I used the following codes (related to my question)

fig = plt.Figure()                       
canvas = FigureCanvasTkAgg(fig, root)     
canvas.get_tk_widget().grid(row=6, column=0, columnspan=3, rowspan=3, sticky=W E N S, padx=0, pady=0)  
ax = fig.add_subplot(111)
fig.subplots_adjust(bottom=0.25)
X = np.arange(1,rec[1] 1,1)
Y = np.arange(1,rec[0] 1,1)
x , y = np.meshgrid(X,Y)  
    

# Initial plots
con = ax.contourf(x,y,dfs[1], levels = levels, cmap=cm.jet, alpha = 0.5, antialiased = True)
cbar = fig.colorbar(con, ax=ax)
ax.axis([1, 12, 1, 6])
ax.axis('equal')        #<-------------------------
ax.set_title('Frequency: f=%f' %float(avector[1]))

Here ax.axis('equal') set the x & y-axis same scale. I got the following plot

How to fit the frame to the blue plot? (I want to remove the white region)

Thanks!

Complete codes:

The following codes is to plot contours from five (slider: 0 ~ 4) .xlsx files on tkinter. Each file just contains numerical data in the matrix 12X6 such as

from tkinter import *
import tkinter.ttk as ttk
import matplotlib
import matplotlib.pyplot as plt
from matplotlib import cm
import numpy as np
import ipywidgets as wg
import os
import pandas as pd
from matplotlib.ticker import MaxNLocator
from matplotlib.colors import BoundaryNorm
import math
from matplotlib.ticker import LinearLocator
%matplotlib widget
from matplotlib.widgets import Slider
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
matplotlib.use('TkAgg')

root = Tk()
root.title('TEST')
root.geometry("800x800")

cbar = None
def plot_noise():
    # ============================================Read .xlsx file=====================================
    folder = r'C:\Users\Dian-Jing Chen\Desktop\Work\test_read'
    files = os.listdir(folder)
    dfs = {}
    for i, file in enumerate(files):
        if file.endswith('.xlsx'):
            dfs[i] = pd.read_excel(os.path.join(folder,file), sheet_name='Z=143', header = None, skiprows=[0], usecols = "B:M")

    num = i   1
    rec = np.shape(dfs[0])
    rmm = np.concatenate([dfs[0], dfs[1]])
    for jj in range(2,num):
        rmm = np.concatenate([rmm, dfs[jj]])
    # =================================================PLOT===========================================
    fig, ax = plt.subplots()                       
    canvas = FigureCanvasTkAgg(fig, root)     
    canvas.get_tk_widget().grid(row=3, column=0, columnspan=3, rowspan=3, sticky=W E N S, padx=0, pady=0) 
    # ===============================================contourf=========================================          
    fig.subplots_adjust(bottom=0.25)          
    X = np.arange(1,rec[1] 1,1)
    Y = np.arange(1,rec[0] 1,1)
    x , y = np.meshgrid(X,Y)  
    # ==============================================color bar=========================================
    cbar_max = math.floor(np.min(rmm))
    cbar_min = math.ceil(np.max(rmm))
    cbar_num_colors = 200
    cbar_num_format = "%d"
    levels = MaxNLocator(nbins=cbar_num_colors).tick_values(cbar_min, cbar_max)
    # ============================================Initial plot======================================== 
    con = ax.contourf(x,y,dfs[1], levels = levels, cmap=cm.jet, alpha = 0.5, antialiased = True)  
    cbar = fig.colorbar(con,ax = ax)
    ax.axis([1, 12, 1, 6])
    ax.axis('equal')
    # ================================================Slider==========================================
    slider_bar = fig.add_axes([0.12, 0.1, 0.78, 0.03])     
    slider_de = Slider(slider_bar, 's_bar', 0, num-1, valinit=1,valfmt='%0.0f',  valstep=1)
    num_on_slider = []
    def update(val):
        num_on_slider.append(slider_de.val)
        for ii in range(0,num):
            if num_on_slider[-1] == ii:
                con = ax.contourf(x,y,dfs[ii], levels = levels, cmap=cm.jet, alpha = 0.5, antialiased = True)
                ax.axis([1, 12, 1, 6])
                ax.axis('equal')
                
    slider_de.on_changed(update)            
                
    
# =================================================GUI - Tkinter======================================= 
resultButton = ttk.Button(root, text = 'show', command = plot_noise)
resultButton.grid(column=0, row=1, pady=15, sticky=W)

root.mainloop()

CodePudding user response：

you can change this line:

ax.axis('equal')

to:

ax.set_aspect('equal', 'box')

Output: tip: Im use fake data to this fig!