Fix issue with get_edgecolor and get_facecolor

Author: oscargus

lib/mpl_toolkits/mplot3d/art3d.py

@@ -867,9 +867,19 @@ def set_alpha(self, alpha):
         self.stale = True
 
     def get_facecolor(self):
+        # docstring inherited
+        # self._facecolors2d is not initialized until do_3d_projection
+        if not hasattr(self, '_facecolors2d'):
+            self.axes.M = self.axes.get_proj()
+            self.do_3d_projection()
         return self._facecolors2d
 
     def get_edgecolor(self):
+        # docstring inherited
+        # self._edgecolors2d is not initialized until do_3d_projection
+        if not hasattr(self, '_edgecolors2d'):
+            self.axes.M = self.axes.get_proj()
+            self.do_3d_projection()
         return self._edgecolors2d
 
 

lib/mpl_toolkits/tests/test_mplot3d.py

@@ -1812,6 +1812,28 @@ def test_scatter_spiral():
     fig.canvas.draw()
 
 
+def test_Poly3DCollection_get_facecolor():
+    # Smoke test to see that get_facecolor does not raise
+    # See GH#4067
+    y, x = np.ogrid[1:10:100j, 1:10:100j]
+    z2 = np.cos(x) ** 3 - np.sin(y) ** 2
+    fig = plt.figure()
+    ax = fig.add_subplot(111, projection='3d')
+    r = ax.plot_surface(x, y, z2, cmap='hot')
+    r.get_facecolor()
+
+
+def test_Poly3DCollection_get_edgecolor():
+    # Smoke test to see that get_edgecolor does not raise
+    # See GH#4067
+    y, x = np.ogrid[1:10:100j, 1:10:100j]
+    z2 = np.cos(x) ** 3 - np.sin(y) ** 2
+    fig = plt.figure()
+    ax = fig.add_subplot(111, projection='3d')
+    r = ax.plot_surface(x, y, z2, cmap='hot')
+    r.get_edgecolor()
+
+
 @pytest.mark.parametrize(
     "vertical_axis, proj_expected, axis_lines_expected, tickdirs_expected",
     [