from tkinter import ttk, Tk, Scale
import numpy as np
# Implement the default Matplotlib key bindings.
from matplotlib.backend_bases import key_press_handler
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg,
NavigationToolbar2Tk)
from matplotlib.figure import Figure
class Window(Tk):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.button_quit = ttk.Button(text="Quit", command=self.destroy)
self.slider_update = Scale(
from_=1, to=5, orient='horizontal',
command=self.update_frequency,
label="Frequency [Hz]",
)
fig = Figure(figsize=(5, 4), dpi=100)
self.t = np.arange(0, 3, .01)
ax = fig.add_subplot()
self.line, = ax.plot(self.t, 2 * np.sin(2 * np.pi * self.t))
ax.set_xlabel("time [s]")
ax.set_ylabel("f(t)")
self.canvas = FigureCanvasTkAgg(fig) # A tk.DrawingArea.
self.canvas.draw()
# pack_toolbar=False will make it easier to use a layout manager later on.
self.toolbar = NavigationToolbar2Tk(self.canvas, pack_toolbar=False)
self.toolbar.update()
# pack顺序很重要。部件是按顺序处理的，如果因为窗口太小而没有剩余空间，它们就不会被显示。
# 画布的大小相当灵活，所以我们将其放在最后打包，这样可以确保UI控件在可能的情况下尽可能长时间地显示。
self.button_quit.pack(side='bottom')
self.slider_update.pack(side='bottom')
self.toolbar.pack(side='bottom', fill="x")
self.canvas.get_tk_widget().pack(side="top", fill="both", expand=True)
self.canvas.mpl_connect(
"key_press_event", lambda event: print(f"you pressed {event.key}"))
self.canvas.mpl_connect("key_press_event", key_press_handler)
def update_frequency(self, new_val):
# retrieve frequency
f = float(new_val)
# update data
y = 2 * np.sin(2 * np.pi * f * self.t)
self.line.set_data(self.t, y)
# required to update canvas and attached toolbar!
self.canvas.draw()
