Display RPi IP address on Adafruit's i2c Pi OLED (128x32) screen via python 3 subprocess (hostname -I). If MAC address is present in hostname output (no idea why this happens BTW) split by space and only pass IP to screen. Note: this file is written by Adafruit unless denoted otherwise.

displayIP-OLED-128x32.py

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

"""
This demo will fill the screen with white, draw a black box on top
and then print Hello World! in the center of the display

This example is for use on (Linux) computers that are using CPython with
Adafruit Blinka to support CircuitPython libraries. CircuitPython does
not support PIL/pillow (python imaging library)!
"""

import board
import digitalio
from PIL import Image, ImageDraw, ImageFont
import adafruit_ssd1306

# added by CTA
import subprocess

# Define the Reset Pin
oled_reset = digitalio.DigitalInOut(board.D4)

# Change these
# to the right size for your display!
WIDTH = 128
HEIGHT = 32  # Change to 64 if needed
BORDER = 5

# Use for I2C.
i2c = board.I2C()
oled = adafruit_ssd1306.SSD1306_I2C(WIDTH, HEIGHT, i2c, addr=0x3C, reset=oled_reset)

# Clear display.
oled.fill(0)
oled.show()

# Create blank image for drawing.
# Make sure to create image with mode '1' for 1-bit color.
image = Image.new("1", (oled.width, oled.height))

# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)

# Draw a white background
draw.rectangle((0, 0, oled.width, oled.height), outline=255, fill=255)

# Draw a smaller inner rectangle
draw.rectangle(
    (BORDER, BORDER, oled.width - BORDER - 1, oled.height - BORDER - 1),
    outline=0,
    fill=0,
)

# Load default font.
font = ImageFont.load_default()

# Draw Some Text
# 60 - 70 added by CTA
IP = subprocess.Popen(['hostname', '-I'],stdout=subprocess.PIPE)
ip_output = IP.communicate()[0].decode('utf-8')

if ip_output.find(" ") != -1:
#     print("there is a space")
    ip_output = ip_output.split()
    text = ip_output[0]
else:
#     print("no space")
    text = ip_output

(font_width, font_height) = font.getsize(text)
draw.text(
    (oled.width // 2 - font_width // 2, oled.height // 2 - font_height // 2),
    text,
    font=font,
    fill=255,
)

# Display image
oled.image(image)
oled.show()