Changing font size for multiple labels in tkinter

Question

I have a group of 10 labels in tkinter that I want to change the font size of. I know there exists option to change the font size for every single label, but I am interested to see if there is an elegant solution to changing font size of selected group of labels. Right now, I just hardcoded the size in all of them.

if you will keep labels on list then you can use `for`-loop to change all of them. — furas, Apr 12 '20 at 21:30
see also themed widgets [tkinter.ttk](https://docs.python.org/3/library/tkinter.ttk.html) which can use styles. You can assign the same style to all labels and change style to change all labels. — furas, Apr 12 '20 at 21:32
every widget has function `.children` with list of widgets inside it. You can use it to find all labels (i.e. inside Window, Frame or other widget) and change them. — furas, Apr 12 '20 at 21:34
if you want to set it only once then you can define options as dictionary ie. `options = {'bg': 'red'}` and use it in all labels as `tk.Label(root, **options)` — furas, Apr 12 '20 at 21:38
Does this answer your question? [How to change a widget's font style without knowing the widget's font family/size?](https://stackoverflow.com/questions/4072150/how-to-change-a-widgets-font-style-without-knowing-the-widgets-font-family-siz) — stovfl, Apr 12 '20 at 21:42

score 2 · Accepted Answer · answered Apr 12 '20 at 21:41

2

Use ttk widgets. They have support for "themes" (aka "styles").

You can create a single style, and apply it to all the labels. (Example inspired by the documentation)

style = ttk.Style()
style.configure(
    "BW.TLabel",
    foreground="black",
    background="white",
    font="Helvetica",
    fontsize=12
)

l1 = ttk.Label(text="Test", style="BW.TLabel")
l2 = ttk.Label(text="Test", style="BW.TLabel")

answered Apr 12 '20 at 21:41

Roland Smith

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I have tried a simplified version as `ttk.Style().configure('heading.TLabel',fontsize=48)`, without and without the `font=` part. I can’t get this to change the font size. – Manngo Sep 08 '21 at 06:45

score 2 · Answer 2 · answered Apr 12 '20 at 21:48

You can define options as dictionary and use this dictionary with every widget

import tkinter as tk

root = tk.Tk()

options = {'font': (None, 20)}

l = tk.Label(root, text="Label 1", **options)
l.pack()

l = tk.Label(root, text="Label 2", **options)
l.pack()

l = tk.Label(root, text="Label 3", **options)
l.pack()

root.mainloop()

If you will keep labels on list then you can use for-loop to change them

import tkinter as tk

root = tk.Tk()

all_labels = []

l = tk.Label(root, text="Label 1")
l.pack()
all_labels.append(l)

l = tk.Label(root, text="Label 2")
l.pack()
all_labels.append(l)

l = tk.Label(root, text="Label 3")
l.pack()
all_labels.append(l)

for l in all_labels:
    l['font'] = (None, 20)

root.mainloop()

Every widget keep information about children widgets and you can use it to find all Labels

import tkinter as tk

root = tk.Tk()

l = tk.Label(root, text="Label 1")
l.pack()

l = tk.Label(root, text="Label 2")
l.pack()

l = tk.Label(root, text="Label 3")
l.pack()

for widget in root.winfo_children():
    if isinstance(widget, tk.Label):
        widget['font'] = (None, 20)

root.mainloop()

In Roland Smith answer you can see how to use tkinter.ttk

Björn · Answer 3 · 2020-04-12T21:52:12.760

Here an elegant oneliner that sets the font for all labels in your root (mainwindow) to font size 30

[wid.config(font=(None,30)) for wid in root.winfo_children() if isinstance(wid, Label) ]

In a many liner
You can also iterate over all widgets in your main window, filter out all Labels and then change there properties with a loop

# Iterate through all widgets of your main window / root
for wid in root.winfo_children():
    # check if it's a label
    if isinstance(wid, Label):
        wid.config(font=(None,30))

Changing font size for multiple labels in tkinter

3 Answers3