Re: Comments on SVG Compositing

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.


>On Thu, Apr 14, 2011 at 9:44 PM, Alex Danilo <> wrote:
>Hi Rik,
>--Original Message--:
>>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.

Received on Sunday, 24 April 2011 07:30:04 UTC