Fix antialiased default in LineCollection; add comments

efiring · efiring · commit e048bf1eda9b · 2021-02-12T09:51:01.000-10:00
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -170,10 +170,10 @@ def __init__(self,
         # list of unbroadcast/scaled linewidths
         self._us_lw = [0]
         self._linewidths = [0]
-        # Flags: do colors come from mapping an array?
+        # Flags set by _set_mappable_flags: are colors from mapping an array?
         self._face_is_mapped = None
         self._edge_is_mapped = None
-        self._mapped_colors = None  # Calculated in update_scalarmappable
+        self._mapped_colors = None  # calculated in update_scalarmappable
         self._hatch_color = mcolors.to_rgba(mpl.rcParams['hatch.color'])
         self.set_facecolor(facecolors)
         self.set_edgecolor(edgecolors)
@@ -736,10 +736,13 @@ def set_antialiased(self, aa):
         aa : bool or list of bools
         """
         if aa is None:
-            aa = mpl.rcParams['patch.antialiased']
+            aa = self._get_default_antialiased()
         self._antialiaseds = np.atleast_1d(np.asarray(aa, bool))
         self.stale = True
 
+    def _get_default_antialiased(self):
+        return mpl.rcParams['patch.antialiased']
+
     def set_color(self, c):
         """
         Set both the edgecolor and the facecolor.
@@ -868,11 +871,14 @@ def _set_mappable_flags(self):
 
         Returns
         -------
-        mapping_change: bool
+        mapping_change : bool
             True if either flag is True, or if a flag has changed.
         """
+        # The flags are initialized to None to ensure this returns True
+        # the first time it is called.
         edge0 = self._edge_is_mapped
         face0 = self._face_is_mapped
+        # After returning, the flags must be Booleans, not None.
         self._edge_is_mapped = False
         self._face_is_mapped = False
         if self._A is not None:
@@ -1506,6 +1512,9 @@ def _add_offsets(self, segs):
     def _get_default_linewidth(self):
         return mpl.rcParams['lines.linewidth']
 
+    def _get_default_antialiased(self):
+        return mpl.rcParams['lines.antialiased']
+
     def _get_default_edgecolor(self):
         return mpl.rcParams['lines.color']
 
