如何将Slider的更新值始终设置在中心

Question

跟随Matplotlib的Slider Demohttps://matplotlib.org/gallery/widgets/slider_demo.html，我想更新滑块范围，以便每次更改滑块值时，这些值都会在滑块中重新居中。

我试图将Sliders定义为

sfreq = Slider(axfreq, 'Freq', freq-10, freq+10, valinit=freq)
samp = Slider(axamp, 'Amp', amp-5, amp+5, valinit=amp)

但是由于update((函数不返回任何内容，所以这是不起作用的。我还尝试在函数中使这些变量全局化，但也没有成功。我最后尝试在更新功能中定义Sliders

def update(val):
amp = samp.val
freq = sfreq.val
l.set_ydata(amp*np.sin(2*np.pi*freq*t))
fig.canvas.draw_idle()
Slider(axfreq, 'Freq', freq-10, freq+10, valinit=freq)
Slider(axamp, 'Amp', amp-5, amp+5, valinit=amp)

但随着我改变数值，它覆盖了越来越多的Slider。有什么建议吗？

Answer 1

所以我决定让滑块的范围覆盖参数的几个数量级，并以对数刻度显示值。如果有人想知道，并遵循matplotlib演示：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.widgets import Slider, Button, RadioButtons
fig, ax = plt.subplots()
plt.subplots_adjust(left=0.25, bottom=0.25)
t = np.arange(0.0, 1.0, 0.001)
a0 = 5
f0 = 10
delta_f = 5.0
s = a0*np.sin(2*np.pi*f0*t)
l, = plt.plot(t, s, lw=2, color='red')
plt.axis([0, 1, -10, 10])
axcolor = 'lightgoldenrodyellow'
axfreq = plt.axes([0.25, 0.1, 0.65, 0.03], facecolor=axcolor)
axamp = plt.axes([0.25, 0.15, 0.65, 0.03], facecolor=axcolor)
sfreq = Slider(axfreq, 'Freq', np.log(1), np.log10(1000), valinit=np.log10(f0), valfmt='%4.2E')
samp = Slider(axamp, 'Amp', a0-5, a0+5, valinit=a0)
def update(val):
amp = samp.val
freq = sfreq.val
sfreq.valtext.set_text('{:4.2E}'.format(10**freq))
l.set_ydata(amp*np.sin(2*np.pi*10**freq*t))
fig.canvas.draw_idle()
sfreq.on_changed(update)
samp.on_changed(update)
resetax = plt.axes([0.8, 0.025, 0.1, 0.04] )
button = Button(resetax, 'Reset', color=axcolor, hovercolor='0.975')
def reset(event):
sfreq.reset()
samp.reset()
button.on_clicked(reset)
rax = plt.axes([0.025, 0.5, 0.15, 0.15], facecolor=axcolor)
radio = RadioButtons(rax, ('red', 'blue', 'green'), active=0)
def colorfunc(label):
l.set_color(label)
fig.canvas.draw_idle()
radio.on_clicked(colorfunc)
plt.show()