Bug report

Bug summary

The color of the 3D arrow head does not match that of the arrow body. (In fact, the two segments of head itself don't even match.)

Not sure if it is related to #11746, so I posted it separately just to make things clearer.

Code for reproduction

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

x = np.zeros(10)
y = np.zeros(10)
z = np.arange(10.)
dx = np.zeros(10)
dy = np.arange(10.)
dz = np.zeros(10)

ax = plt.figure().add_subplot(projection='3d')

arrow_color = plt.cm.Reds(dy/dy.max())

ax.quiver(x, y, z, dx, dy, dz, colors=arrow_color)
ax.set_ylim(0,10)
plt.show()

Actual outcome

Expected outcome

The entire arrow should have a single color.

Matplotlib version

• Operating system: macOS 10.13.6
• Matplotlib version: 2.2.2
• Matplotlib backend (print(matplotlib.get_backend())): MacOSX
• Python version: 2.7.15
• Jupyter version (if applicable): 5.6.0
• Other libraries:

matplotlib and Python were installed with Anaconda.