bug#65070: 29.1; (Only on Windows) Both touchpad scroll gestures scroll the screen up and down.

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: Kazuhiro Ito <kzhr@d1.dion.ne.jp>,  65070@debbugs.gnu.org,
>   hiroya.ebine1@gmail.com,  max@mal-richtig.de
> Date: Sun, 20 Aug 2023 08:16:27 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Date: Sun, 20 Aug 2023 00:27:13 +0900
> >> From: Kazuhiro Ito <kzhr@d1.dion.ne.jp>
> >> Cc: 65070@debbugs.gnu.org,
> >>    hiroya.ebine1@gmail.com,
> >>    max@mal-richtig.de
> >> 
> >> > Is scrolling with the touchpad
> >> > more smooth if you set mwheel-coalesce-scroll-events to the nil value?
> >> 
> >> No, as far as I tested.
> >> When mwheel-coalesce-scroll-events is nil, it is very hard to
> >> scrolling few lines, beacause slowly slinding fingers doesn't make
> >> valid wheel event of which line count is non-zero.  It seems that
> >> Emacs shows more similar behavior with other Windows applications when
> >> mwheel-coalesce-scroll-events is non-nil on especially small amount
> >> scrolling.
> >
> > Po Lu, is this expected?  Or, put it another way: how would a user set
> > up Emacs for smooth scrolling when the touchpad can produce scrolling
> > amounts smaller than "one scroll unit"?
> 
> By enabling pixel-scroll-precision-mode, thanks.

Kazuhiro Ito and Max, could you perhaps try that and provide feedback?
I wrote that code flying blind, having no access to a system where the
scrolling gestures could provide such fine resolution.  So I would be
interested to know the results.

Thanks.