Display fill column indicator issue.

Display fill column indicator issue.

[Ergus]

Hi Eli:

I have observed that recently the column indicator changed its behavior
(maybe it did some time ago but I haven't noticed).

When scrolling horizontally the indicator line is supposed to scroll too
with the text; but right now it is always in the same "screen" column.

The issue is only on terminal because in gui the line moves
correctly. So the problem should be in xdisp.c:22390 because it should
substract the horizontal offset of the current starting column (maybe
it->first_visible_x or similar).

Could you push this fix please? I have to recover my Savannah private
keys and I don't have time now.

Thanks in advance,
Ergus

[PATCH] Display fill column indicator issue.

[Ergus]

[-- Attachment #1: Type: text/plain, Size: 776 bytes --]

Hi Eli:

Could you check and apply this fix?

Best,
Ergus

On Wed, Jun 02, 2021 at 12:24:23PM +0200, Ergus wrote:
>Hi Eli:
>
>I have observed that recently the column indicator changed its behavior
>(maybe it did some time ago but I haven't noticed).
>
>When scrolling horizontally the indicator line is supposed to scroll too
>with the text; but right now it is always in the same "screen" column.
>
>The issue is only on terminal because in gui the line moves
>correctly. So the problem should be in xdisp.c:22390 because it should
>substract the horizontal offset of the current starting column (maybe
>it->first_visible_x or similar).
>
>Could you push this fix please? I have to recover my Savannah private
>keys and I don't have time now.
>
>Thanks in advance,
>Ergus
>

[-- Attachment #2: fix_dfci.patch --]
[-- Type: text/plain, Size: 587 bytes --]

diff --git a/src/xdisp.c b/src/xdisp.c
index 0a95aa32f9..68bcbbe5d1 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -22387,7 +22387,8 @@ extend_face_to_end_of_line (struct it *it)
                      default_face->id : face->id);
 
       /* Display fill-column indicator if needed.  */
-      const int indicator_column = fill_column_indicator_column (it, 1);
+      const int indicator_column =
+	fill_column_indicator_column (it, 1) - it->first_visible_x;
 
       /* Make sure our idea of current_x is in sync with the glyphs
 	 actually in the glyph row.  They might differ because

Re: [PATCH] Display fill column indicator issue.

[Eli Zaretskii]

> Date: Thu, 3 Jun 2021 09:28:17 +0200
> From: Ergus <spacibba@aol.com>
> Cc: emacs-devel@gnu.org
> 
> Could you check and apply this fix?

I've seen your original message.  The issue is on my TODO.

I'm surprised that this correction is needed, let alone on TTY only,
because AFAIR it->current_x already takes horizontal scrolling into
account.  But I may be misremembering something.  I will investigate.

Thanks.

Re: [PATCH] Display fill column indicator issue.

[Eli Zaretskii]

> Date: Thu, 03 Jun 2021 11:07:38 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> > Date: Thu, 3 Jun 2021 09:28:17 +0200
> > From: Ergus <spacibba@aol.com>
> > Cc: emacs-devel@gnu.org
> > 
> > Could you check and apply this fix?
> 
> I've seen your original message.  The issue is on my TODO.

Now done.

AFAICT, this never worked correctly on TTY frames.

Re: [PATCH] Display fill column indicator issue.

[Ergus]

On Thu, Jun 03, 2021 at 05:46:50PM +0300, Eli Zaretskii wrote:
>> Date: Thu, 03 Jun 2021 11:07:38 +0300
>> From: Eli Zaretskii <eliz@gnu.org>
>> Cc: emacs-devel@gnu.org
>>
>> > Date: Thu, 3 Jun 2021 09:28:17 +0200
>> > From: Ergus <spacibba@aol.com>
>> > Cc: emacs-devel@gnu.org
>> >
>> > Could you check and apply this fix?
>>
>> I've seen your original message.  The issue is on my TODO.
>
>Now done.
>
>AFAICT, this never worked correctly on TTY frames.

Hi Eli:

If I have time I will try to bisect this, but it worked fine some time
(not very long) ago.

I know it because I only use tty and need this feature very often; and I
know I have check my lines length with it more than once. Specially when
using my laptop that has a small screen.

Any way, very thanks,
Ergus

Re: [PATCH] Display fill column indicator issue.

[Eli Zaretskii]

> Date: Fri, 4 Jun 2021 12:38:46 +0200
> From: Ergus <spacibba@aol.com>
> Cc: emacs-devel@gnu.org
> 
> >AFAICT, this never worked correctly on TTY frames.
> 
> Hi Eli:
> 
> If I have time I will try to bisect this, but it worked fine some time
> (not very long) ago.
> 
> I know it because I only use tty and need this feature very often; and I
> know I have check my lines length with it more than once. Specially when
> using my laptop that has a small screen.

All I know is that the same problem exists in Emacs 27.2, at least in
"emacs -Q -nw".  So if this is a regression, it is a very old one.