1375543 - wheel event's deltaY value is not consistent on mac and windows

Status: RESOLVED DUPLICATE of bug 1392460

(Core :: Widget: Win32, defect, P3)

Description

[François Romain]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

Steps to reproduce:

- Go to: https://codepen.io/francoisromain/pen/MooqGK?editors=1111
- Scroll over the red element
- Check the values in the console


Actual results:

On windows, the values are either -3, 0 or 3
On mac, the values are actual pixels.


Expected results:

Expected the same values on mac and windows (and every other browsers): pixels. 

I read about this here:
- https://bugzilla.mozilla.org/show_bug.cgi?id=1057252

Still, this is annoying…

Comment 1

[François Romain]

On Firefox mac, deltaMode changes depending on the mouse: 
- with apple magicmouse and apple mighty mouse: deltaMode is 0
- with Logitech optical mouse m-bd58: deltaMode is 1

Comment 2

[Tracy Walker [:tracy]]

Why this is different per platform from comment in noted bug above: https://bugzilla.mozilla.org/show_bug.cgi?id=1057252#c4

"Because we don't actually have any accurate pixel information in this case.
We deal with line or page scrolling only in Windows widget code."

marking P3 for eventual investigation, but it's likely a wontfix too.