如何在Tkinter Canvas集成的Matplotlib图表中添加第二个Y轴

Hey there! I see you've got a solid start embedding a Matplotlib chart in Tkinter, and you want to add a second Y-axis—great question! Let's break down how to do this without disrupting your existing setup.

Key Concept: twinx() #

The core tool here is Matplotlib's ax.twinx() method, which creates a new axis that shares the same X-axis as your original plot but has its own independent Y-axis on the right. Here's how to integrate it into your code:

Modified Full Code #

I've updated your code to include a second Y-axis, with comments pointing out the new sections and example data you can replace with your own:

# coding:utf-8
#version 3.x python
import tkinter as tk
from tkinter import ttk
import sys
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.figure import Figure
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

print("TkVersion", tk.TkVersion)
print("TclVersion", tk.TclVersion)
print("Python version", sys.version_info)
print('Python %s on %s' % (sys.version, sys.platform))
print("MatPlotLib version : ", matplotlib.__version__)
print('MatPlotLib version : {}'.format(matplotlib.__version__))

def _on_tab_changed(event):
    print("\n")
    nb = event.widget
    nb.update_idletasks()
    tab = nb.nametowidget(nb.select())
    nb.configure(height=tab.winfo_reqheight())
    nb.configure(width=tab.winfo_reqwidth())

def Create_notebook(master=None, **kw):
    nb = ttk.Notebook(master, **kw)
    nb.bind("<<NotebookTabChanged>>", _on_tab_changed)
    return nb

root = tk.Tk()
root.title("Titre")
root.resizable(False, False)
window_height = 800
window_width = 900
screen_width = root.winfo_screenwidth()
screen_height = root.winfo_screenheight()
x_cordinate = int((screen_width/2) - (window_width/2))
y_cordinate = int((screen_height/2) - (window_height/2))
root.geometry("{}x{}+{}+{}".format(window_width, window_height, x_cordinate, y_cordinate))

RightFrame = tk.LabelFrame(root, text="[Label]", font=('verdana', 8, ''), foreground="blue", relief=tk.SOLID, borderwidth=0)
RightFrame.place(x=130, y=5, width=900, height=900)
RightFrame.anchor(anchor="center")

notebook = Create_notebook(RightFrame)
notebook.add(tk.Frame(notebook, bg="white", width=709, height=725, name="1"), text="GRAPH")
notebook.place(x=5, y=5)

# Original dataset
Liste_TEST = [11.81, 4.91, 4.62, 4.19, 4.35, 4.22, 4.03, 4.31, 4.06, 4.23, 4.01, 4.28, 4.06, 3.81, 4.05, 4.04, 4.13, 4.08, 3.99, 4.05, 4.15, 4.26, 4.3, 4.35, 4.77, 4.65, 4.77, 4.52, 4.6]
# Example second dataset (replace with your own actual data!)
Liste_TEST2 = [20, 25, 22, 28, 30, 27, 24, 26, 23, 29, 21, 28, 25, 22, 27, 24, 26, 23, 29, 21, 28, 25, 22, 27, 32, 30, 33, 29, 31]

chiffre_inf = tk.IntVar()
chiffre_inf.set(np.floor(min(Liste_TEST)))
chiffre_sup = tk.IntVar()
chiffre_sup.set(np.ceil(max(Liste_TEST)))

fig = plt.Figure(figsize=(1, 1), dpi=96)
ax = fig.add_subplot(1, 1, 1, frameon=True)

# Original axis styling
ax.spines['top'].set_color('none')
ax.spines['right'].set_color('none')
ax.spines['bottom'].set_color('#000000')
ax.yaxis.set_ticks_position('left')
ax.spines['left'].set_position(('data', 0))
ax.spines['left'].set_color('#000000')
ax.tick_params(labelcolor='#000000', top=False, bottom=True, left=True, right=False)
plt.xlim(1, len(Liste_TEST))
plt.ylim(chiffre_inf.get(), chiffre_sup.get())

major_ticks = np.arange(chiffre_inf.get(), chiffre_sup.get(), 1)
minor_ticks = np.arange(chiffre_inf.get(), chiffre_sup.get(), 0.5)
ax.set_yticks(major_ticks * 1)
ax.set_yticks(minor_ticks * 1, minor=True)
ax.grid(which='minor', alpha=0.2)
ax.grid(which='major', alpha=0.5)
ax.grid(True)

ax.set_xlabel("Nombre de plein(s)", fontsize=6)
ax.set_ylabel("Litre(s)", fontsize=6)
ax.set_title("<" + "Titre tableau" + ">", fontsize=8, color='dimgrey')

# Plot original data
line1, = ax.plot(range(len(Liste_TEST)), Liste_TEST, color="red", linewidth=.85, linestyle="dotted", label='Effective')

# --------------------------
# NEW: Add second Y-axis
# --------------------------
ax2 = ax.twinx()  # Create shared X-axis, separate Y-axis on right

# Style the second axis to make it visually distinct
ax2.spines['top'].set_color('none')
ax2.spines['left'].set_color('none')
ax2.spines['bottom'].set_color('#000000')
ax2.yaxis.set_ticks_position('right')
ax2.spines['right'].set_position(('data', len(Liste_TEST)))
ax2.spines['right'].set_color('#0000ff')  # Blue to stand out from left axis
ax2.tick_params(labelcolor='#0000ff', top=False, bottom=False, left=False, right=True)

# Set limits for the second Y-axis (adjust to fit your dataset!)
ax2.set_ylim(np.floor(min(Liste_TEST2)), np.ceil(max(Liste_TEST2)))
ax2.set_ylabel("Second Metric (e.g., Cost)", fontsize=6, color='#0000ff')

# Plot second dataset using the new Y-axis
line2, = ax2.plot(range(len(Liste_TEST2)), Liste_TEST2, color="blue", linewidth=.85, linestyle="solid", label='Second Series')

# Combine legends from both axes for clarity
fig.legend([line1, line2], ['Effective', 'Second Series'], loc='upper right', fontsize=6)

# --------------------------
# End of second Y-axis code
# --------------------------

print("Liste_TEST >", Liste_TEST)

graph = FigureCanvasTkAgg(fig, master=notebook.winfo_children()[0])
canvas = graph.get_tk_widget()
canvas.config(width=700, height=370, relief=tk.RIDGE, borderwidth=2)
canvas.place(x=2, y=50)

root.mainloop()

Key Changes Explained #

• Create the second axis: ax2 = ax.twinx() creates a new axis that shares the X-axis with your original ax but uses a separate Y-axis on the right.
• Style the second axis: I adjusted the spine color, tick position, and label color to make it easy to distinguish from the left axis—feel free to tweak these to match your app's theme.
• Plot second data: Use ax2.plot() to add your second dataset; this will automatically map to the right Y-axis.
• Combine legends: Since we have two axes, we collect both line objects and create a single legend so viewers can easily identify each series.

Customization Tips #

• Update the ylim for ax2 to match the range of your actual second dataset.
• Modify colors, line styles, and axis labels to fit your specific use case.
• Adjust the loc parameter in fig.legend() if you want to move the legend to a different position (e.g., 'upper left').

This should seamlessly add the second Y-axis to your existing Tkinter-embedded chart. Let me know if you hit any bumps along the way!

内容的提问来源于stack exchange，提问作者Taratata