@libraz/libcantus - v1.1.0
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    Function createsHiddenParallelPerfect

    • Whether two voices reach a perfect interval by similar motion from an imperfect one (a hidden/direct fifth or octave).

      How strictly the approach is judged is the caller's to say, because the two textures do not agree about it:

      • fourPart (the default) applies the step exception of the chorale — the approach is allowed when the upper of the two voices moves by step, so only leaps into the perfect interval are flagged. That exception is written for the outer voices of a four-part texture, where the other two cover the arrival.
      • twoVoice exempts no approach. With nothing between them, two voices moving the same way into a perfect fifth or octave expose it however the upper one got there, and strict sixteenth-century writing forbids it outright.

      Parameters

      Returns boolean

    • Whether two voices reach a perfect interval by similar motion from an imperfect one (a hidden/direct fifth or octave).

      How strictly the approach is judged is the caller's to say, because the two textures do not agree about it:

      • fourPart (the default) applies the step exception of the chorale — the approach is allowed when the upper of the two voices moves by step, so only leaps into the perfect interval are flagged. That exception is written for the outer voices of a four-part texture, where the other two cover the arrival.
      • twoVoice exempts no approach. With nothing between them, two voices moving the same way into a perfect fifth or octave expose it however the upper one got there, and strict sixteenth-century writing forbids it outright.

      Parameters

      • aPrev: number
      • aCur: number
      • bPrev: number
      • bCur: number
      • Optionalstrictness: "twoVoice" | "fourPart"

        Which reading to judge the approach by.

      Returns boolean