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From: martin rudalics <rudalics@gmx.at>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 12401@debbugs.gnu.org, l26wang@gmail.com
Subject: bug#12401: scroll-preserve-screen-position broken with font	height faces
Date: Wed, 12 Sep 2012 10:08:48 +0200	[thread overview]
Message-ID: <50504310.8070505@gmx.at> (raw)
In-Reply-To: <83a9wxlpnc.fsf@gnu.org>

 >>> scroll-preserve-screen-position?  Is it just that doing N C-v's
 >>> followed by N M-v's brings point to the same location where it was
 >>> before this sequence of 2N commands?
 >> I think this should be the main point, yes.
 >
 > For this to work, we would need to make sure that C-v followed by M-v
 > end up with a window that has the same window-start as the one before
 > C-v.

Why?

 > But this is impossible to ensure with the way we compute
 > window-start, because the move_it family of functions used for that
 > can only move forward; therefore moving back is necessarily
 > implemented differently, and the results differ when variable-size
 > fonts are present.
 >
 > IOW, this is a limitation of the current design of the
 > window-scrolling functions that can only be lifted by redesigning.

I'm completely happy with the following solution: Whenever, after a
sequence of scrolling commands, the original position (that is the
position before the sequence started) reappears in a window, move to
that position and leave the window start position alone.  See also

http://lists.gnu.org/archive/html/emacs-devel/2008-02/msg01892.html

martin





  parent reply	other threads:[~2012-09-12  8:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-10  6:12 bug#12401: scroll-preserve-screen-position broken with font height faces Le Wang
2012-09-10  7:23 ` Eli Zaretskii
2012-09-10 12:37   ` Le Wang
2012-09-10 18:02     ` Eli Zaretskii
2012-09-10 13:26   ` Stefan Monnier
2012-09-10 18:05     ` Eli Zaretskii
2012-09-10 20:42       ` Stefan Monnier
2012-09-12  8:08       ` martin rudalics [this message]
2012-09-12 16:48         ` Eli Zaretskii
2012-09-12 17:38           ` martin rudalics
2022-02-09  9:17 ` Lars Ingebrigtsen
2022-03-09 16:22   ` Lars Ingebrigtsen

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