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Re: Comments on SVG Compositing

From: Alex Danilo <alex@abbra.com>
Date: Sun, 24 Apr 2011 17:29:35 +1000
Message-Id: <BHB5KL.TSLSA5NPJWBL@abbra.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: public-fx@w3.org, www-svg <www-svg@w3.org>
Hi Rik,

--Original Message--:
>Hi Alex,
>
>I read in today's CSS WG meeting notes that everyone is OK with the spec as-is. In a way it's too bad that it will be ratified in its current state since it is not specific enough.
>If it is adopted, can we get started on the next version on short notice?

Sounds good to me.

>As stated before, the following things need to happen:
>- add additional comments for knockout. The current section is very vague.
>- split up the spec into PorterDuff and regular blending. Describe exactly how the blending is supposed to happen in each scenario.
>- add a section on grouping and how it affects blending. I'm unsure if grouping can work with PD so it might become part of the regular blending.
>- work on adding additional blend modes.

All that sounds sensible - we should be able to provide implementation for the
additional blend modes once we agree on what the additional set should be.

Alex

>Rik
>
>On Thu, Apr 14, 2011 at 9:44 PM, Alex Danilo <alex@abbra.com> wrote:
>
>Hi Rik,
>
>--Original Message--:
>><snip/>
>>As an aside, we probably also want to extend the list of blending modes. 
>>For instance, the current list is missing the following PDF blendmodes: hue | saturation | color | luminosity
>>Flash also defines some useful basic blendmodes (such as 'erase') that could be of interest.
>
>I totally agree that would be a good idea. At the time we did the original blending modes, I had to work out the equations from scratch since they
>were not publlished anywhere (i.e. pre-date the PDF spec.). So we started
>by looking at what Photoshop seemed to do and then did the math to take
>into account source and destination alpha. The result had some errors that
>have been fixed over time.
>
>For the best round-tripping scenarios with Quartz2D as well as AIM,
>I think adding these would be a great idea.
>
>Alex
>
>
>
>
>
Received on Sunday, 24 April 2011 07:32:37 GMT

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