From: Eli Zaretskii <eliz@gnu.org>
To: martin rudalics <rudalics@gmx.at>
Cc: kelly@prtime.org, 19060@debbugs.gnu.org
Subject: bug#19060: [FIX INCLUDED] Off-by-one-line scrolling bug in window_scroll_pixel_based
Date: Sat, 15 Nov 2014 13:17:47 +0200 [thread overview]
Message-ID: <83lhncg1b8.fsf@gnu.org> (raw)
In-Reply-To: <5467354D.3000600@gmx.at>
> Date: Sat, 15 Nov 2014 12:13:17 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: 19060@debbugs.gnu.org
>
> > diff --git a/src/window.c b/src/window.c
> > index b002423..7462fdc 100644
> > --- a/src/window.c
> > +++ b/src/window.c
> > @@ -4956,8 +4956,8 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, int noerror)
> > int px;
> > int dy = frame_line_height;
> > if (whole)
> > - dy = max ((window_box_height (w)
> > - - next_screen_context_lines * dy),
> > + dy = max ((window_box_height (w) / dy
> > + - next_screen_context_lines) * dy,
> > dy);
> > dy *= n;
> >
> > @@ -5039,8 +5039,7 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, int noerror)
> > {
> > ptrdiff_t start_pos = IT_CHARPOS (it);
> > int dy = frame_line_height;
> > - dy = max ((window_box_height (w)
> > - - next_screen_context_lines * dy),
> > + dy = max ((window_box_height (w) / dy - next_screen_context_lines) * dy,
> > dy) * n;
> >
> > /* Note that move_it_vertically always moves the iterator to the
>
> If it works for you, please apply it.
It evidently works for Kelly.
> I'm too silly to understand it, though. IIUC we have a rounding
> issue which makes us go by one line too far or too few when
> scrolling up and your patch compensates that rounding issue by
> putting it back into that window_box_height (w) / dy calculation.
Yes. Why is it hard to understand?
> Could you add comments which tell more or less how you corrected the
> issue?
Will do, once we agree that this is the right fix.
next prev parent reply other threads:[~2014-11-15 11:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <emacs-mail-is-unusable-4@[87.69.4.28]>
2014-11-15 9:27 ` bug#19060: [FIX INCLUDED] Off-by-one-line scrolling bug in window_scroll_pixel_based Eli Zaretskii
2014-11-15 11:13 ` martin rudalics
2014-11-15 11:17 ` Eli Zaretskii [this message]
2014-11-15 12:12 ` martin rudalics
2014-11-15 13:05 ` Eli Zaretskii
2014-11-15 13:29 ` martin rudalics
2014-11-15 13:47 ` Eli Zaretskii
2014-11-15 14:32 ` martin rudalics
2014-11-15 17:06 ` Eli Zaretskii
[not found] <emacs-mail-is-unusable-4>
2014-11-15 14:10 ` Angelo Graziosi
2014-11-15 14:33 ` martin rudalics
2014-11-15 17:18 ` Angelo Graziosi
2014-11-16 11:37 ` martin rudalics
2014-11-15 6:57 Kelly Dean
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