Re: [compositing-1] please move non-separable effects to Level 2

On Sat, Apr 19, 2014 at 6:30 AM, Rik Cabanier <cabanier@gmail.com> wrote:

> On Fri, Apr 18, 2014 at 3:56 AM, Robert O'Callahan <robert@ocallahan.org>wrote:
>
>> On Fri, Apr 18, 2014 at 6:15 PM, Rik Cabanier <cabanier@gmail.com> wrote:
>>
>>> How do you feel about making the non-sep blend modes optional for now?
>>>  I can see Dean's view of wanting to support the whole spec so WebKit
>>> doesn't get called out for only supporting a subset.
>>>
>>
>> Is that really what Dean is concerned about? I did not think so.
>>
>
> From Dean's email:
>
> If they are not moved, we’ll probably put the prefix back on, because *we
> don’t want to ship a non-prefixed incorrect implementation.*
>
>
An incomplete implementation should not necessarily be described as
"incorrect". It's common practice for a browser to choose to ship some
useful subset of a specification. Whether that subset matches some formal
specification level doesn't matter in practice. For example every browser
implements a different subset of HTML5 but we don't say they're all
"incorrect".

It's clear at this point that the CSS Blending spec will need to change.
> The spec is in CR and we have feedback from a browser vendor that they
> can't implement certain features because of a technical reason. Having a
> spec that is interoperable is (to me at least) more important than one that
> is more complete but only partly implemented.
>

We need interopable behavior for the features browsers have in common.
Browsers having the same set of features would be nice but it's an ideal we
can't even get close to we don't stress about it. For example entire
features like WebGL or Device Orientation are not present on some browsers
and can't be. We don't reject them because of that.

Either the subset is removed, or it is made optional.
>

In practice, every Web feature is optional, although there are some subsets
of features that don't make sense because they're useless.

I agree it's nice for purely marketing reasons to be able to say "our
browser has full support for CSS Compositing Level 1". Is that the point of
this thread?

Rob
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