Can ticks be turned outward when an AxisArtist is used?

Question

I'm using an AxisArtist and would like to turn the ticks of the "twinned" x-axis outward. However, when I execute demo_parasite_axes2.py with the insertion of the line, host.axis["bottom"].tick_params(direction = "out"), a slight modification intended to evert the tick marks, I get the following error:

host.axis["bottom"].tick_params(direction = "out")

AttributeError: 'AxisArtist' object has no attribute 'tick_params'

Is there a viable workaround for this?

The code including the inserted line appears below.

from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
import matplotlib.pyplot as plt

host = host_subplot(111, axes_class=AA.Axes)
plt.subplots_adjust(right=0.75)

par1 = host.twinx()
par2 = host.twinx()

offset = 60
new_fixed_axis = par2.get_grid_helper().new_fixed_axis
par2.axis["right"] = new_fixed_axis(loc="right",
                                    axes=par2,
                                    offset=(offset, 0))

par2.axis["right"].toggle(all=True)

host.set_xlim(0, 2)
host.set_ylim(0, 2)

host.set_xlabel("Distance")
host.set_ylabel("Density")
par1.set_ylabel("Temperature")
par2.set_ylabel("Velocity")

p1, = host.plot([0, 1, 2], [0, 1, 2], label="Density")
p2, = par1.plot([0, 1, 2], [0, 3, 2], label="Temperature")
p3, = par2.plot([0, 1, 2], [50, 30, 15], label="Velocity")

par1.set_ylim(0, 4)
par2.set_ylim(1, 65)

host.axis["left"].label.set_color(p1.get_color())
par1.axis["right"].label.set_color(p2.get_color())
par2.axis["right"].label.set_color(p3.get_color())

# Produces the "AxisArtist object has no attribute 'tick_params'" error
host.axis["bottom"].tick_params(direction = "out")

plt.draw()
plt.show() 

Answer 1

After learning that xaxis is still included in an AxisArtist, I was able to devise a solution.

from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
import matplotlib.pyplot as plt

host = host_subplot(111, axes_class=AA.Axes)
plt.subplots_adjust(right=0.75)

par1 = host.twinx()
par2 = host.twinx()

offset = 60
new_fixed_axis = par2.get_grid_helper().new_fixed_axis
par2.axis["right"] = new_fixed_axis(loc="right",
                                    axes=par2,
                                    offset=(offset, 0))

par2.axis["right"].toggle(all=True)

host.set_xlim(0, 2)
host.set_ylim(0, 2)

host.set_xlabel("Distance")
host.set_ylabel("Density")
par1.set_ylabel("Temperature")
par2.set_ylabel("Velocity")

p1, = host.plot([0, 1, 2], [0, 1, 2], label="Density")
p2, = par1.plot([0, 1, 2], [0, 3, 2], label="Temperature")
p3, = par2.plot([0, 1, 2], [50, 30, 15], label="Velocity")

par1.set_ylim(0, 4)
par2.set_ylim(1, 65)

host.axis["left"].label.set_color(p1.get_color())
par1.axis["right"].label.set_color(p2.get_color())
par2.axis["right"].label.set_color(p3.get_color())

# Hide the AxisArtist's bottom axis.
host.axis["bottom"].set_visible(False)
# Turns out the old xaxis is still around, it just needs to be made visible.
host.get_xaxis().set_visible(True)
# The spine needs to be turned back on though.
host.spines['bottom'].set_visible(True)
# Change the direction of the tick marks.
host.get_xaxis().set_tick_params(direction='out')
# The newly visible xaxis applies to the top of the graph too. Turn the xaxis
# ticks off up there. This demonstrates that you can have the ticks on the
# bottom x-axis pointing outward, and those on the top x-axis pointing inward.
host.tick_params(top = "off")

plt.draw()
plt.show()