song_api_example.py

   1 import os
   2 import sys
   3 import struct
   4 import time
   5 import unittest
   6
   7 sys.path = ["./py"] + sys.path
   8
   9 import cbox
  10
  11 global Document
  12 global Transport
  13 Document = cbox.Document
  14 Transport = cbox.Transport
  15
  16 song = Document.get_song()
  17
  18 # Delete all the tracks and patterns
  19 song.clear()
  20
  21 # Add the first track
  22 trk = song.add_track()
  23
  24 # Create a binary blob that contains the MIDI events
  25 pblob = bytes()
  26 for noteindex in range(20):
  27     # note on
  28     pblob += cbox.Pattern.serialize_event(noteindex * 24, 0x90, 36+noteindex*3, 127)
  29     # note off
  30     pblob += cbox.Pattern.serialize_event(noteindex * 24 + 23, 0x90, 36+noteindex*3, 0)
  31
  32 # This will be the length of the pattern (in pulses). It should be large enough
  33 # to fit all the events
  34 pattern_len = 10 * 24 * 2
  35
  36 # Create a new pattern object using events from the blob
  37 pattern = song.pattern_from_blob(pblob, pattern_len)
  38
  39 # Add an instance (clip) of the pattern to the track at position 0
  40 # The clip will contain the whole pattern (it is also possible to insert
  41 # a single slice of the pattern)
  42 clip = trk.add_clip(0, 0, pattern_len, pattern)
  43
  44 # Stop the song at the end
  45 song.set_loop(pattern_len, pattern_len)
  46
  47 # Set tempo - the argument must be a float
  48 Transport.set_tempo(160.0)
  49
  50 # Send the updated song data to the realtime thread
  51 song.update_playback()
  52
  53 print ("Song length (seconds) is %f" % (cbox.Transport.ppqn_to_samples(pattern_len) * 1.0 / Transport.status().sample_rate))
  54
  55 # The /master object API doesn't have any nice Python wrapper yet, so accessing
  56 # it is a bit ugly, still - it works
  57
  58 # Start playback
  59 Transport.play()
  60 print ("Playing")
  61
  62 while True:
  63     # Get transport information - current position (samples and pulses), current tempo etc.
  64     master = Transport.status()
  65     print (master.pos_ppqn)
  66     # Query JACK ports, new USB devices etc.
  67     cbox.call_on_idle()
  68     time.sleep(0.1)