class DisplayDriver(object):
"""
This class represents the display driver that links the raspberry pi to the display. This driver will have high-
level control over the data being sent to the display, but will do this mostly through the help of smaller utility
classes.
"""
logger = logging.getLogger("display")
def __init__(self):
"""
Ctor - Initialises the display driver, setting up the database helper and display controller.
"""
self._db_helper = DatabaseHelper(db_name)
self._display_controller = DisplayController(serial_name, serial_baudrate)
def start(self):
"""
Starts the application: begins checking the current time and working out what information needs to be sent
to the display at that time.
"""
mode = ScreensaverMode(self._db_helper.get_random_screensaver())
last_pattern = None
last_check_time = datetime.datetime.now() - datetime.timedelta(minutes=10)
while True:
# Check the current time and make it accurate to the second
current_time = datetime.datetime.now()
min_current_time = minutify(current_time)
if (current_time.minute % 5) == 0 and (min_current_time > last_check_time):
# If the current time is on one of the five min. intervals, attempt to pull a pattern from the
# internal database.
last_check_time = min_current_time
t_format = "%Y-%m-%d %H:%M:00.000000"
pattern = self._db_helper.get_run_for_time(current_time.strftime(t_format))
if pattern:
# If a pattern is successfully pulled, run the display's 'run mode' on it.
mode = RunMode(pattern)
else:
# Otherwise pull a random screensaver from the internal database and run that in 'screensaver
# mode'
mode = ScreensaverMode(self._db_helper.get_random_screensaver(), last_pattern)
if not mode.is_active():
# If the current pattern finishes before the five minute timer has stopped, switch to
# screensaver mode
mode = ScreensaverMode(self._db_helper.get_random_screensaver(), last_pattern)
# Retrieve the latest pattern to be sent to the display
last_pattern = mode.get_display_pattern()
# Send the pattern to the display controller for printing.
self._display_controller.output_pattern(last_pattern)
# While not working, sleep
sleep_until_time = current_time + datetime.timedelta(seconds=sleep_time)
time.sleep((sleep_until_time - datetime.datetime.now()).microseconds / 1000000)
self.logger.warn("Outputted pattern at: %s" % current_time)
def test_get_random_screensaver(self):
"""
Tests the ability of the database helper to retrieve a random screen saver from the internal database.
"""
database_helper = DatabaseHelper(db_name=test_db_name)
con = database_helper._db_connection
con.execute("INSERT INTO screensavers VALUES ('TEST');")
con.execute("INSERT INTO screensavers VALUES ('TEST1');")
con.execute("INSERT INTO screensavers VALUES ('TEST2');")
con.commit()
# Assert that a database has retrieved the random screensaver
assert database_helper.get_random_screensaver()
