* bug#3512: Interaction between scroll variables, scroll-up, scroll-down, and redisplay.
@ 2009-06-09 11:47 ` Paul Whittaker
2009-06-18 19:50 ` bug#3512: marked as done (Interaction between scroll variables, scroll-up, scroll-down, and redisplay.) Emacs bug Tracking System
0 siblings, 1 reply; 2+ messages in thread
From: Paul Whittaker @ 2009-06-09 11:47 UTC (permalink / raw
To: bug-gnu-emacs
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There appears to be a bug under the following conditions:
- Emacs is running in graphical (X11) mode, without the -nw flag;
- scroll-margin is set to a value greater than 0;
- scroll-preserve-screen-position is set to a non-nil, non-t value;
- Point is at or near the start of the buffer (any line <= scroll-margin);
- An attempt is made to scroll the window using scroll-up;
which leads to:
- Window contents are not updated correctly.
Less tersely, I have experienced the following sequence of events, on
both Ubuntu 8.10 and Fedora 10 systems.
- Start emacs with -Q option to launch a fresh Emacs window on the
desktop. Set the variables scroll-margin to (say) 5, and
scroll-preserve-screen-position to 1. (Setting the latter to
'always also works.)
- Populate the buffer with many lines of input. I normally use the
output of "ls -R /" and use head to keep only the first couple of
hundred lines of it. The exact nature of the content appears not
to be important, as I have also loaded in files, or used M-:
(dolist ..... (insert ....)) to populate the buffer.
- Ensure that point is at the start of the buffer.
- Attempt to view text that is currently off the bottom of the window
by pressing Page Down once or more to run the scroll-up command.
- At this point, the cursor moves to roughly the middle of the
window, the (GTK) scroll bar moves downwards, but the window
contents remain the same (i.e. the same text is visible as was
before pressing Page Down).
- Further presses of Page Down do not move point visibly, do not
update the visisble window contents, but *do* move the GTK scroll
bar. This makes me believe that (internally) everything is working
correctly, but the normal text update routines are not being
called.
- Using scroll-down (i.e. pressing Page Up) maintains this behaviour:
the scroll bar moves back in the opposite direction, but the window
contents are not updated. The scroll bar can be moved back and
forth at will using sequences of scroll-up and scroll-down commands
in this manner.
- Getting point close to either end of the buffer, or using any other
command (such as next-line), causes the window contents to be
updated correctly. This can lead to a significant apparent jump in
the position of point. The location displayed appears to be
consistent with the number of times that the scroll-down and
scroll-up commands were used.
- If the point is moved back to the start of the buffer, e.g. with
M-<, this behaviour can be repeated as often as desired.
- Running Emacs with the -nw flag (i.e. running inside an XTerm) does
not exhibit this behaviour for me.
If you need any more details, please let me know.
Best regards, and happy hunting,
Paul.
PS The Emacs I'm running this on does not have mail set up, so I have
cut and pasted the content into my webmail session. If for some
reason this has caused a problem, again, let me know.
[Content generated automatically by M-x report-emacs-bug follows:]
In GNU Emacs 22.2.1 (i486-pc-linux-gnu, GTK+ Version 2.14.1)
of 2008-09-05 on vernadsky, modified by Ubuntu
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
configured using `configure '--build=i486-linux-gnu'
'--host=i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib'
'--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info'
'--mandir=/usr/share/man' '--with-pop=yes'
'--enable-locallisppath=/etc/emacs22:/etc/emacs:/usr/local/share/emacs/22.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/22.2/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/22.2/leim'
'--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=i486-linux-gnu'
'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000
-g -O2' 'LDFLAGS=-g -Wl,--as-needed' 'CPPFLAGS=''
Important settings:
value of $LC_ALL: nil
value of $LC_COLLATE: nil
value of $LC_CTYPE: nil
value of $LC_MESSAGES: nil
value of $LC_MONETARY: nil
value of $LC_NUMERIC: nil
value of $LC_TIME: nil
value of $LANG: en_GB.UTF-8
locale-coding-system: utf-8
default-enable-multibyte-characters: t
Major mode: Lisp Interaction
Minor modes in effect:
tooltip-mode: t
tool-bar-mode: t
mouse-wheel-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
unify-8859-on-encoding-mode: t
utf-translate-cjk-mode: t
auto-compression-mode: t
line-number-mode: t
Recent input:
M-x s e t - v a r i a b l e <return> s c r o l l -
m a r g i n <return> 5 <return> M-x s e t - v a r i
a b l e <return> s c r o l l - p r e s e r v e - s
c r e e n - p o s i t i o n <return> 1 <return> C-u
M-! l s SPC - R SPC / SPC | S-SPC h e a d SPC - 2 0
0 <return> <next> <next> <next> M-x r e p o r t - e
m a c s - b u g <return>
Recent messages:
("emacs" "-Q")
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading help-fns...done
Loading easymenu...done
Loading pp...done
Loading emacsbug...
Loading regexp-opt...done
Loading emacsbug...done
[End of automatically-generated content.]
[-- Attachment #2: Type: text/html, Size: 5966 bytes --]
^ permalink raw reply [flat|nested] 2+ messages in thread
* bug#3512: marked as done (Interaction between scroll variables, scroll-up, scroll-down, and redisplay.)
2009-06-09 11:47 ` bug#3512: Interaction between scroll variables, scroll-up, scroll-down, and redisplay Paul Whittaker
@ 2009-06-18 19:50 ` Emacs bug Tracking System
0 siblings, 0 replies; 2+ messages in thread
From: Emacs bug Tracking System @ 2009-06-18 19:50 UTC (permalink / raw
To: Glenn Morris
[-- Attachment #1: Type: text/plain, Size: 956 bytes --]
Your message dated Thu, 18 Jun 2009 15:43:39 -0400
with message-id <l87hz9wcno.fsf@fencepost.gnu.org>
and subject line Re: Bug#3512: Interaction between scroll variables, scroll-up, scroll-down, and redisplay.
has caused the Emacs bug report #3512,
regarding Interaction between scroll variables, scroll-up, scroll-down, and redisplay.
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 owner@emacsbugs.donarmstrong.com
immediately.)
--
3512: http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=3512
Emacs Bug Tracking System
Contact owner@emacsbugs.donarmstrong.com with problems
[-- Attachment #2: Type: message/rfc822, Size: 14948 bytes --]
[-- Attachment #2.1.1: Type: text/plain, Size: 5168 bytes --]
There appears to be a bug under the following conditions:
- Emacs is running in graphical (X11) mode, without the -nw flag;
- scroll-margin is set to a value greater than 0;
- scroll-preserve-screen-position is set to a non-nil, non-t value;
- Point is at or near the start of the buffer (any line <= scroll-margin);
- An attempt is made to scroll the window using scroll-up;
which leads to:
- Window contents are not updated correctly.
Less tersely, I have experienced the following sequence of events, on
both Ubuntu 8.10 and Fedora 10 systems.
- Start emacs with -Q option to launch a fresh Emacs window on the
desktop. Set the variables scroll-margin to (say) 5, and
scroll-preserve-screen-position to 1. (Setting the latter to
'always also works.)
- Populate the buffer with many lines of input. I normally use the
output of "ls -R /" and use head to keep only the first couple of
hundred lines of it. The exact nature of the content appears not
to be important, as I have also loaded in files, or used M-:
(dolist ..... (insert ....)) to populate the buffer.
- Ensure that point is at the start of the buffer.
- Attempt to view text that is currently off the bottom of the window
by pressing Page Down once or more to run the scroll-up command.
- At this point, the cursor moves to roughly the middle of the
window, the (GTK) scroll bar moves downwards, but the window
contents remain the same (i.e. the same text is visible as was
before pressing Page Down).
- Further presses of Page Down do not move point visibly, do not
update the visisble window contents, but *do* move the GTK scroll
bar. This makes me believe that (internally) everything is working
correctly, but the normal text update routines are not being
called.
- Using scroll-down (i.e. pressing Page Up) maintains this behaviour:
the scroll bar moves back in the opposite direction, but the window
contents are not updated. The scroll bar can be moved back and
forth at will using sequences of scroll-up and scroll-down commands
in this manner.
- Getting point close to either end of the buffer, or using any other
command (such as next-line), causes the window contents to be
updated correctly. This can lead to a significant apparent jump in
the position of point. The location displayed appears to be
consistent with the number of times that the scroll-down and
scroll-up commands were used.
- If the point is moved back to the start of the buffer, e.g. with
M-<, this behaviour can be repeated as often as desired.
- Running Emacs with the -nw flag (i.e. running inside an XTerm) does
not exhibit this behaviour for me.
If you need any more details, please let me know.
Best regards, and happy hunting,
Paul.
PS The Emacs I'm running this on does not have mail set up, so I have
cut and pasted the content into my webmail session. If for some
reason this has caused a problem, again, let me know.
[Content generated automatically by M-x report-emacs-bug follows:]
In GNU Emacs 22.2.1 (i486-pc-linux-gnu, GTK+ Version 2.14.1)
of 2008-09-05 on vernadsky, modified by Ubuntu
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
configured using `configure '--build=i486-linux-gnu'
'--host=i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib'
'--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info'
'--mandir=/usr/share/man' '--with-pop=yes'
'--enable-locallisppath=/etc/emacs22:/etc/emacs:/usr/local/share/emacs/22.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/22.2/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/22.2/leim'
'--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=i486-linux-gnu'
'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000
-g -O2' 'LDFLAGS=-g -Wl,--as-needed' 'CPPFLAGS=''
Important settings:
value of $LC_ALL: nil
value of $LC_COLLATE: nil
value of $LC_CTYPE: nil
value of $LC_MESSAGES: nil
value of $LC_MONETARY: nil
value of $LC_NUMERIC: nil
value of $LC_TIME: nil
value of $LANG: en_GB.UTF-8
locale-coding-system: utf-8
default-enable-multibyte-characters: t
Major mode: Lisp Interaction
Minor modes in effect:
tooltip-mode: t
tool-bar-mode: t
mouse-wheel-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
unify-8859-on-encoding-mode: t
utf-translate-cjk-mode: t
auto-compression-mode: t
line-number-mode: t
Recent input:
M-x s e t - v a r i a b l e <return> s c r o l l -
m a r g i n <return> 5 <return> M-x s e t - v a r i
a b l e <return> s c r o l l - p r e s e r v e - s
c r e e n - p o s i t i o n <return> 1 <return> C-u
M-! l s SPC - R SPC / SPC | S-SPC h e a d SPC - 2 0
0 <return> <next> <next> <next> M-x r e p o r t - e
m a c s - b u g <return>
Recent messages:
("emacs" "-Q")
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading help-fns...done
Loading easymenu...done
Loading pp...done
Loading emacsbug...
Loading regexp-opt...done
Loading emacsbug...done
[End of automatically-generated content.]
[-- Attachment #2.1.2: Type: text/html, Size: 5966 bytes --]
[-- Attachment #3: Type: message/rfc822, Size: 1738 bytes --]
From: Glenn Morris <rgm+emacsbugs@gnu.org>
To: 3512-done@emacsbugs.donarmstrong.com
Subject: Re: Bug#3512: Interaction between scroll variables, scroll-up, scroll-down, and redisplay.
Date: Thu, 18 Jun 2009 15:43:39 -0400
Message-ID: <l87hz9wcno.fsf@fencepost.gnu.org>
Thanks for the report. Whilst I see what you describe in Emacs 22.2, I
do not see it in 22.3 or the current CVS. So it looks like this is
already fixed. Please let us know if you still see a problem in 22.3.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2009-06-18 19:50 UTC | newest]
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2009-06-09 11:47 ` bug#3512: Interaction between scroll variables, scroll-up, scroll-down, and redisplay Paul Whittaker
2009-06-18 19:50 ` bug#3512: marked as done (Interaction between scroll variables, scroll-up, scroll-down, and redisplay.) Emacs bug Tracking System
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