clim doesn't update after draw #6352
Description
I am running under 1.5.1 and am having trouble getting the color limit of a figure when only one bound is given. I think this is a bug, and not and intended feature (it used to work in the past):
# no bound given
im = plt.matshow([[1, 2,], [3, 4]])
print(im.get_clim()) # (1, 4)
# only give one bound
im = plt.matshow([[1, 2,], [3, 4]], vmin=0)
print(im.get_clim()) # (1, None)
# draw should update the clim but doesn't
plt.draw()
print(im.get_clim()) # (1, None), expected (1, 4)
# show() updates clim
plt.show()
print(im.get_clim()) # (1, 4)