KIKIMR-19287: add task_stats_drawing script

1 files changed, 1252 insertions, 0 deletions

diff --git a/contrib/python/matplotlib/py3/mpl_toolkits/mplot3d/art3d.py b/contrib/python/matplotlib/py3/mpl_toolkits/mplot3d/art3d.py
new file mode 100644
index 0000000000..4aff115b0c
--- /dev/null
+++ b/contrib/python/matplotlib/py3/mpl_toolkits/mplot3d/art3d.py
@@ -0,0 +1,1252 @@
+# art3d.py, original mplot3d version by John Porter
+# Parts rewritten by Reinier Heeres <reinier@heeres.eu>
+# Minor additions by Ben Axelrod <baxelrod@coroware.com>
+
+"""
+Module containing 3D artist code and functions to convert 2D
+artists into 3D versions which can be added to an Axes3D.
+"""
+
+import math
+
+import numpy as np
+
+from contextlib import contextmanager
+
+from matplotlib import (
+    artist, cbook, colors as mcolors, lines, text as mtext,
+    path as mpath)
+from matplotlib.collections import (
+    Collection, LineCollection, PolyCollection, PatchCollection, PathCollection)
+from matplotlib.colors import Normalize
+from matplotlib.patches import Patch
+from . import proj3d
+
+
+def _norm_angle(a):
+    """Return the given angle normalized to -180 < *a* <= 180 degrees."""
+    a = (a + 360) % 360
+    if a > 180:
+        a = a - 360
+    return a
+
+
+def _norm_text_angle(a):
+    """Return the given angle normalized to -90 < *a* <= 90 degrees."""
+    a = (a + 180) % 180
+    if a > 90:
+        a = a - 180
+    return a
+
+
+def get_dir_vector(zdir):
+    """
+    Return a direction vector.
+
+    Parameters
+    ----------
+    zdir : {'x', 'y', 'z', None, 3-tuple}
+        The direction. Possible values are:
+
+        - 'x': equivalent to (1, 0, 0)
+        - 'y': equivalent to (0, 1, 0)
+        - 'z': equivalent to (0, 0, 1)
+        - *None*: equivalent to (0, 0, 0)
+        - an iterable (x, y, z) is converted to an array
+
+    Returns
+    -------
+    x, y, z : array
+        The direction vector.
+    """
+    if zdir == 'x':
+        return np.array((1, 0, 0))
+    elif zdir == 'y':
+        return np.array((0, 1, 0))
+    elif zdir == 'z':
+        return np.array((0, 0, 1))
+    elif zdir is None:
+        return np.array((0, 0, 0))
+    elif np.iterable(zdir) and len(zdir) == 3:
+        return np.array(zdir)
+    else:
+        raise ValueError("'x', 'y', 'z', None or vector of length 3 expected")
+
+
+class Text3D(mtext.Text):
+    """
+    Text object with 3D position and direction.
+
+    Parameters
+    ----------
+    x, y, z : float
+        The position of the text.
+    text : str
+        The text string to display.
+    zdir : {'x', 'y', 'z', None, 3-tuple}
+        The direction of the text. See `.get_dir_vector` for a description of
+        the values.
+
+    Other Parameters
+    ----------------
+    **kwargs
+         All other parameters are passed on to `~matplotlib.text.Text`.
+    """
+
+    def __init__(self, x=0, y=0, z=0, text='', zdir='z', **kwargs):
+        mtext.Text.__init__(self, x, y, text, **kwargs)
+        self.set_3d_properties(z, zdir)
+
+    def get_position_3d(self):
+        """Return the (x, y, z) position of the text."""
+        return self._x, self._y, self._z
+
+    def set_position_3d(self, xyz, zdir=None):
+        """
+        Set the (*x*, *y*, *z*) position of the text.
+
+        Parameters
+        ----------
+        xyz : (float, float, float)
+            The position in 3D space.
+        zdir : {'x', 'y', 'z', None, 3-tuple}
+            The direction of the text. If unspecified, the *zdir* will not be
+            changed. See `.get_dir_vector` for a description of the values.
+        """
+        super().set_position(xyz[:2])
+        self.set_z(xyz[2])
+        if zdir is not None:
+            self._dir_vec = get_dir_vector(zdir)
+
+    def set_z(self, z):
+        """
+        Set the *z* position of the text.
+
+        Parameters
+        ----------
+        z : float
+        """
+        self._z = z
+        self.stale = True
+
+    def set_3d_properties(self, z=0, zdir='z'):
+        """
+        Set the *z* position and direction of the text.
+
+        Parameters
+        ----------
+        z : float
+            The z-position in 3D space.
+        zdir : {'x', 'y', 'z', 3-tuple}
+            The direction of the text. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        self._z = z
+        self._dir_vec = get_dir_vector(zdir)
+        self.stale = True
+
+    @artist.allow_rasterization
+    def draw(self, renderer):
+        position3d = np.array((self._x, self._y, self._z))
+        proj = proj3d._proj_trans_points(
+            [position3d, position3d + self._dir_vec], self.axes.M)
+        dx = proj[0][1] - proj[0][0]
+        dy = proj[1][1] - proj[1][0]
+        angle = math.degrees(math.atan2(dy, dx))
+        with cbook._setattr_cm(self, _x=proj[0][0], _y=proj[1][0],
+                               _rotation=_norm_text_angle(angle)):
+            mtext.Text.draw(self, renderer)
+        self.stale = False
+
+    def get_tightbbox(self, renderer=None):
+        # Overwriting the 2d Text behavior which is not valid for 3d.
+        # For now, just return None to exclude from layout calculation.
+        return None
+
+
+def text_2d_to_3d(obj, z=0, zdir='z'):
+    """
+    Convert a `.Text` to a `.Text3D` object.
+
+    Parameters
+    ----------
+    z : float
+        The z-position in 3D space.
+    zdir : {'x', 'y', 'z', 3-tuple}
+        The direction of the text. Default: 'z'.
+        See `.get_dir_vector` for a description of the values.
+    """
+    obj.__class__ = Text3D
+    obj.set_3d_properties(z, zdir)
+
+
+class Line3D(lines.Line2D):
+    """
+    3D line object.
+
+    .. note:: Use `get_data_3d` to obtain the data associated with the line.
+            `~.Line2D.get_data`, `~.Line2D.get_xdata`, and `~.Line2D.get_ydata` return
+            the x- and y-coordinates of the projected 2D-line, not the x- and y-data of
+            the 3D-line. Similarly, use `set_data_3d` to set the data, not
+            `~.Line2D.set_data`, `~.Line2D.set_xdata`, and `~.Line2D.set_ydata`.
+    """
+
+    def __init__(self, xs, ys, zs, *args, **kwargs):
+        """
+
+        Parameters
+        ----------
+        xs : array-like
+            The x-data to be plotted.
+        ys : array-like
+            The y-data to be plotted.
+        zs : array-like
+            The z-data to be plotted.
+        *args, **kwargs
+            Additional arguments are passed to `~matplotlib.lines.Line2D`.
+        """
+        super().__init__([], [], *args, **kwargs)
+        self.set_data_3d(xs, ys, zs)
+
+    def set_3d_properties(self, zs=0, zdir='z'):
+        """
+        Set the *z* position and direction of the line.
+
+        Parameters
+        ----------
+        zs : float or array of floats
+            The location along the *zdir* axis in 3D space to position the
+            line.
+        zdir : {'x', 'y', 'z'}
+            Plane to plot line orthogonal to. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        xs = self.get_xdata()
+        ys = self.get_ydata()
+        zs = cbook._to_unmasked_float_array(zs).ravel()
+        zs = np.broadcast_to(zs, len(xs))
+        self._verts3d = juggle_axes(xs, ys, zs, zdir)
+        self.stale = True
+
+    def set_data_3d(self, *args):
+        """
+        Set the x, y and z data
+
+        Parameters
+        ----------
+        x : array-like
+            The x-data to be plotted.
+        y : array-like
+            The y-data to be plotted.
+        z : array-like
+            The z-data to be plotted.
+
+        Notes
+        -----
+        Accepts x, y, z arguments or a single array-like (x, y, z)
+        """
+        if len(args) == 1:
+            args = args[0]
+        for name, xyz in zip('xyz', args):
+            if not np.iterable(xyz):
+                raise RuntimeError(f'{name} must be a sequence')
+        self._verts3d = args
+        self.stale = True
+
+    def get_data_3d(self):
+        """
+        Get the current data
+
+        Returns
+        -------
+        verts3d : length-3 tuple or array-like
+            The current data as a tuple or array-like.
+        """
+        return self._verts3d
+
+    @artist.allow_rasterization
+    def draw(self, renderer):
+        xs3d, ys3d, zs3d = self._verts3d
+        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)
+        self.set_data(xs, ys)
+        super().draw(renderer)
+        self.stale = False
+
+
+def line_2d_to_3d(line, zs=0, zdir='z'):
+    """
+    Convert a `.Line2D` to a `.Line3D` object.
+
+    Parameters
+    ----------
+    zs : float
+        The location along the *zdir* axis in 3D space to position the line.
+    zdir : {'x', 'y', 'z'}
+        Plane to plot line orthogonal to. Default: 'z'.
+        See `.get_dir_vector` for a description of the values.
+    """
+
+    line.__class__ = Line3D
+    line.set_3d_properties(zs, zdir)
+
+
+def _path_to_3d_segment(path, zs=0, zdir='z'):
+    """Convert a path to a 3D segment."""
+
+    zs = np.broadcast_to(zs, len(path))
+    pathsegs = path.iter_segments(simplify=False, curves=False)
+    seg = [(x, y, z) for (((x, y), code), z) in zip(pathsegs, zs)]
+    seg3d = [juggle_axes(x, y, z, zdir) for (x, y, z) in seg]
+    return seg3d
+
+
+def _paths_to_3d_segments(paths, zs=0, zdir='z'):
+    """Convert paths from a collection object to 3D segments."""
+
+    if not np.iterable(zs):
+        zs = np.broadcast_to(zs, len(paths))
+    else:
+        if len(zs) != len(paths):
+            raise ValueError('Number of z-coordinates does not match paths.')
+
+    segs = [_path_to_3d_segment(path, pathz, zdir)
+            for path, pathz in zip(paths, zs)]
+    return segs
+
+
+def _path_to_3d_segment_with_codes(path, zs=0, zdir='z'):
+    """Convert a path to a 3D segment with path codes."""
+
+    zs = np.broadcast_to(zs, len(path))
+    pathsegs = path.iter_segments(simplify=False, curves=False)
+    seg_codes = [((x, y, z), code) for ((x, y), code), z in zip(pathsegs, zs)]
+    if seg_codes:
+        seg, codes = zip(*seg_codes)
+        seg3d = [juggle_axes(x, y, z, zdir) for (x, y, z) in seg]
+    else:
+        seg3d = []
+        codes = []
+    return seg3d, list(codes)
+
+
+def _paths_to_3d_segments_with_codes(paths, zs=0, zdir='z'):
+    """
+    Convert paths from a collection object to 3D segments with path codes.
+    """
+
+    zs = np.broadcast_to(zs, len(paths))
+    segments_codes = [_path_to_3d_segment_with_codes(path, pathz, zdir)
+                      for path, pathz in zip(paths, zs)]
+    if segments_codes:
+        segments, codes = zip(*segments_codes)
+    else:
+        segments, codes = [], []
+    return list(segments), list(codes)
+
+
+class Collection3D(Collection):
+    """A collection of 3D paths."""
+
+    def do_3d_projection(self):
+        """Project the points according to renderer matrix."""
+        xyzs_list = [proj3d.proj_transform(*vs.T, self.axes.M)
+                     for vs, _ in self._3dverts_codes]
+        self._paths = [mpath.Path(np.column_stack([xs, ys]), cs)
+                       for (xs, ys, _), (_, cs) in zip(xyzs_list, self._3dverts_codes)]
+        zs = np.concatenate([zs for _, _, zs in xyzs_list])
+        return zs.min() if len(zs) else 1e9
+
+
+def collection_2d_to_3d(col, zs=0, zdir='z'):
+    """Convert a `.Collection` to a `.Collection3D` object."""
+    zs = np.broadcast_to(zs, len(col.get_paths()))
+    col._3dverts_codes = [
+        (np.column_stack(juggle_axes(
+            *np.column_stack([p.vertices, np.broadcast_to(z, len(p.vertices))]).T,
+            zdir)),
+         p.codes)
+        for p, z in zip(col.get_paths(), zs)]
+    col.__class__ = cbook._make_class_factory(Collection3D, "{}3D")(type(col))
+
+
+class Line3DCollection(LineCollection):
+    """
+    A collection of 3D lines.
+    """
+
+    def set_sort_zpos(self, val):
+        """Set the position to use for z-sorting."""
+        self._sort_zpos = val
+        self.stale = True
+
+    def set_segments(self, segments):
+        """
+        Set 3D segments.
+        """
+        self._segments3d = segments
+        super().set_segments([])
+
+    def do_3d_projection(self):
+        """
+        Project the points according to renderer matrix.
+        """
+        xyslist = [proj3d._proj_trans_points(points, self.axes.M)
+                   for points in self._segments3d]
+        segments_2d = [np.column_stack([xs, ys]) for xs, ys, zs in xyslist]
+        LineCollection.set_segments(self, segments_2d)
+
+        # FIXME
+        minz = 1e9
+        for xs, ys, zs in xyslist:
+            minz = min(minz, min(zs))
+        return minz
+
+
+def line_collection_2d_to_3d(col, zs=0, zdir='z'):
+    """Convert a `.LineCollection` to a `.Line3DCollection` object."""
+    segments3d = _paths_to_3d_segments(col.get_paths(), zs, zdir)
+    col.__class__ = Line3DCollection
+    col.set_segments(segments3d)
+
+
+class Patch3D(Patch):
+    """
+    3D patch object.
+    """
+
+    def __init__(self, *args, zs=(), zdir='z', **kwargs):
+        """
+        Parameters
+        ----------
+        verts :
+        zs : float
+            The location along the *zdir* axis in 3D space to position the
+            patch.
+        zdir : {'x', 'y', 'z'}
+            Plane to plot patch orthogonal to. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        super().__init__(*args, **kwargs)
+        self.set_3d_properties(zs, zdir)
+
+    def set_3d_properties(self, verts, zs=0, zdir='z'):
+        """
+        Set the *z* position and direction of the patch.
+
+        Parameters
+        ----------
+        verts :
+        zs : float
+            The location along the *zdir* axis in 3D space to position the
+            patch.
+        zdir : {'x', 'y', 'z'}
+            Plane to plot patch orthogonal to. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        zs = np.broadcast_to(zs, len(verts))
+        self._segment3d = [juggle_axes(x, y, z, zdir)
+                           for ((x, y), z) in zip(verts, zs)]
+
+    def get_path(self):
+        return self._path2d
+
+    def do_3d_projection(self):
+        s = self._segment3d
+        xs, ys, zs = zip(*s)
+        vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs,
+                                                        self.axes.M)
+        self._path2d = mpath.Path(np.column_stack([vxs, vys]))
+        return min(vzs)
+
+
+class PathPatch3D(Patch3D):
+    """
+    3D PathPatch object.
+    """
+
+    def __init__(self, path, *, zs=(), zdir='z', **kwargs):
+        """
+        Parameters
+        ----------
+        path :
+        zs : float
+            The location along the *zdir* axis in 3D space to position the
+            path patch.
+        zdir : {'x', 'y', 'z', 3-tuple}
+            Plane to plot path patch orthogonal to. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        # Not super().__init__!
+        Patch.__init__(self, **kwargs)
+        self.set_3d_properties(path, zs, zdir)
+
+    def set_3d_properties(self, path, zs=0, zdir='z'):
+        """
+        Set the *z* position and direction of the path patch.
+
+        Parameters
+        ----------
+        path :
+        zs : float
+            The location along the *zdir* axis in 3D space to position the
+            path patch.
+        zdir : {'x', 'y', 'z', 3-tuple}
+            Plane to plot path patch orthogonal to. Default: 'z'.
+            See `.get_dir_vector` for a description of the values.
+        """
+        Patch3D.set_3d_properties(self, path.vertices, zs=zs, zdir=zdir)
+        self._code3d = path.codes
+
+    def do_3d_projection(self):
+        s = self._segment3d
+        xs, ys, zs = zip(*s)
+        vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs,
+                                                        self.axes.M)
+        self._path2d = mpath.Path(np.column_stack([vxs, vys]), self._code3d)
+        return min(vzs)
+
+
+def _get_patch_verts(patch):
+    """Return a list of vertices for the path of a patch."""
+    trans = patch.get_patch_transform()
+    path = patch.get_path()
+    polygons = path.to_polygons(trans)
+    return polygons[0] if len(polygons) else np.array([])
+
+
+def patch_2d_to_3d(patch, z=0, zdir='z'):
+    """Convert a `.Patch` to a `.Patch3D` object."""
+    verts = _get_patch_verts(patch)
+    patch.__class__ = Patch3D
+    patch.set_3d_properties(verts, z, zdir)
+
+
+def pathpatch_2d_to_3d(pathpatch, z=0, zdir='z'):
+    """Convert a `.PathPatch` to a `.PathPatch3D` object."""
+    path = pathpatch.get_path()
+    trans = pathpatch.get_patch_transform()
+
+    mpath = trans.transform_path(path)
+    pathpatch.__class__ = PathPatch3D
+    pathpatch.set_3d_properties(mpath, z, zdir)
+
+
+class Patch3DCollection(PatchCollection):
+    """
+    A collection of 3D patches.
+    """
+
+    def __init__(self, *args, zs=0, zdir='z', depthshade=True, **kwargs):
+        """
+        Create a collection of flat 3D patches with its normal vector
+        pointed in *zdir* direction, and located at *zs* on the *zdir*
+        axis. 'zs' can be a scalar or an array-like of the same length as
+        the number of patches in the collection.
+
+        Constructor arguments are the same as for
+        :class:`~matplotlib.collections.PatchCollection`. In addition,
+        keywords *zs=0* and *zdir='z'* are available.
+
+        Also, the keyword argument *depthshade* is available to indicate
+        whether to shade the patches in order to give the appearance of depth
+        (default is *True*). This is typically desired in scatter plots.
+        """
+        self._depthshade = depthshade
+        super().__init__(*args, **kwargs)
+        self.set_3d_properties(zs, zdir)
+
+    def get_depthshade(self):
+        return self._depthshade
+
+    def set_depthshade(self, depthshade):
+        """
+        Set whether depth shading is performed on collection members.
+
+        Parameters
+        ----------
+        depthshade : bool
+            Whether to shade the patches in order to give the appearance of
+            depth.
+        """
+        self._depthshade = depthshade
+        self.stale = True
+
+    def set_sort_zpos(self, val):
+        """Set the position to use for z-sorting."""
+        self._sort_zpos = val
+        self.stale = True
+
+    def set_3d_properties(self, zs, zdir):
+        """
+        Set the *z* positions and direction of the patches.
+
+        Parameters
+        ----------
+        zs : float or array of floats
+            The location or locations to place the patches in the collection
+            along the *zdir* axis.
+        zdir : {'x', 'y', 'z'}
+            Plane to plot patches orthogonal to.
+            All patches must have the same direction.
+            See `.get_dir_vector` for a description of the values.
+        """
+        # Force the collection to initialize the face and edgecolors
+        # just in case it is a scalarmappable with a colormap.
+        self.update_scalarmappable()
+        offsets = self.get_offsets()
+        if len(offsets) > 0:
+            xs, ys = offsets.T
+        else:
+            xs = []
+            ys = []
+        self._offsets3d = juggle_axes(xs, ys, np.atleast_1d(zs), zdir)
+        self._z_markers_idx = slice(-1)
+        self._vzs = None
+        self.stale = True
+
+    def do_3d_projection(self):
+        xs, ys, zs = self._offsets3d
+        vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs,
+                                                        self.axes.M)
+        self._vzs = vzs
+        super().set_offsets(np.column_stack([vxs, vys]))
+
+        if vzs.size > 0:
+            return min(vzs)
+        else:
+            return np.nan
+
+    def _maybe_depth_shade_and_sort_colors(self, color_array):
+        color_array = (
+            _zalpha(color_array, self._vzs)
+            if self._vzs is not None and self._depthshade
+            else color_array
+        )
+        if len(color_array) > 1:
+            color_array = color_array[self._z_markers_idx]
+        return mcolors.to_rgba_array(color_array, self._alpha)
+
+    def get_facecolor(self):
+        return self._maybe_depth_shade_and_sort_colors(super().get_facecolor())
+
+    def get_edgecolor(self):
+        # We need this check here to make sure we do not double-apply the depth
+        # based alpha shading when the edge color is "face" which means the
+        # edge colour should be identical to the face colour.
+        if cbook._str_equal(self._edgecolors, 'face'):
+            return self.get_facecolor()
+        return self._maybe_depth_shade_and_sort_colors(super().get_edgecolor())
+
+
+class Path3DCollection(PathCollection):
+    """
+    A collection of 3D paths.
+    """
+
+    def __init__(self, *args, zs=0, zdir='z', depthshade=True, **kwargs):
+        """
+        Create a collection of flat 3D paths with its normal vector
+        pointed in *zdir* direction, and located at *zs* on the *zdir*
+        axis. 'zs' can be a scalar or an array-like of the same length as
+        the number of paths in the collection.
+
+        Constructor arguments are the same as for
+        :class:`~matplotlib.collections.PathCollection`. In addition,
+        keywords *zs=0* and *zdir='z'* are available.
+
+        Also, the keyword argument *depthshade* is available to indicate
+        whether to shade the patches in order to give the appearance of depth
+        (default is *True*). This is typically desired in scatter plots.
+        """
+        self._depthshade = depthshade
+        self._in_draw = False
+        super().__init__(*args, **kwargs)
+        self.set_3d_properties(zs, zdir)
+        self._offset_zordered = None
+
+    def draw(self, renderer):
+        with self._use_zordered_offset():
+            with cbook._setattr_cm(self, _in_draw=True):
+                super().draw(renderer)
+
+    def set_sort_zpos(self, val):
+        """Set the position to use for z-sorting."""
+        self._sort_zpos = val
+        self.stale = True
+
+    def set_3d_properties(self, zs, zdir):
+        """
+        Set the *z* positions and direction of the paths.
+
+        Parameters
+        ----------
+        zs : float or array of floats
+            The location or locations to place the paths in the collection
+            along the *zdir* axis.
+        zdir : {'x', 'y', 'z'}
+            Plane to plot paths orthogonal to.
+            All paths must have the same direction.
+            See `.get_dir_vector` for a description of the values.
+        """
+        # Force the collection to initialize the face and edgecolors
+        # just in case it is a scalarmappable with a colormap.
+        self.update_scalarmappable()
+        offsets = self.get_offsets()
+        if len(offsets) > 0:
+            xs, ys = offsets.T
+        else:
+            xs = []
+            ys = []
+        self._offsets3d = juggle_axes(xs, ys, np.atleast_1d(zs), zdir)
+        # In the base draw methods we access the attributes directly which
+        # means we cannot resolve the shuffling in the getter methods like
+        # we do for the edge and face colors.
+        #
+        # This means we need to carry around a cache of the unsorted sizes and
+        # widths (postfixed with 3d) and in `do_3d_projection` set the
+        # depth-sorted version of that data into the private state used by the
+        # base collection class in its draw method.
+        #
+        # Grab the current sizes and linewidths to preserve them.
+        self._sizes3d = self._sizes
+        self._linewidths3d = np.array(self._linewidths)
+        xs, ys, zs = self._offsets3d
+
+        # Sort the points based on z coordinates
+        # Performance optimization: Create a sorted index array and reorder
+        # points and point properties according to the index array
+        self._z_markers_idx = slice(-1)
+        self._vzs = None
+        self.stale = True
+
+    def set_sizes(self, sizes, dpi=72.0):
+        super().set_sizes(sizes, dpi)
+        if not self._in_draw:
+            self._sizes3d = sizes
+
+    def set_linewidth(self, lw):
+        super().set_linewidth(lw)
+        if not self._in_draw:
+            self._linewidths3d = np.array(self._linewidths)
+
+    def get_depthshade(self):
+        return self._depthshade
+
+    def set_depthshade(self, depthshade):
+        """
+        Set whether depth shading is performed on collection members.
+
+        Parameters
+        ----------
+        depthshade : bool
+            Whether to shade the patches in order to give the appearance of
+            depth.
+        """
+        self._depthshade = depthshade
+        self.stale = True
+
+    def do_3d_projection(self):
+        xs, ys, zs = self._offsets3d
+        vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs,
+                                                        self.axes.M)
+        # Sort the points based on z coordinates
+        # Performance optimization: Create a sorted index array and reorder
+        # points and point properties according to the index array
+        z_markers_idx = self._z_markers_idx = np.argsort(vzs)[::-1]
+        self._vzs = vzs
+
+        # we have to special case the sizes because of code in collections.py
+        # as the draw method does
+        #      self.set_sizes(self._sizes, self.figure.dpi)
+        # so we cannot rely on doing the sorting on the way out via get_*
+
+        if len(self._sizes3d) > 1:
+            self._sizes = self._sizes3d[z_markers_idx]
+
+        if len(self._linewidths3d) > 1:
+            self._linewidths = self._linewidths3d[z_markers_idx]
+
+        PathCollection.set_offsets(self, np.column_stack((vxs, vys)))
+
+        # Re-order items
+        vzs = vzs[z_markers_idx]
+        vxs = vxs[z_markers_idx]
+        vys = vys[z_markers_idx]
+
+        # Store ordered offset for drawing purpose
+        self._offset_zordered = np.column_stack((vxs, vys))
+
+        return np.min(vzs) if vzs.size else np.nan
+
+    @contextmanager
+    def _use_zordered_offset(self):
+        if self._offset_zordered is None:
+            # Do nothing
+            yield
+        else:
+            # Swap offset with z-ordered offset
+            old_offset = self._offsets
+            super().set_offsets(self._offset_zordered)
+            try:
+                yield
+            finally:
+                self._offsets = old_offset
+
+    def _maybe_depth_shade_and_sort_colors(self, color_array):
+        color_array = (
+            _zalpha(color_array, self._vzs)
+            if self._vzs is not None and self._depthshade
+            else color_array
+        )
+        if len(color_array) > 1:
+            color_array = color_array[self._z_markers_idx]
+        return mcolors.to_rgba_array(color_array, self._alpha)
+
+    def get_facecolor(self):
+        return self._maybe_depth_shade_and_sort_colors(super().get_facecolor())
+
+    def get_edgecolor(self):
+        # We need this check here to make sure we do not double-apply the depth
+        # based alpha shading when the edge color is "face" which means the
+        # edge colour should be identical to the face colour.
+        if cbook._str_equal(self._edgecolors, 'face'):
+            return self.get_facecolor()
+        return self._maybe_depth_shade_and_sort_colors(super().get_edgecolor())
+
+
+def patch_collection_2d_to_3d(col, zs=0, zdir='z', depthshade=True):
+    """
+    Convert a `.PatchCollection` into a `.Patch3DCollection` object
+    (or a `.PathCollection` into a `.Path3DCollection` object).
+
+    Parameters
+    ----------
+    zs : float or array of floats
+        The location or locations to place the patches in the collection along
+        the *zdir* axis. Default: 0.
+    zdir : {'x', 'y', 'z'}
+        The axis in which to place the patches. Default: "z".
+        See `.get_dir_vector` for a description of the values.
+    depthshade
+        Whether to shade the patches to give a sense of depth. Default: *True*.
+
+    """
+    if isinstance(col, PathCollection):
+        col.__class__ = Path3DCollection
+        col._offset_zordered = None
+    elif isinstance(col, PatchCollection):
+        col.__class__ = Patch3DCollection
+    col._depthshade = depthshade
+    col._in_draw = False
+    col.set_3d_properties(zs, zdir)
+
+
+class Poly3DCollection(PolyCollection):
+    """
+    A collection of 3D polygons.
+
+    .. note::
+        **Filling of 3D polygons**
+
+        There is no simple definition of the enclosed surface of a 3D polygon
+        unless the polygon is planar.
+
+        In practice, Matplotlib fills the 2D projection of the polygon. This
+        gives a correct filling appearance only for planar polygons. For all
+        other polygons, you'll find orientations in which the edges of the
+        polygon intersect in the projection. This will lead to an incorrect
+        visualization of the 3D area.
+
+        If you need filled areas, it is recommended to create them via
+        `~mpl_toolkits.mplot3d.axes3d.Axes3D.plot_trisurf`, which creates a
+        triangulation and thus generates consistent surfaces.
+    """
+
+    def __init__(self, verts, *args, zsort='average', shade=False,
+                 lightsource=None, **kwargs):
+        """
+        Parameters
+        ----------
+        verts : list of (N, 3) 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 (N, 3).
+        zsort : {'average', 'min', 'max'}, default: 'average'
+            The calculation method for the z-order.
+            See `~.Poly3DCollection.set_zsort` for details.
+        shade : bool, default: False
+            Whether to shade *facecolors* and *edgecolors*. When activating
+            *shade*, *facecolors* and/or *edgecolors* must be provided.
+
+            .. versionadded:: 3.7
+
+        lightsource : `~matplotlib.colors.LightSource`, optional
+            The lightsource to use when *shade* is True.
+
+            .. versionadded:: 3.7
+
+        *args, **kwargs
+            All other parameters are forwarded to `.PolyCollection`.
+
+        Notes
+        -----
+        Note that this class does a bit of magic with the _facecolors
+        and _edgecolors properties.
+        """
+        if shade:
+            normals = _generate_normals(verts)
+            facecolors = kwargs.get('facecolors', None)
+            if facecolors is not None:
+                kwargs['facecolors'] = _shade_colors(
+                    facecolors, normals, lightsource
+                )
+
+            edgecolors = kwargs.get('edgecolors', None)
+            if edgecolors is not None:
+                kwargs['edgecolors'] = _shade_colors(
+                    edgecolors, normals, lightsource
+                )
+            if facecolors is None and edgecolors is None:
+                raise ValueError(
+                    "You must provide facecolors, edgecolors, or both for "
+                    "shade to work.")
+        super().__init__(verts, *args, **kwargs)
+        if isinstance(verts, np.ndarray):
+            if verts.ndim != 3:
+                raise ValueError('verts must be a list of (N, 3) array-like')
+        else:
+            if any(len(np.shape(vert)) != 2 for vert in verts):
+                raise ValueError('verts must be a list of (N, 3) array-like')
+        self.set_zsort(zsort)
+        self._codes3d = None
+
+    _zsort_functions = {
+        'average': np.average,
+        'min': np.min,
+        'max': np.max,
+    }
+
+    def set_zsort(self, zsort):
+        """
+        Set the calculation method for the z-order.
+
+        Parameters
+        ----------
+        zsort : {'average', 'min', 'max'}
+            The function applied on the z-coordinates of the vertices in the
+            viewer's coordinate system, to determine the z-order.
+        """
+        self._zsortfunc = self._zsort_functions[zsort]
+        self._sort_zpos = None
+        self.stale = True
+
+    def get_vector(self, segments3d):
+        """Optimize points for projection."""
+        if len(segments3d):
+            xs, ys, zs = np.vstack(segments3d).T
+        else:  # vstack can't stack zero arrays.
+            xs, ys, zs = [], [], []
+        ones = np.ones(len(xs))
+        self._vec = np.array([xs, ys, zs, ones])
+
+        indices = [0, *np.cumsum([len(segment) for segment in segments3d])]
+        self._segslices = [*map(slice, indices[:-1], indices[1:])]
+
+    def set_verts(self, verts, closed=True):
+        """
+        Set 3D vertices.
+
+        Parameters
+        ----------
+        verts : list of (N, 3) 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 (N, 3).
+        closed : bool, default: True
+            Whether the polygon should be closed by adding a CLOSEPOLY
+            connection at the end.
+        """
+        self.get_vector(verts)
+        # 2D verts will be updated at draw time
+        super().set_verts([], False)
+        self._closed = closed
+
+    def set_verts_and_codes(self, verts, codes):
+        """Set 3D vertices with path codes."""
+        # set vertices with closed=False to prevent PolyCollection from
+        # setting path codes
+        self.set_verts(verts, closed=False)
+        # and set our own codes instead.
+        self._codes3d = codes
+
+    def set_3d_properties(self):
+        # Force the collection to initialize the face and edgecolors
+        # just in case it is a scalarmappable with a colormap.
+        self.update_scalarmappable()
+        self._sort_zpos = None
+        self.set_zsort('average')
+        self._facecolor3d = PolyCollection.get_facecolor(self)
+        self._edgecolor3d = PolyCollection.get_edgecolor(self)
+        self._alpha3d = PolyCollection.get_alpha(self)
+        self.stale = True
+
+    def set_sort_zpos(self, val):
+        """Set the position to use for z-sorting."""
+        self._sort_zpos = val
+        self.stale = True
+
+    def do_3d_projection(self):
+        """
+        Perform the 3D projection for this object.
+        """
+        if self._A is not None:
+            # force update of color mapping because we re-order them
+            # below.  If we do not do this here, the 2D draw will call
+            # this, but we will never port the color mapped values back
+            # to the 3D versions.
+            #
+            # We hold the 3D versions in a fixed order (the order the user
+            # passed in) and sort the 2D version by view depth.
+            self.update_scalarmappable()
+            if self._face_is_mapped:
+                self._facecolor3d = self._facecolors
+            if self._edge_is_mapped:
+                self._edgecolor3d = self._edgecolors
+        txs, tys, tzs = proj3d._proj_transform_vec(self._vec, self.axes.M)
+        xyzlist = [(txs[sl], tys[sl], tzs[sl]) for sl in self._segslices]
+
+        # This extra fuss is to re-order face / edge colors
+        cface = self._facecolor3d
+        cedge = self._edgecolor3d
+        if len(cface) != len(xyzlist):
+            cface = cface.repeat(len(xyzlist), axis=0)
+        if len(cedge) != len(xyzlist):
+            if len(cedge) == 0:
+                cedge = cface
+            else:
+                cedge = cedge.repeat(len(xyzlist), axis=0)
+
+        if xyzlist:
+            # sort by depth (furthest drawn first)
+            z_segments_2d = sorted(
+                ((self._zsortfunc(zs), np.column_stack([xs, ys]), fc, ec, idx)
+                 for idx, ((xs, ys, zs), fc, ec)
+                 in enumerate(zip(xyzlist, cface, cedge))),
+                key=lambda x: x[0], reverse=True)
+
+            _, segments_2d, self._facecolors2d, self._edgecolors2d, idxs = \
+                zip(*z_segments_2d)
+        else:
+            segments_2d = []
+            self._facecolors2d = np.empty((0, 4))
+            self._edgecolors2d = np.empty((0, 4))
+            idxs = []
+
+        if self._codes3d is not None:
+            codes = [self._codes3d[idx] for idx in idxs]
+            PolyCollection.set_verts_and_codes(self, segments_2d, codes)
+        else:
+            PolyCollection.set_verts(self, segments_2d, self._closed)
+
+        if len(self._edgecolor3d) != len(cface):
+            self._edgecolors2d = self._edgecolor3d
+
+        # Return zorder value
+        if self._sort_zpos is not None:
+            zvec = np.array([[0], [0], [self._sort_zpos], [1]])
+            ztrans = proj3d._proj_transform_vec(zvec, self.axes.M)
+            return ztrans[2][0]
+        elif tzs.size > 0:
+            # FIXME: Some results still don't look quite right.
+            #        In particular, examine contourf3d_demo2.py
+            #        with az = -54 and elev = -45.
+            return np.min(tzs)
+        else:
+            return np.nan
+
+    def set_facecolor(self, colors):
+        # docstring inherited
+        super().set_facecolor(colors)
+        self._facecolor3d = PolyCollection.get_facecolor(self)
+
+    def set_edgecolor(self, colors):
+        # docstring inherited
+        super().set_edgecolor(colors)
+        self._edgecolor3d = PolyCollection.get_edgecolor(self)
+
+    def set_alpha(self, alpha):
+        # docstring inherited
+        artist.Artist.set_alpha(self, alpha)
+        try:
+            self._facecolor3d = mcolors.to_rgba_array(
+                self._facecolor3d, self._alpha)
+        except (AttributeError, TypeError, IndexError):
+            pass
+        try:
+            self._edgecolors = mcolors.to_rgba_array(
+                    self._edgecolor3d, self._alpha)
+        except (AttributeError, TypeError, IndexError):
+            pass
+        self.stale = True
+
+    def get_facecolor(self):
+        # docstring inherited
+        # self._facecolors2d is not initialized until do_3d_projection
+        if not hasattr(self, '_facecolors2d'):
+            self.axes.M = self.axes.get_proj()
+            self.do_3d_projection()
+        return np.asarray(self._facecolors2d)
+
+    def get_edgecolor(self):
+        # docstring inherited
+        # self._edgecolors2d is not initialized until do_3d_projection
+        if not hasattr(self, '_edgecolors2d'):
+            self.axes.M = self.axes.get_proj()
+            self.do_3d_projection()
+        return np.asarray(self._edgecolors2d)
+
+
+def poly_collection_2d_to_3d(col, zs=0, zdir='z'):
+    """
+    Convert a `.PolyCollection` into a `.Poly3DCollection` object.
+
+    Parameters
+    ----------
+    zs : float or array of floats
+        The location or locations to place the polygons in the collection along
+        the *zdir* axis. Default: 0.
+    zdir : {'x', 'y', 'z'}
+        The axis in which to place the patches. Default: 'z'.
+        See `.get_dir_vector` for a description of the values.
+    """
+    segments_3d, codes = _paths_to_3d_segments_with_codes(
+            col.get_paths(), zs, zdir)
+    col.__class__ = Poly3DCollection
+    col.set_verts_and_codes(segments_3d, codes)
+    col.set_3d_properties()
+
+
+def juggle_axes(xs, ys, zs, zdir):
+    """
+    Reorder coordinates so that 2D *xs*, *ys* can be plotted in the plane
+    orthogonal to *zdir*. *zdir* is normally 'x', 'y' or 'z'. However, if
+    *zdir* starts with a '-' it is interpreted as a compensation for
+    `rotate_axes`.
+    """
+    if zdir == 'x':
+        return zs, xs, ys
+    elif zdir == 'y':
+        return xs, zs, ys
+    elif zdir[0] == '-':
+        return rotate_axes(xs, ys, zs, zdir)
+    else:
+        return xs, ys, zs
+
+
+def rotate_axes(xs, ys, zs, zdir):
+    """
+    Reorder coordinates so that the axes are rotated with *zdir* along
+    the original z axis. Prepending the axis with a '-' does the
+    inverse transform, so *zdir* can be 'x', '-x', 'y', '-y', 'z' or '-z'.
+    """
+    if zdir in ('x', '-y'):
+        return ys, zs, xs
+    elif zdir in ('-x', 'y'):
+        return zs, xs, ys
+    else:
+        return xs, ys, zs
+
+
+def _zalpha(colors, zs):
+    """Modify the alphas of the color list according to depth."""
+    # FIXME: This only works well if the points for *zs* are well-spaced
+    #        in all three dimensions. Otherwise, at certain orientations,
+    #        the min and max zs are very close together.
+    #        Should really normalize against the viewing depth.
+    if len(colors) == 0 or len(zs) == 0:
+        return np.zeros((0, 4))
+    norm = Normalize(min(zs), max(zs))
+    sats = 1 - norm(zs) * 0.7
+    rgba = np.broadcast_to(mcolors.to_rgba_array(colors), (len(zs), 4))
+    return np.column_stack([rgba[:, :3], rgba[:, 3] * sats])
+
+
+def _generate_normals(polygons):
+    """
+    Compute the normals of a list of polygons, one normal per polygon.
+
+    Normals point towards the viewer for a face with its vertices in
+    counterclockwise order, following the right hand rule.
+
+    Uses three points equally spaced around the polygon. This method assumes
+    that the points are in a plane. Otherwise, more than one shade is required,
+    which is not supported.
+
+    Parameters
+    ----------
+    polygons : list of (M_i, 3) array-like, or (..., M, 3) array-like
+        A sequence of polygons to compute normals for, which can have
+        varying numbers of vertices. If the polygons all have the same
+        number of vertices and array is passed, then the operation will
+        be vectorized.
+
+    Returns
+    -------
+    normals : (..., 3) array
+        A normal vector estimated for the polygon.
+    """
+    if isinstance(polygons, np.ndarray):
+        # optimization: polygons all have the same number of points, so can
+        # vectorize
+        n = polygons.shape[-2]
+        i1, i2, i3 = 0, n//3, 2*n//3
+        v1 = polygons[..., i1, :] - polygons[..., i2, :]
+        v2 = polygons[..., i2, :] - polygons[..., i3, :]
+    else:
+        # The subtraction doesn't vectorize because polygons is jagged.
+        v1 = np.empty((len(polygons), 3))
+        v2 = np.empty((len(polygons), 3))
+        for poly_i, ps in enumerate(polygons):
+            n = len(ps)
+            i1, i2, i3 = 0, n//3, 2*n//3
+            v1[poly_i, :] = ps[i1, :] - ps[i2, :]
+            v2[poly_i, :] = ps[i2, :] - ps[i3, :]
+    return np.cross(v1, v2)
+
+
+def _shade_colors(color, normals, lightsource=None):
+    """
+    Shade *color* using normal vectors given by *normals*,
+    assuming a *lightsource* (using default position if not given).
+    *color* can also be an array of the same length as *normals*.
+    """
+    if lightsource is None:
+        # chosen for backwards-compatibility
+        lightsource = mcolors.LightSource(azdeg=225, altdeg=19.4712)
+
+    with np.errstate(invalid="ignore"):
+        shade = ((normals / np.linalg.norm(normals, axis=1, keepdims=True))
+                 @ lightsource.direction)
+    mask = ~np.isnan(shade)
+
+    if mask.any():
+        # convert dot product to allowed shading fractions
+        in_norm = mcolors.Normalize(-1, 1)
+        out_norm = mcolors.Normalize(0.3, 1).inverse
+
+        def norm(x):
+            return out_norm(in_norm(x))
+
+        shade[~mask] = 0
+
+        color = mcolors.to_rgba_array(color)
+        # shape of color should be (M, 4) (where M is number of faces)
+        # shape of shade should be (M,)
+        # colors should have final shape of (M, 4)
+        alpha = color[:, 3]
+        colors = norm(shade)[:, np.newaxis] * color
+        colors[:, 3] = alpha
+    else:
+        colors = np.asanyarray(color).copy()
+
+    return colors