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

On Mon, Feb 29, 2016 at 2:49 PM Matt Woodrow <mwoodrow@mozilla.com> wrote:

>
>
> On 26/02/16 5:47 PM, Robert O'Callahan wrote:
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> On Sat, Feb 27, 2016 at 10:20 AM, Simon Fraser <smfr@me.com> wrote:
>
> When finishing off CSS Transforms, we’re going to have to be willing to
>> create combat issues; there’s no way we can avoid them with the current
>> lack of compat between browsers. I’d like to see more breakage than [4]
>> before speccing broken Blink/WebKit behavior.
>>
>
> If you think we should move to a better behavior, ship it in Webkit and
> then I think we'd be willing to follow and update the spec.
>
>
> Right, the new spec seems like a big improvement, but I think we'll need
> to coordinate to get away with such big compatibility changes.
>
> It still seems valuable to update some version of the spec, or otherwise
> document the current state of affairs rather than only having the desired
> future state.
>
> I plan on fixing Gecko to be compatible with the Blink/WebKit behaviour in
> the mean time.
>

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 before this 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>.

Thanks,
Chris



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