31 EDO Retuner plugin for Musescore 2 / 3

Musescore plugin to automatically retune notes in 31-EDO

Usage

To retune the entire score as is, run the plugin located in Plugins > 31-TET > Retune 31-TET

To only retune certain notes / parts, make a selection before running the plugin.

Depending on the type of notation you prefer, you may use the QML scripts for ups-and-downs notation which uses these accidentals or the quartertone-accidental 1/4-comma meantone approximation notation which uses these accidentals.

You may enable both QML files simultaneously and both of the modes will show up in the plugin menu.

Accidentals

Ups and Downs notation (diatonic enharmonic equivalent)

In ups and downs notation mode, these are the accidentals used by the plugin. They can be found in the advanced palette.

Diesis steps	Accidental
-5
-4
-3
-2
-1	or
0
+1	or
+2
+3
+4
+5

Important: This notation differs from the more conventional meantone notation which uses quarter-tone accidentals instead.

The benefits of using this notation over meantone is that it allows for proper spelling of notes and chords in all 31 keys as it still supports enharmonic diatonic-tone equivalents by means of the double flat and double sharp accidentals.

1/4-comma meantone approximation (quarter-tone accidentals)

When using the meantone version of the plugin, these are the accidentals used by the plugin.

Diesis steps	Accidental
-4
-3
-2
-1
0
+1
+2
+3
+4

Custom key signatures

As MuseScore doesn't completely support custom key signatures, any custom key signature can't be read by the plugin, at least for now.

Should you want to create a microtonal key signature and have it affect the playback, you have to explicitly declare the custom key signature using some accidental code:

Note that explicit accidentals will still take precedence over the declared custom key signature, behaving exactly the same way a key signature would.

Accidental Code

Diesis steps	accidental code (Ups-and-downs)	accidental code (1/4-comma meantone approximation)
-5	bb	None
-4	db	bb
-3	bv	db
-2	b	b
-1	b^ or v	d
0	Leave blank	Leave blank
1	^ or #v	+
2	#	#
3	#^	#+
4	#+	x
5	x	None

You can indicate custom key signatures in the score itself by entering super-special key signature code inside System Text or Staff Text.

• Use System Text (Ctrl + Shift + T) if you want the super-special key signature code to affect all staves from there onwards
• Use Staff Text (Shift + T) if you only want the code to affect the staff that it is on. This is especially useful when using custom local time signatures!
• Remember to make the custom key signature code invisible! (Press V to toggle visibility)

The syntax of this super-special key signature code is simple:

1. Start with a dot .
2. Put the required accidental for the note C using the accidental code
3. Put another dot .
4. Put the required accidental for D
5. Repeat from C thru B

Note that There must be seven . in total, natural accidentals are denoted by leaving the space blank, and spaces/newlines can be placed before or after the dots to improve readability.

For example: Ab-down major in ups-and-downs mode can be denoted like this: .v.bv.bv.v.v.bv.bv representing the key signature of Cv, Dbv, Ebv, Fv, Gv, Abv, Bbv.

IMPORTANT! Following a custom key signature, should there be a modulation to any standard key signature, it is still necessary to reset the custom key signature to the default, that is, ........ Otherwise, the previous custom key signature would still be in effect, as it is being overriden.

Note to self / developers:

Definitions:

tpc : Tonal pitch class

segment.annotations[idx].textStyleType : 22 if Staff Text, : 21 if System Text

segment.annotations[idx].text : Contains given text

TODO:

• Handle cross-staff notation (ctrl + shift + up/down in connected staves, e.g. grand staff) where note appears to be in another staff other than the cursor's staffIdx. Currently, accidentals in the cross-staff do not work on the notes that came from another staff. See Add Courtesy Accidentals plugin for how to do this
• Meantone mode
• Transpose Diesis up/down for both enharmonic up-and-downs mode and meantone mode
• Tonal-center / harmonic series based enharmonic equivalent switching for enharmonic up-and-downs mode (e.g. Cv = B# and C = B#^ = Dbb)
• Don't hard-code frequencies, just use a dictionary of exponential operations instead

Changes:

1.3.3

• Fixed custom key signatures not working if multiple annotations exist on same segment (caused by JavaScript insanity)

1.3.2

• Now supports MuseScore version 3!

1.3

• Removed unecessary GUI dialog --- planning to make a 31-TET suite of micro-plugin features which users can take advantage of custom-assigned plugin key bindings to improve workflow. (E.g. Alt + W to transpose up 1 diesis, Alt + S to transpose down 1 diesis, Alt + E to rotate enharmonical equivalents)
• Added meantone mode
• Fixed microtonal accidentals from notes in same staff not affecting subsequent notes of other voices in same staff in measure.

1.2

• Fixed non-naturalised explicit natural accidental in note affected by a custom key signature
• Added support for declaring custom key signature changes in SystemText/StaffText
• Added usage guide in this file
• Preparing for meantone quartertone-accidental mode support

1.1

• Fixed occassional bug where microtonal accidentals carry over the bar line when it shouldn't
• Attempted to fix UI bug in Windows, haven't tested it yet though :/