Merge pull request matplotlib#4800 from jenshnielsen/funcanimfixes

FIX: Fixes to funcanimation

Author: tacaswell

examples/animation/animate_decay.py

@@ -10,10 +10,17 @@ def data_gen(t=0):
         t += 0.1
         yield t, np.sin(2*np.pi*t) * np.exp(-t/10.)
 
+
+def init():
+    ax.set_ylim(-1.1, 1.1)
+    ax.set_xlim(0, 10)
+    del xdata[:]
+    del ydata[:]
+    line.set_data(xdata, ydata)
+    return line,
+
 fig, ax = plt.subplots()
 line, = ax.plot([], [], lw=2)
-ax.set_ylim(-1.1, 1.1)
-ax.set_xlim(0, 5)
 ax.grid()
 xdata, ydata = [], []
 
@@ -33,5 +40,5 @@ def run(data):
     return line,
 
 ani = animation.FuncAnimation(fig, run, data_gen, blit=False, interval=10,
-                              repeat=False)
+                              repeat=False, init_func=init)
 plt.show()

lib/matplotlib/animation.py

@@ -613,6 +613,7 @@ def _start(self, *args):
         # actually start the event_source. We also disconnect _start
         # from the draw_events
         self.event_source.add_callback(self._step)
+        self._init_draw()
         self.event_source.start()
         self._fig.canvas.mpl_disconnect(self._first_draw_id)
         self._first_draw_id = None  # So we can check on save
@@ -762,6 +763,9 @@ def save(self, filename, writer=None, fps=None, dpi=None, codec=None,
         # since GUI widgets are gone. Either need to remove extra code to
         # allow for this non-existant use case or find a way to make it work.
         with writer.saving(self._fig, filename, dpi):
+            for anim in all_anim:
+                # Clear the initial frame
+                anim._init_draw()
             for data in zip(*[a.new_saved_frame_seq()
                               for a in all_anim]):
                 for anim, d in zip(all_anim, data):
@@ -1135,7 +1139,10 @@ def new_saved_frame_seq(self):
         # no saved frames, generate a new frame sequence and take the first
         # save_count entries in it.
         if self._save_seq:
-            return iter(self._save_seq)
+            # While iterating we are going to update _save_seq
+            # so make a copy to safely iterate over
+            self._old_saved_seq = self._save_seq.copy()
+            return iter(self._old_saved_seq)
         else:
             return itertools.islice(self.new_frame_seq(), self.save_count)