GNU bug report logs -
#29002
it.first_visible_x is erroneously 0 while horizontal scrolling.
Previous Next
Full log
Message #47 received at 29002 <at> debbugs.gnu.org (full text, mbox):
Horizontal scroll bars are not visible in this example. I have been using the horizontal mouse-wheel. I can reproduce the issue by evaluating (scroll-right 1) in the minibuffer when at the end of a long-line, and then pressing the left arrow-key, and then calling F5 (bound to bug-hscroll).
It appears to me that (scroll-right 1) is kind of a temporary form of horizontal scrolling, which automatically cancels as to non-current lines in a vareity of situations when keyboard input is received. Plain old scroll-right without the optional distance argument is semi-permanent, and non-current lines do not automatically return to a non-scrolled state.
F8 is undefined on OSX, but I saw in a grep search that "C-x >" is bound to scroll-right. That behaves differently than (scroll-right 1) using the optional argument to control the distance. I also tried using "C-u 1 C-x >", but it behaves the same as "C-x >".
The issue described in #29002 is not present when invoking "C-u 1 C-x >" or "C-x >" -- i.e., both of which appear to be semi-permanent forms of horizontal scrolling.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DATE: [10-29-2017 12:23:33] <29 Oct 2017 21:23:33 +0200>
FROM: Eli Zaretskii <eliz <at> gnu.org>
>
> > Date: Sun, 29 Oct 2017 11:56:22 -0700
> > From: Keith David Bershatsky <esq <at> lawlist.com>
> > Cc: 29002 <at> debbugs.gnu.org
> >
> > I agree ... and that leads us to bug #29002. :)
> >
> > In the normal situation, the screen refreshes when the arrow key is used and non-current lines cease to be horizontally scrolled. In the current example, however, non-current lines remain horizontally scrolled and Emacs "thinks" that they are not. When I say that Emacs "thinks" they are not, I am referring to IT.
>
> What Emacs "thinks" is on display. And there we see hscrolled lines.
> So first_visible_x must be non-zero, and that is what I see. If
> first_visible_x were zero, you'd see the line's text starting with the
> first character of each line. I very much doubt that this is somehow
> Windows-specific, since xdisp.c is the platform-independent part of
> the display engine.
>
> Or maybe the horizontal scroll bar on macOS somehow causes this. What
> happens if you scroll-right with some key, like F8, and not with the
> mouse?
>
> (In any case, invoking scroll-right in this situation makes very
> little sense to me.)
This bug report was last modified 7 years and 291 days ago.
Previous Next
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.