show label on hover over vertically spanned area

Question

when I hover over spanned region, labels are being showed only along the sides of spanned area but not through out the area.

I want the label to be viewed in the whole area when I hover in it. How can I implement this logic?

import matplotlib.pyplot as plt
import mplcursors


plt.axvspan(2,3,gid='yes',alpha=0.3,label = 'y')


mplcursors.cursor(hover=True).connect(
      "add", lambda sel: sel.annotation.set_text(sel.artist.get_label()))


plt.show()

Answer 1

I don't know why mplcursors does not work in the code from the question; but here is how to show an annotation upon hovering an axes span (without mplcursors):

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
span = ax.axvspan(2,3,gid='yes',alpha=0.3,label = 'y')

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

def hover(event):
    vis = annot.get_visible()
    if event.inaxes == ax:
        cont, ind = span.contains(event)
        if cont:
            annot.xy = (event.xdata, event.ydata)
            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()

• The annotation moves wherever the cursor points on the plot.