''Under construction''
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 [[Trigger|triggers]] or [[Gpio button|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 <googa>https://github.com/boxofstops/boxofstops-examples|https://github.com/boxofstops/boxofstops-examples</googa> for the latest examples of Extras scripts.
== Using ==
To add an Extras script to Box Of Stops, please look for the <tt>~/boxofstops/.python</tt> directory (see [[Directories]] for more information). By default the Extras script is called <tt>extras.py</tt> in this directory. Just add this file and [[Starting|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 <tt>extras.py</tt>. Please look for the <tt>python.extras.script</tt> 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.
* <tt>boxofstops.add_device_channel(device_name,channel)</tt> - register a new input device and channel to play to a [[Bank]] in Box Of Stops.<br/>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.
* <tt>boxofstops.midi_in_event(device_name,msg)</tt> - inject a note (or other MIDI event) into the Box Of Stops playing engine.<br/>This note_on/note_off will be played on the appropriate [[Bank]] for the <tt>device_name</tt> and the <tt>channel</tt> in the message.<br/>The <tt>msg</tt> is a <googa>https://mido.readthedocs.io/en/latest/messages.html|MIDO Message</googa>. Again please see the <googa>https://github.com/boxofstops/boxofstops-examples|examples code</googa> for an example of this being used.