Changes Script Computer Keyboard Control

Changes : K a

A Changes script can read the state (0 or 1) of a computer keyboard key and use it as a value in any expression. This allows near-real-time user control of the performance.

The format is K a, where a is an alphanumeric character (case ignored). For example, UA=Kq will set User Variable A to 1 if the ' q' key is down at the time the command is processed, or else 0 if it is up.

The main use for keyboard states is with IF statements to control execution pathways. For example, you could use [Ka=1 a2=3 | a2=0 ] to set Voice 2 Arpeggio to a value of 3 whenever the ' a' key is down, and 0 when it is up.

You can use one key can set one value, and a second key to set another. Or, use multiple keys to set multiple values. Following the previous example:

[Ka=1 a2=3] ;IF 'a' down, set a2=3

[Kb=1 a2=0] ;IF 'b' down, set a2=0

Alternatively, you can get a "push-On, push-Off" action from a single key, by using a User Variables and a pair of nested IFs:

[Ka=1 [U1=3 U1=0 | U1=3] ]

(If 'a' is down and U1 = 3, then set it to 0, else set it to 3 if it wasn't already.)

But many commands only need a 0 or 1 value to change state, so controlling them with a key is even simpler. For example, b2=Kb sets Note Bend for Voice 2 when the ' b' key is down, and clears it when it is up.

Note that there is no way to make this truly real-time. Changes scripts must always have a least one Wait command, and for performances that use Voice Tempo this may delay response by a beat. However, for live Pitch Track performances where you don't use Voice Tempo the response latency can be as low as the Trace Update interval.

For fastest response, you can dedicate the Changes script of one Voice Setup just for commands that must be run on every note. Set W=1 at the start of the script, and then include the commands.

You can control any voice from any script, so using one just for this purpose doesn't compromise control over that voice... you just control it from another script. Since scripts are multi-tasking they all appear to run at the same time, so this won't slow down other scripts.

Note: Be careful not to confuse these K Keyboard data values with K Pattern Key commands. Commands are always on the left side of the equal sign, while data is always on the right.

See also Changes Script Overview, Changes Script Editor, MIDI Voice Setup Dialogs, Pitch-to-MIDI dialog, Pitch Track Toolbox - Overview