From: Eli Zaretskii <eliz@gnu.org>
To: E Sabof <esabof@gmail.com>
Cc: 18923@debbugs.gnu.org
Subject: bug#18923: Alternative scrolling model
Date: Sun, 02 Nov 2014 18:31:08 +0200 [thread overview]
Message-ID: <8338a1y377.fsf@gnu.org> (raw)
In-Reply-To: <87r3xla7zw.fsf@gmail.com>
> From: E Sabof <esabof@gmail.com>
> Cc: 18923@debbugs.gnu.org
> Date: Sun, 02 Nov 2014 16:21:23 +0000
>
> > What are the advantages of this alternative way of scrolling, beyond
> > being in Lisp and eliminating the jumps when encountering an image?
> > (Btw, a test case for the latter would be nice, perhaps as a separate
> > bug report.) If the only advantage is better handling of in-line
> > images, then perhaps fixing the existing implementation is a better
> > path forward?
>
> There aren't. Do you have ideas on how this could be accommodated? Technically
Sorry, I'm not sure I understand the question. If you mean how to
avoid jumps with the existing C implementation when there are inline
images, then please show a recipe to see the problem, and let's take
it from there.
> >> (defun st-height (&optional pos)
> >> "Won't report accurately, if the line is higher than window."
> >> (cl-flet (( posn-y ()
> >> (cdr (posn-x-y (or (posn-at-point)
> >> (progn
> >> (vertical-motion 0)
> >> (set-window-start nil (point))
> >> (posn-at-point)))))))
> >
> > Did you try using pos-visible-in-window-p? I think it's what you
> > want.
>
> Reading through the documentation of `pos-visible-in-window-p' didn't suggest how it could be useful.
Do you still not understand that? If so, I will elaborate why I think
that function is what you want.
> A more descriptive name for the function would be `st-get-pixel-height-of-line-at-point'.
Yes, I think I understood that.
> >> (cl-loop do (push (st-height) rows)
> >> until (or (zerop (vertical-motion direction))
> >> ;; >= ?
> >> (>= (cl-reduce '+ rows)
> >> (abs ammount))))
> >
> > I don't understand why you needed this loop. Can't you use
> > window-body-height instead?
>
> What I need mostly depends on the amount of pixels I want to scroll - (for 2 "normal" lines, this loop would run twice) which is usually less than window-body-height, but could potentially be more.
IME, the most important use case is scrolling by "almost the full
window", in which case it is better to start with window-body-height
and subtract from it, instead of starting with zero and add to it.
The most expensive part here is vertical-motion, so I think you want
to call it as little as possible.
> > This doesn't support the equivalent of a nil argument, which means
> > move by "near full screen".
>
> I can implement this if the overall approach gets a green light.
I think we need to decide first whether the slowdown is acceptable.
IMO it is too significant to be ignored, if we want to replace
existing code.
next prev parent reply other threads:[~2014-11-02 16:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-02 1:15 bug#18923: Alternative scrolling model E Sabof
[not found] ` <jwv61ey5qfb.fsf-monnier+emacsbugs@gnu.org>
[not found] ` <87vbmy9wdx.fsf@gmail.com>
2014-11-02 2:31 ` E Sabof
2014-11-02 15:16 ` Eli Zaretskii
2014-11-02 18:25 ` E Sabof
2014-11-02 18:36 ` Eli Zaretskii
[not found] ` <jwvioiy416g.fsf-monnier+emacsbugs@gnu.org>
[not found] ` <87sii1ahy9.fsf@gmail.com>
[not found] ` <jwvppd538tu.fsf-monnier+emacsbugs@gnu.org>
2014-11-02 23:10 ` E Sabof
2014-11-03 2:35 ` Stefan Monnier
2014-11-03 16:03 ` Eli Zaretskii
2014-11-03 19:02 ` E Sabof
2014-11-02 15:14 ` Eli Zaretskii
2014-11-02 15:56 ` Stefan Monnier
2014-11-02 16:06 ` Eli Zaretskii
2014-11-02 16:21 ` E Sabof
2014-11-02 16:31 ` Eli Zaretskii [this message]
2014-11-02 17:43 ` E Sabof
2014-11-02 18:22 ` Eli Zaretskii
2014-11-02 19:09 ` E Sabof
2014-11-02 19:29 ` Eli Zaretskii
2014-11-03 3:45 ` Eli Zaretskii
2019-11-04 9:14 ` Stefan Kangas
2022-04-22 12:16 ` Lars Ingebrigtsen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8338a1y377.fsf@gnu.org \
--to=eliz@gnu.org \
--cc=18923@debbugs.gnu.org \
--cc=esabof@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.