Re: Bug: ruler-mode breaks scroll-conservatively (HEAD)

[Juanma Barranquero <lektu@terra.es>]

On Sun, 15 Dec 2002 12:50:20 -0800, Karl Chen <quarl@hkn.eecs.berkeley.edu> wrote:

> Synopsis:
> 
>      emacs-21-3.50 -q    # in X (the bug doesn't occur with -nw)
> 
>      C-x C-f file_with_more_lines_than_window_height.txt
> 
>      M-x set-variable scroll-conservatively 99999
> 
>      ;; Scrolling occurs one line at a time when the cursor moves past the
>      ;; first or last lines in the window (expected/desired behavior)
> 
>      M-x ruler-mode
> 
>      ;; Moving point past to/past the last line of the window recenters it
>      ;; rather than scrolling by one line (bug).

This problem has already been reported several times. The behavior
appeared after a patch by RMS to fix a bug in the redisplay of
partially-visible lines.

See:

http://mail.gnu.org/pipermail/emacs-devel/2002-July/010505.html
http://mail.gnu.org/pipermail/emacs-devel/2002-July/010512.html
http://mail.gnu.org/pipermail/emacs-devel/2002-July/010588.html
http://mail.gnu.org/pipermail/emacs-devel/2002-September/012049.html
http://mail.gnu.org/pipermail/emacs-devel/2002-September/012539.html

for part of the little bugger's history.

> This may ahve to do with the fact that with ruler-mode on, the last line of
> text has one or two pixels less than without it.

Yes. In fact, anything that would make the last line of the window to be
only partially visible should trigger the bug.

                                                           /L/e/k/t/u