The adafruit_progressbar library makes it easy to create and display progress bars. The code initializes a ProgressBar with a size, location, and some colors. To change the bar, set the progress property, after that, refresh the display so the MagTag will show the updated bar.

These colors can be used to show the 4 available colors on the MagTag screen: 0x000000, 0x666666, 0x999999, 0xFFFFFF.

Simpletest Example

To use with CircuitPython, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update with the example script.

Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the file in a zip file. Extract the contents of the zip file, open the directory examples/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.

Your CIRCUITPY/lib folder should now contain the following files and directories:

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

Basic progressbar example script
adapted for use on MagTag.
import time
import board
import displayio
import digitalio
from adafruit_progressbar.progressbar import HorizontalProgressBar

# use built in display (PyPortal, PyGamer, PyBadge, CLUE, etc.)
# see guide for setting up external displays (TFT / OLED breakouts, RGB matrices, etc.)
display = board.DISPLAY

# B/up button will be used to increase the progress
up_btn = digitalio.DigitalInOut(board.BUTTON_B)
up_btn.direction = digitalio.Direction.INPUT
up_btn.pull = digitalio.Pull.UP

# C/down button will be used to increase the progress
down_btn = digitalio.DigitalInOut(board.BUTTON_C)
down_btn.direction = digitalio.Direction.INPUT
down_btn.pull = digitalio.Pull.UP

# Make the display context
splash = displayio.Group()
display.root_group = splash

# set progress bar width and height relative to board's display
BAR_WIDTH = display.width - 40

x = display.width // 2 - BAR_WIDTH // 2
y = display.height // 3

# Create a new progress_bar object at (x, y)
progress_bar = HorizontalProgressBar(
    (x, y),

# Append progress_bar to the splash group

# Get a random starting value within our min/max range
current_progress = time.monotonic() % 101
progress_bar.value = current_progress

# refresh the display

value_incrementor = 3

prev_up = up_btn.value
prev_down = down_btn.value
while True:
    cur_up = up_btn.value
    cur_down = down_btn.value
    do_refresh = False
    # if up_btn was just pressed down
    if not cur_up and prev_up:
        current_progress += value_incrementor
        # Wrap if we get over the maximum value
        if current_progress > progress_bar.maximum:
            current_progress = progress_bar.minimum

        do_refresh = True

    if not cur_down and prev_down:
        current_progress -= value_incrementor
        # Wrap if we get below the minimum value
        if current_progress < progress_bar.minimum:
            current_progress = progress_bar.maximum

        do_refresh = True

    if do_refresh:
        progress_bar.value = current_progress


    prev_up = cur_up
    prev_down = cur_down

Now to pull some data from the internet and populate the progress bar with it.

This guide was first published on Dec 02, 2020. It was last updated on Jun 17, 2024.

This page (ProgressBar Basics) was last updated on Jun 17, 2024.

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