Source code for mpl_toolkits.mplot3d.art3d

# art3d.py, original mplot3d version by John Porter
# Parts rewritten by Reinier Heeres <[email protected]>
# Minor additions by Ben Axelrod <[email protected]>

"""
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 matplotlib import (
    artist, colors as mcolors, lines, text as mtext, path as mpath)
from matplotlib.collections import (
    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


[docs]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 returned unchanged. Returns ------- x, y, z : array-like The direction vector. This is either a numpy.array or *zdir* itself if *zdir* is already a length-3 iterable. """ 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 zdir else: raise ValueError("'x', 'y', 'z', None or vector of length 3 expected")
[docs]class Text3D(mtext.Text): """ Text object with 3D position and direction. Parameters ---------- x, y, z 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`. """
[docs] 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)
[docs] def set_3d_properties(self, z=0, zdir='z'): x, y = self.get_position() self._position3d = np.array((x, y, z)) self._dir_vec = get_dir_vector(zdir) self.stale = True
[docs] @artist.allow_rasterization def draw(self, renderer): proj = proj3d.proj_trans_points( [self._position3d, self._position3d + self._dir_vec], renderer.M) dx = proj[0][1] - proj[0][0] dy = proj[1][1] - proj[1][0] angle = math.degrees(math.atan2(dy, dx)) self.set_position((proj[0][0], proj[1][0])) self.set_rotation(_norm_text_angle(angle)) mtext.Text.draw(self, renderer) self.stale = False
[docs] def get_tightbbox(self, renderer): # Overwriting the 2d Text behavior which is not valid for 3d. # For now, just return None to exclude from layout calculation. return None
[docs]def text_2d_to_3d(obj, z=0, zdir='z'): """Convert a Text to a Text3D object.""" obj.__class__ = Text3D obj.set_3d_properties(z, zdir)
[docs]class Line3D(lines.Line2D): """ 3D line object. """
[docs] def __init__(self, xs, ys, zs, *args, **kwargs): """ Keyword arguments are passed onto :func:`~matplotlib.lines.Line2D`. """ lines.Line2D.__init__(self, [], [], *args, **kwargs) self._verts3d = xs, ys, zs
[docs] def set_3d_properties(self, zs=0, zdir='z'): xs = self.get_xdata() ys = self.get_ydata() zs = np.broadcast_to(zs, xs.shape) self._verts3d = juggle_axes(xs, ys, zs, zdir) self.stale = True
[docs] 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: self._verts3d = args[0] else: self._verts3d = args self.stale = True
[docs] 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
[docs] @artist.allow_rasterization def draw(self, renderer): xs3d, ys3d, zs3d = self._verts3d xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, renderer.M) self.set_data(xs, ys) lines.Line2D.draw(self, renderer) self.stale = False
[docs]def line_2d_to_3d(line, zs=0, zdir='z'): """Convert a 2D line to 3D.""" 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.""" zs = np.broadcast_to(zs, len(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)
[docs]class Line3DCollection(LineCollection): """ A collection of 3D lines. """
[docs] def set_sort_zpos(self, val): """Set the position to use for z-sorting.""" self._sort_zpos = val self.stale = True
[docs] def set_segments(self, segments): """ Set 3D segments. """ self._segments3d = segments LineCollection.set_segments(self, [])
[docs] def do_3d_projection(self, renderer): """ Project the points according to renderer matrix. """ # see _update_scalarmappable docstring for why this must be here _update_scalarmappable(self) xyslist = [ proj3d.proj_trans_points(points, renderer.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
[docs] @artist.allow_rasterization def draw(self, renderer, project=False): if project: self.do_3d_projection(renderer) LineCollection.draw(self, renderer)
[docs]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)
[docs]class Patch3D(Patch): """ 3D patch object. """
[docs] def __init__(self, *args, zs=(), zdir='z', **kwargs): Patch.__init__(self, *args, **kwargs) self.set_3d_properties(zs, zdir)
[docs] def set_3d_properties(self, verts, zs=0, zdir='z'): zs = np.broadcast_to(zs, len(verts)) self._segment3d = [juggle_axes(x, y, z, zdir) for ((x, y), z) in zip(verts, zs)] self._facecolor3d = Patch.get_facecolor(self)
[docs] def get_path(self): return self._path2d
[docs] def get_facecolor(self): return self._facecolor2d
[docs] def do_3d_projection(self, renderer): s = self._segment3d xs, ys, zs = zip(*s) vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs, renderer.M) self._path2d = mpath.Path(np.column_stack([vxs, vys])) # FIXME: coloring self._facecolor2d = self._facecolor3d return min(vzs)
[docs]class PathPatch3D(Patch3D): """ 3D PathPatch object. """
[docs] def __init__(self, path, *, zs=(), zdir='z', **kwargs): Patch.__init__(self, **kwargs) self.set_3d_properties(path, zs, zdir)
[docs] def set_3d_properties(self, path, zs=0, zdir='z'): Patch3D.set_3d_properties(self, path.vertices, zs=zs, zdir=zdir) self._code3d = path.codes
[docs] def do_3d_projection(self, renderer): s = self._segment3d xs, ys, zs = zip(*s) vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs, renderer.M) self._path2d = mpath.Path(np.column_stack([vxs, vys]), self._code3d) # FIXME: coloring self._facecolor2d = self._facecolor3d 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) if len(polygons): return polygons[0] else: return []
[docs]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)
[docs]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)
[docs]class Patch3DCollection(PatchCollection): """ A collection of 3D patches. """
[docs] 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 or not 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)
[docs] def set_sort_zpos(self, val): """Set the position to use for z-sorting.""" self._sort_zpos = val self.stale = True
[docs] def set_3d_properties(self, zs, zdir): # 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._facecolor3d = self.get_facecolor() self._edgecolor3d = self.get_edgecolor() self.stale = True
[docs] def do_3d_projection(self, renderer): # see _update_scalarmappable docstring for why this must be here _update_scalarmappable(self) xs, ys, zs = self._offsets3d vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs, renderer.M) fcs = (_zalpha(self._facecolor3d, vzs) if self._depthshade else self._facecolor3d) fcs = mcolors.to_rgba_array(fcs, self._alpha) self.set_facecolors(fcs) ecs = (_zalpha(self._edgecolor3d, vzs) if self._depthshade else self._edgecolor3d) ecs = mcolors.to_rgba_array(ecs, self._alpha) self.set_edgecolors(ecs) PatchCollection.set_offsets(self, np.column_stack([vxs, vys])) if vzs.size > 0: return min(vzs) else: return np.nan
[docs]class Path3DCollection(PathCollection): """ A collection of 3D paths. """
[docs] 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 or not 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)
[docs] def set_sort_zpos(self, val): """Set the position to use for z-sorting.""" self._sort_zpos = val self.stale = True
[docs] def set_3d_properties(self, zs, zdir): # 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._facecolor3d = self.get_facecolor() self._edgecolor3d = self.get_edgecolor() self._sizes3d = self.get_sizes() self._linewidth3d = self.get_linewidth() self.stale = True
[docs] def do_3d_projection(self, renderer): # see _update_scalarmappable docstring for why this must be here _update_scalarmappable(self) xs, ys, zs = self._offsets3d vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs, renderer.M) fcs = (_zalpha(self._facecolor3d, vzs) if self._depthshade else self._facecolor3d) ecs = (_zalpha(self._edgecolor3d, vzs) if self._depthshade else self._edgecolor3d) sizes = self._sizes3d lws = self._linewidth3d # 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 = np.argsort(vzs)[::-1] # Re-order items vzs = vzs[z_markers_idx] vxs = vxs[z_markers_idx] vys = vys[z_markers_idx] if len(fcs) > 1: fcs = fcs[z_markers_idx] if len(ecs) > 1: ecs = ecs[z_markers_idx] if len(sizes) > 1: sizes = sizes[z_markers_idx] if len(lws) > 1: lws = lws[z_markers_idx] vps = np.column_stack((vxs, vys)) fcs = mcolors.to_rgba_array(fcs, self._alpha) ecs = mcolors.to_rgba_array(ecs, self._alpha) self.set_edgecolors(ecs) self.set_facecolors(fcs) self.set_sizes(sizes) self.set_linewidth(lws) PathCollection.set_offsets(self, vps) return np.min(vzs) if vzs.size else np.nan
def _update_scalarmappable(sm): """ Update a 3D ScalarMappable. With ScalarMappable objects if the data, colormap, or norm are changed, we need to update the computed colors. This is handled by the base class method update_scalarmappable. This method works by, detecting if work needs to be done, and if so stashing it on the ``self._facecolors`` attribute. With 3D collections we internally sort the components so that things that should be "in front" are rendered later to simulate having a z-buffer (in addition to doing the projections). This is handled in the ``do_3d_projection`` methods which are called from the draw method of the 3D Axes. These methods: - do the projection from 3D -> 2D - internally sort based on depth - stash the results of the above in the 2D analogs of state - return the z-depth of the whole artist the last step is so that we can, at the Axes level, sort the children by depth. The base `draw` method of the 2D artists unconditionally calls update_scalarmappable and rely on the method's internal caching logic to lazily evaluate. These things together mean you can have the sequence of events: - we create the artist, do the color mapping and stash the results in a 3D specific state. - change something about the ScalarMappable that marks it as in need of an update (`ScalarMappable.changed` and friends). - We call do_3d_projection and shuffle the stashed colors into the 2D version of face colors - the draw method calls the update_scalarmappable method which overwrites our shuffled colors - we get a render that is wrong - if we re-render (either with a second save or implicitly via tight_layout / constrained_layout / bbox_inches='tight' (ex via inline's defaults)) we again shuffle the 3D colors - because the CM is not marked as changed update_scalarmappable is a no-op and we get a correct looking render. This function is an internal helper to: - sort out if we need to do the color mapping at all (has data!) - sort out if update_scalarmappable is going to be a no-op - copy the data over from the 2D -> 3D version This must be called first thing in do_3d_projection to make sure that the correct colors get shuffled. Parameters ---------- sm : ScalarMappable The ScalarMappable to update and stash the 3D data from """ if sm._A is None: return copy_state = sm._update_dict['array'] ret = sm.update_scalarmappable() if copy_state: if sm._is_filled: sm._facecolor3d = sm._facecolors elif sm._is_stroked: sm._edgecolor3d = sm._edgecolors
[docs]def patch_collection_2d_to_3d(col, zs=0, zdir='z', depthshade=True): """ Convert a :class:`~matplotlib.collections.PatchCollection` into a :class:`Patch3DCollection` object (or a :class:`~matplotlib.collections.PathCollection` into a :class:`Path3DCollection` object). Parameters ---------- za The location or locations to place the patches in the collection along the *zdir* axis. Default: 0. zdir The axis in which to place the patches. Default: "z". depthshade Whether to shade the patches to give a sense of depth. Default: *True*. """ if isinstance(col, PathCollection): col.__class__ = Path3DCollection elif isinstance(col, PatchCollection): col.__class__ = Patch3DCollection col._depthshade = depthshade col.set_3d_properties(zs, zdir)
[docs]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. """
[docs] def __init__(self, verts, *args, zsort='average', **kwargs): """ Parameters ---------- verts : list of array-like Nx3 Each element describes a polygon as a sequence of ``N_i`` points ``(x, y, z)``. zsort : {'average', 'min', 'max'}, default: 'average' The calculation method for the z-order. See `~.Poly3DCollection.set_zsort` for details. *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. """ super().__init__(verts, *args, **kwargs) self.set_zsort(zsort) self._codes3d = None
_zsort_functions = { 'average': np.average, 'min': np.min, 'max': np.max, }
[docs] 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
[docs] def get_vector(self, segments3d): """Optimize points for projection.""" if len(segments3d): xs, ys, zs = np.row_stack(segments3d).T else: # row_stack 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:])]
[docs] def set_verts(self, verts, closed=True): """Set 3D vertices.""" self.get_vector(verts) # 2D verts will be updated at draw time PolyCollection.set_verts(self, [], False) self._closed = closed
[docs] 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
[docs] 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
[docs] def set_sort_zpos(self, val): """Set the position to use for z-sorting.""" self._sort_zpos = val self.stale = True
[docs] def do_3d_projection(self, renderer): """ Perform the 3D projection for this object. """ # see _update_scalarmappable docstring for why this must be here _update_scalarmappable(self) txs, tys, tzs = proj3d._proj_transform_vec(self._vec, renderer.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) # 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) zzs, segments_2d, self._facecolors2d, self._edgecolors2d, idxs = \ zip(*z_segments_2d) 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, renderer.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
[docs] def set_facecolor(self, colors): PolyCollection.set_facecolor(self, colors) self._facecolor3d = PolyCollection.get_facecolor(self)
[docs] def set_edgecolor(self, colors): PolyCollection.set_edgecolor(self, colors) self._edgecolor3d = PolyCollection.get_edgecolor(self)
[docs] 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
[docs] def get_facecolor(self): return self._facecolors2d
[docs] def get_edgecolor(self): return self._edgecolors2d
[docs]def poly_collection_2d_to_3d(col, zs=0, zdir='z'): """Convert a PolyCollection to a Poly3DCollection object.""" 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()
[docs]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
[docs]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 == 'x': return ys, zs, xs elif zdir == '-x': return zs, xs, ys elif zdir == 'y': return zs, xs, ys elif zdir == '-y': return ys, zs, xs else: return xs, ys, zs
def _get_colors(c, num): """Stretch the color argument to provide the required number *num*.""" return np.broadcast_to( mcolors.to_rgba_array(c) if len(c) else [0, 0, 0, 0], (num, 4)) 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])