Difference between revisions of "OLA Python API"

Latest revision as of 16:48, 7 June 2011

Building the Python Bindings

You should install readline if you haven't already:

sudo easy_install readline

You need the python version of protocol buffers installed.

See Building OLA but run

$ ./configure --enable-python-libs

Check where the modules are going to be installed:

$ grep ^pythondir config.log
pythondir='/Library/Python/2.5/site-packages'

Run the usual: make, make check, make install.

Check that the modules have been installed correctly in the $pythondir above.

Check that $pythondir appears in sys.path:

$ python -c "import sys; print sys.path"

If it doesn't add it to $PYTHONPATH:

$ export PYTHONPATH=$PYTHONPATH:/path/to/your/install/dir

You probably want to put this line in your shell .rc file.

Interesting Classes

ClientWrapper

A helper class that connects to the server and creates a new OlaClient

OlaClient

The main API

The best documentation is the set of example programs in the python/examples directory.

Sending DMX

A simple example to send one frame of DMX data:

import array
from ola.ClientWrapper import ClientWrapper

def DmxSent(state):
  wrapper.Stop()

universe = 1
data = array.array('B')
data.append(10)
data.append(50)
data.append(255)
wrapper = ClientWrapper()
client = wrapper.Client()
client.SendDmx(universe, data, DmxSent)
wrapper.Run()

Sending Multiple Frames

import array
from ola.ClientWrapper import ClientWrapper

wrapper = None
loop_count = 0
TICK_INTERVAL = 100  # in ms

def DmxSent(state):
  if not state.Succeeded():
    wrapper.Stop()

def SendDMXFrame():
  # schdule a function call in 100ms
  # we do this first in case the frame computation takes a long time.
  wrapper.AddEvent(TICK_INTERVAL, SendDMXFrame)

  # compute frame here
  data = array.array('B')
  global loop_count
  data.append(loop_count % 255)
  loop_count += 1

  # send
  wrapper.Client().SendDmx(1, data, DmxSent)
                                                                                                                        

wrapper = ClientWrapper()
wrapper.AddEvent(TICK_INTERVAL, SendDMXFrame)
wrapper.Run()

Receiving DMX

Here is some code to receive DMX on universe 1.

from ola.ClientWrapper import ClientWrapper

def NewData(data):
  print data

universe = 1

wrapper = ClientWrapper()
client = wrapper.Client()
client.RegisterUniverse(universe, client.REGISTER, NewData)
wrapper.Run()