Scrolling up at the end of buffer

Scrolling up at the end of buffer

[Evgeny Zajcev]

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I've got nasty unexpected thing.  Consider scenario in "emacs -q":
1) Open file that does not fit into Emacs window (C-x C-f /etc/services RET)
2) Goto bottom with M->
3) Show maximum content with C- - C-l (-1 arg to C-l)
4) At this moment point is at the `eobp`, nothing to be shown below the
point, now press C-v

I was expecting C-v to signal "End of buffer" error, however got ugly
scrolling resulting in showing a single line at the top.

Second C-v triggers "End of buffer"

If I recenter with -2 argument to C-l, then C-v triggers "End of buffer" as
expected.

Is there something in Emacs I can set to stop behaving like this?

Thanks

-- 
lg

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Re: Scrolling up at the end of buffer

[Eli Zaretskii]

> From: Evgeny Zajcev <lg.zevlg@gmail.com>
> Date: Fri, 4 Dec 2020 14:57:23 +0300
> 
> I've got nasty unexpected thing.  Consider scenario in "emacs -q":
> 1) Open file that does not fit into Emacs window (C-x C-f /etc/services RET)
> 2) Goto bottom with M->
> 3) Show maximum content with C- - C-l (-1 arg to C-l)
> 4) At this moment point is at the `eobp`, nothing to be shown below the point, now press C-v
> 
> I was expecting C-v to signal "End of buffer" error, however got ugly scrolling resulting in showing a single
> line at the top.
> 
> Second C-v triggers "End of buffer"
> 
> If I recenter with -2 argument to C-l, then C-v triggers "End of buffer" as expected.
> 
> Is there something in Emacs I can set to stop behaving like this?

Set next-screen-context-lines to 1 or less?

(FWIW, I don't see this behavior as unexpected or "nasty".)

Re: Scrolling up at the end of buffer

[Evgeny Zajcev]

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пт, 4 дек. 2020 г. в 15:25, Eli Zaretskii <eliz@gnu.org>:

> > From: Evgeny Zajcev <lg.zevlg@gmail.com>
> > Date: Fri, 4 Dec 2020 14:57:23 +0300
> >
> > I've got nasty unexpected thing.  Consider scenario in "emacs -q":
> > 1) Open file that does not fit into Emacs window (C-x C-f /etc/services
> RET)
> > 2) Goto bottom with M->
> > 3) Show maximum content with C- - C-l (-1 arg to C-l)
> > 4) At this moment point is at the `eobp`, nothing to be shown below the
> point, now press C-v
> >
> > I was expecting C-v to signal "End of buffer" error, however got ugly
> scrolling resulting in showing a single
> > line at the top.
> >
> > Second C-v triggers "End of buffer"
> >
> > If I recenter with -2 argument to C-l, then C-v triggers "End of buffer"
> as expected.
> >
> > Is there something in Emacs I can set to stop behaving like this?
>
> Set next-screen-context-lines to 1 or less?
>
>
Thanks! setting it to 0 does what I want

(FWIW, I don't see this behavior as unexpected or "nasty".)
>

It was unexpected default behaviour, because why scrolling if there is
nothing to show more?

-- 
lg

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Re: Scrolling up at the end of buffer

[Eli Zaretskii]

> From: Evgeny Zajcev <lg.zevlg@gmail.com>
> Date: Fri, 4 Dec 2020 15:40:31 +0300
> Cc: emacs-devel <emacs-devel@gnu.org>
> 
>  (FWIW, I don't see this behavior as unexpected or "nasty".)
> 
> It was unexpected default behaviour, because why scrolling if there is nothing to show more?

But there is: the context lines.

Re: Scrolling up at the end of buffer

[Evgeny Zajcev]

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пт, 4 дек. 2020 г. в 15:54, Eli Zaretskii <eliz@gnu.org>:

> > From: Evgeny Zajcev <lg.zevlg@gmail.com>
> > Date: Fri, 4 Dec 2020 15:40:31 +0300
> > Cc: emacs-devel <emacs-devel@gnu.org>
> >
> >  (FWIW, I don't see this behavior as unexpected or "nasty".)
> >
> > It was unexpected default behaviour, because why scrolling if there is
> nothing to show more?
>
> But there is: the context lines.
>

But they are invisible :)

As I understand, context lines is option to skip less lines then window
height when scrolling.  However, it heavily affects how scrolling is done.
For example in non-0 context lines setup, when you scroll down (with M-v)
from the very bottom of the buffer and only one line is display in the
buffer at moment, scrolling won't even move a point!  just show more
content.  At least now, I see this context lines concept very complex,
undocumented, triggering unexpected results.

For me, scrolling is just a way to *move* your point fast in a predictable
way, showing maximum content to the user, that is not what we get with
default Emacs settings right now.

I would like to have scroll behaviour I got with setting context lines to
0, but yet skip less lines then window height :))

-- 
lg

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Re: Scrolling up at the end of buffer

[Eli Zaretskii]

> From: Evgeny Zajcev <lg.zevlg@gmail.com>
> Date: Fri, 4 Dec 2020 16:52:18 +0300
> Cc: emacs-devel <emacs-devel@gnu.org>
> 
> For me, scrolling is just a way to *move* your point fast in a predictable way, showing maximum content to
> the user, that is not what we get with default Emacs settings right now.

That's because Emacs always behaved differently in this regard.  It is
very natural to me, probably because I'm accustomed to it (and miss it
in other applications).  To each his/her own.

Re: Scrolling up at the end of buffer

[Christopher Dimech]

> Sent: Friday, December 04, 2020 at 4:43 PM
> From: "Eli Zaretskii" <eliz@gnu.org>
> To: "Evgeny Zajcev" <lg.zevlg@gmail.com>
> Cc: emacs-devel@gnu.org
> Subject: Re: Scrolling up at the end of buffer
>
> > From: Evgeny Zajcev <lg.zevlg@gmail.com>
> > Date: Fri, 4 Dec 2020 16:52:18 +0300
> > Cc: emacs-devel <emacs-devel@gnu.org>
> >
> > For me, scrolling is just a way to *move* your point fast in a predictable way, showing maximum content to
> > the user, that is not what we get with default Emacs settings right now.
>
> That's because Emacs always behaved differently in this regard.  It is
> very natural to me, probably because I'm accustomed to it (and miss it
> in other applications).  To each his/her own.

Natural and being accustomed to it are two different things.  Being accustomed to
something is likely not natural for the rest.  Perhaps it could be described?