Recentering on scroll

Recentering on scroll

[Chong Yidong]

Can anyone reproduce bug#873 (occasional recentering during C-n)?  I
thought I could reproduce it at some point, using the recipe given in
that bug report, but I can't seem to do it now.

> After setting this in .emacs:
>
> (setq scroll-preserve-screen-position 'always
>       scroll-conservatively           most-positive-fixnum ;; any large number
>       scroll-step                     0)
>
> scroll-down causes recentering. This is a regression.

Re: Recentering on scroll

[Juanma Barranquero]

On Sat, Oct 25, 2008 at 19:03, Chong Yidong <cyd@stupidchicken.com> wrote:

> Can anyone reproduce bug#873 (occasional recentering during C-n)?  I

I can still reproduce it on Windows, though the effect's frequency
varies with frame size and font (it seems to happen more often with
DejaVu Sans Mono than Courier New, for example).

  Juanma

Re: Recentering on scroll

[Chong Yidong]

"Juanma Barranquero" <lekktu@gmail.com> writes:

> On Sat, Oct 25, 2008 at 19:03, Chong Yidong <cyd@stupidchicken.com> wrote:
>
>> Can anyone reproduce bug#873 (occasional recentering during C-n)?  I
>
> I can still reproduce it on Windows, though the effect's frequency
> varies with frame size and font (it seems to happen more often with
> DejaVu Sans Mono than Courier New, for example).

I managed to reproduce it, and found the bug that (I think) was causing
this problem.  I've checked in a fix.

bug#873: Annoying recentering when scrolling down

[Juanma Barranquero]

Package: emacs
Version: 23.0.60
Severity: normal

After setting this in .emacs:

(setq scroll-preserve-screen-position 'always
      scroll-conservatively           most-positive-fixnum ;; any large number
      scroll-step                     0)

scroll-down causes recentering. This is a regression.

The bug was apparently introduced by the following change:

2008-08-06  Chong Yidong  <address@hidden>

        * xdisp.c (try_scrolling): Use iterator to find the scroll margin,
        instead of window-end which does the wrong thing at eob.
        (try_cursor_movement): Minor optimization.
        (redisplay_window): If scroll margin is defined, don't assume
        window doesn't need scrolling.


emacs-devel discussion:

http://lists.gnu.org/archive/html/emacs-devel/2008-08/msg00903.html

bug#873: marked as done (Annoying recentering when scrolling down)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 820 bytes --]


Your message dated Mon, 27 Oct 2008 01:19:00 -0400
with message-id <87d4hm4nuj.fsf@cyd.mit.edu>
and subject line Re: Recentering on scroll
has caused the Emacs bug report #873,
regarding Annoying recentering when scrolling down
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact don@donarmstrong.com
immediately.)


-- 
873: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=873
Emacs Bug Tracking System
Contact don@donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 3006 bytes --]

From: "Juanma Barranquero" <lekktu@gmail.com>
To: "Emacs Bug Tracker" <submit@emacsbugs.donarmstrong.com>
Subject: Annoying recentering when scrolling down
Date: Wed, 3 Sep 2008 18:15:14 +0200
Message-ID: <f7ccd24b0809030915w1a667fc9k6ce0d656c29b1257@mail.gmail.com>

Package: emacs
Version: 23.0.60
Severity: normal

After setting this in .emacs:

(setq scroll-preserve-screen-position 'always
      scroll-conservatively           most-positive-fixnum ;; any large number
      scroll-step                     0)

scroll-down causes recentering. This is a regression.

The bug was apparently introduced by the following change:

2008-08-06  Chong Yidong  <address@hidden>

        * xdisp.c (try_scrolling): Use iterator to find the scroll margin,
        instead of window-end which does the wrong thing at eob.
        (try_cursor_movement): Minor optimization.
        (redisplay_window): If scroll margin is defined, don't assume
        window doesn't need scrolling.


emacs-devel discussion:

http://lists.gnu.org/archive/html/emacs-devel/2008-08/msg00903.html



[-- Attachment #3: Type: message/rfc822, Size: 1769 bytes --]

From: Chong Yidong <cyd@stupidchicken.com>
To: "Juanma Barranquero" <lekktu@gmail.com>
Cc: emacs-devel@gnu.org, 873-done@emacsbugs.donarmstrong.com
Subject: Re: Recentering on scroll
Date: Mon, 27 Oct 2008 01:19:00 -0400
Message-ID: <87d4hm4nuj.fsf@cyd.mit.edu>

"Juanma Barranquero" <lekktu@gmail.com> writes:

> On Sat, Oct 25, 2008 at 19:03, Chong Yidong <cyd@stupidchicken.com> wrote:
>
>> Can anyone reproduce bug#873 (occasional recentering during C-n)?  I
>
> I can still reproduce it on Windows, though the effect's frequency
> varies with frame size and font (it seems to happen more often with
> DejaVu Sans Mono than Courier New, for example).

I managed to reproduce it, and found the bug that (I think) was causing
this problem.  I've checked in a fix.

bug#873: marked as done (Annoying recentering when scrolling down)

[Emacs bug Tracking System]

[-- Attachment #1: Type: text/plain, Size: 828 bytes --]


Your message dated Thu, 20 Nov 2008 10:25:03 +0100
with message-id <f7ccd24b0811200125g54fb5812wc3f67e5de87ec345@mail.gmail.com>
and subject line 
has caused the Emacs bug report #873,
regarding Annoying recentering when scrolling down
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact don@donarmstrong.com
immediately.)


-- 
873: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=873
Emacs Bug Tracking System
Contact don@donarmstrong.com with problems

[-- Attachment #2: Type: message/rfc822, Size: 3006 bytes --]

From: "Juanma Barranquero" <lekktu@gmail.com>
To: "Emacs Bug Tracker" <submit@emacsbugs.donarmstrong.com>
Subject: Annoying recentering when scrolling down
Date: Wed, 3 Sep 2008 18:15:14 +0200
Message-ID: <f7ccd24b0809030915w1a667fc9k6ce0d656c29b1257@mail.gmail.com>

Package: emacs
Version: 23.0.60
Severity: normal

After setting this in .emacs:

(setq scroll-preserve-screen-position 'always
      scroll-conservatively           most-positive-fixnum ;; any large number
      scroll-step                     0)

scroll-down causes recentering. This is a regression.

The bug was apparently introduced by the following change:

2008-08-06  Chong Yidong  <address@hidden>

        * xdisp.c (try_scrolling): Use iterator to find the scroll margin,
        instead of window-end which does the wrong thing at eob.
        (try_cursor_movement): Minor optimization.
        (redisplay_window): If scroll margin is defined, don't assume
        window doesn't need scrolling.


emacs-devel discussion:

http://lists.gnu.org/archive/html/emacs-devel/2008-08/msg00903.html



[-- Attachment #3: Type: message/rfc822, Size: 2534 bytes --]

From: "Juanma Barranquero" <lekktu@gmail.com>
To: 873-done@emacsbugs.donarmstrong.com
Subject: 
Date: Thu, 20 Nov 2008 10:25:03 +0100
Message-ID: <f7ccd24b0811200125g54fb5812wc3f67e5de87ec345@mail.gmail.com>

Fixed by Chong Yidong with this change:


2008-10-27  Chong Yidong  <cyd@stupidchicken.com>

        * xdisp.c (try_scrolling): When computing the distance from the
        scroll margin to PT, try moving some distance past the window
        bottom before giving up.


http://cvs.savannah.gnu.org/viewvc/emacs/emacs/src/xdisp.c?r1=1.1268&r2=1.1269&pathrev=MAIN

Re: Recentering on scroll

[Chong Yidong]

Chong Yidong <cyd@stupidchicken.com> writes:

> I managed to reproduce it, and found the bug that (I think) was causing
> this problem.  I've checked in a fix.

Actually, the fix caused a few problems; I've reverted it for now, and
will check in a new version in a couple of hours.

Re: Recentering on scroll

[Juanma Barranquero]

On Mon, Oct 27, 2008 at 06:33, Chong Yidong <cyd@stupidchicken.com> wrote:

> Actually, the fix caused a few problems; I've reverted it for now, and
> will check in a new version in a couple of hours.

With your most recent patch the unwanted recentering does not happen. Thanks.

Line-by-line scroll is quite jumpy, though, as compared to next-line
in Emacs 22.X, or even to previous-line in the current trunk.

  Juanma

bug#873: Recentering on scroll

[Juanma Barranquero]

On Mon, Oct 27, 2008 at 06:33, Chong Yidong <cyd@stupidchicken.com> wrote:

> Actually, the fix caused a few problems; I've reverted it for now, and
> will check in a new version in a couple of hours.

With your most recent patch the unwanted recentering does not happen. Thanks.

Line-by-line scroll is quite jumpy, though, as compared to next-line
in Emacs 22.X, or even to previous-line in the current trunk.

  Juanma

bug#873: Recentering on scroll

[Juanma Barranquero]

On Sat, Oct 25, 2008 at 19:03, Chong Yidong <cyd@stupidchicken.com> wrote:

> Can anyone reproduce bug#873 (occasional recentering during C-n)?  I

I can still reproduce it on Windows, though the effect's frequency
varies with frame size and font (it seems to happen more often with
DejaVu Sans Mono than Courier New, for example).

  Juanma

bug#873: Recentering on scroll

[Chong Yidong]

Can anyone reproduce bug#873 (occasional recentering during C-n)?  I
thought I could reproduce it at some point, using the recipe given in
that bug report, but I can't seem to do it now.

> After setting this in .emacs:
>
> (setq scroll-preserve-screen-position 'always
>       scroll-conservatively           most-positive-fixnum ;; any large number
>       scroll-step                     0)
>
> scroll-down causes recentering. This is a regression.