Question

我试图在多轴的matplotlib上显示悬停标签。

我将python 3.6.8和matplotlib 3.0.3一起使用

我的情节有多个轴，我看了这篇文章中的例子：

Possible to make labels appear when hovering over a point in matplotlib?

但是什么也没发生（不能看到标签）。

这是我的代码：

import matplotlib.pyplot as plt
import numpy as np; np.random.seed(1)

x = np.sort(np.random.rand(15))
y = np.sort(np.random.rand(15))
y2 = np.sort(np.random.rand(15))

fig = plt.figure()
ax1 = plt.subplot(2, 2, 1)
line, = plt.plot(x,y)
ax1.grid(True)

ax2 = ax1.twinx()
ax2.plot(x, y2, color='green')
ax2.tick_params(axis='y', labelcolor='green')

annot = ax1.annotate("", xy=(0,0), xytext=(-20,20),textcoords="offset points",
                    bbox=dict(boxstyle="round", fc="w"),
                    arrowprops=dict(arrowstyle="->"))
annot.set_visible(False)

def update_annot(ind):
    x,y = line.get_data()
    annot.xy = (x[ind["ind"][0]], y[ind["ind"][0]])
    text = "x = {}\ny= {}".format(x[ind["ind"][0]], y[ind["ind"][0]])
    annot.set_text(text)
    annot.get_bbox_patch().set_alpha(0.4)


def hover(event):
    vis = annot.get_visible()
    if event.inaxes == ax1:
        cont, ind = line.contains(event)
        if cont:
            update_annot(ind)
            annot.set_visible(True)
            fig.canvas.draw_idle()
        else:
            if vis:
                annot.set_visible(False)
                fig.canvas.draw_idle()

fig.canvas.mpl_connect("motion_notify_event", hover)

plt.show()

当我禁用（注释）第二个轴（ax2）时，我可以看到标签。

使用多轴时如何显示悬停标签？

Answer 1

问题是确实仅对双轴之一触发了事件。因此，如果要标记两个轴的内容，则需要多路复用标记，即创建两个注释，每个轴一个，并调整代码以使两个注释都可能可见。

如下所示：

import matplotlib.pyplot as plt
import numpy as np; np.random.seed(1)

x = np.sort(np.random.rand(15))
y = np.sort(np.random.rand(15))
y2 = np.sort(np.random.rand(15))

fig = plt.figure()
ax1 = plt.subplot(2, 2, 1)
line1, = plt.plot(x,y)
ax1.grid(True)

ax2 = ax1.twinx()
line2, = ax2.plot(x, y2, color='green')
ax2.tick_params(axis='y', labelcolor='green')

annots = []
for ax in [ax1, ax2]:
    annot = ax1.annotate("", xy=(0,0), xytext=(-20,20),textcoords="offset points",
                        bbox=dict(boxstyle="round", fc="w", alpha=0.4),
                        arrowprops=dict(arrowstyle="->"))
    annot.set_visible(False)
    annots.append(annot)

annot_dic = dict(zip([ax1, ax2], annots))
line_dic = dict(zip([ax1, ax2], [line1, line2]))

def update_annot(line, annot, ind):
    x,y = line.get_data()
    annot.xy = (x[ind["ind"][0]], y[ind["ind"][0]])
    text = "x = {}\ny= {}".format(x[ind["ind"][0]], y[ind["ind"][0]])
    annot.set_text(text)

def hover(event):

    if event.inaxes in [ax1, ax2]:
        for ax in [ax1, ax2]:
            cont, ind = line_dic[ax].contains(event)
            annot = annot_dic[ax]
            if cont:
                update_annot(line_dic[ax], annot, ind)
                annot.set_visible(True)
                fig.canvas.draw_idle()
            else:
                if annot.get_visible():
                    annot.set_visible(False)
                    fig.canvas.draw_idle()

fig.canvas.mpl_connect("motion_notify_event", hover)

plt.show()

将鼠标悬停在多轴上的点上时如何显示标签？

1 个答案: