Update heart and spade logic (#327)

Author: stefmolin

src/data_morph/shapes/bases/point_collection.py

@@ -16,6 +16,8 @@
 
     from matplotlib.axes import Axes
 
+    from ...bounds.bounding_box import BoundingBox
+
 
 class PointCollection(Shape):
     """
@@ -37,6 +39,32 @@ def __init__(self, *points: Iterable[Number]) -> None:
     def __repr__(self) -> str:
         return f'<{self.__class__.__name__} of {len(self.points)} points>'
 
+    @staticmethod
+    def _center(points: np.ndarray, bounds: BoundingBox) -> np.ndarray:
+        """
+        Center the points within the bounding box.
+
+        Parameters
+        ----------
+        points : np.ndarray
+            The points to center.
+        bounds : BoundingBox
+            The bounding box within which to center the points.
+
+        Returns
+        -------
+        np.ndarray
+            The centered points.
+        """
+        maxes = points.max(axis=0)
+        span = maxes - points.min(axis=0)
+        gap = (np.array(bounds.range) - span) / 2
+
+        (_, xmax), (_, ymax) = bounds
+        shift = np.array([xmax, ymax]) - maxes - gap
+
+        return points + shift
+
     def distance(self, x: Number, y: Number) -> float:
         """
         Calculate the minimum distance from the points of this shape

src/data_morph/shapes/points/heart.py

@@ -35,17 +35,20 @@ class Heart(PointCollection):
     """
 
     def __init__(self, dataset: Dataset) -> None:
-        _, xmax = dataset.data_bounds.x_bounds
-        x_shift, y_shift = dataset.data_bounds.center
+        data_bounds = dataset.data_bounds
+        (_, xmax), (_, ymax) = data_bounds
+        x_shift, y_shift = data_bounds.center
 
         t = np.linspace(-3, 3, num=80)
 
         x = 16 * np.sin(t) ** 3
         y = 13 * np.cos(t) - 5 * np.cos(2 * t) - 2 * np.cos(3 * t) - np.cos(4 * t)
 
         # scale by the half the widest width of the heart
-        scale_factor = (xmax - x_shift) / 16
+        scale_factor = min((xmax - x_shift), (ymax - y_shift)) / 16
 
         super().__init__(
-            *np.stack([x * scale_factor + x_shift, y * scale_factor + y_shift], axis=1)
+            *self._center(
+                np.stack([x * scale_factor, y * scale_factor], axis=1), data_bounds
+            )
         )

src/data_morph/shapes/points/spade.py

@@ -30,8 +30,9 @@ class Spade(PointCollection):
     """
 
     def __init__(self, dataset: Dataset) -> None:
-        _, xmax = dataset.data_bounds.x_bounds
-        x_shift, y_shift = dataset.data_bounds.center
+        data_bounds = dataset.data_bounds
+        _, xmax = data_bounds.x_bounds
+        x_shift, y_shift = data_bounds.center
 
         # upside-down heart
         heart_points = self._get_inverted_heart(dataset, y_shift)
@@ -43,7 +44,7 @@ def __init__(self, dataset: Dataset) -> None:
         x = np.concatenate((heart_points[:, 0], base_x), axis=0)
         y = np.concatenate((heart_points[:, 1], base_y), axis=0)
 
-        super().__init__(*np.stack([x, y], axis=1))
+        super().__init__(*self._center(np.stack([x, y], axis=1), data_bounds))
 
     @staticmethod
     def _get_inverted_heart(dataset: Dataset, y_shift: Number) -> np.ndarray:

tests/shapes/bases/test_point_collection.py

@@ -3,8 +3,10 @@
 import re
 
 import matplotlib.pyplot as plt
+import numpy as np
 import pytest
 
+from data_morph.bounds.bounding_box import BoundingBox
 from data_morph.shapes.bases.point_collection import PointCollection
 
 
@@ -18,6 +20,19 @@ def point_collection(self):
         """An instance of PointCollection."""
         return PointCollection([0, 0], [20, 50])
 
+    @pytest.mark.parametrize(
+        'bounding_box',
+        [BoundingBox([0, 100], [-50, 50]), BoundingBox([0, 20], [0, 50])],
+    )
+    def test_center(self, point_collection, bounding_box):
+        """Test that points are centered within the bounding box."""
+        points = point_collection._center(point_collection.points, bounding_box)
+
+        (xmin, xmax), (ymin, ymax) = bounding_box
+        upper = np.array([xmax, ymax]) - points.max(axis=0)
+        lower = points.min(axis=0) - np.array([xmin, ymin])
+        assert np.array_equal(upper, lower)
+
     def test_distance_zero(self, point_collection):
         """Test the distance() method on points in the collection."""
         for point in point_collection.points:

tests/shapes/points/test_heart.py

@@ -12,10 +12,10 @@ class TestHeart(PointsModuleTestBase):
 
     shape_name = 'heart'
     distance_test_cases = (
-        ((19.89946048, 54.82281916), 0.0),
-        ((10.84680454, 70.18556376), 0.0),
-        ((29.9971295, 67.66402445), 0.0),
-        ((27.38657942, 62.417184), 0.0),
-        ((20, 50), 4.567369),
-        ((10, 80), 8.564365),
+        ((22.424114, 59.471779), 0.0),
+        ((10.405462, 70.897342), 0.0),
+        ((21.064032, 72.065253), 0.0),
+        ((16.035166, 60.868470), 0.0),
+        ((20, 50), 6.065782511791651),
+        ((10, 80), 7.173013322704914),
     )

tests/shapes/points/test_spade.py

@@ -12,10 +12,11 @@ class TestSpade(PointsModuleTestBase):
 
     shape_name = 'spade'
     distance_test_cases = (
-        ((19.97189615, 75.43271708), 0),
-        ((23.75, 55), 0),
-        ((11.42685318, 59.11304904), 0),
-        ((20, 75), 0.2037185),
-        ((0, 0), 57.350348),
-        ((10, 80), 10.968080),
+        ((19.818701, 60.065370), 0),
+        ((23.750000, 55.532859), 0),
+        ((20.067229, 60.463689), 0),
+        ((18.935968, 58.467606), 0),
+        ((20, 75), 0.5335993101603015),
+        ((0, 0), 57.861566654807596),
+        ((10, 80), 11.404000978114487),
     )