Class PolyCollection

lib/matplotlib/collections.py:1300–1378

class PolyCollection(_CollectionWithSizes):

    def __init__(self, verts, sizes=None, *, closed=True, **kwargs):
        """
        Parameters
        ----------
        verts : list of array-like
            The sequence of polygons [*verts0*, *verts1*, ...] where each
            element *verts_i* defines the vertices of polygon *i* as a 2D
            array-like of shape (M, 2).
        sizes : array-like, default: None
            Squared scaling factors for the polygons. The coordinates of each
            polygon *verts_i* are multiplied by the square-root of the
            corresponding entry in *sizes* (i.e., *sizes* specify the scaling
            of areas). The scaling is applied before the Artist master
            transform.
        closed : bool, default: True
            Whether the polygon should be closed by adding a CLOSEPOLY
            connection at the end.
        **kwargs
            Forwarded to `.Collection`.
        """
        super().__init__(**kwargs)
        self.set_sizes(sizes)
        self.set_verts(verts, closed)
        self.stale = True

    def set_verts(self, verts, closed=True):
        """
        Set the vertices of the polygons.

        Parameters
        ----------
        verts : list of array-like
            The sequence of polygons [*verts0*, *verts1*, ...] where each
            element *verts_i* defines the vertices of polygon *i* as a 2D
            array-like of shape (M, 2).
        closed : bool, default: True
            Whether the polygon should be closed by adding a CLOSEPOLY
            connection at the end.
        """
        self.stale = True
        if isinstance(verts, np.ma.MaskedArray):
            verts = verts.astype(float).filled(np.nan)

        # No need to do anything fancy if the path isn't closed.
        if not closed:
            self._paths = [mpath.Path(xy) for xy in verts]
            return

        # Fast path for arrays
        if isinstance(verts, np.ndarray) and len(verts.shape) == 3 and verts.size:
            verts_pad = np.concatenate((verts, verts[:, :1]), axis=1)
            # It's faster to create the codes and internal flags once in a
            # template path and reuse them.
            template_path = mpath.Path(verts_pad[0], closed=True)
            codes = template_path.codes
            _make_path = mpath.Path._fast_from_codes_and_verts