From: Keith David Bershatsky <esq@lawlist.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 22404@debbugs.gnu.org
Subject: bug#22404: 25.1.50; Forcing `window-scroll-functions` to run.
Date: Wed, 20 Jan 2016 18:32:40 -0800 [thread overview]
Message-ID: <m2io2nk6gn.wl%esq@lawlist.com> (raw)
In-Reply-To: <m260yqdsp7.wl%esq@lawlist.com>
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`set-window-start` (without the third option) would indeed trigger the WSF because it contains a key ingredient: `w->force_start = true`.
Because the second argument (i.e., POS) cannot be known from the PCH when point has moved beyond the visible window, `set-window-start` is not a viable substitute for this feature request.
The attached patch is an example of an implementation of this feature request. I created a new function called `force-wsf`, whose sole purpose is to trigger the WSF to run during redisplay -- after the PCH has already finished. As noted in a previous e-mail, `run-window-scroll-functions` doesn't accomplish what `force-wsf` can achieve because the former runs the function attached to the WSF immediately -- instead of waiting until later on during redisplay when the correct values of `window-start` and `window-end` are ascertainable.
This is my first attempt at writing something like this, and I'm not sure exactly if everything is correct. It does, however, appear to achieve the desired affect -- i.e., run the WSF at least once every command loop (even if no scrolling occurs) so we can always know the correct values for `window-start` and `window-end`. It is no longer necessary to guess with `elisp` from the PCH regarding whether WSF will run.
I would, however, still like to come up with a test at the C-source code level that tells me whether the WSF will run more than one time -- because I only care about the last call on the WSF when the final values for `window-start` and `window-end` become available.
The usage for the new function `force-wsf` is as follows:
(defun pch-fn ()
(force-wsf (selected-window)))
(add-hook 'post-command-hook 'pch-fn nil 'local)
(defun wsf-fn (win start)
(message "point: %s | win: %s | start: %s | end: %s"
;; A better test at the C-source code level appears to be needed to ascertain whether
;; the WSF will run more than one time -- because we want the value for `window-start`
;; and `window-end win t` based on the LAST time WSF runs during the command loop.
(if (pos-visible-in-window-p nil nil nil)
"visible"
"NOT visible")
win start (window-end win t)))
(add-hook 'window-scroll-functions 'wsf-fn nil 'local)
The new function in window.c looks like this:
DEFUN ("force-wsf", Fforce_wsf, Sforce_wsf, 0, 1, 0,
doc: /* Set force_start so that redisplay_window will run the
window-scroll-functions. */)
(Lisp_Object window)
{
register struct window *w = decode_live_window (window);
w->optional_new_start = true;
return;
}
And, the there is one additional line that may also be required further on down in window.d:
defsubr (&Sforce_wsf);
Thanks,
Keith
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
At Wed, 20 Jan 2016 15:34:41 +0200,
Eli Zaretskii wrote:
>
> > . . . you need to call set-window-start with its 3rd
> argument omitted or nil. Does that solve your problem?
[-- Attachment #2: patch.diff --]
[-- Type: application/diff, Size: 1092 bytes --]
next prev parent reply other threads:[~2016-01-21 2:32 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-19 5:49 bug#22404: 25.1.50; Forcing `window-scroll-functions` to run Keith David Bershatsky
2016-01-19 17:50 ` Eli Zaretskii
2016-01-19 18:49 ` Keith David Bershatsky
2016-01-19 19:39 ` Eli Zaretskii
2016-01-19 18:53 ` John Wiegley
2016-01-19 19:26 ` Keith David Bershatsky
2016-01-19 20:35 ` Keith David Bershatsky
2016-01-20 13:34 ` Eli Zaretskii
2016-01-19 23:07 ` Keith David Bershatsky
2016-01-21 2:32 ` Keith David Bershatsky [this message]
2016-01-21 17:41 ` Eli Zaretskii
2016-01-21 19:54 ` Keith David Bershatsky
2016-01-21 20:28 ` Eli Zaretskii
2016-01-29 12:00 ` Michael Heerdegen
2016-01-29 14:37 ` Eli Zaretskii
2016-01-29 14:57 ` Michael Heerdegen
2016-01-29 15:33 ` Eli Zaretskii
2016-01-21 21:11 ` Keith David Bershatsky
2016-01-29 2:14 ` John Wiegley
2016-01-29 3:08 ` Keith David Bershatsky
2016-01-29 8:42 ` Eli Zaretskii
2016-01-29 15:54 ` Keith David Bershatsky
2016-02-01 3:50 ` Keith David Bershatsky
2016-02-01 19:54 ` Eli Zaretskii
2016-02-01 13:18 ` Keith David Bershatsky
2016-02-02 16:34 ` Eli Zaretskii
2016-02-02 5:58 ` Keith David Bershatsky
2016-02-02 18:16 ` Keith David Bershatsky
2016-02-02 18:43 ` Eli Zaretskii
2016-02-02 20:00 ` Keith David Bershatsky
2016-02-02 21:05 ` Keith David Bershatsky
2016-02-08 8:51 ` Keith David Bershatsky
2016-02-08 17:17 ` Eli Zaretskii
2016-02-09 16:00 ` Keith David Bershatsky
2016-02-09 17:48 ` Eli Zaretskii
2016-02-12 0:14 ` Keith David Bershatsky
2016-02-12 8:18 ` Eli Zaretskii
2016-02-16 3:39 ` Keith David Bershatsky
2016-02-12 8:25 ` Why do idle timers trigger redisplay? Eli Zaretskii
2016-02-22 6:05 ` bug#22404: 25.1.50; Forcing `window-scroll-functions` to run Keith David Bershatsky
2016-03-11 16:21 ` Keith David Bershatsky
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