1050357 - Partial pixel height element positioned with 'bottom' with 'skewX(0deg)' appears differently from block without 'skewX'

Status: NEW

(Core :: Layout, defect, P3)

Description

[Brandon Frohs]

Attachment: Example showing difference between skewX and no skewX

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:31.0) Gecko/20100101 Firefox/31.0 (Beta/Release)
Build ID: 20140715214327

Steps to reproduce:

Apply `transform:skewX(0deg);height:100.5px;bottom:0;` to an element.

The attachment has two elements, A and B. Both elements are identical, except B has `transform:skewX(0deg);` applied.


Actual results:

The element is 101 pixels tall. Without `skewX(0deg)`, the element is 100 pixels tall.

In the attachment, element B is 101 pixels tall while element A is 100 pixels tall.


Expected results:

The element should be the same height, regardless of whether or not `skewX(0deg)` is applied.

In the attachment, both element A and B should be the same height.

Comment 1

[(mostly gone) XtC4UaLL [:xtc4uall]]

Confirmed against Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0 ID:20140808100211 CSet: 1e0fd78becce

Last good revision: ea059733677c (2013-05-09)
First bad revision: 2673016e7df4 (2013-05-10)
Pushlog: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=ea059733677c&tochange=2673016e7df4

Comment 2

[Loic]

It's FF23, I think.

Comment 3

[Alice0775 White]

I got a different range

Regression window(m-c)
Good:
http://hg.mozilla.org/mozilla-central/rev/f7c89de3ab43
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/18.0 Firefox/18.0 ID:20120915201302
Bad:
http://hg.mozilla.org/mozilla-central/rev/b3f462d96fb5
Pushlog
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=f7c89de3ab43&tochange=b3f462d96fb5

Regression window(m-i)
Good:
http://hg.mozilla.org/integration/mozilla-inbound/rev/33087122ace7
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/18.0 Firefox/18.0 ID:20120916022601
Bad:
http://hg.mozilla.org/integration/mozilla-inbound/rev/6ee831a85d12
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/18.0 Firefox/18.0 ID:20120916033402
Pushlog
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=33087122ace7&tochange=6ee831a85d12

Resgressed by: Bug 788044

Comment 4

[Loic]

How do you observe the difference of 1px between the 2 element heights? It's not obvious for my eyes. :D

Comment 5

[Alice0775 White]

Attachment: screenshot

It is easy for my eyes.

Comment 6

[Loic]

With Ctrl+0, I don't see the difference: http://i.imgur.com/Ak0TFw7.jpg
I need to play with the zoom level to see the difference.

Comment 7

[Alice0775 White]

It does not happen if setting monitor resolution to HiDPI such as 125% and 150%.

Comment 8

[(mostly gone) XtC4UaLL [:xtc4uall]]

(In reply to Alice0775 White from comment #3)
> I got a different range

Yeah, i feared so since the checkins in my range made no sense. Was about to double check but then you were faster :-)
Sorry about that.