Subject: bug#53275: closed (Re: bug#53275: 29.0.50; Cursor shows up at the middle of the screen after window start is forced when vscroll is set)

From: [email-masked] (GNU bug Tracking System)
Date: Sun, 16 Jan 2022 00:31:02 +0000

Your bug report

#53275: 29.0.50; Cursor shows up at the middle of the screen after window start is forced when vscroll is set

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
53275: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=53275
GNU Bug Tracking System
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Subject: Re: bug#53275: 29.0.50; Cursor shows up at the middle of the screen after window start is forced when vscroll is set
From: Po Lu <[email-masked]>
To: Eli Zaretskii <[email-masked]>
Cc: [email-masked]
Date: Sun, 16 Jan 2022 08:30:28 +0800
List-Id: <debbugs-submit.debbugs.gnu.org>

Eli Zaretskii <[email-masked]> writes:

>> From: Po Lu <[email-masked]>
>> Cc: [email-masked]
>> Date: Sat, 15 Jan 2022 15:52:50 +0800
>> 
>> Eli Zaretskii <[email-masked]> writes:
>> 
>> >>   (progn
>> >>     (set-window-vscroll nil 30 t)
>> >>     (redisplay)
>> >>     (set-window-start nil (point-max)))
>> 
>> > Sorry, I missed the "M-<" part.  With it, the behavior is
>> > reproducible, but I'm not sure I understand what is "the correct
>> > position" of the cursor in this case
>> 
>> It should show up where point is, which in this case is at the window
>> start.
>> 
>> > or why does it matter what Emacs does in that case (except that it
>> > should not crash).
>> 
>> Precision scrolling relies on this: when the buffer cannot be scrolled
>> downwards sufficiently, it sets the window start to point-max and
>> redisplays, which right now results in the cursor being displayed in the
>> middle of the screen until the next redisplay.
>
> Should be fixed now on the master branch.

Indeed, I'm closing this bug.  Many thanks!

Subject: 29.0.50; Cursor shows up at the middle of the screen after window start is forced when vscroll is set
From: Po Lu <[email-masked]>
To: [email-masked]
Date: Sat, 15 Jan 2022 11:56:23 +0800
List-Id: <debbugs-submit.debbugs.gnu.org>

Starting from 'emacs -Q', press M-< in the scratch buffer, then say M-:
and evaluate:

  (progn
    (set-window-vscroll nil 30 t)
    (redisplay)
    (set-window-start nil (point-max)))

The cursor will then display in the center of the screen, which is not
the correct position.

Thanks.

In GNU Emacs 29.0.50 (build 353, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.17.4)
 of 2022-01-15 built on trinity
Repository revision: 1f5f3b7e8955154c28342e63ba1216f83ff6d73d
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Fedora Linux 35 (Workstation Edition)

Configured using:
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RSVG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11
XDBE XIM XINPUT2 XPM XWIDGETS GTK3 ZLIB

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Load-path shadows:
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Memory information:
((conses 16 50551 13063)
 (symbols 48 6108 1)
 (strings 32 19557 2143)
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