1030124 - Canvas drawImage incorrect offset if backface-visibility is hidden

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[info]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0 (Beta/Release)
Build ID: 20140605174243

Steps to reproduce:

apply backface-visibility: hidden to an canvas with absolute position


http://jsfiddle.net/0ldsk3wl/vJ6Rk/6/


Actual results:

Canvas drawImage draws incorrect offset by start position



Expected results:

Canvas drawImage draws offset should be 0,0

Comment 1

[(mostly gone) XtC4UaLL [:xtc4uall]]

Regressed within ESR 24 and 30 by a quick check.

Comment 2

[info]

Attachment: bug sample

Comment 3

[Alice0775 White]

Regression widnow(m-i)
Good:
https://hg.mozilla.org/integration/mozilla-inbound/rev/de17e5deb35d
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0 ID:20140226185711
Bad:
https://hg.mozilla.org/integration/mozilla-inbound/rev/88723262c85c
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0 ID:20140226185811
Pushlog:
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=de17e5deb35d&tochange=88723262c85c

Suspect: 
88723262c85c	Matt Woodrow — Bug 968555 - Don't create a stacking context for backface-visibility:hidden. r=dbaron

Comment 4

[Sylvestre Ledru [:Sylvestre]]

Matt, does it ring a bell? Thanks

Comment 5

[Sylvestre Ledru [:Sylvestre]]

This is now too late for 31. However, there is still some time for 32.

Comment 6

[Matt Woodrow (:mattwoodrow)]

I'll fix this. I don't think this is super urgent, so it won't be this week.

Comment 7

[Lawrence Mandel [:lmandel] (use needinfo)]

I'm marking this as won't fix for 32 based on comment 6. 

Matt - Can you get to this in the next two weeks before 33 hits beta? Or, if you think it's less urgent than that, perhaps we should just untrack and let this ride the trains.

Comment 8

[Matt Woodrow (:mattwoodrow)]

Attachment: Handle reference frames correctly

Previously, all nsDisplayTransform items existed for frames that were also 'reference frames', and child display items had their coordinates relative to that. When building the transform we include a translation from the child coordinate space into that of the parent.

Since we're no longer marking backface-visibility as transformed/stacking context, then it's also no longer a reference frame. To get the correct behaviour we need to apply the translation when computing the transform for the parent, which is transformed and a reference frame.

Comment 9

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8474978 [details] [diff] [review]
Handle reference frames correctly

Actually, I think roc probably knows this code better

Comment 10

[Matt Woodrow (:mattwoodrow)]

 https://hg.mozilla.org/integration/mozilla-inbound/rev/789d20c54b14

Comment 11

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/789d20c54b14

Comment 12

[Sylvestre Ledru [:Sylvestre]]

Matt, as it is affecting 33, we could take a patch for this. Could you fill an uplift request? Thanks

Comment 13

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8474978 [details] [diff] [review]
Handle reference frames correctly

Approval Request Comment
[Feature/regressing bug #]: Bug 968555
[User impact if declined]: Incorrect positioning of backface-visibility:hidden elements that don't have a transform.
[Describe test coverage new/current, TBPL]: Tested manually, added reftest for this case.
[Risks and why]: Low risk, just changes the transforms on elements.
[String/UUID change made/needed]: None

Comment 14

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/56bd99846222

Comment 15

[Ryan VanderMeulen [:RyanVM]]

(In reply to Ryan VanderMeulen [:RyanVM UTC-4] from comment #14)
> https://hg.mozilla.org/releases/mozilla-aurora/rev/56bd99846222

This time with a version that actually builds:
https://hg.mozilla.org/releases/mozilla-aurora/rev/11e62d865e99

Comment 16

[vasilicamihasca]

I was able to reproduce this bug on Nightly 30.0a1 (2014-06-25), using Windows 7 x64.

Verified fixed on Windows 7 x64 using Firefox 33.0b9 (20141002185629).

This fix can be marked as verified.

[bugday-20141008]

Comment 17

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

(In reply to vasilicamihasca from comment #16)
> I was able to reproduce this bug on Nightly 30.0a1 (2014-06-25), using
> Windows 7 x64.
> 
> Verified fixed on Windows 7 x64 using Firefox 33.0b9 (20141002185629).
> 
> This fix can be marked as verified.
> 
> [bugday-20141008]

Thank you for the verification on Beta. Setting status flag.