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Re: [css-transforms] Handling combined opacity and preserve-3d

From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Fri, 27 May 2016 11:09:39 +1200
To: Chris Harrelson <chrishtr@google.com>, Simon Fraser <smfr@me.com>
Cc: "www-style@w3.org" <www-style@w3.org>, Tien-Ren Chen <trchen@google.com>, Rossen.Atanassov@microsoft.com
Message-ID: <26a5aaad-6469-5ea1-2093-74a4f95c3e2c@mozilla.com>

On 27/05/16 5:03 AM, Chris Harrelson wrote:
> Hi Matt/Simon/Rossen/all,
> I'm the lead for paint/compositing integration in Blink.
> TL;DR:
> - Blink/Chrome would like to change its implementation to have opacity 
> force flattening, and AIUI match what Firefox was doing beforethis 
> Mozilla bug <https://bugzilla.mozilla.org/show_bug.cgi?id=1250718>wax 
> recently fixed.
> - We'd like other implementations to make the change also if there is 
> consensus.
> As noted already in this thread, this changed behavior matches the 
> latest spec, is more well-defined and rational, and significantly 
> reduces the complexity of Blink's implementation. (Matt, from reading 
> the Mozilla bug, I think you would agree?)
> Other implementers: does this change sound good? Would you be willing 
> to commit to changing behavior if it is web compatible enough? (We are 
> already collecting compatibility data in the Canary & Dev channels).
> Here is one example:
> Before <http://jsbin.com/tabuxo/edit?html,output>
> After <http://jsbin.com/tekuratiba/1/edit?html,output>
> Our work is tracked in this bug 
> <https://bugs.chromium.org/p/chromium/issues/detail?id=612956>.

Firefox only temporarily had that behaviour, it was a regression due to 
a refactoring we did. We reverted to matching the current Blink/WebKit 
behaviour since we had reports of real sites breaking because of it.

I do agree that this change is the preferable behaviour though, so will 
be interested in the results of the compatability data you're collecting.

- Matt
Received on Thursday, 26 May 2016 23:10:15 UTC

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