(wrong string) ’s backdrop

On Wed, Sep 18, 2013 at 9:06 PM, Dirk Schulze <dschulze@adobe.com> wrote:

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> On Sep 19, 2013, at 5:28 AM, "Rik Cabanier" <cabanier@gmail.com> wrote:
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> On Wed, Sep 18, 2013 at 8:15 PM, Brad Kemper <brad.kemper@gmail.com>wrote:
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>> On Sep 18, 2013, at 4:33 PM, Rik Cabanier wrote:
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>>  Blurring of the backdrop is not quite the same as a CSS image.
>> You typically only want to blur where you're actually painting. For
>> instance, if you draw large text or an SVG graphic, you only want to blur
>> where the pixels of the text or graphic are drawn.
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>> I guess you could pull in the backdrop as a rectangular region of a
>> certain size, but seems too primitive for CSS.
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>> The backdrop is whatever is behind the element, right? That can change,
>> due to scrolling, resizing, dragging, animating, etc., and you'd want the
>> blurring to continue to blur whatever is behind it.
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> Yes, since this is all declarative, the effect should look correct if the
> content or its backdrop change. (Just like it should with blending)
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> Exactly that was my intention with 'backdrop'. It always references what
> is behind the element. (And that might change by transforming elements or
> scrolling.) The effect is of course limited to the background size and
> position of the element. This gets you exactly the possibility to blur or
> blend the areas that are exactly behind your element. I don't think this is
> to primitive though.
>

So, is the area of the backdrop that is filtered rectangular, or is it the
shape of the content you draw?
SVG's backgroundimage primitive will pull in a rectangular area so if you
want it to just affect the content, you'd have to calculate the coverage of
the element and use that as a mask/clip