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From: Eli Zaretskii <eliz@gnu.org>
To: JD Smith <jdtsmith@gmail.com>
Cc: emacs-devel@gnu.org
Subject: Re: Temporarily select-window, without updating mode-line face and cursor fill?
Date: Sun, 02 May 2021 09:49:34 +0300	[thread overview]
Message-ID: <83im418wap.fsf@gnu.org> (raw)
In-Reply-To: <6168853E-E5B1-4247-A0D7-4D4191DCED0A@gmail.com> (message from JD Smith on Sat, 1 May 2021 16:32:22 -0400)

> From: JD Smith <jdtsmith@gmail.com>
> Date: Sat, 1 May 2021 16:32:22 -0400
> Cc: emacs-devel@gnu.org
> 
> Sure, thanks.  I compute line positions at a number of points (window-start, window-end, and point-max)
> inside a mode line :eval form.  To compute line numbers at these positions, for speed in very long files, I’m
> actually using:
> 
> (defun mlscroll-fast-line-number-at-pos (pos)
>   (save-excursion
>     (goto-char pos)
>     (string-to-number (format-mode-line "%l"))))

I think your are doing premature optimization here.  Which alternative
method of counting lines you thought would be too slow?

> The operative bits of the “move within” look like:
> 
>    (when (/= targ start)
>       (forward-line (- targ start))
>       (recenter))

forward-line works on the current buffer, it doesn't care about the
window, AFAIK.

> During normal automatic mode-line update, the selected window is automatically bound correctly while the
> mode line string is computed (without updating the mode line face, I might add!).  But during the mouse event
> callback, I must use the starting window of the mouse event (a press) as the window to target, since the user
> could click on any of them. 

Sure, but the event gives you the window, and through it the buffer of
that window, so I see no particular reason to make the window
selected.

Alternatively, you could try doing this as mwheel.el does it.



  reply	other threads:[~2021-05-02  6:49 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-01 18:46 Temporarily select-window, without updating mode-line face and cursor fill? JD Smith
2021-05-01 19:31 ` Eli Zaretskii
2021-05-01 20:32   ` JD Smith
2021-05-02  6:49     ` Eli Zaretskii [this message]
2021-05-03  2:15       ` JD Smith
2021-05-03  7:50         ` martin rudalics
2021-05-03 16:16           ` JD Smith
2021-05-03 17:32             ` martin rudalics
2021-05-02  7:40     ` martin rudalics
2021-05-03  2:23       ` JD Smith
2021-05-01 22:17   ` JD Smith
2021-05-02  6:55     ` Eli Zaretskii
2021-05-03  2:08       ` JD Smith
2021-05-03  2:25         ` Stefan Monnier
2021-05-03  2:49           ` JD Smith
2021-05-04 19:28           ` JD Smith
2021-05-04 19:40             ` Stefan Monnier
2021-05-05  0:49           ` Stefan Kangas
2021-05-05 11:54             ` Eli Zaretskii
2021-05-05 19:32               ` Stefan Kangas
2021-05-05 19:47                 ` Stefan Monnier
2021-05-06  0:16                 ` JD Smith

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