在嵌入 tkinter 的按钮按下时暂停/停止 matplotlib 的 animation

Question

I am using the following code from Tutorials Point. Here the Quit button stops the program, but I want to pause the animation on another button press. I found other resources that work on onclick() in the figure, but I want to do this from a Pause button.

How can I implement that?

import tkinter
from matplotlib.backends.backend_tkagg import (
    FigureCanvasTkAgg, NavigationToolbar2Tk)
from matplotlib.backend_bases import key_press_handler
from matplotlib import pyplot as plt, animation
import numpy as np

plt.rcParams["figure.figsize"] = [7.00, 3.50]
plt.rcParams["figure.autolayout"] = True

root = tkinter.Tk()
root.wm_title("Embedding in Tk")

plt.axes(xlim=(0, 2), ylim=(-2, 2))
fig = plt.Figure(dpi=100)
ax = fig.add_subplot(xlim=(0, 2), ylim=(-1, 1))
line, = ax.plot([], [], lw=2)

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()

toolbar = NavigationToolbar2Tk(canvas, root, pack_toolbar=False)
toolbar.update()

canvas.mpl_connect(
    "key_press_event", lambda event: print(f"you pressed {event.key}"))
canvas.mpl_connect("key_press_event", key_press_handler)

button = tkinter.Button(master=root, text="Quit", command=root.quit)
button.pack(side=tkinter.BOTTOM)

toolbar.pack(side=tkinter.BOTTOM, fill=tkinter.X)
canvas.get_tk_widget().pack(side=tkinter.TOP, fill=tkinter.BOTH, expand=1)

def init():
    line.set_data([], [])
    return line,

def animate(i):
    x = np.linspace(0, 2, 1000)
    y = np.sin(2 * np.pi * (x - 0.01 * i))
    line.set_data(x, y)
    return line,

anim = animation.FuncAnimation(fig, animate, init_func=init,frames=200, interval=20, blit=True)

tkinter.mainloop()

Answer 1

I based my answer on the answer here , which has a great explanation of using a click to pause the animation (which you had already researched). The functionality of my answer is the same as the example, just modifying the pause function to be driven by a tkinter button instead of a mouse click and implementing it in your code.

import matplotlib.pyplot as plt
import numpy as np
import matplotlib.animation as animation
import tkinter as tkinter
from matplotlib.backends.backend_tkagg import (
    FigureCanvasTkAgg, NavigationToolbar2Tk)
from matplotlib.backend_bases import key_press_handler

plt.rcParams["figure.figsize"] = [7.00, 3.50]
plt.rcParams["figure.autolayout"] = True

root = tkinter.Tk()
root.wm_title("Embedding in Tk")

plt.axes(xlim=(0, 2), ylim=(-1, 1))
fig = plt.Figure(dpi=100)
ax = fig.add_subplot(xlim=(0, 2), ylim=(-1, 1))
line, = ax.plot([], [], lw=2)

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()

toolbar = NavigationToolbar2Tk(canvas, root, pack_toolbar=False)
toolbar.update()

canvas.mpl_connect(
    "key_press_event", lambda event: print(f"you pressed {event.key}"))
canvas.mpl_connect("key_press_event", key_press_handler)

button = tkinter.Button(master=root, text="Quit", command=root.quit)
button.pack(side=tkinter.BOTTOM)

# Pause button and function
pause = False
def pause_animation():
    global pause
    pause ^= True
button2 = tkinter.Button(master=root, text="Pause", command=pause_animation)
button2.pack(side=tkinter.BOTTOM)

toolbar.pack(side=tkinter.BOTTOM, fill=tkinter.X)
canvas.get_tk_widget().pack(side=tkinter.TOP, fill=tkinter.BOTH, expand=1)

def animation_data():
    tMax = 100  # 0.01*tMax/dt needs to be an int for smooth animation
    dt = 1      # Changing dt changes the "speed" that the curve moves on the plot
    y = 0.0
    t = 0
    x = np.linspace(0, 2, 1000)
    while t<tMax:   # This is included to reset t so it doesn't get too large for long runs
        if not pause:
            y = np.sin(2 * np.pi * (x - 0.01 *t))
            t = t + dt
        yield x, y

def animate(animation_data):
    x, y = animation_data[0], animation_data[1]
    line.set_data(x, y)
    return line,

ani = animation.FuncAnimation(fig, animate, animation_data, blit=True, interval=10,
    repeat=True)

tkinter.mainloop()