Proposal : 4 more sources for the "in" property of filters

[Sorry if this appears to be a repost - After some hours, I still don't see
my original message in the archive list, so I posted again]

Hello SVG WG

I looked at the

http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input

I wish we had the following 4 more sources for the "in" property of filters
:

StrokeGraphic + FillGraphic (that combined together are equal
to SourceGraphic)
StrokeAlpha   + FillAlpha   (= SourceAlpha)

By now, if you know the stroke width then you could (somewhat) emulate this
by using

fillgraphic   = sourcegraphic IN (morphology(sourcegraphic, expand 1/2
strokewidth))
strokegraphic = sourcegraphic - fillgraphic
but this is very CPU intensive because of morphology.

V.