>>> """
===============
Patheffect Demo
===============

"""
... import matplotlib.pyplot as plt
... from matplotlib import patheffects
... import numpy as np
... 
... fig, (ax1, ax2, ax3) = plt.subplots(1, 3, figsize=(8, 3))
... ax1.imshow([[1, 2], [2, 3]])
... txt = ax1.annotate("test", (1., 1.), (0., 0),
...                    arrowprops=dict(arrowstyle="->",
...                                    connectionstyle="angle3", lw=2),
...                    size=20, ha="center",
...                    path_effects=[patheffects.withStroke(linewidth=3,
...                                                         foreground="w")])
... txt.arrow_patch.set_path_effects([
...     patheffects.Stroke(linewidth=5, foreground="w"),
...     patheffects.Normal()])
... 
... pe = [patheffects.withStroke(linewidth=3,
...                              foreground="w")]
... ax1.grid(True, linestyle="-", path_effects=pe)
... 
... arr = np.arange(25).reshape((5, 5))
... ax2.imshow(arr)
... cntr = ax2.contour(arr, colors="k")
... 
... plt.setp(cntr.collections, path_effects=[
...     patheffects.withStroke(linewidth=3, foreground="w")])
... 
... clbls = ax2.clabel(cntr, fmt="%2.0f", use_clabeltext=True)
... plt.setp(clbls, path_effects=[
...     patheffects.withStroke(linewidth=3, foreground="w")])
... 
... # shadow as a path effect
... p1, = ax3.plot([0, 1], [0, 1])
... leg = ax3.legend([p1], ["Line 1"], fancybox=True, loc='upper left')
... leg.legendPatch.set_path_effects([patheffects.withSimplePatchShadow()])
... 
... plt.show()
...