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RE: Filter Templates

From: Rik Cabanier <cabanier@adobe.com>
Date: Sun, 6 Feb 2011 16:45:52 -0800
To: "robert@ocallahan.org" <robert@ocallahan.org>
CC: Cameron McCormack <cam@mcc.id.au>, Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>, "public-fx@w3.org" <public-fx@w3.org>
Message-ID: <8A13F0222395BD428969E5BA529EFA7477673EF710@NAMBX01.corp.adobe.com>

> I don't think those are reasons to make CSS filters simple. I don't think any significant browser is going to refuse to implement SVG filters indefinitely. 
True. However, if svg filters prove impossible to accelerate, they will end up not being used.

> And it is not necessary to keep CSS filters simple for them to be GPU-accelerated. Blurred shadows are already relatively difficult to implement on the GPU.
Once you have the framebuffer of the content you want to shadow, it's not that complicated. (We know that browsers can get the buffer, since they can accelerate CSS animation.)
Part of the proposal would describe exactly what operations need to be done for a dropshadow.

> Individual CSS filters should be simple so that authors find them easy to use. I suspect authors will find it difficult to remember how to use a function with 
> nine parameters, as you have proposed.
The parameters are optional. If you don't specify them, they will fall back to the default value.
I'm also not sure how a dropshadow can be implemented with less parameters. I guess 'strength' can be removed but it's a handy tool in animations.

Looking at the complexity of doing a dropshadow in SVG, a single function seems a lot simpler.

Rik

From: rocallahan@gmail.com [mailto:rocallahan@gmail.com] On Behalf Of Robert O'Callahan
Sent: Sunday, February 06, 2011 3:56 PM
To: Rik Cabanier
Cc: Cameron McCormack; Brad Kemper; www-style list; public-fx@w3.org
Subject: Re: Filter Templates

On Mon, Feb 7, 2011 at 11:06 AM, Rik Cabanier <cabanier@adobe.com> wrote:
I never heard back on my proposal.
Is it because it’s too limited or doesn’t rely on SVG?
 
I believe the CSS filters need to be very simple so
-          They can be accelerated on the GPU
-          The can be implemented by browsers that choose not to implement SVG filters.

I don't think those are reasons to make CSS filters simple. I don't think any significant browser is going to refuse to implement SVG filters indefinitely. And it is not necessary to keep CSS filters simple for them to be GPU-accelerated. Blurred shadows are already relatively difficult to implement on the GPU.

Individual CSS filters should be simple so that authors find them easy to use. I suspect authors will find it difficult to remember how to use a function with nine parameters, as you have proposed.

Rob
-- 
"Now the Bereans were of more noble character than the Thessalonians, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true." [Acts 17:11]
Received on Monday, 7 February 2011 00:47:36 GMT

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