music-notation

Cross-Platform Music Notation API written in Swift. It is written so that it can be used in most any operating system, such as iOS, macOS, tvOS. Windows & Linux is aspirational at this point, but since the plan is to eschew all dependencies, this should not be much of a stretch. This library is being created with the goal of having 0 dependencies; not even Foundation.

music-notation is meant to implement the model and controller layers, which understands how music notation works. It will have no render capabilities, nor input/output. Those functionalities will be implemented in add-on packages.

See music-notation-render and music-notation-io as well as music-notation-import.

The goal is to provide these as Swift Package Manager based packages. Cocoapods and Carthage will no longer be supported. Manually adding the package into Xcode projects will still be supported.

Please consult this Swift style guide for coding style guidelines used in this repo and be sure to adhere to them.

There is a Slack channel you can join if you want to see more into the development process at Music Notation Swift Slack.

Contents

• 1. Features
• 2. Requirements
• 3. Installation
  • 3.1 Swift Package Manager
  • 3.2 Manual Installation
• 4. Getting Started
• 5. Configuration
• 6. Examples
• 7. Definitions
  • 7.1 Score
  • 7.2 Parts
  • 7.3 Staves
  • 7.4 Notes
    • 7.4.1 Duration
    • 7.4.2 Pitch
    • 7.4.3 Rests
  • 7.5 Measures
  • 7.6 Multiple Notes and Time
    • 7.6.1 More than one staff
    • 7.6.2 Multiple voices within a staff
  • 7.7 Lyrics
  • 7.8 Clefs
  • 7.9 Time Signatures
  • 7.10 Cue Notes
• 8. FAQ
• 9. Development Notes
  • 9.1 Code formatting and Linting
    • 9.1.1 Github actions
  • 9.2 Time & Note Chronology
• 10. Contributing
• 11. License
• 12. Attributions

1. Features

• ☑ Modern Swift API
• ☑ High Performance Music Notation modeling
• ☑ No 3rd party dependencies
• ☑ Comprehensive Unit and Performance Test Coverage
• ☑ Complete Documentation
• ☑ Modular Design for Package Based Extension

2. Requirements

• macOS 10.15+ / iOS 13+ / tvOS 13+ / watchOS 7+
• Swift 5.3+

Note please see Package.swift for the latest Requirements

3. Installation

music-notation can be installed using Swift Package Manager, or manually.

3.1 Swift Package Manager

Swift Package Manager requires Swift version 4.0 or higher. First, create a Package.swift file. It should look like:

dependencies: [
    .package(url: "https://github.com/music-notation-swift/music-notation.git", from: "0.2.9")
]

swift build should then pull in and compile music-notation for you to begin using.

3.1.1 Xcode SPM Support

You can also install SPM packages directly within your Xcode project.

3.2 Manual Installation

To install manually, you'll need to clone the music-notation repository. You can do this in a separate directory or you can make use of git submodules. Once this is done, you can just drop the files that are in the Sources/music-notation folder into your project. If you use a folder reference instead of a group, every time you pull from the source repository you will get any newly added files without having to determine if new files were added and then manually adding them.

NOTE: if you're targeting iOS 7, you'll have to install manually because embedded frameworks require a minimum deployment target of iOS 8 or OSX Mavericks.

4. Getting Started

WIP music-notation-import is currently the first real client and usage example for the package. It isn't on github yet, but as soon as it starts working, I will be selecting snippets to show here.

5. Configuration

WIP Since much of the concrete implementation will be in packages, this will be the main avenue for configuration.

6. Examples

WIP

7. Definitions

For the purpose of describing music and the parts that are modelled by this library, some definitions will be required. This will inform the name of the classes and structs that model these components.

7.1 Score

A score is description in music notation of a piece of music which contains one or more parts. It also contains descriptions which pertain to the score overall.

Examples include:

• Name of the score
• Name of the Artist
• Subtitle of the piece of music that the score describes.

Here is an example of (part of) a score (Beethoven - Symphony No. 9 Op. 125, downloaded from Musescore.com).

In the example you can see elements of the score as well as the staves that make up each of the individual parts.

7.2 Parts

A part models a single instrument in the score and as such describes the attributes of the Instrument, as well as part specific data, including one or more staves.

Examples include:

• Transposition data
• Which staves are present

Here are some examples of a part. In this case they are all a Piano part of a score made for illustration purposes.

• A part with a single staff (note: this shows the title, subtitle, and more)
• A part with a grand staff (treble and bass clef staves)
• A part with a single staff, as well as a slash notation staff and a Tablature staff

7.3 Staves

Music notation at its essense is represented by one or more staves. One staff consists of five horizontal lines, called staff lines:

7.4 Notes

Each staff usually contains a single melody, which often is played by a single instrument. A melody consists of a sequence of tones, which are to be played. Each tone is a sound, which a pitch and a duration, and the musician that plats the melody, is supposed to emit the sounds corresponding to these tones.

7.4.1 Duration

A note consist of a note head, an optional stem connected to the note head, and an optional flag or beam connected to the stem. The attributes of these decide the duration of a tone:

The duration of one whole note equals the duration of sixteen 16th notes, and so on. The speed, or tempo, of the music, is constant throughout a score. This means that each whole note in a score takes equally long time to play; this is usually between 1 and 4 seconds.

7.4.2 Pitch

The vertical position of a note head defines the tone’s frequency, or pitch. Each pitch is named with an alphabetic letter between a and g, followed by a number of ′ symbols; each ′ symbol denotes that the frequency is multiplied by two. Each staff line represents a pitch. Usually, the pitch on the middle line is b′; this is indicated by drawing a clef in the left edge of the staff. With other clefs, staff lines represent other pitches.

Notes that are typeset in the upper half of a staff, are often typeset upside down. This is a purely typographical decision, and does not affect the semantics of music.

7.4.3 Rests

Silence can be notated using rests. A rest works like a note, except that the musician is silent for the duration of the rest. Rests are notated with special symbols:

The vertical position of a rest has no significance, and unlike notes, rests can not be typeset upside down.

7.5 Measures

Notes are played in sequence, from left to right. Time is split into measures of equal duration, separated by bar lines. The duration of each measure is defined by the time signature, which denotes a fraction of a whole note and the meter at which these are accentuated. Until a new time signature is annotated, all the following measures are of the same time signature.

7.6 Multiple Notes and Time

When multiple notes are being played at the same time, it can occur because the notes are played as chords (harmony, as played by instruments that can play multiple notes at the same time, for instance a piano). It can also occur when two instruments are playing notes in different parts or even when they are being played from different staves in the same part.

7.6.1 More than one staff

A score normally consists of several connected staves, where each staff contains the music played by one instruments. Notes that are played at the same time, are always written in the same horizontal position:

Not only scores use several connected staves: For example, piano music normally uses two staves, containing the notes for the left and right hand, respectively. This can also be seen in guitar music, which needs two staves to be played accurately. One standard notation staff and one tablature staff.

7.6.2 Multiple voices within a staff

Sometimes multiple independant voices of an instrument appear in one staff; in this case, the stem direction decides which notes that should be played by which instrument. The notes with up and down stems are often called the upper and lower voice, respectively. The term “voice” originates from choral music, where this notation is common. Many software notation editors support 4 voices, and during editing are differentiated using colors for each voice.

As mentioned above, a single instrument can also play a chord, consisting of many simultaneous tones. This is notated by adding many note heads to the same stem:

7.7 Lyrics

Vocal music, such as songs, can be notated using music notation. This is done by writing the song text, or lyrics, below the staff that represents the melody to be sung. Each syllable is written right below the note it belongs to:

7.8 Clefs

Music notation has a variety of clefs to indicate what notes the staff lines represent. They all have a symbol within which a point is designated as the note choice.

For instance, the treble clef is a stylized letter G and the curly-cue of the G represents where the G note is on the staff line. See below where the stylized G points to the G staff line (note: this is a French Violin treble clefn).

The bass clef is similar and represents a stylized letter F and the two dots surround the staff line for F.

The alto clef is not similar but represents a stylized way of pointing to the staff in question.

And here a few of them on a staff for comparison.

7.9 Time Signatures

7.10 Cue Notes

8. FAQ

9. Development Notes

music-notation and the libraries that flesh out specific components based on it, are based on earlier work that can be found in:

• MusicNotationCore
• MusicNotationKit

music-notation and the add-on packages are first and foremost designed as Swift Package Manager packages and as such will not provide Xcode projects.

A notable exception is music-notation-import which is a macOS command line utility to parse various other formats and convert them into music-notation data structures. Import is primarily a consumer of the packages, which explains the choice of an Xcode project.

9.1 Code formatting and Linting

To avoid any conflicts with code formatting, a complete style guide has been provided, as well as project wide linting settings. Please use the base music-notation settings, and copy them into any sub-packages intact.

Each project should copy the Github Actions format of: build & test, code coverage, as well as linting badges so that developers can see at a glance whether the project is in a good state.

9.1.1 Github actions

music-notation as well as the sub-packages use Github Actions as a Continuous Integration system. Note the provided workflows. Each contributing repository should have at least the following actions:

• build-test.yml This action checks out the code and build it, as well as runs the tests. A badge appears on the repository indicating Pass/Fail.

• llvm-cov.yml This action checks out the code and runs the tests while capturing the code coverage. A badge appears on the repository indicating a coverage percentage.

• swiftlint.yml This action runs swiftlint on the code using the settings in the repository's .swiftlint.yml settings. These settings should be the same in every package and constitute the base code settings for all packages and projects in the music-notation family. A badge appears on the repository indicating Pass/Fail.

9.2 Time & Note Chronology

Since the music-notation allows for the entering of notes in any old order (within API constraints), and musical interpretation of those notes requires some sort of chronological ordering, which path to take?

Do we sort each note chronologically as they are added, or do we provide API for chronologically correct ordering.

If the latter course is taken, do we provide the ordering with a provided granularity?

For instance, do we provide an API that provides all of the notes in order per score, part, measure, staff, voice?

For now, an on demand note stream is the path music-notation is aiming for. It will provide the best path towards fulfilling the needs to the target audience for rendering and for semantic analysis.

10. Contributing

See CONTRIBUTING for guidelines to contribute back to music-notation. This might be a bit premature, but once things start working, please feel free to ask.

11. License

music-notation is released under the MIT license. See LICENSE for details.

12. Attributions

WIP This is where pointers to documentation attributions go.

Some of the descriptions of basic music theory comes from and/or is adapted from: • Separating input language and formatter in GNU Lilypond, Erik Sandberg [email protected] Master’s Thesis / Examensarbete NV3, 20 credits