From: npostavs@users.sourceforge.net
To: Eli Zaretskii <eliz@gnu.org>
Cc: ahyatt@gmail.com, 5718@debbugs.gnu.org, gavenkoa@gmail.com
Subject: bug#5718: scroll-margin in buffer with small line count.
Date: Sat, 13 Aug 2016 18:01:43 -0400 [thread overview]
Message-ID: <87a8ggwcoo.fsf@users.sourceforge.net> (raw)
In-Reply-To: <83fuqbfhpb.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 11 Aug 2016 18:28:32 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
>>
>> I think the complaint is that the `scroll-margin' effective value is
>> capped at a 1/4 of the window height, as seen in this
>> window_scroll_pixel_based (window.c):
>>
>> this_scroll_margin = max (0, scroll_margin);
>> this_scroll_margin
>> = min (this_scroll_margin, window_total_lines / 4);
>
> Which reveals a subtle bug: the actual scroll margin should be 1 for 7
> lines, 2 for 11, etc. The problem is that the value of
> window_total_lines includes the mode line, which it shouldn't. Maybe
> this should be fixed.
I was looking at fixing it, but I got confused by this comment in
window.h:
/* Height in pixels, and in lines, of the mode line.
May be zero if W doesn't have a mode line. */
#define WINDOW_MODE_LINE_HEIGHT(W) \
How is the height "in pixels, and in lines"? Doesn't it have to be one
or the other?
>
>> Whereas, it seems more logical to cap it at half window height.
>
> No, I think it would leave too few lines for moving the cursor. This
> has been Emacs behavior since time immemoriam, so if we want to have a
> different behavior, it should be implemented an opt-in option, not the
> default.
Yes, sure. This is about Emacs' behaviour after the user has customized
scroll-margin, so the default isn't in question anyway. I imagine
something like this:
DEFVAR_LISP ("minimum-non-scroll-lines", Vminimum_non_scroll_lines,
doc: /* Lines around window's center where `scoll-margin' doesn't apply.
If point is within this many lines from the window's center, it will
not cause scrolling regardless of the value of `scroll-margin'. If
this is a float then it represents a fraction of the current window's
lines. */);
Vminimum_non_scroll_lines = make_float (1.0/4.0);
And then setting this to 1 would make scroll-margin have the effect that
the OP expects.
next prev parent reply other threads:[~2016-08-13 22:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-14 17:26 bug#5718: scroll-margin in buffer with small line count Oleksandr Gavenko
2016-08-11 4:11 ` Andrew Hyatt
2016-08-11 12:03 ` npostavs
2016-08-11 13:05 ` Oleksandr Gavenko
2016-08-11 13:24 ` Noam Postavsky
2016-08-12 7:54 ` Oleksandr Gavenko
2016-08-11 15:28 ` Eli Zaretskii
2016-08-13 22:01 ` npostavs [this message]
2016-08-14 2:36 ` Eli Zaretskii
2016-09-11 20:58 ` npostavs
2016-09-12 6:19 ` martin rudalics
2016-09-14 2:23 ` npostavs
2016-09-14 5:30 ` martin rudalics
2016-09-12 17:36 ` Eli Zaretskii
2016-09-14 2:40 ` npostavs
2016-09-14 17:26 ` Eli Zaretskii
2017-01-03 0:48 ` npostavs
2017-01-07 8:17 ` Eli Zaretskii
2017-01-14 4:18 ` npostavs
2017-01-14 7:58 ` Eli Zaretskii
2017-01-15 21:43 ` npostavs
2017-01-16 17:08 ` Eli Zaretskii
2017-01-21 18:46 ` npostavs
2017-01-21 19:17 ` Eli Zaretskii
2017-01-22 17:21 ` npostavs
2017-01-22 17:58 ` Eli Zaretskii
2017-01-29 0:57 ` npostavs
2017-01-30 15:29 ` Eli Zaretskii
2017-01-31 4:52 ` npostavs
2017-01-31 15:33 ` Eli Zaretskii
2017-02-03 2:40 ` npostavs
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