Struct Key 

pub struct Key { /* private fields */ }

A tonal key with a tonic pitch and mode.

Implementations

impl Key

pub fn from_tonic_mode<'a, M>(tonic: &str, mode: M) -> Result<Self>

where M: Into<Option<&'a str>>,

Builds a key from a tonic and mode.

Pass a mode string such as "major", "minor", "dorian", or None::<&str> to infer major/minor from tonic case. Builds a key from a tonic name and a mode. Without a mode the name decides, as music21’s Key reads it: a trailing m is minor and a trailing M major (F#m, EM), otherwise a lower-case name is minor and an upper-case one major.

pub fn from_tonic(tonic: &str) -> Result<Self>

Builds a key and infers major/minor from tonic case.

pub fn tonic(&self) -> Pitch

Returns a cloned tonic pitch.

pub fn tonic_pitch(&self) -> &Pitch

Returns a borrowed tonic pitch.

pub fn mode(&self) -> &str

Returns the key mode.

pub fn transpose(&self, interval: &Interval) -> Result<Self>

Returns this key moved by the interval, keeping its mode.

pub fn as_scale(&self) -> Result<Scale>

Returns the Scale for this key’s mode on its tonic. Major and minor cover ionian and aeolian; the other church modes map to their scale types, and any other mode is an error.

pub fn tonic_pitch_name_with_case(&self) -> String

Returns the tonic name in music21’s case convention: upper case for major, lower case for minor, unchanged for other modes.

pub fn sharps(&self) -> IntegerType

Returns the number of sharps in the key signature.

pub fn key_signature(&self) -> KeySignature

Returns the matching key signature.

pub fn scale(&self) -> DiatonicScale

Returns the diatonic scale for this key.

pub fn pitch_from_degree(&self, degree: usize) -> Result<Pitch>

Returns the pitch at a one-based scale degree.

pub fn pitches(&self) -> Result<Vec<Pitch>>

Returns scale pitches from degree 1 through the octave.

pub fn triad_from_degree(&self, degree: usize) -> Result<Chord>

Builds the diatonic triad on a one-based degree.

pub fn seventh_chord_from_degree(&self, degree: usize) -> Result<Chord>

Builds the diatonic seventh chord on a one-based degree.

pub fn harmonized_triads(&self) -> Result<Vec<Chord>>

Returns all seven diatonic triads.

pub fn harmonized_sevenths(&self) -> Result<Vec<Chord>>

Returns all seven diatonic seventh chords.

pub fn derive_by_degree(&self, degree: usize, pitch: &Pitch) -> Result<Self>

Returns the relative major or minor key when applicable. Returns the key of the same mode in which pitch is the given scale degree: music21’s deriveByDegree, so C major with E as degree 5 is A major and A minor with C as degree 3 is A minor again.

pub fn derive_by_degree_of( &self, scale_type: ScaleType, degree: usize, pitch: &Pitch, ) -> Result<Self>

The same, reading the degree off a scale pattern the caller chooses rather than the key’s own.

music21 spells this as a settable .abstract on the key: the seventh degree of a minor key is a whole tone below the tonic in the natural form and a semitone below it in the harmonic form, so the key that has E as its seventh is F-sharp minor by one reading and F minor by the other. The key that comes back keeps this one’s mode either way.

pub fn relative(&self) -> Result<Self>

Returns the relative major or minor key – the one sharing this key’s signature. A mode that is neither answers with itself.

pub fn parallel(&self) -> Result<Self>

Returns the parallel major or minor key when applicable.

Trait Implementations

impl Clone for Key

fn clone(&self) -> Key

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Key

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Key

Available on crate feature serde only.

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl FromStr for Key

type Err = Error

The associated error which can be returned from parsing.

fn from_str(value: &str) -> Result<Self>

Parses a string s to return a value of this type.

impl Serialize for Key

Available on crate feature serde only.

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFrom<&str> for Key

type Error = Error

The type returned in the event of a conversion error.

fn try_from(value: &str) -> Result<Self>

Performs the conversion.

impl TryFrom<String> for Key

type Error = Error

The type returned in the event of a conversion error.

fn try_from(value: String) -> Result<Self>

Performs the conversion.