) that this veteran
> feature stopped working on TTY frames.

My point is that now -- 20 years after this stopped working -- we should
step back a bit and look at whether this functionality (which must at
this remove be seen to be a new feature) makes sense.

And I don't think it does much.  Setting a variable that makes the Emacs
display go inverse?  That's just kinda odd.

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