OLA Python API: Difference between revisions

Latest revision as of 00:48, 8 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()

@@ Line 1: / Line 1: @@
 == Building the Python Bindings ==
-See [[Building LLA]]  but run ''./configure --enable-python-libs''
+You should install readline if you haven't already:
-Note that you have to install Swig in order to build the python bindings (sudo apt-get install swig)
+<pre>
+sudo easy_install readline
+</pre>
+You need the python version of protocol buffers installed.
-== Interesting Classes ==
+See [[Building OLA]]  but run
-; LlaClient
+<pre>
-: the main connection class
+$ ./configure --enable-python-libs
-; dmxBuffer
+</pre>
-: represents a list of DMX channel values
-; LlaClientObserver
-: base class to handle events
-; LlaPlugin
-: represents a Plugin
-; LlaDevice
-: represents a Device
-== Sending DMX ==
+Check where the modules are going to be installed:
-A simple example to send DMX:
 <pre>
-from lla import *
+$ grep ^pythondir config.log
-import sys
+pythondir='/Library/Python/2.5/site-packages'
+</pre>
+Run the usual: make, make check, make install.
+Check that the modules have been installed correctly in the $pythondir above.
-con = LlaClient()
+Check that $pythondir appears in sys.path:
-if con.start():
-  sys.exit()
-universe = 0
+<pre>
+$ python -c "import sys; print sys.path"
+</pre>
-# create a dmxBuffer for the channel values
+If it doesn't add it to $PYTHONPATH:
-DMX_LEN = 512
-dmx = dmxBuffer(DMX_LEN)
-for i in range(0, DMX_LEN):
-  dmx[i] = i
-con.send_dmx(universe, dmx, DMX_LEN)
+<pre>
+$ export PYTHONPATH=$PYTHONPATH:/path/to/your/install/dir
 </pre>
-== Receiving DMX ==
+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
-Receiving is slightly harder, we need to setup an Observer object to handle the events:
+The best documentation is the set of example programs in the python/examples directory.
-''' THIS ISN'T WORKING YET ''' [simonn]
+== Sending DMX ==
+A simple example to send one frame of DMX data:
 <pre>
-from lla import *
+import array
-import sys
+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()
+</pre>
+== Sending Multiple Frames ==
-class Observer(LlaClientObserver):
+<pre>
-  """ Handle the events """
+import array
-  def new_dmx(self, uni, length, data):
+from ola.ClientWrapper import ClientWrapper
-    """ Called with new dmx buffer """
-    return 0
+wrapper = None
+loop_count = 0
+TICK_INTERVAL = 100  # in ms
-# create a new LlaClient
+def DmxSent(state):
-con = LlaClient()
+  if not state.Succeeded():
+    wrapper.Stop()
-# create an observer object and register
+def SendDMXFrame():
-ob = Observer()
+  # schdule a function call in 100ms
-con.set_observer(ob)
+  # we do this first in case the frame computation takes a long time.
+  wrapper.AddEvent(TICK_INTERVAL, SendDMXFrame)
-if con.start():
+  # compute frame here
-   sys.exit()
+  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()
+</pre>
+== Receiving DMX ==
+Here is some code to receive DMX on universe 1.
+<pre>
+from ola.ClientWrapper import ClientWrapper
-con.register_uni(1, LlaClient.REGISTER)
+def NewData(data):
+  print data
-while True:
+universe = 1
-  con.fd_action(1)
+wrapper = ClientWrapper()
+client = wrapper.Client()
+client.RegisterUniverse(universe, client.REGISTER, NewData)
+wrapper.Run()
 </pre>

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