From: Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: 55312@debbugs.gnu.org
Subject: bug#55312: 29.0.50; Cannot set vscroll when mini-window is resized
Date: Sun, 08 May 2022 19:53:10 +0800 [thread overview]
Message-ID: <877d6w44wp.fsf@yahoo.com> (raw)
In-Reply-To: 877d6w44wp.fsf.ref@yahoo.com
It seems that this code in redisplay_window always clears out the
vscroll when the mini-window is taller than a single line of text:
/* If someone specified a new starting point but did not insist,
check whether it can be used. */
if ((w->optional_new_start || window_frozen_p (w))
&& CHARPOS (startp) >= BEGV
&& CHARPOS (startp) <= ZV)
{
ptrdiff_t it_charpos;
w->optional_new_start = false;
start_display (&it, w, startp);
move_it_to (&it, PT, 0, it.last_visible_y, -1,
MOVE_TO_POS | MOVE_TO_X | MOVE_TO_Y);
/* Record IT's position now, since line_bottom_y might change
that. */
it_charpos = IT_CHARPOS (it);
/* Make sure we set the force_start flag only if the cursor row
will be fully visible. Otherwise, the code under force_start
label below will try to move point back into view, which is
not what the code which sets optional_new_start wants. */
if ((it.current_y == 0 || line_bottom_y (&it) < it.last_visible_y)
&& !w->force_start)
{
if (it_charpos == PT)
w->force_start = true;
/* IT may overshoot PT if text at PT is invisible. */
else if (it_charpos > PT && CHARPOS (startp) <= PT)
w->force_start = true;
This can easily be reproduced by typing "M-x C-q C-j" and trying to use
`pixel-scroll-precision' with the mouse pointer on top of a window that
is not the `minibuf-scroll-window': the vscroll will not take effect,
since force_start will be set to true, and that resets the vscroll.
I think this "frozen" behavior is required to ensure that the start of
windows do not aimlessly move when the mini-window is being resized, but
it interferes with features that need to set the vscroll.
Any ideas?
Thanks in advance.
next parent reply other threads:[~2022-05-08 11:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <877d6w44wp.fsf.ref@yahoo.com>
2022-05-08 11:53 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2022-05-08 13:40 ` bug#55312: 29.0.50; Cannot set vscroll when mini-window is resized Eli Zaretskii
2022-05-09 0:29 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-05-09 1:38 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-05-09 13:48 ` Eli Zaretskii
2022-05-10 0:43 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
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