Adding support for priority TEXT files.

alphasign/text.py

@@ -10,13 +10,16 @@ class Text(object):
   This class is aliased as :class:`alphasign.Text` in :mod:`alphasign.__init__`.
   """
   def __init__(self, data=None, label=None, size=None,
-               position=None, mode=None):
+               position=None, mode=None, priority=False):
     """
     :param data: initial string to insert into object
     :param label: file label (default: "A")
     :param size: amount of bytes to allocate for object on sign (default: 64)
     :param position: constant from :mod:`alphasign.positions`
     :param mode: constant from :mod:`alphasign.modes`
+    :param priority: set this text to be displayed instead of
+                     all other TEXT files. Set to True with an empty message to
+                     clear a priority TEXT.
     """
     if data is None:
       data = ""
@@ -40,15 +43,22 @@ class Text(object):
     self.data = data
     self.position = position
     self.mode = mode
+    self.priority = priority
 
   def __str__(self):
     # [WRITE_TEXT][File Label][ESC][Display Position][Mode Code]
     #   [Special Specifier][ASCII Message]
-    packet = Packet("%s%s%s%s%s%s" % (constants.WRITE_TEXT, self.label,
-                                      constants.ESC,
-                                      self.position,
-                                      self.mode,
-                                      self.data))
+
+    if self.data:
+      packet = Packet("%s%s%s%s%s%s" % (constants.WRITE_TEXT,
+                                        (self.priority and "0" or self.label),
+                                        constants.ESC,
+                                        self.position,
+                                        self.mode,
+                                        self.data))
+    else:
+      packet = Packet("%s%s" % (constants.WRITE_TEXT,
+                                (self.priority and "0" or self.label)))
     return str(packet)
 
   def __repr__(self):