Re: [css-compositing] Request to move Compositing and Blending spec to CR

On Thu, Dec 12, 2013 at 7:29 PM, Robert O'Callahan <>wrote:

> On Fri, Dec 13, 2013 at 4:13 PM, Rik Cabanier <> wrote:
>> No, the spec should not refer to blogs. Also, this is not 'potentially'
>> useful as the absence of this description has caused confusion in the past.
> I agree with James. Having the spec define behavior that is never used by
> any Web feature is very confusing.
> Section 4 is not really needed at all since the HTML5 canvas spec defines
> the canvas compositing behavior.

Can you point where that is defined in the canvas spec?

> If you want the Compositing and Blending spec to define new compositing
> modes for canvas, then define a list of operators that the HTML canvas spec
> can refer to, but don't define globalCompositeOperation here. Don't even
> mention canvas here.

It's needed because the canvas spec doesn't say anything about how
compositing should happen.
I don't want to break canvas by removing this.

This was discussed on the mailing lists a year ago and there were no
objections at that point.

> Another very important reason is also that if this property/behavior is
>> included in the spec, the W3C patent policy will apply.
> Describing something in a W3C spec that is not actually used by any
> features in that spec, just so we can get the patent policy to apply to it,
> borders on bad faith.

It *is* being used.
Also, future spec might want to refer to this. Another example is the
proposal for masking in canvas which has an option for clip-to-self. It
would be unfortunate that we would have to rev the compositing spec to
progress canvas or filters.

Received on Friday, 13 December 2013 03:51:16 UTC