Merge pull request #274 from ajhynes7/add_cylinder_surface_area

Add cylinder surface area

docs/source/api_reference/skspatial.objects.Cylinder.rst

@@ -13,8 +13,10 @@ Methods
    ~skspatial.objects.Cylinder.from_points
    ~skspatial.objects.Cylinder.intersect_line
    ~skspatial.objects.Cylinder.is_point_within
+   ~skspatial.objects.Cylinder.lateral_surface_area
    ~skspatial.objects.Cylinder.length
    ~skspatial.objects.Cylinder.plot_3d
+   ~skspatial.objects.Cylinder.surface_area
    ~skspatial.objects.Cylinder.to_mesh
    ~skspatial.objects.Cylinder.to_points
    ~skspatial.objects.Cylinder.volume

pyproject.toml

@@ -26,6 +26,7 @@ classifiers = [
 ]
 
 packages = [{ include = "skspatial", from = "src" }]
+include = ["tests"]
 
 
 [tool.poetry.dependencies]
@@ -37,9 +38,6 @@ matplotlib = "^3"
 # Pre-commit
 pre-commit = { version = "2.11.1", optional = true }
 
-# Types
-mypy = { version = "0.812", optional = true }
-
 # Testing
 pytest = { version = "6.2.2", optional = true }
 pytest-cov = { version = "2.11.1", optional = true }
@@ -59,7 +57,6 @@ build-backend = "poetry.core.masonry.api"
 
 [tool.poetry.extras]
 pre_commit = ["pre-commit"]
-types = ["mypy"]
 base_test = ["pytest", "pytest-cov"]
 property = ["hypothesis"]
 docs = ["Sphinx", "numpydoc", "sphinx-bootstrap-theme", "sphinx-gallery"]

src/skspatial/_functions.py

@@ -5,6 +5,7 @@
 from functools import wraps
 from typing import Any
 from typing import Callable
+from typing import Optional
 
 import numpy as np
 
@@ -69,7 +70,7 @@ def wrapper(*args):
     return wrapper
 
 
-def _solve_quadratic(a: float, b: float, c: float, n_digits: int | None = None) -> np.ndarray:
+def _solve_quadratic(a: float, b: float, c: float, n_digits: Optional[int] = None) -> np.ndarray:
     """
     Solve a quadratic equation.
 

src/skspatial/objects/_base_array.py

@@ -1,6 +1,5 @@
 """Private base classes for arrays."""
 import warnings
-from typing import cast
 from typing import Type
 from typing import TypeVar
 
@@ -161,18 +160,15 @@ def round(self, decimals: int = 0) -> Array:  # type: ignore[override]  # noqa:
         Point([1.  , 2.  , 3.53])
 
         """
-        result = np.around(self, decimals=decimals, out=self)
-        result = cast(Array, result)
-
-        return result
+        return np.around(self, decimals=decimals, out=self)
 
 
 class _BaseArray1D(_BaseArray):
     """Private base class for spatial objects based on a single 1D NumPy array."""
 
     def __new__(cls: Type[Array1D], array: array_like) -> Array1D:
 
-        obj = super().__new__(cls, array)
+        obj = super().__new__(cls, array)  # pytype: disable=wrong-arg-count
 
         if obj.ndim != 1:
             raise ValueError("The array must be 1D.")
@@ -231,7 +227,7 @@ class _BaseArray2D(_BaseArray):
 
     def __new__(cls: Type[Array2D], array: array_like) -> Array2D:
 
-        obj = super().__new__(cls, array)
+        obj = super().__new__(cls, array)  # pytype: disable=wrong-arg-count
 
         if obj.ndim != 2:
             raise ValueError("The array must be 2D.")

src/skspatial/objects/_base_spatial.py

@@ -1,4 +1,7 @@
 class _PlotterMixin:
+
+    dimension: int
+
     def plotter(self, **kwargs):
         """Return a function that plots the object when passed a matplotlib axes."""
         if self.dimension == 2:

src/skspatial/objects/cylinder.py

@@ -1,6 +1,7 @@
 """Module for the Cylinder class."""
 from __future__ import annotations
 
+from typing import Optional
 from typing import Tuple
 
 import numpy as np
@@ -178,6 +179,58 @@ def length(self) -> np.float64:
         """
         return self.vector.norm()
 
+    def lateral_surface_area(self) -> np.float64:
+        """
+        Return the lateral surface area of the cylinder.
+
+        Returns
+        -------
+        np.float64
+            Lateral surface area of the cylinder.
+
+        Examples
+        --------
+        >>> from skspatial.objects import Cylinder
+
+        >>> Cylinder([0, 0, 0], [0, 0, 1], 1).lateral_surface_area().round(3)
+        6.283
+
+        >>> Cylinder([0, 0, 0], [0, 0, 1], 2).lateral_surface_area().round(3)
+        12.566
+
+        >>> Cylinder([0, 0, 0], [0, 0, 2], 2).lateral_surface_area().round(3)
+        25.133
+
+        """
+        return 2 * np.pi * self.radius * self.length()
+
+    def surface_area(self) -> np.float64:
+        """
+        Return the total surface area of the cylinder.
+
+        This is the lateral surface area plus the area of the two circular caps.
+
+        Returns
+        -------
+        np.float64
+            Total surface area of the cylinder.
+
+        Examples
+        --------
+        >>> from skspatial.objects import Cylinder
+
+        >>> Cylinder([0, 0, 0], [0, 0, 1], 1).surface_area().round(3)
+        12.566
+
+        >>> Cylinder([0, 0, 0], [0, 0, 1], 2).surface_area().round(3)
+        37.699
+
+        >>> Cylinder([0, 0, 0], [0, 0, 2], 2).surface_area().round(3)
+        50.265
+
+        """
+        return self.lateral_surface_area() + 2 * np.pi * self.radius ** 2
+
     def volume(self) -> np.float64:
         r"""
         Return the volume of the cylinder.
@@ -256,7 +309,7 @@ def is_point_within(self, point: array_like) -> bool:
 
         return within_radius and within_planes
 
-    def intersect_line(self, line: Line, n_digits: int | None = None) -> Tuple[Point, Point]:
+    def intersect_line(self, line: Line, n_digits: Optional[int] = None) -> Tuple[Point, Point]:
         """
         Intersect the cylinder with a 3D line.
 

src/skspatial/objects/line.py

@@ -1,6 +1,8 @@
 """Module for the Line class."""
 from __future__ import annotations
 
+from typing import Optional
+
 import numpy as np
 from matplotlib.axes import Axes
 from mpl_toolkits.mplot3d import Axes3D
@@ -576,7 +578,7 @@ def intersect_line(self, other: Line, **kwargs) -> Point:
         return self.point + vector_a_scaled
 
     @classmethod
-    def best_fit(cls, points: array_like, tol: float | None = None, **kwargs) -> Line:
+    def best_fit(cls, points: array_like, tol: Optional[float] = None, **kwargs) -> Line:
         """
         Return the line of best fit for a set of points.
 

src/skspatial/objects/plane.py

@@ -1,7 +1,7 @@
 """Module for the Plane class."""
 from __future__ import annotations
 
-from typing import cast
+from typing import Optional
 from typing import Tuple
 
 import numpy as np
@@ -236,12 +236,6 @@ def cartesian(self) -> Tuple[np.number, np.number, np.number, np.number]:
 
         d = -self.normal.dot(self.point)
 
-        # Type casting to satisfy mypy.
-        a = cast(np.number, a)
-        b = cast(np.number, b)
-        c = cast(np.number, c)
-        d = cast(np.number, d)
-
         return a, b, c, d
 
     def project_point(self, point: array_like) -> Point:
@@ -567,7 +561,7 @@ def intersect_plane(self, other: Plane, **kwargs) -> Line:
         return Line(point_line, direction_line)
 
     @classmethod
-    def best_fit(cls, points: array_like, tol: float | None = None, **kwargs) -> Plane:
+    def best_fit(cls, points: array_like, tol: Optional[float] = None, **kwargs) -> Plane:
         """
         Return the plane of best fit for a set of 3D points.
 

tests/unit/objects/test_cylinder.py

@@ -65,6 +65,22 @@ def test_properties(cylinder, length_expected, volume_expected):
     assert isclose(cylinder.volume(), volume_expected)
 
 
+@pytest.mark.parametrize(
+    ("cylinder", "lateral_surface_area_expected", "surface_area_expected"),
+    [
+        (Cylinder([0, 0, 0], [0, 0, 1], 1), 2 * pi, 4 * pi),
+        (Cylinder([0, 0, 0], [0, 0, 2], 1), 4 * pi, 6 * pi),
+        (Cylinder([0, 0, 0], [0, 0, 1], 2), 4 * pi, 12 * pi),
+        (Cylinder([0, 0, 0], [0, 0, 2], 2), 8 * pi, 16 * pi),
+        (Cylinder([0, 0, 0], [0, 0, -2], 2), 8 * pi, 16 * pi),
+    ],
+)
+def test_surface_area(cylinder, lateral_surface_area_expected, surface_area_expected):
+
+    assert isclose(cylinder.lateral_surface_area(), lateral_surface_area_expected)
+    assert isclose(cylinder.surface_area(), surface_area_expected)
+
+
 @pytest.mark.parametrize(
     ("cylinder", "point", "bool_expected"),
     [

tox.ini

@@ -24,8 +24,8 @@ commands =
 
 [testenv:types]
 commands =
-    poetry install -E types
-    poetry run mypy src/
+    pip install pytype==2021.7.19
+    pytype src/
 
 [testenv:readme]
 commands =