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Re: [css-transforms] CSS3D issue with opacity in Chrome 53

From: Rik Cabanier <cabanier@gmail.com>
Date: Sun, 25 Sep 2016 04:31:15 +0200
Message-ID: <CAGN7qDAx1urgavC=GMdhYbJWrs=qa_B54w8NjTnD5njLeAnRag@mail.gmail.com>
To: Andrew Prendergast <ap@vizdynamics.com>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, "public-fx@w3.org" <public-fx@w3.org>
On Sun, Sep 25, 2016 at 1:15 AM, Andrew Prendergast <ap@vizdynamics.com>
wrote:

> Hi TJ,
>
> Thanks for the note.
>
> I looked over the various threads myself and I think the core issue is
> best summarised as follows:
>
> *Setting opacity is causing the side effect of modifying the
> transformation of child nodes and is highly unexpected.*
>
> Those working with SVG and CSS3D have provided detailed examples of why
> this is a problem.
>
> The fix is straightforward - setting opacity should only affect opacity.
>

Can you tell us how that would work?
Keep in mind that if you apply opacity to a group (=multiple elements), the
rendering of that group is defined here:
https://www.w3.org/TR/compositing-1/#groups


>
> On 20 Sep 2016, at 6:56 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
>
> On Wed, Sep 14, 2016 at 10:39 PM, Andrew Prendergast <ap@vizdynamics.com>
> wrote:
>
> I am maintaining the repo at http://github.org/aprender/refamous and would
>
> like to add my +1 on the issues caused by the recent opacity “feature”
>
> creeping into Chrome 53 based on the W3C spec.
>
>
> There is a link to more info here:
>
> https://bugs.chromium.org/p/chromium/issues/detail?id=646993
>
>
> I believe that the W3C spec on the matter in question is functionally
>
> incorrect and propose it be amended for two reasons:
>
>
> -        Philosophically, the scene graph model taught in 3D programming
>
> courses around the world simply will not work with these sort of unintended
>
> side-effects being introduced.
>
> -        From an application perspective, this issue effectively causes one
>
> to add logic to disable use of transparency if one goes anywhere near a
>
> matrix3d().
>
>
> As I've responded to identical threads a few times in the last few
> days, I'll just point to my earlier response at
> <https://github.com/w3c/svgwg/issues/264#issuecomment-246750601>.
>
> ~TJ
>
>
Received on Sunday, 25 September 2016 02:31:44 UTC

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