python matplotlib使用按钮事件在图上添加和删除文本 [英] python matplotlib add and remove text to figure using button events

问题描述

我试图在调用 button_press_event 时将文本添加到鼠标指针位置的图形中，并在调用 button_release_event 时将其删除.我已经成功添加了文本，但无法删除它.这是我使用的部分代码:

I'm trying to add text to a graph at the location of the mouse pointer when button_press_event is called and remove it when button_release_event is called. I have successfully added the text but I can not get it to erase. Here is part of the code I used:

def onclick(event):
    print 'you pressed', event.button, event.xdata, event.ydata
    plt.text(event.xdata, event.ydata, 'TESTTEST', fontsize=8)
    fig.canvas.draw()

def offclick(event):
    print 'you released', event.button, event.xdata, event.ydata
    #not sure what to put here
    #I tried:
    #plt.text(event.xdata, event.ydata, '')
    fig.canvas.draw()

fig.canvas.mpl_connect('button_press_event', onclick)
fig.canvas.mpl_connect('button_release_event', offclick) 

plt.show()

推荐答案

假设你应该在一个类中使用它并且将下面的 txt 引用为 self.txt 我为方便起见，请在此处使用 global:

Assuming you should use it in a class and refer to the following txt as self.txt I use global here for sake of ease:

txt = None

def onclick(event):
    global txt
    txt = plt.text(event.xdata, event.ydata, 'TESTTEST', fontsize=8)
    fig.canvas.draw()

def offclick(event):
    txt.remove()
    fig.canvas.draw()

fig.canvas.mpl_connect('button_press_event', onclick)
fig.canvas.mpl_connect('button_release_event', offclick) 

plt.show()

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