1675949 - Consider not using a fixed value for lines-to-pixel hacks from bug 1392460

Status: RESOLVED FIXED

(Core :: DOM: Events, task, P3)

Description

[Emilio Cobos Álvarez (:emilio)]

Masayuki comments:

Hmm, I found this post:
https://stackoverflow.com/questions/20110224/what-is-the-height-of-a-line-in-a-wheel-event-deltamode-dom-delta-line

So, some web developers may use wheel event as "beforescroll" event and want to know how much pixels will be scrolled. So, perhaps, using fixed value may cause some custom scroll elements may be scrolled too fast or too slow. So, I think we should not use fixed scale value here.

On the other hand, this patch's inline comments are now too many and makes it harder to read the source code. So, I'm okay to land as-is for now, but please file a follow up bug if you want to fix it in this patch.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1675949 - Use a non-fixed value for pixel deltas. r=masayuki

Your call if you think this is worth it. Might need some test
adjustments.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/2d9ef4afb05d
Use a non-fixed value for pixel deltas. r=masayuki

Comment 3

[Alexandru Michis [:malexandru]]

Backed out changeset 2d9ef4afb05d (bug 1675949) for causing mochitest plain failures in test_dom_wheel_event.html
Backout link: https://hg.mozilla.org/integration/autoland/rev/7d657720a92b2b2c6c8a43c2f984e3917acc00e8
Push with failures, failure log.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Tweaked the patch, will wait for masayuki to review it. Thanks Alexandru!

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1f3e2135ec4b
Use a non-fixed value for pixel deltas. r=masayuki

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c743864f4e39
Keep rounding to integer sizes. a=orange

Comment 7

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/1f3e2135ec4b
https://hg.mozilla.org/mozilla-central/rev/c743864f4e39