在 x-axis 上的点之间注释 underbrace(方括号)

Annotate underbrace(brackets) between points on the x-axis

我怎样才能拍下这个图并注释或直接添加一个在每个单词之间添加一些文本的大括号,然后我假设将 x-label 稍微向下移动以使其清晰易读。

要创建的示例:

起始码:

import numpy as np
import matplotlib.pyplot as plt

# Array of values
values = np.array([[1,2,3], [1,2,3]])

# Line plot
fig, ax = plt.subplots()
plt.plot(values[0,:], values[1,:], 'bo-',label='$P_{1}$')


# Annotate the points of interest
ax.annotate('s', xy=(1.5, 0), xytext=(1.5, -0.8),
            fontsize=1.5, ha='center', va='bottom',
            bbox=dict(boxstyle='square', fc='white'),
            arrowprops=dict(arrowstyle='-[, widthB=45.0, lengthB=1.5', lw=2.0))

ax.annotate('t-s', xy=(2.5, 0), xytext=(2.5, -0.8),
            fontsize=1.5, ha='center', va='bottom',
            bbox=dict(boxstyle='square', fc='white'),
            arrowprops=dict(arrowstyle='-[, widthB=43.0, lengthB=2.5', lw=2.0))

plt.legend();

标注坐标轴设置,位置手动设置

ax.annotate('s', xy=(0.275, -0.15), xytext=(0.275, -0.35),
            fontsize=14, ha='center', va='bottom', xycoords='axes fraction', 
            bbox=dict(boxstyle='square', fc='0.8'),
            arrowprops=dict(arrowstyle='-[, widthB=5.0, lengthB=.5', lw=2.0))

ax.annotate('t-s', xy=(0.725, -0.15), xytext=(0.725, -0.35),
            fontsize=14, ha='center', va='bottom', xycoords='axes fraction', 
            bbox=dict(boxstyle='square', fc='0.8'),
            arrowprops=dict(arrowstyle='-[, widthB=5.0, lengthB=.5', lw=2.0))