import numpy as np
import matplotlib.pyplot as plt
from matplotlib.legend_handler import HandlerLineCollection
from matplotlib.collections import LineCollection
class HandlerColorLineCollection(HandlerLineCollection):
def create_artists(self, legend, artist ,xdescent, ydescent,
width, height, fontsize,trans):
x = np.linspace(0,width,self.get_numpoints(legend)+1)
y = np.zeros(self.get_numpoints(legend)+1)+height/2.-ydescent
points = np.array([x, y]).T.reshape(-1, 1, 2)
segments = np.concatenate([points[:-1], points[1:]], axis=1)
lc = LineCollection(segments, cmap=artist.cmap,
transform=trans)
lc.set_array(x)
lc.set_linewidth(artist.get_linewidth())
return [lc]
t = np.linspace(0, 10, 200)
x = np.cos(np.pi * t)
y = np.sin(t)
points = np.array([x, y]).T.reshape(-1, 1, 2)
segments = np.concatenate([points[:-1], points[1:]], axis=1)
lc = LineCollection(segments, cmap=plt.get_cmap('copper'),
norm=plt.Normalize(0, 10), linewidth=3)
lc.set_array(t)
fig, ax = plt.subplots()
ax.add_collection(lc)
plt.legend([lc], ["test"],\
handler_map={lc: HandlerColorLineCollection(numpoints=4)}, framealpha=1)
ax.autoscale_view()
plt.show()