F4) or a pair the axis sits between (D4/E4).Leave blank to let the generator choose a window around the cantus firmus.
The method adds an imaginary cantus firmus (ICF): a copy of your cantus firmus shifted by the opposite of the canon's interval and distance of entrance. The vertical interval between the cantus firmus and the ICF at each measure is the guide interval — it governs which proposta notes are admissible.
A proposta note works when it is consonant with the cantus firmus and with the ICF (which guarantees the risposta will be consonant with the cantus firmus later), and consonant with any risposta already sounding. The generator also avoids parallel fifths and octaves.
This version writes a whole-note framework only (one note per voice per measure). Generation is strictly diatonic: review the result for diminished fifths or tritones and add accidentals where the style needs them. Imitation in the last measures is left free for the cadence.