Expose universe plotting for the cell class (#2648)

Co-authored-by: Paul Romano <paul.k.romano@gmail.com>

openmc/cell.py

@@ -559,6 +559,67 @@ class Cell(IDManagerMixin):
 
         return memo[self]
 
+    def plot(self, *args, **kwargs):
+        """Display a slice plot of the cell.
+
+        .. versionadded:: 0.13.4
+
+        Parameters
+        ----------
+        origin : iterable of float
+            Coordinates at the origin of the plot. If left as None then the
+            bounding box center will be used to attempt to ascertain the origin.
+            Defaults to (0, 0, 0) if the bounding box is not finite
+        width : iterable of float
+            Width of the plot in each basis direction. If left as none then the
+            bounding box width will be used to attempt to ascertain the plot
+            width. Defaults to (10, 10) if the bounding box is not finite
+        pixels : Iterable of int or int
+            If iterable of ints provided, then this directly sets the number of
+            pixels to use in each basis direction. If int provided, then this
+            sets the total number of pixels in the plot and the number of pixels
+            in each basis direction is calculated from this total and the image
+            aspect ratio.
+        basis : {'xy', 'xz', 'yz'}
+            The basis directions for the plot
+        color_by : {'cell', 'material'}
+            Indicate whether the plot should be colored by cell or by material
+        colors : dict
+            Assigns colors to specific materials or cells. Keys are instances of
+            :class:`Cell` or :class:`Material` and values are RGB 3-tuples, RGBA
+            4-tuples, or strings indicating SVG color names. Red, green, blue,
+            and alpha should all be floats in the range [0.0, 1.0], for example:
+
+            .. code-block:: python
+
+               # Make water blue
+               water = openmc.Cell(fill=h2o)
+               universe.plot(..., colors={water: (0., 0., 1.))
+        seed : int
+            Seed for the random number generator
+        openmc_exec : str
+            Path to OpenMC executable.
+        axes : matplotlib.Axes
+            Axes to draw to
+        legend : bool
+            Whether a legend showing material or cell names should be drawn
+        legend_kwargs : dict
+            Keyword arguments passed to :func:`matplotlib.pyplot.legend`.
+        outline : bool
+            Whether outlines between color boundaries should be drawn
+        axis_units : {'km', 'm', 'cm', 'mm'}
+            Units used on the plot axis
+        **kwargs
+            Keyword arguments passed to :func:`matplotlib.pyplot.imshow`
+
+        Returns
+        -------
+        matplotlib.axes.Axes
+            Axes containing resulting image
+
+        """
+        return openmc.Universe(cells=[self]).plot(*args, **kwargs)
+
     def create_xml_subelement(self, xml_element, memo=None):
         """Add the cell's xml representation to an incoming xml element