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

On Thu, Apr 17, 2014 at 1:42 PM, Dean Jackson <dino@apple.com> wrote:

> As of https://trac.webkit.org/r167448 WebKit supports mix-blend-mode
> unprefixed.
>
> We did this knowing that we will be unable to implement the non-separable
> modes in the near future (hue, saturation, color and luminosity). We
> suggest these be moved to Level 2 of the specification.
>
> 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.
>
> [I don’t want to go into much detail here, but these effects are difficult
> to implement in our composited mode, and we wouldn’t want to have the
> content break as it becomes composited (which could be for any number of
> hard-to-determine reasons)]
>

This sounds reasonable to me since you simply can't implement the spec
as-defined. There are also no shipping implementations so we're not going
to break any real world content.
It's unfortunate that we're dropping them, but hopefully we can add them
back in when OSX and iOS support them.
I will send the spec back to LC and make the appropriate edits.

Maybe we can flag the non-separable blend modes as optional? It would be
easy for authors to feature test this.