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Re: Compositing math in SVG

From: Rik Cabanier <cabanier@gmail.com>
Date: Mon, 9 Jul 2012 11:51:36 -0700
Message-ID: <CAGN7qDA7uP_oE79L-AbrHrabQf-Cp2QCNi__D2rhb6Xzq+5R5Q@mail.gmail.com>
To: Calculemus <calculemus1988@gmail.com>
Cc: www-svg@w3.org
Hi,

take a look as the draft CSS blending spec:
https://dvcs.w3.org/hg/FXTF/rawfile/tip/compositing/index.html#blending
Those should match what you see in the Adobe reference guides. (Can you
post a link to these?)

The reason for the differences is that the SVG spec combines blending and
src-over compositing to the same formula.
The Adobe and CSS spec don't do this. The define it as:
1. the blending formula which combines foreground and background colors
(ignoring alpha)
2. if the foreground has alpha, blend the original color with the blended
color
3. composite this color with alpha using the specified compositing formula

Rik

On Sun, Jul 8, 2012 at 1:43 AM, Calculemus <calculemus1988@gmail.com> wrote:

> Hello,
>
> I am working on graphics application where we need to implement
> compositing operations also called blending modes such as soft-light,
> hard-light, etc.
>
> The math you use here:
> http://www.w3.org/TR/SVGCompositing/<http://www..w3.org/TR/SVGCompositing/>
> is different than the one in the official Adobe reference
> used for Photoshop and After Effects.
>
> Could you please give me some feedback on that, why is it so, and which
> one should I prefer?
>
> Thanks
>
Received on Monday, 9 July 2012 18:52:04 GMT

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