Difference between revisions of "Extras script"

Latest revision as of 09:14, 27 January 2018

As mentioned elsewhere, Box Of Stops uses a small but crucial Python script to achieve its real-time playback. Most customization work with Box Of Stops can be achieved with triggers or GPIO buttons, but occasionally there is a requirement to inject a note into the live playing engine.

This can be achieved with something called an Extras script. This is typically a short Python script that will be imported into the main Python script that Box Of Stops uses.

Please see https://github.com/boxofstops/boxofstops-examples for the latest examples of Extras scripts.

Using

To add an Extras script to Box Of Stops, please look for the ~/boxofstops/.python directory (see Directories for more information). By default the Extras script is called extras.py in this directory. Just add this file and restart - Box Of Stops will auto-detect the script and call it while initializing.

Renaming the script

It is possible to use a script with a different name than extras.py. Please look for the python.extras.script property in the Application properties file.

Internal API

There is a small internal API available to call back to, to register a device and inject notes or other events into the running Box Of Stops script.

• boxofstops.add_device_channel(device_name,channel) - register a new input device and channel to play to a Bank in Box Of Stops.
  The Bank will see this as new Midi input, but the point of the Extras script is to simulate a Midi input, while generating notes and events from an alternative source.
• boxofstops.midi_in_event(device_name,msg) - inject a note (or other MIDI event) into the Box Of Stops playing engine.
  This note_on/note_off will be played on the appropriate Bank for the device_name and the channel in the message.
  The msg is a MIDO Message. Again please see the examples code for examples of this being used.

boxofstops.midi_in_event(device_name,mido.Message('note_on', note=60, channel=0, velocity=80))
boxofstops.midi_in_event(device_name,mido.Message('note_off', note=60, channel=0, velocity=80))

Debugging

Note that any output from the Extras script is automatically sent to the Logging output.

• If no script is found, the logging output shows: <<< Not loading extras.py
• If the script is found, typically the logging output shows any print statement at the top of the script. E.g. : <<< In extras