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Re: [filters] what should feGaussianBlur sample outside the source image?

From: Dirk Schulze <dschulze@adobe.com>
Date: Mon, 6 Aug 2012 18:50:55 -0700
To: Cameron McCormack <cam@mcc.id.au>
CC: FX Taskforce <public-fx@w3.org>, Robert Longson <longsonr@gmail.com>
Message-ID: <2C81CD69-C825-468F-864C-7D1CE2CC2946@adobe.com>
It clarifies already that requested pixels outside of the current primitive are assumed to be transparent black. Therefore the rendering output of opera and webkit is correct here. FillPaint is a pseudo filter primitive and does not contribute to the context you describe. I can add the quotes in a follow up mail once I am on my desk if you can't find the necessary quotes.


Sent from my iPhone

On Aug 6, 2012, at 5:28 PM, "Cameron McCormack" <cam@mcc.id.au> wrote:

> Consider this document:
>   http://people.mozilla.org/~cmccormack/tests/blur.svg
> The Filters spec (and SVG before it) says the following in the 
> feGaussianBlur section:
>   If the input has infinite extent and is constant (e.g FillPaint,
>   this operation has no effect.
> The document uses FillPaint as the input to feGaussianBlur, but in Opera 
> at least, the blue rectangular area has blurry edges, because it is 
> (presumably) sampling transparent black outside the source image area. 
> For the operation to have no effect, you would expect the rectangle to 
> have sharp edges, which would imply sampling the FillPaint outside the 
> source image area.
> The test 
> http://dev.w3.org/SVG/profiles/1.1F2/test/harness/htmlObjectMiniApproved/filters-overview-01-b.html 
> seems to assume that transparent black is sampled outside the source 
> image area.
> The spec should be clarified to indicate how to sample around the edges 
> of the source image, and if it should be transparent black, the sentence 
> about having no effect with FillPaint should be changed.
Received on Tuesday, 7 August 2012 01:50:26 UTC

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