On Thu, Feb 24, 2011 at 3:17 PM, Chris Lilley <chris@w3.org> wrote:
> On Thursday, February 24, 2011, 11:01:51 PM, Alistair wrote:
>
> AM> I would think it would be quite important to cover the basic
> AM> overlay primitives offered in most graphics packages, such as:
> AM>
> AM> Screen
> AM> Blend
> AM> Add
> AM> Multiply
> AM> Exclusion
> AM> Dodge
> AM> Hard-light
> AM> Soft-light
> AM> Burn
> AM> Difference (difference is also great for getting visual test
> results when comparing builds)
> AM> Etc
> AM>
> AM> ( I am aware we have some of these filter already available to SVG )
>
> They are in the compositing spec, and we have all of them.
>
>
> http://dev.w3.org/SVG/modules/compositing/master/Overview.html#containerElementCompositingOperators
that looks close to the Adobe imaging model with the exception of 'isolate'.
Is that always assumed to be true?
>
>
> AM> Could anyone tell me if there has been an update to the way
> AM> sources work for filters on individual DOM elements yet? Last
> AM> time I checked there was no way to execute the following kind
> AM> of behavior: (Using multiple DOM elements as separate sources)
>
> <svg version="1.1" xmlns="http://www.w3.org/2000/svg">
> <defs>
> <filter id="srcLoadedOverlay">
> <feImage xlink:href="url(#canvas0)" result="img1" />
> <feImage xlink:href="url(#canvas1)" result="img2" />
> <feImage xlink:href="url(#canvas2)" result="img3" />
> <feBlend in="img1" in2="img2" result="blend1" mode="multiply" />
> <feBlend in="blend1" in2="img3" mode="lighten" />
> </filter>
> </defs>
> </svg>
>
That seems like a very complex solution which doesn't seem applicable to
HTML.
Instead you could define blending of 2 groups like this:
<html>
....
<body>
..... <- backdrop
<div style="blend: layer;"> <- group A
... <- text, images, etc
<div style="blend: multiply;"> <- group B
.. <- text, images, etc
</div>
</div>
This would blend group a with b and would ignore the backdrop
>
> xlink:href takes a URL directly, not wrapped in url().
>
> It would seem reasonable to state in the spec that if a canvas element is
> referenced by its id, then the graphics state of the canvas is used as the
> input to the filter. (This already works for svg elements, for example).
>
> Of course this immediately causes same-origin restrictions to apply to the
> filter.
>
>
>
Received on Monday, 28 February 2011 15:17:13 UTC