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Re: Comments on SVG Compositing

From: Rik Cabanier <cabanier@gmail.com>
Date: Thu, 21 Apr 2011 20:47:17 -0700
Message-ID: <BANLkTimSf-ODnajBik7UcHto74UgTp7LwA@mail.gmail.com>
To: Alex Danilo <alex@abbra.com>
Cc: public-fx@w3.org, www-svg <www-svg@w3.org>
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?

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.


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 Friday, 22 April 2011 03:47:44 UTC

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