Merge pull request matplotlib#4586 from efiring/mec_alpha

FIX: respect alpha in RGBA markeredgecolor

closes matplotlib#4580

Author: tacaswell

lib/matplotlib/lines.py

@@ -753,6 +753,12 @@ def draw(self, renderer):
             else:
                 gc.set_foreground(edgecolor)
                 gc.set_linewidth(self._markeredgewidth)
+                mec = self._markeredgecolor
+                if (is_string_like(mec) and mec == 'auto' and
+                        rgbaFace is not None):
+                    gc.set_alpha(rgbaFace[3])
+                else:
+                    gc.set_alpha(self.get_alpha())
 
             marker = self._marker
             tpath, affine = transf_path.get_transformed_points_and_affine()
@@ -779,19 +785,20 @@ def draw(self, renderer):
                     marker_trans = marker_trans.scale(w)
                 else:
                     gc.set_linewidth(0)
-                if rgbaFace is not None:
-                    gc.set_alpha(rgbaFace[3])
 
                 renderer.draw_markers(gc, marker_path, marker_trans,
                                       subsampled, affine.frozen(),
                                       rgbaFace)
 
                 alt_marker_path = marker.get_alt_path()
                 if alt_marker_path:
-                    if rgbaFaceAlt is not None:
-                        gc.set_alpha(rgbaFaceAlt[3])
                     alt_marker_trans = marker.get_alt_transform()
                     alt_marker_trans = alt_marker_trans.scale(w)
+                    if (is_string_like(mec) and mec == 'auto' and
+                            rgbaFaceAlt is not None):
+                        gc.set_alpha(rgbaFaceAlt[3])
+                    else:
+                        gc.set_alpha(self.get_alpha())
 
                     renderer.draw_markers(
                             gc, alt_marker_path, alt_marker_trans, subsampled,