libdaw 0.2.0

A library for Rust for making programmable DAWs
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

mod parse;

use super::{resolve_state::ResolveState, NotePitch};
use crate::{
    metronome::{Beat, Metronome},
    nodes::instrument::Tone,
    parse::IResult,
    pitch::PitchStandard,
};
use nom::{combinator::all_consuming, error::convert_error, Finish as _};
use std::str::FromStr;

/// An absolute chord, contextually relevant.
#[derive(Debug, Clone)]
pub struct Chord {
    pub pitches: Vec<NotePitch>,

    // Conceptual length of the chord in beats
    pub length: Option<Beat>,

    // Actual playtime of the chord in beats, which will default to the length
    // usually.
    pub duration: Option<Beat>,
}

impl Chord {
    /// Resolve all the section's chords to playable instrument tones.
    /// The offset is the beat offset.
    pub(super) fn inner_tones<S>(
        &self,
        offset: Beat,
        metronome: &Metronome,
        pitch_standard: &S,
        mut state: ResolveState,
    ) -> impl Iterator<Item = Tone> + 'static
    where
        S: PitchStandard + ?Sized,
    {
        let start = metronome.beat_to_time(offset);
        let duration = self.inner_duration(&state);
        let end_beat = offset + duration;
        let end = metronome.beat_to_time(end_beat);
        let length = end - start;
        let pitches: Vec<_> = self
            .pitches
            .iter()
            .map(move |pitch| {
                let frequency = pitch_standard.resolve(&pitch.absolute(&state));
                pitch.update_state(&mut state);
                Tone {
                    start,
                    length,
                    frequency,
                }
            })
            .collect();
        pitches.into_iter()
    }

    /// Resolve all the section's chords to playable instrument tones.
    /// The offset is the beat offset.
    pub fn tones<S>(
        &self,
        offset: Beat,
        metronome: &Metronome,
        pitch_standard: &S,
    ) -> impl Iterator<Item = Tone> + 'static
    where
        S: PitchStandard + ?Sized,
    {
        self.inner_tones(offset, metronome, pitch_standard, Default::default())
    }

    pub(super) fn inner_length(&self, state: &ResolveState) -> Beat {
        self.length.unwrap_or(state.length)
    }

    pub(super) fn inner_duration(&self, state: &ResolveState) -> Beat {
        self.duration.or(self.length).unwrap_or(state.length)
    }
    pub fn length(&self) -> Beat {
        self.inner_length(&Default::default())
    }
    pub fn duration(&self) -> Beat {
        self.inner_duration(&Default::default())
    }

    pub fn parse(input: &str) -> IResult<&str, Self> {
        parse::chord(input)
    }
    pub(super) fn update_state(&self, state: &mut ResolveState) {
        state.length = self.inner_length(state);
    }
}

impl FromStr for Chord {
    type Err = String;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let chord = all_consuming(parse::chord)(s)
            .finish()
            .map_err(move |e| convert_error(s, e))?
            .1;
        Ok(chord)
    }
}