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from __future__ import division, print_function, absolute_import
import numpy as np
from scipy.lib.decorator import decorator as _decorator
__all__ = ['delaunay_plot_2d', 'convex_hull_plot_2d', 'voronoi_plot_2d']
@_decorator
def _held_figure(func, obj, ax=None, **kw):
import matplotlib.pyplot as plt
if ax is None:
fig = plt.figure()
ax = fig.gca()
was_held = ax.ishold()
try:
ax.hold(True)
return func(obj, ax=ax, **kw)
finally:
ax.hold(was_held)
def _adjust_bounds(ax, points):
ptp_bound = points.ptp(axis=0)
ax.set_xlim(points[:,0].min() - 0.1*ptp_bound[0],
points[:,0].max() + 0.1*ptp_bound[0])
ax.set_ylim(points[:,1].min() - 0.1*ptp_bound[1],
points[:,1].max() + 0.1*ptp_bound[1])
@_held_figure
def delaunay_plot_2d(tri, ax=None):
"""
Plot the given Delaunay triangulation in 2-D
Parameters
----------
tri : scipy.spatial.Delaunay instance
Triangulation to plot
ax : matplotlib.axes.Axes instance, optional
Axes to plot on
Returns
-------
fig : matplotlib.figure.Figure instance
Figure for the plot
See Also
--------
Delaunay
matplotlib.pyplot.triplot
Notes
-----
Requires Matplotlib.
"""
if tri.points.shape[1] != 2:
raise ValueError("Delaunay triangulation is not 2-D")
ax.plot(tri.points[:,0], tri.points[:,1], 'o')
ax.triplot(tri.points[:,0], tri.points[:,1], tri.simplices.copy())
_adjust_bounds(ax, tri.points)
return ax.figure
@_held_figure
def convex_hull_plot_2d(hull, ax=None):
"""
Plot the given convex hull diagram in 2-D
Parameters
----------
hull : scipy.spatial.ConvexHull instance
Convex hull to plot
ax : matplotlib.axes.Axes instance, optional
Axes to plot on
Returns
-------
fig : matplotlib.figure.Figure instance
Figure for the plot
See Also
--------
ConvexHull
Notes
-----
Requires Matplotlib.
"""
if hull.points.shape[1] != 2:
raise ValueError("Convex hull is not 2-D")
ax.plot(hull.points[:,0], hull.points[:,1], 'o')
for simplex in hull.simplices:
ax.plot(hull.points[simplex,0], hull.points[simplex,1], 'k-')
_adjust_bounds(ax, hull.points)
return ax.figure
@_held_figure
def voronoi_plot_2d(vor, ax=None):
"""
Plot the given Voronoi diagram in 2-D
Parameters
----------
vor : scipy.spatial.Voronoi instance
Diagram to plot
ax : matplotlib.axes.Axes instance, optional
Axes to plot on
Returns
-------
fig : matplotlib.figure.Figure instance
Figure for the plot
See Also
--------
Voronoi
Notes
-----
Requires Matplotlib.
"""
if vor.points.shape[1] != 2:
raise ValueError("Voronoi diagram is not 2-D")
ax.plot(vor.points[:,0], vor.points[:,1], '.')
ax.plot(vor.vertices[:,0], vor.vertices[:,1], 'o')
for simplex in vor.ridge_vertices:
simplex = np.asarray(simplex)
if np.all(simplex >= 0):
ax.plot(vor.vertices[simplex,0], vor.vertices[simplex,1], 'k-')
ptp_bound = vor.points.ptp(axis=0)
center = vor.points.mean(axis=0)
for pointidx, simplex in zip(vor.ridge_points, vor.ridge_vertices):
simplex = np.asarray(simplex)
if np.any(simplex < 0):
i = simplex[simplex >= 0][0] # finite end Voronoi vertex
t = vor.points[pointidx[1]] - vor.points[pointidx[0]] # tangent
t /= np.linalg.norm(t)
n = np.array([-t[1], t[0]]) # normal
midpoint = vor.points[pointidx].mean(axis=0)
direction = np.sign(np.dot(midpoint - center, n)) * n
far_point = vor.vertices[i] + direction * ptp_bound.max()
ax.plot([vor.vertices[i,0], far_point[0]],
[vor.vertices[i,1], far_point[1]], 'k--')
_adjust_bounds(ax, vor.points)
return ax.figure
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