Merge pull request #21 from tmsbrg/simplify2

Simplify example Python client

client.py

@@ -9,9 +9,9 @@ __version__ = 0.3
 __author__ = "Jan Klopper <jan@underdark.nl>"
 
 import random
-from vloed import PixelVloedClient, NewMessage, RGBPixel, MAX_PIXELS
+from vloed import PixelVloedClient, Packet, RGBPixel, MAX_PIXELS
 
-def RandomFill(message, width, height):
+def RandomFill(pixels, width, height):
   """Generates a random number of pixels with a random color"""
   for pixel in xrange(0, random.randint(10, MAX_PIXELS)):
     pixel = RGBPixel(random.randint(0, width),
@@ -19,12 +19,7 @@ def RandomFill(message, width, height):
                      random.randint(0, 255),
                      random.randint(0, 255),
                      random.randint(0, 255))
-    try:
-      message.append(pixel)
-    except IndexError:
-      yield ''.join(message)
-      message[2:] = [pixel]
-  yield ''.join(message)
+    pixels.append(pixel)
 
 def RunClient(options):
   """Discover the servers and start sending to the first one"""
@@ -36,15 +31,20 @@ def RunClient(options):
                             options.width, # Screen pixels wide, None for autodetect
                             options.height  # Screen pixels height, None for autodetect
                             )
-  message = NewMessage() #create a new message that buffers the output etc
 
   # loop the effect until we cancel by pressing ctrl+c / exit the program
   while True:
-    # create a new message and send it every time the buffer is full
+
+    # packet will automatically send its pixels if gets to the maximum pixel length
+    pixels = Packet(client)
+
+    # add some pixels to the output with our functions
     # the width/height are read from the client's config
-    for packet in RandomFill(message, client.width, client.height):
-      # send the message we just filled with random pixels
-      client.SendPacket(packet)
+    RandomFill(pixels, client.width, client.height)
+
+    # send whatever pixels are left in the packet
+    pixels.flush()
+
 
 if __name__ == '__main__':
   # if this script is called from the command line, and thus not imported

vloed.py

@@ -24,6 +24,8 @@ PROTOCOL_VERSION = 1
 MAX_PROTOCOL_VERSION = 1
 PROTOCOL_PREAMBLE = "pixelvloed"
 MAX_PIXELS = 140
+MESSAGE_HEADER_SIZE = 2
+MAX_MESSAGE = MAX_PIXELS + MESSAGE_HEADER_SIZE
 
 class Canvas(object):
   """PixelVloed display class"""
@@ -263,7 +265,11 @@ class PixelVloedClient(object):
 
 def NewMessage():
   """Creates a new message with the correct max size, rgb mode and version"""
-  message = MaxSizeList(MAX_PIXELS+2)
+  message = MaxSizeList(MAX_MESSAGE)
+  InitMessage(message)
+  return message
+
+def InitMessage(message):
   message.append(SetRGBAMode(False))
   message.append(SetVersionBit())
   return message
@@ -299,6 +305,42 @@ class MaxSizeList(list):
       raise IndexError('max size reached')
     super(MaxSizeList, self).append(item)
 
+class Packet(list):
+  """A Pixelvloed packet.
+
+  Append pixels to it. It will send automatically if it has MAX_PIXELS length.
+  """
+
+  def __init__(self, client):
+    """Create a new pixelvloed packet.
+
+    This packet can be reused for the whole program.
+
+    Arguments:
+      client: PixelVloedClient used to send the packet when it is full.
+    """
+    self.client = client
+    super(Packet, self).__init__()
+    InitMessage(self)
+
+  def append(self, item):
+    """Appends a pixel to this packet.
+
+    Sends pixels and resets the packet if packet would exceed MAX_MESSAGE
+    (MAX_PIXELS + MESSAGE_HEADER_SIZE).
+    """
+    if self.__len__() >= MAX_MESSAGE:
+      self._send()
+    super(Packet, self).append(item)
+
+  def flush(self):
+    """Immediately send all pixels currently in this packet and empty it"""
+    self._send()
+
+  def _send(self):
+    self.client.SendPacket(''.join(self))
+    del self[MESSAGE_HEADER_SIZE:] # reset packet
+
 def RunServer(options):
   """Runs a pixelvloed server"""
   PixelVloedServer('%s:%d' %(options.ip, options.port),