[cairo] [RFC] Cairo operators expressed in shader syntax

[Jeff Muizelaar]

On Sat, May 12, 2007 at 03:05:37PM -0700, Daniel Amelang wrote:
> On 5/12/07, Jeff Muizelaar <jeff at infidigm.net> wrote:
> >On Fri, May 11, 2007 at 04:22:11PM -0700, Daniel Amelang wrote:
> >> ; SOURCE
> >> result = src
> >> ; src IN mask SOURCE dst
> >> result = src * mask.a
> >> ; src COMPONENT_IN mask SOURCE dst
> >> result = src * mask
> >
> >Just as a note, although pixman's SOURCE operator behaves this way,
> >Cairo's does not. It looks more like:
> >result = src * mask.a + (1.0 - mask.a) * dst
> 
> So where does cairo actually implement this strange version of SOURCE
> you speak of?

_clip_and_composite_soruce() in cairo-surface-fallback.c around line
279.

-Jeff