如何從條目值立即更新matplotlib的顏色條范圍？

我有一個簡單的代碼來繪制一個圖形。我想手動更改顏色條的范圍。所以，我添加了兩個Entries并定義了第二個函式change()。我想在沒有第二個按鈕的情況下立即更改顏色條。

from tkinter import *
import numpy as np
from matplotlib.figure import Figure
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

root = Tk()
root.geometry("500x500")

Max, Min = IntVar(), IntVar()

label1 = Label(root, text="Max")
label1.place(x=10, y=35)

label2 = Label(root, text="Min")
label2.place(x=10, y=60)

entry1 = Entry(root, textvariable=Max, width=5)
entry1.place(x=50, y=35)

entry2 = Entry(root, textvariable=Min, width=5)
entry2.place(x=50, y=60)

def plot():
    global x, y
    x, y = np.mgrid[slice(0, 100), slice(0, 100)]
    z = (x*y)

    figure = Figure(figsize=(4, 4))
    ax = figure.add_subplot(111)

    c = ax.pcolormesh(x, y, z, cmap='YlGn')
    ax.figure.colorbar(c)

    canvas = FigureCanvasTkAgg(figure, root)
    canvas.get_tk_widget().place(x=0, y=80)

def change():
    z = (x*y)
    figure = Figure(figsize=(4, 4))
    ax = figure.add_subplot(111)

    c = ax.pcolormesh(x, y, z, cmap='YlGn', vmin=entry1.get(), vmax=entry2.get())
    ax.figure.colorbar(c)

    canvas = FigureCanvasTkAgg(figure, root)
    canvas.get_tk_widget().place(x=0, y=80)

button1 = Button(root, text="Plot", command=plot)
button1.place(x=30, y=0)

button2 = Button(root, text="change", command=change)
button2.place(x=80, y=0)

root.mainloop()

我發現這篇文章Constantly Update Label Widgets From Entry Widgets TKinter，我嘗試使用方法 2，并更改了這部分的代碼：

...
def auto():
    c.config(vmin=entry1.get(), vmax=entry2.get())

entry1 = Entry(root, textvariable=Max, width=5)
entry1.place(x=50, y=35)

entry2 = Entry(root, textvariable=Min, width=5)
entry2.place(x=50, y=60)

auto()
...

但是作為c區域變數，代碼不起作用。誰能幫我立即更新彩條范圍？

uj5u.com熱心網友回復：

所以你最終想要的是改變顏色圖vmin，vmax當用戶改變 Min 和 Max 輸入時。您不需要不斷更新顏色圖，只需更改這些輸入即可。

您可以通過使用更新回呼跟蹤輸入更改來做到這一點。

這是修改后的代碼，當 Min 和 Max 輸入更改時會更新顏色圖：

from tkinter import *

import numpy as np
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure

root = Tk()
root.geometry("500x500")

Max, Min = IntVar(), IntVar()

label1 = Label(root, text="Min")
label1.place(x=10, y=35)

label2 = Label(root, text="Max")
label2.place(x=10, y=60)

vmin_entry = Entry(root, textvariable=Min, width=5)
vmin_entry.place(x=50, y=35)

vmax_entry = Entry(root, textvariable=Max, width=5)
vmax_entry.place(x=50, y=60)

# Define global variables
c, canvas = None, None

def plot():
    global x, y, c, canvas
    x, y = np.mgrid[slice(0, 100), slice(0, 100)]
    z = (x * y)
    figure = Figure(figsize=(4, 4))
    ax = figure.add_subplot(111)

    c = ax.pcolormesh(x, y, z, cmap='YlGn')
    ax.figure.colorbar(c)

    canvas = FigureCanvasTkAgg(figure, root)
    canvas.get_tk_widget().place(x=0, y=80)
    canvas.draw()


def update_colormap(*args, **kwargs):
    global c, canvas
    if c is not None:
        try:
            # Get vmin and vmax
            vmin, vmax = int(vmin_entry.get()), int(vmax_entry.get())
        except ValueError:
            # Could not convert values to int, non integer value
            return
        if vmin > vmax:
            return
        # Set new limits
        c.set_clim(vmin, vmax)
        # Update plot
        canvas.flush_events()
        canvas.draw()


# Trace change of Min and Max and call update_colormap as a callabck
Min.trace("w", update_colormap)
Max.trace("w", update_colormap)

button1 = Button(root, text="Plot", command=plot)
button1.place(x=30, y=0)

root.mainloop()

uj5u.com熱心網友回復：

您可以將"<Key>"Entry 小部件的事件作為回呼系結到 change 函式，這將在任何時候在 entry 小部件中鍵入任何內容時呼叫 change 函式。

entry1.bind('<Key>', lambda x : change())

對這兩個條目執行此操作會將這些行添加到您的代碼中-：

entry1.bind('<Key>', lambda x : change())
entry2.bind('<Key>', lambda x : change())

完整的代碼將變成-：

from tkinter import *
import numpy as np
from matplotlib.figure import Figure
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

root = Tk()
root.geometry("500x500")

Max, Min = IntVar(), IntVar()

label1 = Label(root, text="Max")
label1.place(x=10, y=35)

label2 = Label(root, text="Min")
label2.place(x=10, y=60)

entry1 = Entry(root, textvariable=Max, width=5)
entry1.place(x=50, y=35)

entry2 = Entry(root, textvariable=Min, width=5)
entry2.place(x=50, y=60)

def plot():
    global x, y
    x, y = np.mgrid[slice(0, 100), slice(0, 100)]
    z = (x*y)

    figure = Figure(figsize=(4, 4))
    ax = figure.add_subplot(111)

    c = ax.pcolormesh(x, y, z, cmap='YlGn')
    ax.figure.colorbar(c)

    canvas = FigureCanvasTkAgg(figure, root)
    canvas.get_tk_widget().place(x=0, y=80)

def change():
    z = (x*y)
    figure = Figure(figsize=(4, 4))
    ax = figure.add_subplot(111)

    c = ax.pcolormesh(x, y, z, cmap='YlGn', vmin=entry1.get(), vmax=entry2.get())
    ax.figure.colorbar(c)

    canvas = FigureCanvasTkAgg(figure, root)
    canvas.get_tk_widget().place(x=0, y=80)

button1 = Button(root, text="Plot", command=plot)
button1.place(x=30, y=0)

entry1.bind('<Key>', lambda x : change()) # binding the first entry's keypress event to the change function.
entry2.bind('<Key>', lambda x : change()) # binding the second entry's keypress event to the change function.

root.mainloop()

筆記：

每當在小部件內按下一個鍵時都會觸發事件的"<Key>"回呼，有關更多資訊，請查看events 和 bindings。

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