Merge pull request #8954 from tacaswell/fix_scatter_alpha

efiring · web-flow · commit 3b3278e92145 · 2017-08-21T09:58:43.000-10:00
Fix scatter alpha
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -711,6 +711,7 @@ def set_alpha(self, alpha):
                 float(alpha)
             except TypeError:
                 raise TypeError('alpha must be a float or None')
+        self.update_dict['array'] = True
         artist.Artist.set_alpha(self, alpha)
         self._set_facecolor(self._original_facecolor)
         self._set_edgecolor(self._original_edgecolor)
diff --git a/lib/matplotlib/tests/baseline_images/test_collections/scatter_post_alpha.png b/lib/matplotlib/tests/baseline_images/test_collections/scatter_post_alpha.png
diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
@@ -624,3 +624,14 @@ def test_lslw_bcast():
     col.set_linestyles(['-', '-', '-'])
     assert_equal(col.get_linestyles(), [(None, None)] * 3)
     assert_equal(col.get_linewidths(), [1, 2, 3])
+
+
+@image_comparison(baseline_images=['scatter_post_alpha'],
+                  extensions=['png'], remove_text=True,
+                  style='default')
+def test_scatter_post_alpha():
+    fig, ax = plt.subplots()
+    sc = ax.scatter(range(5), range(5), c=range(5))
+    # this needs to be here to update internal state
+    fig.canvas.draw()
+    sc.set_alpha(.1)
