Bug report

Bug summary

Not sure if this is really a bug or just a user issue. I expected that passing a clim tuple to pcolormesh with no vmin or vmax specified would update the color scale limits. I found that I had to use vmin and vmax instead. Maybe I am misunderstanding and vmin and vmax should always be used. However, it looks like the kwargs are passed into the QuadMesh constructor and then clim is overwritten with vmin and vmax, even in they are None and clim is given. (https://github.com/heath730/matplotlib/blob/master/lib/matplotlib/axes/_axes.py#L5629).

Code for reproduction

import matplotlib.pyplot as plt
import numpy as np


plot_me = np.random.rand(5, 5)

plt.subplot(211)
plt.title("Expected")
plt.pcolormesh(plot_me, vmin=0, vmax=0.5)
plt.colorbar()

plt.subplot(212)
plt.title("Result")
plt.pcolormesh(plot_me, clim=(0, 0.5))
plt.colorbar()

plt.show()

Matplotlib version

• Operating system: win7
• Matplotlib version: 2.1.2
• Matplotlib backend (print(matplotlib.get_backend())): TkAgg
• Python version: 3.5.1
• Jupyter version (if applicable):
• Other libraries:

Would something like:

  (vmin, vmax) = kwargs.pop('clim', (None, None))

Before the vmin and vmax pops on this line be a reasonable update?