Python Matplotlib Multicursor：在图例中显示光标下的值

Question

我正在使用 Multicursor 在每个图形上获取一个光标。 我想在将鼠标悬停在图表上时在图例中显示被光标击中的数据点的值，例如

其实我一直以为这是matplotlib分别Multicursor的一个标准特性，但好像不是。有人已经这样做了还是我必须自己实现它。

我已经找到了这个帖子matplotlib multiple values under cursor，但这可能只是我想要的实现的开始。

Answer 1

我已经开发了一个解决方案。

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.widgets import MultiCursor
from bisect import bisect_left


fig = plt.figure(figsize=(15, 8))

# create random graph with 60 datapoints, 0 till 59
x = list(range(0,60))

axes_list = [] 

def createRandomGraph(ax,x):
    y = np.random.randint(low=0, high=15, size=60)
    data.append(y)
    ax.plot(x,y, marker='.')


def take_closest(myList, myNumber):
    """
    Assumes myList is sorted. Returns closest value to myNumber.

    If two numbers are equally close, return the smallest number.
    """
    pos = bisect_left(myList, myNumber)
    if pos == 0:
        return myList[0]
    if pos == len(myList):
        return myList[-1]
    before = myList[pos - 1]
    after = myList[pos]
    if after - myNumber < myNumber - before:
       return after, pos
    else:
       return before, pos-1



def show_Legend(event): 
    #get mouse coordinates
    mouseXdata = event.xdata    

    # the value of the closest data point to the current mouse position shall be shown
    closestXValue, posClosestXvalue = take_closest(data[0], mouseXdata)

    i = 1
    for ax in axes_list:
        datalegend = ax.text(1.05, 0.5, data[i][posClosestXvalue],  fontsize=7,
                                      verticalalignment='top', bbox=props, transform=ax.transAxes)               
        ax.draw_artist(datalegend) 

        # this remove is required because otherwise after a resizing of the window there is 
        # an artifact of the last label, which lies behind the new one
        datalegend.remove()
        i +=1

    fig.canvas.update()


# store the x value of the graph in the first element of the list
data = [x]

# properties of the legend labels
props = dict(boxstyle='round', edgecolor='black', facecolor='wheat', alpha=1.5)

for i in range(5):
    if(i>0):        
        # all plots share the same x axes, thus during zooming and panning 
        # we will see always the same x section of each graph
        ax = plt.subplot(5, 1, i+1, sharex=ax)             
    else:
        ax = plt.subplot(5, 1, i+1)        

    axes_list.append(ax)    
    createRandomGraph(ax,x)  

multi = MultiCursor(fig.canvas, axes_list, color='r', lw=1)   

# function show_Legend is called while hovering over the graphs 
fig.canvas.mpl_connect('motion_notify_event', show_Legend)

plt.show()

输出如下所示

也许你喜欢它并觉得它有用