defaultFor
Returns the default style for shape's concrete type — black ink, so an unstyled shape is visible.
Points and dipoles get the filled-marker defaults (POINT, DIPOLE); lines, segments, circles, polygons, and polylines the stroked ones (LINE, SEGMENT, CIRCLE, POLYGON, POLYLINE). A Shape outside the known categories gets NONE.
Return
The matching per-shape constant.
Parameters
shape
The shape to pick a default for.