Expanding with Weights in Tkinter

In Tkinter, the concept of weights controls how the available space within a layout is distributed among columns and rows. Each row or column has a weight grid option that determines how much it should expand when there's additional room.

The Default Weight

By default, all rows and columns have a weight of 0, indicating that they should not expand to fill space. This means that any extra space will remain unused.

Adding Weights

A non-zero weight causes a row or column to grow if there's extra space. The value of the weight determines how much it should expand relative to other weighted elements. For example, a weight of 1 allocates twice as much space as a weight of 0.5.

Code Example

Consider the following code:

import tkinter as tk

root = tk.Tk()
root.geometry("200x100")

f1 = tk.Frame(root, background="bisque", width=10, height=100)
f2 = tk.Frame(root, background="pink", width=10, height=100)

f1.grid(row=0, column=0, sticky="nsew")
f2.grid(row=0, column=1, sticky="nsew")

root.grid_columnconfigure(0, weight=0) # no extra space for column 0
root.grid_columnconfigure(1, weight=0) # no extra space for column 1

root.mainloop()

This code creates a window larger than the contained frames. Because none of the columns have weight, the extra space remains unused.

Using Weights to Expand

Adding weight to a column or row allows it to expand into the additional space. For example, the following code gives a weight of 1 to column 0:

root.grid_columnconfigure(0, weight=1)

Now, the extra space is allocated to column 0, making it wider.

Weighting Multiple Elements

When multiple columns or rows have weights, they share the available space proportionally to their weights. For instance, to allocate 1/4 of the space to column 0 and 3/4 to column 1, you can use the following weights:

root.grid_columnconfigure(0, weight=1)
root.grid_columnconfigure(1, weight=3)

This results in a layout where column 0 is a quarter of the width of column 1.

Conclusion

Weights in Tkinter provide a way to control the distribution of space within a layout. By assigning weights to columns or rows, you can determine how the available space is utilized, allowing for flexible and responsive layouts.