如何使用 tkinter 和 matplotlib 从图中选择点而不关闭它

Question

我正在尝试获得一些使用 Tkinter 制作应用程序的经验。这个练习应用程序将在两个面板图中显示一些数据，有一个按钮来制作新数据，并且能够选择和突出显示数据的区域。在最后一部分我被卡住了。我有一个类（PointSelector），它将两个轴（axarr）的列表作为输入，一个整数选择将被突出显示（ax2select），图形（fig），画布（canv），要突出显示的范围（NumRanges）和数据（xdat 和 ydat）。

除非我在 mpl_connect 行之后使用命令 plt.show()，否则代码不会等待点击事件。但是，如果我确实使用 plt.show()，则会出现一个新的绘图窗口（我不想要），并且 matplotlib 将阻塞，直到所有窗口都关闭（我希望在大腿突出显示完成后窗口保持打开）。

有没有办法在调用 mpl_disconnect 后解除 matplotlib 的阻塞（也不会出现第二个窗口，即使用 plt.plot()）？或者有没有办法不用命令plt.show()就可以使用matplotlib的事件系统？

import Tkinter as tk
import numpy as np
import matplotlib
matplotlib.use('TkAgg')

from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
import matplotlib.pyplot as plt
import tkFileDialog 

LARGE_FONT = ("Verdana", 12)


class PointSelector():
'''
classdocs
'''
def __init__(self, axarr, ax2select, fig, canv, NumRanges, xdat, ydat):
    '''
    Constructor
    '''
    self.axarr = axarr
    self.ax2select = ax2select
    self.fig = fig
    self.canv = canv
    self.NumRanges = NumRanges
    SelectedPoints = []
    self.Ranges = []
    self.xdat = xdat
    self.ydat = ydat
    self.Nselected = 0
    self.SelectedL = False
    self.SelectedR = False
    self.LeftArr = []
    self.RightArr = []
    self.cid = canv.mpl_connect('button_press_event', self.onclick)
#         plt.ion()
#         plt.show()
    canv.show()




    print 'Done With ALL!'


    def PlotRange(self,rng):
        x = self.xdat[range(rng[0],rng[1]+1)]
        y = self.ydat[range(rng[0],rng[1]+1)]
        self.axarr[self.ax2select].plot(x,y,color='r')

        self.canv.draw()

    def PlotPoint(self,x,y):
        self.axarr[self.ax2select].scatter(x,y,color='r')
        self.canv.draw()

    def onclick(self, event):
        print('button=%d, x=%d, y=%d, xdata=%f, ydata=%f' %
      (event.button, event.x, event.y, event.xdata, event.ydata))

        if event.inaxes == self.axarr[self.ax2select]:

            xval = np.argmin(np.abs(event.xdata-self.xdat))
            if self.SelectedL:
                self.RightArr.append(xval)
                self.SelectedR = True
                self.PlotPoint(self.xdat[xval], self.ydat[xval])
            else:
                self.LeftArr.append(xval)
                self.SelectedL = True
                self.PlotPoint(self.xdat[xval], self.ydat[xval])

            if self.SelectedL and self.SelectedR:
                self.SelectedL = False
                self.SelectedR = False
                self.Nselected += 1
                self.PlotRange([self.LeftArr[-1], self.RightArr[-1]])
                if self.Nselected == self.NumRanges:
                    for i in range(len(self.LeftArr)):
                        self.Ranges.append([self.LeftArr[i], self.RightArr[i]])
                    self.canv.mpl_disconnect(self.cid)
                    print 'Done With Selection'


        else:
            print 'Outside Window'

class Driver(tk.Tk):
'''
classdocs
'''
    def __init__(self, *args, **kwargs):
    '''
    Constructor
    '''
        tk.Tk.__init__(self, *args, **kwargs)
        container = tk.Frame(self)
        container.pack(side="top", fill="both",expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)
        self.frames = dict()
        F = StartPage
        frame = F(container, self)
        self.frames[F] = frame
        frame.grid(row=0,column=0,sticky="nsew")
        self.show_frame(StartPage)
    def show_frame(self, cont):
        frame = self.frames[cont]
        frame.tkraise()

class StartPage(tk.Frame):
'''
classdocs
'''


    def __init__(self, parent, controller):
    '''
    Constructor
    '''
        tk.Frame.__init__(self, parent)
        self.controller = controller
        label = tk.Label(self,text="Start Page", font=LARGE_FONT)
        label.pack(pady=10,padx=10)

        quitButton = tk.Button(self, text="Quit",command=self._quit)
        quitButton.pack(side="bottom")



        NewDataButton = tk.Button(self, text="Get New Data",command=self.GetNewData)
        NewDataButton.pack(side="top")


        menu = tk.Menu(parent)
        controller.config(menu=menu)

        submenuFile = tk.Menu(menu)
        menu.add_cascade(label="File",menu=submenuFile)
        submenuFile.add_command(label='Open File', command=self.onOpen)
        submenuFile.add_command(label='Load Configuration File', command=self.onOpen)
        submenuFile.add_separator()

        submenuFile.add_command(label='Exit', command=self._quit)




        submenuContinuum = tk.Menu(menu)
        menu.add_cascade(label="Continuum",menu=submenuContinuum)



        canvas_width = 100
        canvas_height = 100
        canv = tk.Canvas(self,width=canvas_width,height=canvas_height)
        canv.pack()

        self.x = np.linspace(0.0,4.0*np.pi,100)

        self.fig = plt.figure(figsize=(6,6))

        self.axarr = []
        self.axarr.append(plt.subplot(211))
        self.axarr.append(plt.subplot(212))


        self.canv = FigureCanvasTkAgg(self.fig,master=self)
        self.canv.show()
        self.canv.get_tk_widget().pack()
        self.canv._tkcanvas.pack(side=tk.TOP,fill=tk.BOTH,expand=1)
        self.GetNewData()

        self.txt=tk.Text(self)
        submenuContinuum.add_command(label='Select Continuum', 
                                 command=lambda:PointSelector(self.axarr, 0, self.fig, self.canv, 2, 
                                                            self.x, self.y))
        submenuContinuum.add_command(label='Remove Continuum', command=donothing)

    def GetNewData(self):
        rnum = (np.random.rand(1))
        print rnum
        self.y = np.sin(self.x)*(np.random.rand(1)*4.0)*(self.x)**rnum
        self.dy = np.gradient(self.y, self.x[1]-self.x[0])
        self.DrawData()
    def DrawData(self):
        self.axarr[0].clear()
        self.axarr[1].clear()
        self.axarr[0].plot(self.x,self.y)
        self.axarr[1].plot(self.x,self.dy)

        self.canv.draw()

    def onOpen(self):

        ftypes = [('Python files', '*.py'), ('All files', '*')]
        dlg = tkFileDialog.Open(self, filetypes = ftypes)
        fl = dlg.show()

        if fl != '':
            text = self.readFile(fl)
            self.txt.insert('end', text)

    def readFile(self, filename):

        f = open(filename, "r")
        text = f.read()
        return text

    def _quit(self):
        self.controller.quit()
        self.controller.destroy()

def donothing():
    print "nothing"


if __name__ == '__main__':
    app = Driver()
    app.mainloop()

Answer 1

首先，您不想在 GUI 中使用 plt.show() 或 plt.ion() 是正确的，因为它们会干扰 GUI 窗口。
您可能还想在PointSelector 的初始化方法中去掉canv.show()（只是因为我不知道它应该在那里做什么并且__init__ 不是程序中需要重绘的方法东西。）。

所以假设点选择器没问题，实际问题出在这条线

.add_command(label='...', command=lambda:PointSelector(...))

它在匿名函数中被实例化。这样做的问题是，您现在无法在程序中使用此实例，并且一旦其__init__ 完成，它将丢失。

随之而来的问题是您丢失了对 matplotlib 回调的引用。
matplotlib event handling tutorial 声明：

画布只保留对回调的弱引用。因此，如果回调是类实例的方法，则需要保留对该实例的引用。否则实例将被垃圾回收并且回调将消失。

因此，为了能够在您的程序中使用PointSelector，您需要将其分配给类变量，例如self.selector = PointSelector(..)。这可以在从菜单中作为命令调用的方法中完成。

一个可能的解决方案如下所示：

class StartPage(tk.Frame):

    #...

    def __init__(self, parent, controller):
        submenuContinuum.add_command(label='Select Continuum', 
                                 command=self.registerSelector)
        submenuContinuum.add_command(label='Remove Continuum', command=donothing)

    def registerSelector(self):
        self.selector = PointSelector(self.axarr, 0, self.fig, 
                                      self.canv, 2, self.x, self.y)

Answer 2

工作 Python 3 代码：

#copied from https://stackoverflow.com/questions/44357892/how-to-use-tkinter-and-matplotlib-to-select-points-from-a-plot-without-closing-i
#converted to python 3
import tkinter as tk
import numpy as np
import matplotlib
matplotlib.use('TkAgg')
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

import matplotlib.pyplot as plt

LARGE_FONT = ("Verdana", 12)

class PointSelector():
    """
    classdocs
    """
    def __init__(self, axarr, ax2select, fig, canv, NumRanges, xdat, ydat):
        """
        Constructor
        """
        self.axarr = axarr
        self.ax2select = ax2select
        self.fig = fig
        self.canv = canv
        self.NumRanges = NumRanges
        self.Ranges = []
        self.xdat = xdat
        self.ydat = ydat
        self.Nselected = 0
        self.SelectedL = False
        self.SelectedR = False
        self.LeftArr = []
        self.RightArr = []
        self.cid = canv.mpl_connect('button_press_event', self.onclick)
        print('Done With ALL!')


    def PlotRange(self,rng):
        x = self.xdat[range(rng[0],rng[1]+1)]
        y = self.ydat[range(rng[0],rng[1]+1)]
        self.axarr[self.ax2select].plot(x,y,color='r')

        self.canv.draw()

    def PlotPoint(self,x,y):
        self.axarr[self.ax2select].scatter(x,y,color='r')
        self.canv.draw()

    def onclick(self, event):
        print('button=%d, x=%d, y=%d, xdata=%f, ydata=%f' % (event.button, event.x, event.y, event.xdata, event.ydata))

        if event.inaxes == self.axarr[self.ax2select]:

            xval = np.argmin(np.abs(event.xdata-self.xdat))
            if self.SelectedL:
                self.RightArr.append(xval)
                self.SelectedR = True
                self.PlotPoint(self.xdat[xval], self.ydat[xval])
            else:
                self.LeftArr.append(xval)
                self.SelectedL = True
                self.PlotPoint(self.xdat[xval], self.ydat[xval])

            if self.SelectedL and self.SelectedR:
                self.SelectedL = False
                self.SelectedR = False
                self.Nselected += 1
                self.PlotRange([self.LeftArr[-1], self.RightArr[-1]])
                if self.Nselected == self.NumRanges:
                    for i in range(len(self.LeftArr)):
                        self.Ranges.append([self.LeftArr[i], self.RightArr[i]])
                    self.canv.mpl_disconnect(self.cid)
                    print('Done With Selection')

        else:
            print('Outside Window')

class Driver(tk.Tk):
    """
    classdocs
    """
    def __init__(self, *args, **kwargs):
        """
        Constructor
        """
        tk.Tk.__init__(self, *args, **kwargs)
        container = tk.Frame(self)
        container.pack(side="top", fill="both",expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)
        self.frames = dict()
        F = StartPage
        frame = F(container, self)
        self.frames[F] = frame
        frame.grid(row=0,column=0,sticky="nsew")
        self.show_frame(StartPage)
    def show_frame(self, cont):
        frame = self.frames[cont]
        frame.tkraise()

class StartPage(tk.Frame):
    """
    classdocs
    """
    def __init__(self, parent, controller):
        """
        Constructor
        """
        tk.Frame.__init__(self, parent)
        self.controller = controller
        label = tk.Label(self,text="Start Page", font=LARGE_FONT)
        label.pack(pady=10,padx=10)

        quitButton = tk.Button(self, text="Quit",command=self._quit)
        quitButton.pack(side="bottom")

        NewDataButton = tk.Button(self, text="Get New Data",command=self.GetNewData)
        NewDataButton.pack(side="top")

        menu = tk.Menu(parent)
        controller.config(menu=menu)

        submenuFile = tk.Menu(menu)
        menu.add_cascade(label="File",menu=submenuFile)
        submenuFile.add_command(label='Open File', command=self.onOpen)
        submenuFile.add_command(label='Load Configuration File', command=self.onOpen)
        submenuFile.add_separator()

        submenuFile.add_command(label='Exit', command=self._quit)

        submenuContinuum = tk.Menu(menu)
        menu.add_cascade(label="Continuum",menu=submenuContinuum)

        canvas_width = 100
        canvas_height = 100
        canv = tk.Canvas(self,width=canvas_width,height=canvas_height)
        canv.pack()

        self.x = np.linspace(0.0,4.0*np.pi,100)
        self.fig = plt.figure(figsize=(6,6))
        self.axarr = []
        self.axarr.append(plt.subplot(211))
        self.axarr.append(plt.subplot(212))
        self.canv = FigureCanvasTkAgg(self.fig,master=self)
        self.canv.get_tk_widget().pack()
        self.canv._tkcanvas.pack(side=tk.TOP,fill=tk.BOTH,expand=1)
        self.GetNewData()

        self.txt=tk.Text(self)
        submenuContinuum.add_command(label='Select Continuum', command=self.registerSelector)
        submenuContinuum.add_command(label='Remove Continuum', command=donothing)

    def registerSelector(self):
        self.selector = PointSelector(self.axarr, 0, self.fig, self.canv, 2, self.x, self.y)

    def GetNewData(self):
        rnum = (np.random.rand(1))
        print(rnum)
        self.y = np.sin(self.x)*(np.random.rand(1)*4.0)*(self.x)**rnum
        self.dy = np.gradient(self.y, self.x[1]-self.x[0])
        self.DrawData()
    def DrawData(self):
        self.axarr[0].clear()
        self.axarr[1].clear()
        self.axarr[0].plot(self.x,self.y)
        self.axarr[1].plot(self.x,self.dy)
        self.canv.draw()

    def onOpen(self):
        ftypes = [('Python files', '*.py'), ('All files', '*')]
        dlg = tk.filedialog.Open(self, filetypes=ftypes)
        fl = dlg.show()

        if fl != '':
            text = self.readFile(fl)
            self.txt.insert('end', text)

    def readFile(self, filename):
        f = open(filename, "r")
        text = f.read()
        return text

    def _quit(self):
        self.controller.quit()
        self.controller.destroy()

def donothing():
    print("nothing")

if __name__ == '__main__':
    app = Driver()
    app.mainloop()