Equalizer

This example demonstrates the use of styles to differentiate scale functions. Now for some comments on the code; because I wanted the scale value to be reflected in a label below the scale, this application is a lot more complicated than it really needs to be due to some oddities of the Scale implementation. The Scale widget outputs a double type, which means that in order to display a nice rounded integer, that number has to be converted when updated. Fortunately, the scale widget has a command parameter for setting a callback. The callback will get the scale value, which can then be converted into a nice clean format.

Style Summary

The theme used is litera.

Item	Class	Bootstyle
Volume Scale	Scale	success
Gain Scale	Scale	success
Other Scales	Scale	info

Note

For a vertical orientation, the from_ parameter corresponds to the top and to corresponds to the bottom of the widget, so you’ll need to take this into account when you set the minimum and maximum numbers for your scale range.

Example Code

Run this code live on repl.it

import ttkbootstrap as ttk
from ttkbootstrap.constants import *
from random import randint


class Equalizer(ttk.Frame):

    def __init__(self, master):
        super().__init__(master, padding=20)
        self.pack(fill=BOTH, expand=YES)

        controls = ["VOL", "31.25", "62.5", "125", "250",
                    "500", "1K", "2K", "4K", "8K", "16K", "GAIN"]

        for control in controls:
            self.create_band(self, control)

    def create_band(self, master, text):
        """Create and pack an equalizer band"""
        value = randint(1, 99)
        self.setvar(text, value)

        container = ttk.Frame(master)
        container.pack(side=LEFT, fill=Y, padx=10)

        # header label
        hdr = ttk.Label(container, text=text, anchor=CENTER)
        hdr.pack(side=TOP, fill=X, pady=10)

        # volume scale
        if text in ["VOL", "GAIN"]:
            bootstyle = SUCCESS
        else:
            bootstyle = INFO

        scale = ttk.Scale(
            master=container,
            orient=VERTICAL,
            from_=99,
            to=1,
            value=value,
            command=lambda x=value, y=text: self.update_value(x, y),
            bootstyle=bootstyle,
        )
        scale.pack(fill=Y)

        # value label
        val = ttk.Label(master=container, textvariable=text)
        val.pack(pady=10)

    def update_value(self, value, name):
        self.setvar(name, f"{float(value):.0f}")


if __name__ == "__main__":

    app = ttk.Window("Equalizer", "litera", resizable=(False, False))
    Equalizer(app)
    app.mainloop()