Matplotlib 图在 tkinter GUI 中停止更新

Question

我正在开发这个应用程序，它涉及在按下按钮后在空白图上绘制一条线或圆。一切都很好，直到突然，图表停止更新。例如：

import math
import tkinter as tk
from tkinter import *

import matplotlib
import matplotlib.pyplot as plt
from numpy import arange, sin, cos, tan, pi
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, 
NavigationToolbar2TkAgg
from matplotlib.backend_bases import key_press_handler
from matplotlib.figure import Figure
from matplotlib.patches import Circle
# Initialising the graph
f = Figure(figsize=(6, 6), dpi=100)
a = f.add_subplot(111)

root = tk.Tk()

class Application(tk.Frame):
  def __init__(self, master=None):
    super().__init__(master)
    self.pack()
    self.mainwindow()

  def mainwindow(self):
    self.add_loci = Button(self)
    self.add_loci["text"] = "Add Line"
    self.add_loci["command"] = self.line
    self.add_loci.pack(side = TOP)

    # Plotting an empty graph
    a.set_xlabel('Re')
    a.set_ylabel('Im')
    a.grid(b=None)
    a.plot(0, 0)
    # Setting up and showing the toolbar and the graph
    canvas = FigureCanvasTkAgg(f, master=root)
    canvas.show()
    canvas.get_tk_widget().pack(side = BOTTOM, fill=BOTH, expand=1)
    toolbar = NavigationToolbar2TkAgg(canvas, root)
    toolbar.update()
    canvas._tkcanvas.pack(side = BOTTOM, fill=BOTH, expand=1)

  def line(self):
    a.plot([0, 10], [0, 10])
    print('test')

app = Application(master=root)
app.mainloop()

按下按钮时的假设结果是应该出现顺子，但事实并非如此。我添加了打印语句来检查按钮是否正常工作并且确实如此，所以我真的不知道这里的问题是什么。我目前正在使用 Spyder (3.2.4)。

Answer 1

一切正常，即正在绘制线条，但是需要更新图形。您可以在绘图后使用figure.canvas.draw() 执行此操作。您的代码如下所示：

f = Figure(figsize=(6, 6), dpi=100)
a = f.add_subplot(111)

root = tk.Tk()

class Application(tk.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.pack()
        self.mainwindow()

    def mainwindow(self):
        self.add_loci = Button(self)
        self.add_loci["text"] = "Add Line"
        self.add_loci["command"] = self.line
        self.add_loci.pack(side = TOP)

        # Plotting an empty graph
        a.set_xlabel('Re')
        a.set_ylabel('Im')
        a.grid(b=None)
        a.plot(0, 0)
        # Setting up and showing the toolbar and the graph
        canvas = FigureCanvasTkAgg(f, master=root)
        canvas.show()
        canvas.get_tk_widget().pack(side = BOTTOM, fill=BOTH, expand=1)
        toolbar = NavigationToolbar2TkAgg(canvas, root)
        toolbar.update()
        canvas._tkcanvas.pack(side = BOTTOM, fill=BOTH, expand=1)

    def line(self):

        a.plot([0, 10], [0, 10])
        f.canvas.draw()

        print('test')

app = Application(master=root)
app.mainloop()

您还可以使用self.canvas = ... 使您创建实例变量的画布。然后使用self.canvas.draw()。您的 mainwindow 和 line 函数将如下所示：

def mainwindow(self):
    self.add_loci = Button(self)
    self.add_loci["text"] = "Add Line"
    self.add_loci["command"] = self.line
    self.add_loci.pack(side = TOP)

    # Plotting an empty graph
    a.set_xlabel('Re')
    a.set_ylabel('Im')
    a.grid(b=None)
    a.plot(0, 0)
    # Setting up and showing the toolbar and the graph
    self.canvas = FigureCanvasTkAgg(f, master=root)
    self.canvas.show()
    self.canvas.get_tk_widget().pack(side = BOTTOM, fill=BOTH, expand=1)
    toolbar = NavigationToolbar2TkAgg(self.canvas, root)
    toolbar.update()
    self.canvas._tkcanvas.pack(side = BOTTOM, fill=BOTH, expand=1)

def line(self):

    a.plot([0, 10], [0, 10])
    self.canvas.draw()

    print('test')

两者都会产生相同的结果。