1.4.0 RC1 UserWarning: Rasterization of PolyCollection will be ignored

[letmaik]

Since 1.4.0 rc1 I get "../matplotlib/artist.py:686: UserWarning: Rasterization of 'matplotlib.collections.PolyCollection object at 0x6004a90' will be ignored" when using the rasterized=True parameter on a PolyCollection.

This is due to the fact that PolyCollection doesn't have its own draw method anymore (which in 1.3.1 had the @allow_rasterization decorator) but instead uses the inherited one from _CollectionWithSizes which doesn't have the decorator.

[tacaswell]

That does seem like a major regression..

[tacaswell]

@neothemachine I have a patch that should fix the problem

[letmaik]

Without having tested whether the rasterization code path was really broken, I think the only effect was the output of the UserWarning, as set_rasterized() checks hasattr(self.draw, "_supports_rasterization") which fails but self._rasterized = rasterized is set regardless and PolyCollection would invoke Collection.draw which in turn has the allow_rasterization decorator.

EDIT: To clarify, PolyCollection doesn't directly invoke Collection.draw but its inherited _CollectionWithSizes would.