From: E Sabof <esabof@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 18923@debbugs.gnu.org
Subject: bug#18923: Alternative scrolling model
Date: Sun, 02 Nov 2014 19:09:20 +0000 [thread overview]
Message-ID: <87mw89a07z.fsf@gmail.com> (raw)
In-Reply-To: <831tplxy1x.fsf@gnu.org>
Eli Zaretskii <eliz@gnu.org> writes:
> > Imagine there is a buffer with **AN IMAGE** which occupies 30% of the window (ex. a diagram in an org-mode buffer). It's positioned at (window-start). I (scroll-up 1). I'd end up scrolling a lot more than the usual (= (default-line-height) 20) pixels, which is what I mean by "jump".
> If the problem is only with scrolling by single lines (or small
> number of lines), then a very similar problem is already solved in
> line-move-partial. Try C-n in the same situation, and see if that's
> what you want. We could then use the same technique.
I'm not sure that we are talking about the same scenario. I didn't encounter any relevant behavior while using C-n/C-p, when a large image was displayed on the first line (with my default settings or Emacs -Q, both on the latest stable release).
> The problem that you faced, as I understand it, was to get the pixel
> size of a screen line even if it is only partially visible. The RTOP
> and RBOT values returned by pos-visible-in-window-p give you
> information about how many pixels of the line are above the top and
> below the bottom of the window. (For a very tall image or a low
> window, both RTOP and RBOT will be non-zero.) Add those to the
> visible height of the line, and AFIU you get what you wanted. Am I
> missing something?
Maybe not.
>> > 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.
>>
>> window-body-height can be very wrong if a large image is displayed in the buffer.
>
> I meant call window-body-height with PIXELWISE non-nil. Then the
> return value doesn't depend on what is displayed, it just gives you
> the height of the text area in pixels. Subtracting from that the
> pixel coordinates of point returned by pos-visible-in-window-p or
> posn-at-point will give you how many pixels are there to the top and
> bottom of the window. This should eliminate the need to count pixels
> by moving one screen line at a time via vertical-motion, which is less
> efficient, I think.
I'm not sure how knowing the distance of a point to the bottom of the window would benefit me, but indeed I could bulk-measure several lines in some cases.
Evgeni
next prev parent reply other threads:[~2014-11-02 19:09 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
2014-11-02 17:43 ` E Sabof
2014-11-02 18:22 ` Eli Zaretskii
2014-11-02 19:09 ` E Sabof [this message]
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=87mw89a07z.fsf@gmail.com \
--to=esabof@gmail.com \
--cc=18923@debbugs.gnu.org \
--cc=eliz@gnu.org \
/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.