Deprecate truncating saved unsized anims to 100 frames.

anntzer · anntzer · commit acb6d5c2d877 · 2018-01-26T18:37:45.000-08:00
To test that the deprecation is working, uncomment the `ani.save(...)`
line in the simple_anim.py example and modify the anim's save_count.

Animations that happened to generate exactly 100 frames without
truncation will incorrectly trigger a warning; not sure we can do much
about it (because after the 100th frame is generated there is no way to
know whether another frame is coming except by actually calling next()
on the generator, which we do not want to do).
diff --git a/examples/animation/simple_anim.py b/examples/animation/simple_anim.py
@@ -26,7 +26,7 @@ def animate(i):
 
 
 ani = animation.FuncAnimation(
-    fig, animate, init_func=init, interval=2, blit=True)
+    fig, animate, init_func=init, interval=2, blit=True, save_count=50)
 
 # To save the animation, use e.g.
 #
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -38,9 +38,8 @@
 
 from matplotlib._animation_data import (DISPLAY_TEMPLATE, INCLUDED_FRAMES,
                                         JS_INCLUDE)
-from matplotlib.cbook import iterable, deprecated
 from matplotlib.compat import subprocess
-from matplotlib import rcParams, rcParamsDefault, rc_context
+from matplotlib import cbook, rcParams, rcParamsDefault, rc_context
 
 if six.PY2:
     from base64 import encodestring as encodebytes
@@ -1681,7 +1680,7 @@ def __init__(self, fig, func, frames=None, init_func=None, fargs=None,
             self._iter_gen = itertools.count
         elif callable(frames):
             self._iter_gen = frames
-        elif iterable(frames):
+        elif cbook.iterable(frames):
             self._iter_gen = lambda: iter(frames)
             if hasattr(frames, '__len__'):
                 self.save_count = len(frames)
@@ -1723,7 +1722,25 @@ def new_saved_frame_seq(self):
             self._old_saved_seq = list(self._save_seq)
             return iter(self._old_saved_seq)
         else:
-            return itertools.islice(self.new_frame_seq(), self.save_count)
+            it = itertools.islice(self.new_frame_seq(), self.save_count)
+
+            def gen():
+                try:
+                    for _ in range(100):
+                        yield next(it)
+                except StopIteration:
+                    return
+                cbook.warn_deprecated(
+                    "2.2", "FuncAnimation.save has truncated your animation "
+                    "to 100 frames.  In the future, no such truncation will "
+                    "occur; please pass 'save_count' accordingly.")
+                try:
+                    while True:
+                        yield next(it)
+                except StopIteration:
+                    return
+
+            return gen()
 
     def _init_draw(self):
         # Initialize the drawing either using the given init_func or by

Original file line number	Diff line number	Diff line change
`@@ -26,7 +26,7 @@ def animate(i):`
`26`	`26`
`27`	`27`
`28`	`28`	`ani = animation.FuncAnimation(`
`29`		`- fig, animate, init_func=init, interval=2, blit=True)`
	`29`	`+ fig, animate, init_func=init, interval=2, blit=True, save_count=50)`
`30`	`30`
`31`	`31`	`# To save the animation, use e.g.`
`32`	`32`	`#`