检测鼠标悬停在图例上，并在 matplotlib 中显示工具提示(标签/注释)? [英] Detect mouse hover over legend, and show tooltip (label/annotation) in matplotlib?

问题描述

我看过

问题是:如果我移动鼠标指针，所以它将鼠标悬停在图例条目上，那么由于事件的打印输出，我得到的全部是:

<代码>....motion_notify_event:xy =(175，652)xydata =(无，无)按钮=无dblclick =错误的inaxes =无motion_notify_event:xy =(174，652)xydata =(无，无)按钮=无dblclick =错误的inaxes =无motion_notify_event: xy=(173, 652) xydata=(None, None) button=None dblclick=False inaxes=Nonemotion_notify_event: xy=(172, 652) xydata=(None, None) button=None dblclick=False inaxes=None

...这是有道理的，因为我故意将图例放在情节之外.

但是，现在我不知道如何获得对图例条目的引用?我想做的基本上是获得图例条目的引用，以便我可以在工具提示"(即本例中为Matplotlib)中编写与图例标签(此处为我的情节")相同的文本.注释)后跟一些其他文本；然后，一旦鼠标离开图例条目的区域，工具提示/注释就会消失.

我可以使用 Matplotlib 实现这一点吗?如果可以，如何实现?

解决方案

你可以这样做:

def onhover(event):如果leg.get_window_extent().包含(event.x，event.y):打印(事件，传说中！做点什么！")xdata = np.arange(0，101，1)#0至100，都包含ydata1 = np.sin(0.01 * xdata * np.pi/2)无花果，ax1 = plt.subplots(1，1，figsize =(9，6)，dpi = 120)pl11，= ax1.plot(xdata，ydata1，color ="Red"，label =我的情节")leg = ax1.legend(ncol = 1，bbox_to_anchor =(0,1.01)，loc =左下"，borderaxespad = 0，prop = {'size':8})fig.canvas.mpl_connect('motion_notify_event', onhover)plt.show()

I have seen Possible to make labels appear when hovering over a point in matplotlib? - but unfortunately, it does not help me with this specific case.

Consider this example:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import matplotlib
print("matplotlib.__version__ {}".format(matplotlib.__version__))
import matplotlib.pyplot as plt
import numpy as np


def onhover(event, fig, axes):
  print(event)

def main():
  xdata = np.arange(0, 101, 1) # 0 to 100, both included
  ydata1 = np.sin(0.01*xdata*np.pi/2)

  fig, ax1 = plt.subplots(1, 1, figsize=(9, 6), dpi=120)
  fig.subplots_adjust(hspace=0)

  pl11, = ax1.plot(xdata, ydata1, color="Red", label="My plot")

  leg = ax1.legend(ncol=1, bbox_to_anchor=(0,1.01), loc="lower left", borderaxespad=0, prop={'size': 8})

  fig.canvas.mpl_connect('motion_notify_event', lambda event: onhover(event, fig, (ax1,) ))
  plt.show()

# ENTRY POINT
if __name__ == '__main__':
  main()

This results with the following plot:

The thing is: if I move the mouse pointer, so it hovers over the legend entry, all I get as the printout in the event is:

....
motion_notify_event: xy=(175, 652) xydata=(None, None) button=None dblclick=False inaxes=None
motion_notify_event: xy=(174, 652) xydata=(None, None) button=None dblclick=False inaxes=None
motion_notify_event: xy=(173, 652) xydata=(None, None) button=None dblclick=False inaxes=None
motion_notify_event: xy=(172, 652) xydata=(None, None) button=None dblclick=False inaxes=None

... which makes sense, as I've deliberately placed the legend outside of the plot.

However, now I do not know how I can get a reference to the legend entry? What I would like to do, is basically get the reference to the legend entry, so that I could write the same text as the legend label (here "My plot") in a "tooltip" (that is, in this case, Matplotlib annotation) followed by some other text; and then, once the mouse leaves the region of the legend entry, the tooltip/annotation should disappear.

Can I achieve this with Matplotlib - and if so, how?

解决方案

You could do something like that:

def onhover(event):
    if leg.get_window_extent().contains(event.x,event.y):
        print(event, "In legend! do something!")


xdata = np.arange(0, 101, 1) # 0 to 100, both included
ydata1 = np.sin(0.01*xdata*np.pi/2)

fig, ax1 = plt.subplots(1, 1, figsize=(9, 6), dpi=120)
pl11, = ax1.plot(xdata, ydata1, color="Red", label="My plot")
leg = ax1.legend(ncol=1, bbox_to_anchor=(0,1.01), loc="lower left", borderaxespad=0, prop={'size': 8})

fig.canvas.mpl_connect('motion_notify_event', onhover)
plt.show()

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