[debbugs-tracker] bug#21080: closed (Scrolling bug)

[GNU bug Tracking System]

Your message dated Sat, 18 Jul 2015 13:07:20 +0300
with message-id <address@hidden>
and subject line Re: bug#21080: Scrolling bug
has caused the debbugs.gnu.org bug report #21080,
regarding Scrolling bug
to be marked as done.

(If you believe you have received this mail in error, please contact
address@hidden)


-- 
21080: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=21080
GNU Bug Tracking System
Contact address@hidden with problems

--- Begin Message --- Subject: Scrolling bug Date: Fri, 17 Jul 2015 19:51:12 +0300

Hi!

I work in terminal on Ubuntu 15.04 (xterm, GNOME terminal) with very big text files, very long lines and warping (via global-visual-line). I want to scroll by one line, so i set scroll-conservatively to
most-positive-fixnum. When i read text and scroll down everything is fine, but when i want to return back and scroll up *over warped lines*, cursor jumps on the second line from the top of window. According to manual, faq, wiki and google i try to play with other scroll-related settings, such as margin, aggressiveness, step, but with no result. Cursor still jump by two lines when moving up. Looks like a bug. In GUI version everything is good and scrolls by one line. This bug is only in terminals. Confirm with 24.4.1 and 24.5.

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#21080: Scrolling bug
>
>
>
>
> Date: 
>
> Sat, 18 Jul 2015 13:07:20 +0300
>
>
>
>
> > Date: Sat, 18 Jul 2015 00:58:14 +0300
> > From: Bru Rom <address@hidden>
> > 
> > It can be any file with long enough lines.
> > 
> > For standard terminal 80x24, let the part of wikipedia article on Emacs be our
> > "sample file". Emacs history from it:
> > [...]
>
> > Copy text to file, open it in Emacs with emacs -nw -Q
> > 
> > Next, exact sequence of commands:
> > 
> > alt-x customize-option
> > scroll-conservatively
> > Set there 10000, tab into state, enter state, press 0 = Set for Current 
> > Session
> > Press 'q' to exit
> > 
> > Then alt-x visual-line-mode
> > 
> > Then C-End to go to end of buffer. Then scroll up line-by-line with Up. It
> > scrolls by 2 over warped lines, but if you go down from start of buffer -
> > everything will be ok.
>
> Thanks.  This bug is now fixed in the development sources with the
> simple change below (which you could probably easily apply to 24.5 or
> previous versions, as that code was in Emacs since Mar 2002).
>
> commit d3816bf8ad1fcfed2a32d23216a55850ee4325b5
> Author: Eli Zaretskii <address@hidden>
> Date:   Sat Jul 18 13:02:06 2015 +0300
>
>     Fix scrolling backwards on TTY frames under scroll-conservatively
>     
>     * src/xdisp.c (move_it_vertically_backward): Fix off-by-one error
>     in moving backwards on TTY frames.  (Bug#21080)
>
> diff --git a/src/xdisp.c b/src/xdisp.c
> index 5bef44c..16a7a64 100644
> --- a/src/xdisp.c
> +++ b/src/xdisp.c
> @@ -9428,7 +9428,7 @@ struct overlay_entry
>              treating terminal frames specially here.  */
>  
>           if (!FRAME_WINDOW_P (it->f))
> -           move_it_vertically (it, target_y - (it->current_y + line_height));
> +           move_it_vertically (it, target_y - it->current_y);
>           else
>             {
>               do
>
>
> --- End Message ---