bug#29737: 27.0.50; pixel-scroll-mode is laggy

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 01 Jan 2018 09:58:38 +0900 (JST)
> Cc: eliz@gnu.org, 29737@debbugs.gnu.org, tkk@misasa.okayama-u.ac.jp
> From: Tak Kunihiro <tkk@misasa.okayama-u.ac.jp>
> 
> I think that on scrolling of 1000 lines, smooth scroll is not
> necessary.  User wants smooth scrolling only for the first spin of
> mouse wheel.
> 
> This patch introduces a new variable `pixel-dead-time' and
> `pixel-last-scroll-time'.  When another scroll request was delivered
> within `pixel-dead-time', very likely user does not want smooth
> scrolling.
> 
> On such situation, `scroll-down' is called instead of
> `pixel-scroll-pixel-down'.  On theory there should not be lag because
> of smoothing.
> 
> I tested the revised pixel-scroll-mode for a week and confirmed that
> works good.  When `pixel-dead-time' is zero, its behavior is the same
> as before.  I think `pixel-dead-time' 0.1 works better.
> 
> I'm sending ChangeLog and a patch relative to the current master.

There was no response, but do you think we should push this
regardless?  (It should go to the release branch, not to master.)

Thanks.