matplotlib 3D 绘图的刻度标签位置

Question

I am trying to work out how to set/correct the position of tick labels for a 3D matplotlib plot. Tick labels do not align with the ticks. The issue seems to be especially prominent when many tick labels are required.

I have modified an example ( http://matplotlib.org/examples/mplot3d/polys3d_demo.html ) from the matplotlib documentation to illustrate my question.

from mpl_toolkits.mplot3d import Axes3D
from matplotlib.collections import PolyCollection
from matplotlib.colors import colorConverter
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(figsize=(10,10))
ax = fig.gca(projection='3d')

cc = lambda arg: colorConverter.to_rgba(arg, alpha=0.6)

xs = np.arange(0, 10, 0.4)
verts = []
zs = np.arange(50)
for z in zs:
    ys = np.ones(len(xs))*z
    ys[0], ys[-1] = 0, 0
    verts.append(list(zip(xs, ys)))

poly = PolyCollection(verts,facecolor='c')
poly.set_alpha(0.7)
ax.add_collection3d(poly, zs=zs, zdir='y')

ax.set_xlabel('X')
ax.set_xlim3d(0, 10)
ax.set_ylabel('Y')
ax.set_ylim3d(-1, len(zs))
ax.set_yticks(np.arange(len(zs)))
labels = {}
for l_c in zs:
    labels[l_c] = 'This Looks Bad'
ax.set_yticklabels(labels,rotation=-15)
ax.set_zlabel('Z')
ax.set_zlim3d(0, ys.max())

plt.show()

So the question is: how can I get the tick labels to align with the tick positions?

Answer 1

By using these alignments, I get much better placements:

ax.set_yticklabels(labels,rotation=-15,
                   verticalalignment='baseline',
                   horizontalalignment='left')

I've modified the example with less tick markers so you can see the placement:

Answer 2

They do align, but with the horizontal position centered at the tick. Because of the 3D view this makes them appear a bit below where you would expect them to be. The effect is not related to the amount of ticks but to the width.

Specifically setting the alignment will help. Try adding:

ax.set_yticklabels(labels,rotation=-15, va='center', ha='left')

Play around a bit with the different alignments to see which you prefer, i think you're after ha='left'.

Reducing the padding, distance from the tick, might also help.

Answer 3

You can also set the pad argument as negative in the tick_params options for each axis. Like this:

    ax.tick_params(axis='x', which='major', pad=-3)

This might help to adjust the distance between tick labels and axis.