Add feature to allow upside down printing of Tweets.

This is useful when the printer is mounted on a wall.

config.toml.example

@@ -5,3 +5,6 @@ secret="PUT_YOUR_CONSUMER_SECRET_HERE"
 [auth.access]
 token="PUT_YOUR_ACCESS_TOKEN_HERE"
 secret="PUT_YOUR_ACCESS_SECRET_HERE"
+
+[printer]
+flipped=false

printer.py

@@ -6,7 +6,7 @@ TODO: Figure out if/when to show unshortened URLs in links contained in Tweets.
 TODO: Figure out bitmap mode so stuff that is not Latin-1 encodable can still be printed.
 """
 
-__version__ = "0.0.1"
+__version__ = "0.0.2"
 
 import argparse
 import datetime
@@ -93,13 +93,17 @@ def format_header(handle, name, dt, is_rt=None):
 
 
 class Printer:
-    def __init__(self, port):
+    def __init__(self, port, **kwargs):
         self.port = port
+        for arg, default in [("flipped", False)]:
+            setattr(self, arg, kwargs.get(arg, default))
 
     def __enter__(self):
         self.printer = open(self.port, "wb")
         self.printer.write(bytes([0x1b, 0x40]))             # Initialize printer
         self.printer.write(bytes([0x1b, 0x74, 0x06]))       # Set character code table to CP1252/Latin-1
+        if self.flipped:
+            self.printer.write(bytes([0x1b, 0x7b, 0x01]))   # Set printer to upside-down mode
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
@@ -146,6 +150,8 @@ class StreamListener(tweepy.StreamListener):
     def print_tweet(self, text, headers):
         try:
             encoded_lines = self.split_and_encode_text(text, headers)
+            if self.printer.flipped:
+                encoded_lines.reverse()
             for line in encoded_lines:
                 self.printer.write(line)
             self.printer.write("", False, True)
@@ -227,6 +233,8 @@ def main():
     args = parser.parse_args()
 
     config = load_config()
+    printer_config = config.get("printer", {})
+    flip_printer = printer_config.get("flipped", False)
 
     consumer_key = config["auth"]["consumer"]["key"]
     consumer_secret = config["auth"]["consumer"]["secret"]
@@ -258,7 +266,7 @@ def main():
 
     try:
         if args.printer:
-            with Printer(args.printer) as thermal:
+            with Printer(args.printer, flipped=flip_printer) as thermal:
                 logger.info("Streaming {} to thermal printer {}...".format(stream_name, thermal.port))
                 listener = StreamListener(stream_name, ignore_rt=not show_rts, printer=thermal)
                 start_streaming(listener, api)