render.plot now supports any object with a figure attribute pointing …

…to a mpl Figure instance (#230)

shiny/render/_render.py

@@ -281,7 +281,9 @@ def plot(
         1. A :class:`matplotlib.figure.Figure` instance.
         2. An :class:`matplotlib.artist.Artist` instance.
         3. A list/tuple of Figure/Artist instances.
-        4. A :class:`PIL.Image.Image` instance.
+        4. An object with a 'figure' attribute pointing to a
+          :class:`matplotlib.figure.Figure` instance.
+        5. A :class:`PIL.Image.Image` instance.
 
     Tip
     ----

shiny/render/_try_render_plot.py

@@ -2,16 +2,7 @@
 import io
 import os
 import sys
-from typing import (
-    Optional,
-    Union,
-    cast,
-    Tuple,
-    TextIO,
-    BinaryIO,
-    Any,
-    List,
-)
+from typing import Optional, Union, cast, Tuple, TextIO, BinaryIO, Any, List
 
 if sys.version_info >= (3, 8):
     from typing import Literal, Protocol
@@ -174,6 +165,12 @@ def get_matplotlib_figure(x: object) -> Union[MplFigure, None]:
     if isinstance(x, Artist):
         return cast(MplArtist, x).get_figure()
 
+    # Some other custom figure-like classes such as seaborn.axisgrid.FacetGrid attach
+    # their figure as an attribute
+    fig = getattr(x, "figure", None)
+    if isinstance(fig, Figure):
+        return cast(MplFigure, fig)
+
     # Sometimes generic plot() methods will return an iterable of Artists,
     # If they all refer to the same figure, then it seems reasonable to use it
     # https://docs.xarray.dev/en/latest/user-guide/plotting.html#dimension-along-y-axis