Re: master e37eb7f: Add support for pixel wheel deltas on NS

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Sat, 27 Nov 2021 19:13:44 +0800
> 
> @cindex @code{wheel-up} event
> @cindex @code{wheel-down} event
> @item (wheel-up @var{position} @var{clicks} @var{lines} @var{pixel-delta})
> @itemx (wheel-down @var{position})
> These kinds of event are generated by moving a mouse wheel.  The
> @var{position} element is a mouse position list (@pxref{Click
> Events}), specifying the position of the mouse cursor when the event
> occurred.
> 
> @var{clicks}, if present, is the number of times in quick succession
> the wheel has been moved.

By "if present", do you mean it can be absent, or do you mean it can
be nil?  If the latter, then "present" is not the right word.

Also, can this CLICKS member really be anything but 1 when the wheel
is used?

> @var{lines}, if present, is the number of screen lines that should
> be scrolled.  @var{pixel-delta}, if present, is a pair of the form
> @w{@code{(@var{x} . @var{y})}}, where @var{x} and @var{y} are the
> number of pixels to scroll by in each axis.
> 
> WDYT?  Also, it seems that `lines' is only generated by the NS port, so
> it should perhaps be worthwhile to mention that as well?

Doesn't "if present" already handle that?  (Assuming you meant it can
be nil.)

Otherwise LGTM, thanks.