"""

===============

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()