Add contains predicate (#11)

* Add contains predicate

* add to docs

docs/api.rst

@@ -51,3 +51,4 @@ Predicates
 
    equals
    intersects
+   contains

src/predicates.cpp

@@ -24,6 +24,14 @@ bool equals(PyObjectGeography a, PyObjectGeography b) {
     return s2geog::s2_equals(a_index, b_index, options);
 }
 
+bool contains(PyObjectGeography a, PyObjectGeography b) {
+    const auto& a_index = a.as_geog_ptr()->geog_index();
+    const auto& b_index = b.as_geog_ptr()->geog_index();
+
+    S2BooleanOperation::Options options;
+    return s2geog::s2_contains(a_index, b_index, options);
+}
+
 void init_predicates(py::module& m) {
     m.def("intersects", py::vectorize(&intersects), py::arg("a"), py::arg("b"),
           R"pbdoc(
@@ -51,4 +59,18 @@ void init_predicates(py::module& m) {
             Geography object(s)
 
     )pbdoc");
+
+    m.def("contains", py::vectorize(&contains), py::arg("a"), py::arg("b"),
+          R"pbdoc(
+        Returns True if B is completely inside A.
+
+        A contains B if no points of B lie in the exterior of A and at least
+        one point of the interior of B lies in the interior of A.
+
+        Parameters
+        ----------
+        a, b : :py:class:`Geography` or array_like
+            Geography object(s)
+
+    )pbdoc");
 }

src/spherely.pyi

@@ -93,6 +93,7 @@ destroy_prepared: _VFunc_Nin1_Nout1[Literal["destroy_prepared"], Geography, Any]
 
 intersects: _VFunc_Nin2_Nout1[Literal["intersects"], bool, bool]
 equals: _VFunc_Nin2_Nout1[Literal["intersects"], bool, bool]
+contains: _VFunc_Nin2_Nout1[Literal["contains"], bool, bool]
 
 # temp (remove)
 

tests/test_predicates.py

@@ -41,3 +41,23 @@ def test_equals() -> None:
     a2 = spherely.Point(50, 8)
     b2 = spherely.Point(50, 8)
     assert spherely.equals(a2, b2)
+
+
+def test_contains():
+    # test array + scalar
+    a = np.array(
+        [
+            spherely.LineString([(40, 8), (60, 8)]),
+            spherely.LineString([(20, 0), (30, 0)]),
+        ]
+    )
+    b = spherely.Point(40, 8)
+
+    actual = spherely.contains(a, b)
+    expected = np.array([True, False])
+    np.testing.assert_array_equal(actual, expected)
+
+    # two scalars
+    a2 = spherely.LineString([(50, 8), (60, 8)])
+    b2 = spherely.Point(50, 8)
+    assert spherely.contains(a2, b2)