Add tests for Shadow class.

anntzer · anntzer · commit f99506f1c276 · 2018-02-15T11:30:35.000+01:00
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -615,14 +615,10 @@ def _update(self):
         if self.props is not None:
             self.update(self.props)
         else:
-            r, g, b, a = colors.to_rgba(self.patch.get_facecolor())
-            rho = 0.3
-            r = rho * r
-            g = rho * g
-            b = rho * b
-
-            self.set_facecolor((r, g, b, 0.5))
-            self.set_edgecolor((r, g, b, 0.5))
+            self.set_facecolor(
+                .3 * np.asarray(colors.to_rgb(self.patch.get_facecolor())))
+            self.set_edgecolor(
+                .3 * np.asarray(colors.to_rgb(self.patch.get_edgecolor())))
             self.set_alpha(0.5)
 
     def _update_transform(self, renderer):
diff --git a/lib/matplotlib/tests/test_patches.py b/lib/matplotlib/tests/test_patches.py
@@ -9,16 +9,14 @@
 from numpy.testing import assert_almost_equal, assert_array_equal
 import pytest
 
-from matplotlib.patches import Polygon
-from matplotlib.patches import Rectangle
+from matplotlib.patches import Polygon, Rectangle
 from matplotlib.testing.decorators import image_comparison
 import matplotlib.pyplot as plt
-import matplotlib.patches as mpatches
-import matplotlib.collections as mcollections
-from matplotlib import path as mpath
-from matplotlib import transforms as mtransforms
-import matplotlib.style as mstyle
+from matplotlib import (
+    collections as mcollections, colors as mcolors, patches as mpatches,
+    path as mpath, style as mstyle, transforms as mtransforms)
 
+from io import BytesIO
 import sys
 on_win = (sys.platform == 'win32')
 
@@ -410,3 +408,32 @@ def test_contains_points():
     expected = path.contains_points(points, transform, radius)
     result = ell.contains_points(points)
     assert np.all(result == expected)
+
+
+def test_shadow():
+    xy = np.array([.24, .26])
+    dxy = np.array([.4, .6])
+    # Test image.
+    # We need to work around the nonsensical (dpi-dependent) interpretation of
+    # offsets by the Shadow class...
+    with plt.rc_context({"savefig.dpi": "figure"}):
+        f1, a1 = plt.subplots()
+        rect = mpatches.Rectangle(xy=xy, width=.5, height=.5)
+        shadow = mpatches.Shadow(rect, ox=dxy[0], oy=dxy[1])
+        a1.add_patch(rect)
+        a1.add_patch(shadow)
+        b1 = BytesIO()
+        f1.savefig(b1, format="raw")
+    # Reference image.
+    f2, a2 = plt.subplots()
+    rect = mpatches.Rectangle(xy=xy, width=.5, height=.5)
+    shadow = mpatches.Rectangle(
+        xy=xy + f2.dpi / 72 * dxy, width=.5, height=.5,
+        fc=np.asarray(mcolors.to_rgb(rect.get_fc())) * .3,
+        ec=np.asarray(mcolors.to_rgb(rect.get_ec())) * .3,
+        alpha=.5)
+    a2.add_patch(shadow)
+    a2.add_patch(rect)
+    b2 = BytesIO()
+    f2.savefig(b2, format="raw")
+    assert b1.getvalue() == b2.getvalue()
