在tkinter中调用时，matplotlib PolygonSelector冻结

Question

我正在使用tkinter和matplotlib编写脚本进行数据处理，代码的某些部分需要使用多边形选择器来选择感兴趣的区域。但是，PolygonSelector无法检测光标的运动。

应该注意的是，当打开matplotlib图形互动模式时，会发生此问题。

简化的代码和结果如下所示：

private static List<Member> 
convertToFlatList(List<Member> memberList, List<Member> flatList)
{
    for (Member member : memberList)
    {
        // Always add the member to flatList
        flatList.add(memeber);

        // If it has children, add them toore
        if (member.getChildren() != null)
        {
            convertToFlatList(member.getChildren(), flatList);
        }
    }
    return flatList;
}

这是在tkinter GUI上单击“绘制”按钮后的绘图，多边形的起点卡在（0,0），预计将随着光标移动：

当我在tkinter之外致电#!/usr/bin/env python3 import matplotlib matplotlib.use("TkAgg") import tkinter as tk import matplotlib.pyplot as plt from matplotlib.widgets import PolygonSelector root = tk.Tk() def draw(): fig = plt.figure() ax = fig.add_subplot(111) plt.ion() # interactive mode is on plt.show() def onselect(data_input): print(data_input) PS = PolygonSelector(ax, onselect) tk.Button(root, text='draw', command=draw).pack() root.mainloop() 时，PolygonSelector可以正常工作：

draw()

Answer 1

简单的解决方案是确保将多边形选择器设为全局变量。这将使选择器保持可视化更新。

#!/usr/bin/env python3
import tkinter as tk
import matplotlib
import matplotlib.pyplot as plt
from matplotlib.widgets import PolygonSelector
matplotlib.use("TkAgg")


root = tk.Tk()
ps = None

def draw():
    global ps
    fig = plt.figure()
    ax = fig.add_subplot(111)
    plt.ion()
    plt.show()
    ps = PolygonSelector(ax, on_select)


def on_select(data_input):
    print(data_input)

tk.Button(root, text='draw', command=draw).pack()
root.mainloop()

如果将其构建到类中，则可以通过将Polygon Selector用作类属性来避免使用global并获得所需的行为。

#!/usr/bin/env python3
import tkinter as tk
import matplotlib
import matplotlib.pyplot as plt
from matplotlib.widgets import PolygonSelector
matplotlib.use("TkAgg")


class GUI(tk.Tk):
    def __init__(self):
        super().__init__()
        self.ps = None
        tk.Button(self, text='draw', command=self.draw).pack()

    def draw(self):
        fig = plt.figure()
        ax = fig.add_subplot(111)
        plt.ion()
        plt.show()
        self.ps = PolygonSelector(ax, self.on_select)

    def on_select(self, data_input):
        print(data_input)


if __name__ == "__main__":
    GUI().mainloop()

结果：