[cairo] separating compositing and blending

Rik Cabanier cabanier at gmail.com
Sat Oct 20 08:39:55 PDT 2012


the current cairo compositing operators combine blending and compositing
This means that if you do an 'overlay', the result of the 'overlay'
blending formula will always be composited with 'src-over'.

Nikos (from Canon) and I (from Adobe) have a proposed working draft
that allows people to specify blending and compositing in CSS [2]. As
an example, this would allow you to do a 'screen' blend on an HTML
element with a 'src' compositing mode. This separation could also be
extended to canvas.

Looking at the Cairo architecture, it seems that this could be added
by adding an optional blend mode operator to 'set_operator'.
What do people think?


1: http://cairographics.org/operators/
2: https://dvcs.w3.org/hg/FXTF/rawfile/tip/compositing/index.html
3: http://cairographics.org/manual/cairo-cairo-t.html#cairo-set-operator
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.cairographics.org/archives/cairo/attachments/20121020/72dc3af6/attachment.html>

More information about the cairo mailing list