Re: [Gimp-developer] Combining Porter-Duff operations with Blend Modes?

[Ville Sokk <ville sokk gmail com>]

On Fri, Jul 13, 2012 at 2:33 PM, Calculemus <calculemus1988 gmail com> wrote:
> Sorry I replied to previous message with this content, but meant to send
> this
> as new topic.
>
> How does GIMP deal with Porter-Duff operations and Blend modes?
>
> Where can I find an example code of this?
>
> Mathematically there is one formula to mix porter-duff and blending
> into one, but I am interested how is this implemented.
>
> Thanks
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The way blending modes are done in GIMP is a hack using 8-bit integers
and not a good representation of Porter-Duff operations. Look into
GEGL's sources, it even has a Porter-Duff category
http://gegl.org/operations.html