Correctly set default linewidth for unfilled markers.

QuLogic · QuLogic · commit 66289c4f1895 · 2020-05-25T18:25:16.000-04:00
Fixes #17192.
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -4492,7 +4492,12 @@ def scatter(self, x, y, s=None, c=None, marker=None, cmap=None, norm=None,
             marker_obj.get_transform())
         if not marker_obj.is_filled():
             edgecolors = 'face'
-            linewidths = rcParams['lines.linewidth']
+            if linewidths is None:
+                linewidths = rcParams['lines.linewidth']
+            elif np.iterable(linewidths):
+                linewidths = [
+                    lw if lw is not None else rcParams['lines.linewidth']
+                    for lw in linewidths]
 
         offsets = np.ma.column_stack([x, y])
 
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1984,6 +1984,20 @@ def test_scatter_single_color_c(self, fig_test, fig_ref):
         ax_test.scatter(np.ones(3), range(3), c=rgb)
         ax_test.scatter(np.ones(4)*2, range(4), c=rgba)
 
+    def test_scatter_linewidths(self):
+        x = np.arange(5)
+
+        fig, ax = plt.subplots()
+        for i in range(3):
+            pc = ax.scatter(x, np.full(5, i), c=f'C{i}', marker='x', s=100,
+                            linewidths=i + 1)
+            assert pc.get_linewidths() == i + 1
+
+        pc = ax.scatter(x, np.full(5, 3), c='C3', marker='x', s=100,
+                        linewidths=[*range(1, 5), None])
+        assert_array_equal(pc.get_linewidths(),
+                           [*range(1, 5), mpl.rcParams['lines.linewidth']])
+
 
 def _params(c=None, xsize=2, *, edgecolors=None, **kwargs):
     return (c, edgecolors, kwargs if kwargs is not None else {}, xsize)
