Strange text scrolling with Emacs + GTK

Strange text scrolling with Emacs + GTK

[Jérôme Marant]

Hi,

With a fresh CVS checkout, I noticed that text scrolling behaves a
weird way: when moving the scrollbar down, the text of the top line is
horizontaly scrolled from right to left before the line is moved up.

Cheers,

-- 
Jérôme Marant

Re: Strange text scrolling with Emacs + GTK

[Jan D.]

Jérôme Marant wrote:

>Hi,
>
>With a fresh CVS checkout, I noticed that text scrolling behaves a
>weird way: when moving the scrollbar down, the text of the top line is
>horizontaly scrolled from right to left before the line is moved up
>

This happens for me in all Emacs versions, (Lucid Xaw scrollbars, Lucid 
native scroll bars, GTK and Lesstif/Motif).  It must be a general 
redisplay problem.

To see it clearly I do:

% emacs -q --no-site-file
C-h t

Then carfully scroll down one line, the top line is shifted to the 
left.  A C-l fixes it.

    Jan D.

Re: Strange text scrolling with Emacs + GTK

[Jérôme Marant]

Quoting "Jan D." <jan.h.d@swipnet.se>:

> Jérôme Marant wrote:
>
> >Hi,
> >
> >With a fresh CVS checkout, I noticed that text scrolling behaves a
> >weird way: when moving the scrollbar down, the text of the top line is
> >horizontaly scrolled from right to left before the line is moved up
> >
>
> This happens for me in all Emacs versions, (Lucid Xaw scrollbars, Lucid
> native scroll bars, GTK and Lesstif/Motif).  It must be a general
> redisplay problem.
>
> To see it clearly I do:
>
> % emacs -q --no-site-file
> C-h t
>
> Then carfully scroll down one line, the top line is shifted to the
> left.  A C-l fixes it.

My current machine is quite slow so I didn't manage to rebuild it
against another toolkit. Thanks for your investigation.

Cheers,


--
Jérôme Marant

Re: Strange text scrolling with Emacs + GTK

[B. Anyos]

Hi,

Just for you inforamtion it happens with Windows version as well.
I use also the latest checkout.

Jérôme Marant said the following on 12/7/2004 15:42 PM:
> Quoting "Jan D." <jan.h.d@swipnet.se>:
> 
> 
>>Jérôme Marant wrote:
>>
>>
>>>Hi,
>>>
>>>With a fresh CVS checkout, I noticed that text scrolling behaves a
>>>weird way: when moving the scrollbar down, the text of the top line is
>>>horizontaly scrolled from right to left before the line is moved up
>>>
>>
>>This happens for me in all Emacs versions, (Lucid Xaw scrollbars, Lucid
>>native scroll bars, GTK and Lesstif/Motif).  It must be a general
>>redisplay problem.
>>
>>To see it clearly I do:
>>
>>% emacs -q --no-site-file
>>C-h t
>>
>>Then carfully scroll down one line, the top line is shifted to the
>>left.  A C-l fixes it.
> 
> 
> My current machine is quite slow so I didn't manage to rebuild it
> against another toolkit. Thanks for your investigation.
> 
> Cheers,
> 
> 
> --
> Jérôme Marant
> 
> 
> _______________________________________________
> Emacs-devel mailing list
> Emacs-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/emacs-devel
> 
> 

Re: Strange text scrolling with Emacs + GTK

[Kim F. Storm]

"Jan D." <jan.h.d@swipnet.se> writes:

> Jérôme Marant wrote:
>
>>Hi,
>>
>>With a fresh CVS checkout, I noticed that text scrolling behaves a
>>weird way: when moving the scrollbar down, the text of the top line is
>>horizontaly scrolled from right to left before the line is moved up
>>
>
> This happens for me in all Emacs versions, (Lucid Xaw scrollbars,
> Lucid native scroll bars, GTK and Lesstif/Motif).  It must be a
> general redisplay problem.
>
> To see it clearly I do:
>
> % emacs -q --no-site-file
> C-h t
>
> Then carfully scroll down one line, the top line is shifted to the
> left.  A C-l fixes it.

I don't see it -- 

what do you mean by "carefully scroll" ?

Scrolling typically jumps several lines, and clicking on the scroll
down arrow scrolls one line ok.

I'm using:

GNU Emacs 21.3.50.169 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars) of 2004-12-15

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk

Re: Strange text scrolling with Emacs + GTK

[B. Anyos]

With the current CVS snapshot I can't reproduce the problem,
however I was able to do that before (a week ago)
Just drag the scroll bar and carefully move it up & down
so it will scroll a couple lines only.

Examine the top line of the buffer.
Todays CVS works fine strangly.

Bela


Kim F. Storm said the following on 12/15/2004 13:50 PM:
> "Jan D." <jan.h.d@swipnet.se> writes:
> 
> 
>>Jérôme Marant wrote:
>>
>>
>>>Hi,
>>>
>>>With a fresh CVS checkout, I noticed that text scrolling behaves a
>>>weird way: when moving the scrollbar down, the text of the top line is
>>>horizontaly scrolled from right to left before the line is moved up
>>>
>>
>>This happens for me in all Emacs versions, (Lucid Xaw scrollbars,
>>Lucid native scroll bars, GTK and Lesstif/Motif).  It must be a
>>general redisplay problem.
>>
>>To see it clearly I do:
>>
>>% emacs -q --no-site-file
>>C-h t
>>
>>Then carfully scroll down one line, the top line is shifted to the
>>left.  A C-l fixes it.
> 
> 
> I don't see it -- 
> 
> what do you mean by "carefully scroll" ?
> 
> Scrolling typically jumps several lines, and clicking on the scroll
> down arrow scrolls one line ok.
> 
> I'm using:
> 
> GNU Emacs 21.3.50.169 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars) of 2004-12-15
> 

Re: Strange text scrolling with Emacs + GTK

[Sebastien Kirche]

Le 15 Dec 2004, Kim F. Storm a formulé :

> what do you mean by "carefully scroll" ?
> 
> Scrolling typically jumps several lines, and clicking on the scroll
> down arrow scrolls one line ok.
> 
> I'm using:
> 
> GNU Emacs 21.3.50.169 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars) of
> 2004-12-15

I have also noticed it.

One can see that weird first line  scroll by using scroll bars slowly, not to
scroll too  fast (i suppose  it is what  Jan calls carefull scroll)  but one
line at a time.

I  use currently  a  2004-11-12  checkout compiled  with  gtk toolkit.  I'll
checkout a fresh one tonight to see it is still there.

Sébastien Kirche

Re: Strange text scrolling with Emacs + GTK

[Jan D.]

>> what do you mean by "carefully scroll" ?
>>
>> Scrolling typically jumps several lines, and clicking on the scroll
>> down arrow scrolls one line ok.
>>
>> I'm using:
>>
>> GNU Emacs 21.3.50.169 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll 
>> bars) of
>> 2004-12-15
>
> I have also noticed it.
>
> One can see that weird first line  scroll by using scroll bars slowly, 
> not to
> scroll too  fast (i suppose  it is what  Jan calls carefull scroll)  
> but one
> line at a time.

Yes, that is it exactly.  Scroll as slow as you can by dragging the 
scroll bar.  When one line has scrolled out of view, the bug was 
visible.

>
> I  use currently  a  2004-11-12  checkout compiled  with  gtk toolkit. 
>  I'll
> checkout a fresh one tonight to see it is still there.


I'll recheck the other toolkits.

	Jan D.

Re: Strange text scrolling with Emacs + GTK

[Robert J. Chassell]

    >>With a fresh CVS checkout, I noticed that text scrolling behaves
    >>a weird way: when moving the scrollbar down, the text of the top
    >>line is horizontaly scrolled from right to left before the line
    >>is moved up ...

    I don't see it -- 

By clicking on the down arrow of its GTK scroll bar
(`scroll-bar-toolkit-scroll'), 
I was able to duplicate Marant's bug using a `bootfast' build from
last Sunday.

  GNU Emacs 21.3.50.25 (i686-pc-linux-gnu, GTK+ Version 2.4.13) of 2004-12-12
  started with
    emacs -q --no-site-file

I went from

    You are looking at the Emacs tutorial.  See end for copying conditions.
    Copyright (c) 1985, 1996, 1998, 2001, 2002 Free Software Foundation.
to:
    tutorial.  See end for copying conditions.
    Copyright (c) 1985, 1996, 1998, 2001, 2002 Free Software Foundation.

The cursor moved to the middle of the window; the text did not move
down at all.

However, I was not able to duplicate that result using a `bootfast'
build with today's CVS snapshot,
Wed, 2004 Dec 15 13:36 UTC GNU Emacs 21.3.50.27
(i686-pc-linux-gnu, GTK+ Version 2.4.13), 

Instead, I exercised a different bug:  the second click on the scroll
bar down arrow did nothing ... nor did the sixth.

Hmm ... I just reproduced the first bug in this *mail* buffer in which
I am composing this message.  This is my regular Emacs, based on the
build of 2004-12-12, which evaluates a .emacs file that is over 200
kilobytes.  Since I never click on a scroll bar arrow, I have never
seen the bug before.

-- 
    Robert J. Chassell                         
    bob@rattlesnake.com                         GnuPG Key ID: 004B4AC8
    http://www.rattlesnake.com                  http://www.teak.cc

Re: Strange text scrolling with Emacs + GTK

[Jan D.]

>
>
>>
>> I  use currently  a  2004-11-12  checkout compiled  with  gtk 
>> toolkit.  I'll
>> checkout a fresh one tonight to see it is still there.
>
>
>
> I'll recheck the other toolkits. 


I can not reproduce the bug with any Emacs build from a current CVS 
checkout.

    Jan D.

Re: Strange text scrolling with Emacs + GTK

[Jan D.]

Robert J. Chassell wrote:

>Instead, I exercised a different bug:  the second click on the scroll
>bar down arrow did nothing ... nor did the sixth.
>
>Hmm ... I just reproduced the first bug in this *mail* buffer in which
>I am composing this message.  This is my regular Emacs, based on the
>build of 2004-12-12, which evaluates a .emacs file that is over 200
>kilobytes.  Since I never click on a scroll bar arrow, I have never
>seen the bug before.
>  
>

It is strange that nobody has seen it, AFAIK it has been there ever 
since GTK scroll bars where introduced.  I've checked in a fix.

Thanks,

    Jan D.

Changelogs entries [Re: Strange text scrolling with Emacs + GTK]

[Jérôme Marant]

Quoting "Jan D." <jan.h.d@swipnet.se>:

> >
> >
> >>
> >> I  use currently  a  2004-11-12  checkout compiled  with  gtk
> >> toolkit.  I'll
> >> checkout a fresh one tonight to see it is still there.
> >
> >
> >
> > I'll recheck the other toolkits.
>
>
> I can not reproduce the bug with any Emacs build from a current CVS
> checkout.

If so, it must have been silently fixed recently.

The problem with the way changelogs entries are written is that they
never mention the bug they fix; comments like "New variable", "new
function", "use it" and so on are just not enough for anyone to
understand the fix.
I think this is quite annoying from an external sight since people
have to guess with respect to their knowledge of Emacs source files.
(especially when you have to backport fixes).

Cheers,

--
Jérôme Marant

Re: Changelogs entries [Re: Strange text scrolling with Emacs + GTK]

[Kim F. Storm]

Jérôme Marant <jmarant@free.fr> writes:

> Quoting "Jan D." <jan.h.d@swipnet.se>:
>
>> >
>> >
>> >>
>> >> I  use currently  a  2004-11-12  checkout compiled  with  gtk
>> >> toolkit.  I'll
>> >> checkout a fresh one tonight to see it is still there.
>> >
>> >
>> >
>> > I'll recheck the other toolkits.
>>
>>
>> I can not reproduce the bug with any Emacs build from a current CVS
>> checkout.
>
> If so, it must have been silently fixed recently.
>
> The problem with the way changelogs entries are written is that they
> never mention the bug they fix; comments like "New variable", "new
> function", "use it" and so on are just not enough for anyone to
> understand the fix.
>
I fully agree -- and a proper bug tracking system would be nice too.

But this is why I always (intend to) post a following saying that I
have fixed a bug.

Others don't do that, and it wastes time whenever someone starts
looking at a bug that someone else already fixed, but didn't tell us.

> I think this is quite annoying from an external sight since people
> have to guess with respect to their knowledge of Emacs source files.
> (especially when you have to backport fixes).

True.

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk

Re: Strange text scrolling with Emacs + GTK

[YAMAMOTO Mitsuharu]

>>>>> On Wed, 15 Dec 2004 22:44:30 +0100, "Jan D." <jan.h.d@swipnet.se> said:

> I can not reproduce the bug with any Emacs build from a current CVS
> checkout.

I could reproduce the problem with the latest CVS.

  % emacs -Q
  M-x info RET
  M->
  C-l
  C-x ( C-u - 1 C-v C-x )
  C-x e e e e ...

I see the problem around "CC mode" and "Forms".

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

Re: Strange text scrolling with Emacs + GTK

[Kim F. Storm]

YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> writes:

>>>>>> On Wed, 15 Dec 2004 22:44:30 +0100, "Jan D." <jan.h.d@swipnet.se> said:
>
>> I can not reproduce the bug with any Emacs build from a current CVS
>> checkout.
>
> I could reproduce the problem with the latest CVS.
>
>   % emacs -Q
>   M-x info RET
>   M->
>   C-l
>   C-x ( C-u - 1 C-v C-x )
>   C-x e e e e ...
>
> I see the problem around "CC mode" and "Forms".

Ok, I see it.

It is not specific for the first line of a buffer.

Rather it happens for lines which are indented but the
indentation is controlled by a display property and
the newline is part of that display property -- in
that case, the indentation is not recognized for the
first display line.

So it is not a problem with scrolling or the scroll bar 
as such.

I don't have time to look at this right now, but
I have added it to FOR-RELEASE to look at before release.

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk

Re: Changelogs entries [Re: Strange text scrolling with Emacs + GTK]

[Richard Stallman]

Some people have been moving to a practice of somehow referencing bug
reports in ChangeLog entries.  I think it is a good idea to do this.