Table of Contents

• Meantonal
• Installation

Meantonal

Meantonal is a specification for representing pitch information in Western music, and a suite of tools for operating on this information. It's a small, focused library that aims to empower developers to build musical apps more easily.

Meantonal is:

• Flexible with I/O: easily ingest and translate between Scientific Pitch Notation, Helmholtz notation, ABC and Lilypond. Extract MIDI values at any time.
• Semantically nondestructive: the distinction between enharmonic notes such as $\sf{C}\sharp$ and $\sf{D}\flat$ is maintained. Things that don't behave the same way musically are not encoded the same way in Meantonal.
• Just vectors: under the hood pitches and intervals are 2d vectors. Operations are simple to understand, surprisingly powerful, and fast to execute.
• Tuning-agnostic: Target any meantone tuning system, not just 12-tone equal temperament. You want 31 tones per octave? Done.

Installation

Adding Meantonal to your project is as simple as copying the meantonal.h header file somewhere into your project's directory, which can be done via the following bash script:

curl https://meantonal.org/meantonal.h > meantonal.h

You must #define MEANTONAL in exactly one file before the first inclusion of meantonal.h:

// foo.c
#define MEANTONAL
#include "meantonal.h"

Pitch c4, e4; // declares but does not assign values to two Pitch vectors
Pitch g4 = { 28, 11 }; // directly initialises a Pitch
// assigning values
if (pitch_from_spn("C4", &c4))
    fprintf(stderr, "error parsing pitch from SPN");
if (pitch_from_spn("E4", &e4))
    fprintf(stderr, "error parsing pitch from SPN");

Interval M3 = interval_between(c4, e4); // creates a major 3rd Interval vector
Interval P5 = interval_between(c4, g5); // creates a perfect 5th interval vector

// etc.

After that, just include meantonal.h in any other files as needed.

// bar.c
#include "meantonal.h"

Pitch p;
if (pitch_from_spn("E4", &p))
    fprintf(stderr, "error parsing pitch from SPN");

MirrorAxis a;
if (axis_from_spn("C4", "G4"))
    fprintf(stderr, "error parsing pitch(s) from SPN when creating MirrorAxis");

pitch_invert(p, a); // p has been inverted about the axis to Eb4

// etc.