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Re: Updated filters specification

From: Rik Cabanier <cabanier@gmail.com>
Date: Tue, 19 Apr 2011 13:58:54 -0700
Message-ID: <BANLkTinFbjd3L9NNu+2-j++LWuBG5de92Q@mail.gmail.com>
To: Erik Dahlstrom <ed@opera.com>
Cc: Dean Jackson <dino@apple.com>, public-fx@w3.org
On Tue, Apr 19, 2011 at 1:22 AM, Erik Dahlstrom <ed@opera.com> wrote:

> On Tue, 19 Apr 2011 06:23:57 +0200, Rik Cabanier <cabanier@gmail.com>
> wrote:
>  Hi Dean,
>> This looks very good!
>> A couple of questions:
>> 1. Filter region extensions.
>> Why do you need to specify this? I can see that this is necessary for
>> certain types of filters, but for the most common ones, the browser can
>> just
>> calculate if for you.
>> Could this be optional? It will for sure make author's life easier...
> Yeah, that's been discussed before, and they're going away, I have an
> action to remove that (it's basically leftovers from an old SVG 1.2 Full
> draft).
>  2. Accessing the background image
>> Would there ever be a reason to do this? This seems like a very expensive
>> operation that could be worked around by rearranging the content.
> You're right that it can be expensive to generate. I think in some (rare?)
> scenarios it is necessary to have something like enable-background.

A user could put the background content in with the content that has the
filter applied to it.
In addition to that, he would also have to draw a white box to make sure
that the actual background doesn't peek through where there's alpha.

This feature could be especially hard to implement in a world where things
are accelerated in the GPU

> There is also the SVG 1.1 backwards compatibility aspect to consider.

Do we care about this if we move to CSS? SVG1.1 was not designed for this.

> I think that the optional <x>,<y>,<width>,<height> values in
> 'enable-background' should be deprecated, because they are useless in
> practice. We should let the UA compute the necessary background buffer
> region, and just ignore these values if specified.

I agree. We can discuss that in the context of the SVG compositing spec.
Maybe there are workflows were this makes sense.

Received on Tuesday, 19 April 2011 20:59:22 UTC

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