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

[Kazuhiro Ito]

> 1. c-h i (open any vertically long document)
> M-> (move to the bottom of the document) 3.
> 3. perform the scroll down gesture on the touchpad.
> 
> Then you will see the screen scroll up.
> Either scroll down or scroll up, whichever you do, the screen will scroll up.

I noticed that when I input wheel-down with touchpad, line count is
set to negative value, which should be positive integer.

(let ((event (read-event)))
  (cons (car event) (event-line-count event)))

;; Input via touchpad
(wheel-down . -3)
(wheel-up . 3)

;; Input via mouse wheel
(wheel-down . 1)
(wheel-up . 1)

-- 
Kazuhiro Ito