Console Commands: Difference between revisions

To run a command using the console, just type it in and press enter. The console executes JS code, so if you want to go beyond copy/pasting the commands on this page, try [https://developer.mozilla.org/en-US/docs/Learn/JavaScript/First_steps learning some JS].

* The fundamental time units used by the sequencer are quarter notes, starting at 0. So t=10 would mean the half beat after the second beat. If you set the grid to 1/4 (the default) the grid lines match this time unit. Markers can be placed at t=0, 1, 2, etc.

* Instruments are identified using a number, also know as the id. The current instrument is stored in the global variable "instrument". So to figure out the number for an instrument, just choose that instrument in the UI, type "instrument", and press enter. You can also just pass "instrument" directly to use the current instrument, eg "setDetune(instrument, 1200)".

In JS, functions parameters can have [https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters default values]. This means if you don't pass a value to that parameter, it will default to some value. A lot of the functions in this section have default parameters. They're written in the documentation like this: "fadeNotes(fadeIn = false)". This means the "fadeIn" parameter defaults to false, so instead of writing "fadeNotes(false)" you can just write "fadeNotes()".

Fades the selected notes in or out (that is, it sets the volumes of the notes based on their position in the segment). The function takes a single parameter, "fadeIn" which defaults to false. In other words it fades the notes from their original volume to 0 by default, or if you pass "true" it fades in the segment from 0 volume to original volume.

Stretches or squishes the selected segment by the given factor. A factor more than 1 will make the selected segment longer, and less than 1 will make it shorter. A factor less than 0 will reverse the segment.

It also works on selected markers, but since marker times are quantized to whole number times, they might not be moved to exactly the right spot. Also, reversing markers is complicated, and not all marker sequences are reversible, so negative factors are not supported if you have markers selected.

Moves all the selected notes to the "startNote", then creates detune markers to detune each note back to its original pitch. For example, if you select a "D5" and then run this with the default startNote, it will move the note to "C5" and create a detune marker to detune it up 200 cents back to "D5". This is useful for making clear melodies on instruments that get muddy when there's a lot of notes.

Due to the limitations of detune markers, this will only work if the melody sticks to whole number time steps (ie lines up with the quarter note grid), and there's only ever one note at a particular time. This function ignores drum kit instruments.

Divides the selected segment into chunks and mixes them around. This is mainly just for fun, but can be handy to generate a breakdown by remixing a drum loop, or to reshuffle a melody if you need a bit of inspiration. The chunkSize parameter controls how large the chunks are (in quarter notes), and the other parameters control how the chunks are mixed up.

These functions take a predicate (a function that returns true or false) and select all the notes or markers for which the predicate returns true. If addToSelection is true, these notes or markers are added to the existing selection, otherwise they replace the current selection. Both these functions include undo/redo support.

This is probably the single most useful console function. It basically runs tweakFunction on every selected note, and has undo/redo support for any changes that tweakFunction makes to the note. It's roughly equivalent to:

There are a few problems with doing a for loop like this and manually tweaking the notes. For starters you won't get undo/redo support, but the bigger problem is that there are a few optimizations that OS does based on the note time, instrument, length, or pitch that require extra work if you modify those parameters (namely "song.moveNote()" and "song.updateLoopTime()"). Failure to do so could corrupt your sequence. tweakNotes takes care of this work for you so you don't have to worry about it.

Whenever you make changes to the notes of a sequence (adding, removing, moving, etc), the changes won't be visible until the sequencer view is updated. You can either run "SequencerView.repaint()", or just move the view a bit (eg scroll). tweakNotes handles this for you, but in this example you need to do it manually.