lcd-to-ssd1306

#!/usr/bin/python
# Copyright 2018 Cedric Bosdonnat <cedric.bosdonnat@free.fr>
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import Adafruit_SSD1306

from PIL import Image
from PIL import ImageDraw
from PIL import ImageFont

import sys
from datetime import datetime
import subprocess
import atexit
import os.path
import threading
import time
import signal
import time

lock = threading.Lock()
txt = ' '

class Display(threading.Thread):
    def __init__(self):
        super(Display, self).__init__()
        self.currentTxt = ''
        self.disp = Adafruit_SSD1306.SSD1306_128_64(rst=None)

        # Initialize library.
        self.disp.begin()
        self.disp.clear()
        self.disp.display()

    def run(self):
        global lock
        global txt

        font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf', 8)

        while True:
            lock.acquire()
            newtxt = txt
            lock.release()

            if not newtxt:
                break

            # No need to refresh for nothing
            if self.currentTxt == newtxt:
                continue

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

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

            # Draw a black filled box to clear the image.
            draw.rectangle((0, 0, width, height), outline=0, fill=0)

            # osmc's Pillow is too old: can't handle multiline text
            lines = newtxt.split('\n')
            y = 2
            for line in lines:
                draw.text((2, y), line, font=font, fill=255)
                size = font.getsize(line)
                y = y + size[1] + 2

            # Display image.
            self.disp.image(image)
            # This call takes a lot of time for a single frame!
            self.disp.display()

            self.currentTxt = newtxt

def main():
    global lock
    global txt

    proc = subprocess.Popen(['LCDd', '-c', '/home/osmc/lcdd-oled/LCDd.conf', '-f', '-i', 'false', '-d', 'text'],
                            stdout=subprocess.PIPE,
                            universal_newlines=True)

    # Start the display thread
    display = Display()
    display.start()

    def stop(signum, frame):
        raise KeyboardInterrupt()

    signal.signal(signal.SIGTERM, stop)

    def cleanup():
        proc.kill()
    atexit.register(cleanup)

    # Loop over LCDd output to cut into screens
    try:
        line = proc.stdout.readline()
        screen = ''
        while line:
            if line == '+--------------------+\n':
                if len(screen) > 0:
                    lock.acquire()
                    txt = screen
                    lock.release()
                    screen = ''
            else:
                screen = screen + line[1:-2] + '\n'
            line = proc.stdout.readline()

    finally:
        # Wait for display thread to finish
        lock.acquire()
        txt = " ___ _      _ \n" \
              "| __(_)_ _ (_)\n" \
              "| _|| | ' \| |\n" \
              "|_| |_|_||_|_|\n"
        lock.release()
        time.sleep(2)
        txt = None
        display.join()

if __name__ == '__main__':
    main()