Dynamic and linked offset fails with elliptical arcs

[Eugenio]

Dynamic and linked offset operations fail in closed paths which include elliptical arcs. It seems like these operations are performed always taking the convex side of the elliptical arc as the outer side of the closed path.

To reproduce this bug draw two ellipses that intersect each orher. Apply “path>difference” operation and apply “path>linked offset” (or “path>dynamic offset”) to the resulting object.

Note 1: If the object is transformed to a path formed only by Bezier curves (apply “break the path at selected nodes” to a node and immediately “join selected nodes” will do the trick) dynamic and linked offset operations work OK.

Note 2: What you see in the attached SVG file when it is displayed in Inkscape is not what you see when it is displayed in Internet Explorer, Edge or Firefox

- Software version: Inkscape 0.92.2 (5c3e80d, 2017-08-06)
- O.S.: Windows 10 Home 64bits, version 1709, compilation number: 16299.248

[Alvin Penner (apenner)]

confirmed on Windows 10, Inkscape 0.92+devel (9d6b0e8, 2018-02-18)