bug#16129: 24.3.50; Emacs slow with follow-mode when buffer ends before last window

[Anders Lindgren]

Sounds like a good idea to post this feature request. However, being a realist, I doubt that this will happen anytime soon.

I would suggest that we also post feature requests for things that would help the situation on a shorter time scale. Primarily, I would like to be able, on a window-by-window basis, control whether or not a window should be recentered, when empty. Also, we might look into the speed issues, we might be able to avoid double redraws with little effort, for the common cases.

While I'm at it. I updated to the latest trunk today and saw that cursor movements are a lot faster now, including the when the tail is showing. However, I noticed that when the region is active, the region highlight is not updated as fast as it is when follow-mode is off, when running the cursor.

    -- Anders

On Fri, Jan 10, 2014 at 8:00 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> Date: Fri, 10 Jan 2014 19:52:18 +0100
> From: Anders Lindgren <andlind@gmail.com>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 16129@debbugs.gnu.org

>
> Concretely, how do we proceed from here? I don't have the necessary
> knowledge of the internals of the display engine and I don't have much time
> to spend on a major rewrite like this. However, if someone decides to
> proceed with this, I will try to support them as much that I can.

I suggest to file a separate feature request bug report about this,
and include in it the requirements for the display engine to support
follow-mode.  That is, given a set of windows that are "following"
each other, what should redisplay do when certain display-related
events happen.  Then interested volunteers can implement that.