Some properties and methods are missing from `ConvexSpheroPolygon` and `ConvexSpheroPolyhedron`, but they are shown in the docs

[josephburkhart]

Description

The getters and setters for centroid are missing from ConvexSpheroPolygon and ConvexSpheroPolyhedron, but the docs show that they are there:

• ConvexSpheroPolygon.centroid
• ConvexSpheroPolyhedron.centroid

Additionally, the is_inside() method is shown for both of the above classes, but it is only implemented for ConvexSpheroPolyhedron:

• ConvexSpheroPolygon.is_inside()
• ConvexSpheroPolyhedron.is_inside()

The ConvexSpheroPolyhedron.is_inside() implementation ultimately uses the centroid of the underlying polyhedron, so perhaps implementing centroid for this class could be as simple as

class ConvexSpheroPolyhedron(Shape3D):
    ...
    @property
    def centroid(self):
        return self._polyhedron.centroid
    
    @centroid.setter
    def centroid(self, value):
        self._polyhedron.centroid = value

If it is that easy, perhaps this same approach could be used for ConvexSpheroPolygon?

To reproduce

To see that centroid is missing from ConvexSpheroPolyhedron:

verts = [
    [1, 1, 1], [1, -1, 1], [1, 1, -1], [1, -1, -1],
    [-1, 1, 1], [-1, -1, 1], [-1, 1, -1], [-1, -1, -1]
]
spherocube = coxeter.shapes.ConvexSpheropolyhedron(verts, radius=0.5)
print(spherocube.centroid)
spherocube.centroid = [1,1,1]
print(spherocube.centroid)

and from ConvexSpheroPolygon:

verts = [[-1, 0], [0, 1], [1, 0]]
rounded_tri = coxeter.shapes.ConvexSpheropolygon(verts, radius=.1)
print(rounded_tri.centroid)
rounded_tri.centroid = [1,1]
print(rounded_tri.centroid)

To see that is_inside() is missing from ConvexSpheroPolygon:

verts = [[-1, 0], [0, 1], [1, 0]]
rounded_tri = coxeter.shapes.ConvexSpheropolygon(verts, radius=.1)
print(rounded_tri.is_inside([1,1]))

Error output

Each code block given above throws a NotImplementedError originating from the base class Shape2D or Shape3D. I assume that these classes are why the methods show up in the documentation in the first place.

System configuration

Please complete the following information:

• Operating System: Windows 10
• Version of Python: 3.13.3
• Version of coxeter: 0.10.0

[janbridley]

This is similar to #184 which I haven't addressed as it requires some hacking around sphinx doc - however, the idea of implementing the appropriate methods is much easier than figuring that out imo.

I think the code you included is correct, although I'm not 100%: @tfteague do you know if the Minkowski sum of two bodies with the same center of mass retains the center of mass of the inputs? I can't think of why the answer would not be yes but I figured I'd ask.