Is it possible to define a TikZ style that shifts a path perpendicularly? I.e., the resulting path should be obtained from the given path by shifting every point, say, 0.1cm to the right, orthogonal to the direction of the path at this point.
This should work for arbitrary paths (not just straight lines). Also, I do not just want to draw a line along the shifted path, but also do clipping or filling, etc. So using the "raise=..." key together with a decoration as described in "perpendicular shift" for paths won't work I think.