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bug#18739: 24.3; Request for a hook to be provided when scrolling will m
From: |
Josh |
Subject: |
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor |
Date: |
Thu, 16 Oct 2014 07:53:22 -0600 |
>>> The usual technique in Emacs is to put the mark where you were before
>>> scrolling. Then "C-x C-x" will get you back.
>> This requires the forethought to set the mark before scrolling.
> No, you can do it always.
I don't understand. If I don't set the mark, how will "C-x C-x" know
where to jump back to? I have experimented to see if I can replicate
the behavior that you are describing, but I cannot:
(Copy many paragraphs of lorem ipsum text to the OS clipboard)
$ emacs -Q
C-y
C-x h
M-q
C-u 12 C-n
M-f
M-f
SPC
H
E
R
E
<wheel-down> (until the cursor is forced to move)
<wheel-up> (until the word "HERE" is visible again)
C-x C-x
This does not jump the cursor back to the word "HERE" which is the
behavior that I am looking for. I have also tried setting
transient-mark-mode to nil, but it does not do what I want either.
So again, I assert my claim that using "C-x C-x" requires that I have
the forethought to set the mark before I scroll. Please tell me if I
am misunderstanding.
On Thu, Oct 16, 2014 at 7:44 AM, Stefan Monnier
<monnier@iro.umontreal.ca> wrote:
>>> >> It would be helpful to have a hook that would be called before any
>>> >> scrolling command moves the cursor. In other words, I want to be
>>> >> notified when an update to the display will force the location of
>>> >> `point' to change in the current buffer.
>>> > What's wrong with window-scroll-functions?
>>> But these are also called when point is not affected, right?
>> Yes. But it's easy to detect that situation, I think.
>
> Is it?
>
> I think the main reason why I ask is because I truly have no idea when
> window-scroll-functions is called. You seem to be somewhat familiar
> with it, so could you try and clarify it in the docstring?
>
> Currently I see "List of functions to call before redisplaying a window
> with scrolling" and "Note that these functions are also called by
> `set-window-buffer'".
>
> Here are some of the questions this brings up for me:
> - is it called during set-window-buffer itself, or is it called in the
> first redisplay after set-window-buffer?
> - what means "redisplaying a window with scrolling" exactly? Does it
> mean "redisplay with a different window-start then during the last
> redisplay"? Does that include the case where window-start is changed
> so as to follow point or is it only the cases where window-start was
> changed explicitly by a scrolling command?
> - how could a window-scroll-function distinguish the 3 cases:
> "set-window-buffer", "used a scroll command", "moved point out of viewport".
>
> I tried already a few times to understand window-scroll-functions, but
> so far it has eluded me. FWIW, I found 3 kinds of uses:
> - A crutch from when jit-lock didn't exist (in linum and lazy-lock).
> - A way to try and keep a window fully empty showing only point-max by
> calling set-window-start with the same window-start (in follow-mode).
> Not clear exactly why this should work, and arguably goes against the
> warning in window-scroll-functions's docstring.
> - Do fancy auto-scrolling in eshell/em-smart (which does exactly what
> window-scroll-functions's docstring warns not to do, AFAICT), calling
> redisplay internally.
>
>
> Stefan
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, (continued)
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Josh Hunsaker, 2014/10/15
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Ivan Shmakov, 2014/10/15
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Andreas Schwab, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Andreas Schwab, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Stefan Monnier, 2014/10/15
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Stefan Monnier, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor,
Josh <=
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Josh, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Josh, 2014/10/16
- bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Stefan Monnier, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Josh, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Eli Zaretskii, 2014/10/16
bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor, Stefan Monnier, 2014/10/16