1702407 - Incorrect scrollX/scrollY value when use meta viewport in RDM

Status: NEW

(Core :: Layout: Scrolling and Overflow, defect)

Description

[Martin]

Attachment: viewport.html

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36
Firefox for Android

Steps to reproduce:

1. set pref dom.meta-viewport.enabled to true
2. Use Inspect and responsive => 240 x 375
3. open/use attachment html
4. scrollTo(0,30) and scrollY is 0 -- KO
5. scrollTo(30,0) and scrollX is 0 -- KO

Actual results:

Incorrect scrollX/scrollY
scrollTo(0,30) and scrollY is 0
scrollTo(30,0) and scrollX is 0

Expected results:

scrollTo(0,30) and scrollY is 30
scrollTo(30,0) and scrollX is 30

Comment 1

[Hiroyuki Ikezoe (:hiro)]

That's because the root element is not scrollable. If you scroll the content by hand (mouse wheel or some) and query document.scrollingElement.scrollTop then you will see 0. Instead visualViewport.offsetTop is not 0.

Comment 2

[Hiroyuki Ikezoe (:hiro)]

Weird, scrollTo(0, 30) worked now. There's definitely something I am missing.

Comment 3

[Hiroyuki Ikezoe (:hiro)]

This is something in RDM. On mobile scrollTo works always, but in RDM window.scrollMaxY and window.scrollMaxX are zero in the case where scrollTo doesn't work.

Comment 4

[Martin]

Attachment: patch.diff

I think something wrong in UpdateMinimumScaleSize,
I try this patch/attachment, it can work fine.

Comment 5

[Hiroyuki Ikezoe (:hiro)]

As I commented in Matrix, the change doesn't look correct to me. Whether we apply the minimum scale or not is not affected by the current zoom level.

Comment 6

[Hiroyuki Ikezoe (:hiro)]

Anyway, I confirmed this issue yesterday.

Also note that setting "dom.meta-viewport.enabled" is not necessary to reproduce this issue.

Comment 7

[Martin]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #6)

Anyway, I confirmed this issue yesterday.

Also note that setting "dom.meta-viewport.enabled" is not necessary to reproduce this issue.
Hi,
How to reproduce this issue when "dom.meta-viewport.enabled" is flase?

Comment 8

[Martin]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #6)

Anyway, I confirmed this issue yesterday.

Also note that setting "dom.meta-viewport.enabled" is not necessary to reproduce this issue.

Hi,
How to reproduce this issue when "dom.meta-viewport.enabled" is flase?

Comment 9

[Hiroyuki Ikezoe (:hiro)]

In RDM even if "dom.meta-viewport.enabled" is false, it properly emulates mobile viewport stuff.