Merge pull request #14880 from barabanus/fix-animation-for-twin-plots

timhoffm · web-flow · commit c75b8072b3c0 · 2019-07-24T22:26:23.000+02:00
Fix animation blitting for plots with shared axes
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -1216,12 +1216,18 @@ def _blit_draw(self, artists, bg_cache):
         # Handles blitted drawing, which renders only the artists given instead
         # of the entire figure.
         updated_ax = []
+
+        # Enumerate artists to cache axes' backgrounds. We do not draw
+        # artists yet to not cache foreground from plots with shared axes
         for a in artists:
             # If we haven't cached the background for this axes object, do
             # so now. This might not always be reliable, but it's an attempt
             # to automate the process.
             if a.axes not in bg_cache:
                 bg_cache[a.axes] = a.figure.canvas.copy_from_bbox(a.axes.bbox)
+
+        # Make a separate pass to draw foreground
+        for a in artists:
             a.axes.draw_artist(a)
             updated_ax.append(a.axes)
 
