[cairo] a couple requests from Inkscape

[bulia byak]

Hi cairo folks,

we at Inkscape have some feature requests for cairo - I had talked to
Carl and would like to discuss them here as well.

- inversion operator, i.e. rendering an object by inverting what is
below it in z-order. With the existing operators it's impossible,
although it is no less (and probably more) useful than e.g. xor. In
SVG, inversion can be done by a filter; in other vector backends, it
will need rasterization (but you use rasterization anyway for other
operators).

- a new moveto method which does not start a new subpath, so we could
skip some parts of the path during rendering (e.g. those that don't
fit the render area, for speed) and still use the closepath correctly,
i.e. close the real subpath regardless of these interruptions.

-- 
bulia byak
Inkscape. Draw Freely.
http://www.inkscape.org