Function bisector 

pub fn bisector(
    a: &Target2,
    b: &Target2,
    tol: Tolerances,
) -> OgeomResult<Bisector2>

The bisector of two targets: the equidistant locus, as the conic it is.

For circle targets the distance is to the boundary, which is what makes the answer a conic with the centres as foci.

Errors

OgeomError::Construction if the targets coincide, or a point lies on a line or circle target; the locus then degenerates to something that is not a curve.