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Re: [css-compositing] blending in canvas

From: Jeremie Patonnier <jeremie.patonnier@gmail.com>
Date: Thu, 15 Nov 2012 23:49:46 +0100
Message-ID: <CAEi838=tak5gp8eZDUiX8YO1-Wgg6gP0K1pzT4Lzg8rqqEmckQ@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, "public-fx@w3.org" <public-fx@w3.org>
Hi,

As an author (who's not really aware of compositing and blending
subtleties), I wish you to avoid 2 and 3. 2 is a change in a well known
API... it will be confusing and will require again to have polyfills to
deal with implementation inconsistency, please, spare us that. 3 is a bit
the same... we will have to learn two different way of doing the same
thing, please, things are hard enough :)

That said, I don't have any opinion between 1 and 4 Except that Canvas is
out there where CSS B&C is not, so... maybe it worth having CSS to follow
Canvas.

My 2ct
Jeremie


2012/11/15 Rik Cabanier <cabanier@gmail.com>

> Maciej still objects because he feels that this is a substantial
> difference between CSS and Canvas.
>
> I think we have a couple of choices:
> 1. Keep globalCompositeOperator for blending and compositing but collapses the
> 2 CSS properties into one that takes the same arguments as
> globalCompositeOperator
> 2. Keep the 2 CSS properties but split the Canvas properties into
> globalCompositeOperator and globalBlendOperator
> 3. Don't change anything and live with them being different.
> 4. Don't change anything but also define a new CSS shorthand that combines
> blending and compositing. Canvas is compatible with this shorthand.
>
> I'm unsure what approach we should take.
> option 2 has the issue that we can't implement this correctly in the near
> term.
> option 1 has the issue that transitionable blending will be more confusing
> in the future.
> option 4 should cover all concerns but introduces yet another keyword.
>
> Any comments?
>
>  Rik
>
> On Wed, Nov 14, 2012 at 11:10 AM, Tab Atkins Jr. <jackalmage@gmail.com>wrote:
>
>> On Wed, Nov 14, 2012 at 10:48 AM, Rik Cabanier <cabanier@gmail.com>
>> wrote:
>> > Good point!
>> >
>> > They are just strings, so we can later define it so you can say:
>> > mycontext.globalCompositeOperator = "multiply,source-atop"
>>
>> I'd use a space-separated pair, but otherwise, yes.  ^_^
>>
>> ~TJ
>>
>
>


-- 
Jeremie
.............................
Web : http://jeremie.patonnier.net
Twitter : @JeremiePat <http://twitter.com/JeremiePat>
Received on Thursday, 15 November 2012 22:50:34 GMT

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