OpenSheetMusic

A cross-platform, WYSIWYG sheet-music editor that composes, edits, plays back, and exports professional sheet music.

Built with TypeScript, React, VexFlow, and Tauri.

Features

• WYSIWYG Staff Editor: Drag-and-drop note entry, selection, copy/paste, multi-measure edit, undo/redo
• Multi-Staff Support: Piano grand staff, orchestral, choir templates
• Full Notation: Clefs, key/time signatures, tuplets, ties, slurs, beams, rests, articulations, dynamics, grace notes, chord symbols, lyrics, repeats, volta endings
• Playback: MIDI event scheduling, tempo automation, metronome, per-staff mute/solo
• Import/Export: MusicXML (round-trip), MIDI, native project file (.osmproj), PDF (print quality), WAV audio
• Accessibility: Keyboard navigation, screen-reader labels, high-contrast mode
• Cross-Platform: macOS .app/.dmg, Windows .exe/.msi, Linux .deb/.AppImage

Quick Start

Prerequisites

• Node.js 20+
• Rust (stable toolchain)
• Platform-specific dependencies for Tauri: see Tauri Prerequisites

Install & Run

npm ci
npm run dev

Build Desktop App

npm run build
npm run tauri:build

Run Tests

npm test

Check for Comments

npm run check:comments

Project Structure

OpenSheetMusic/
├── src/
│   ├── core/                  # Document model, mutations, I/O, playback
│   │   ├── document-model.ts  # Immutable score data types and constructors
│   │   ├── undo-manager.ts    # Snapshot-based undo/redo
│   │   ├── musicxml-io.ts     # MusicXML parser and serializer
│   │   ├── midi-converter.ts  # MIDI conversion
│   │   ├── playback-engine.ts # WebAudio playback
│   │   ├── pdf-exporter.ts    # PDF generation
│   │   ├── wav-exporter.ts    # WAV audio export
│   │   ├── project-file.ts    # Native .osmproj format
│   │   ├── score-mutations.ts # Immutable score operations
│   │   └── index.ts
│   ├── ui/                    # React UI components
│   │   ├── App.tsx            # Main application component
│   │   ├── ScoreRenderer.tsx  # VexFlow-based notation renderer
│   │   ├── Toolbar.tsx        # Editing toolbar
│   │   ├── StaffPanel.tsx     # Staff mixer panel
│   │   └── StatusBar.tsx      # Status bar
│   ├── main.tsx               # Entry point
│   └── styles.css             # Application styles
├── src-tauri/                 # Rust/Tauri backend
│   ├── src/
│   │   ├── main.rs            # Tauri application entry
│   │   └── midi_bridge.rs     # Native MIDI file handling
│   ├── Cargo.toml
│   └── tauri.conf.json
├── tests/                     # Unit tests
├── tools/                     # Build and CI tools
│   ├── check-no-comments.mjs  # Comment-free enforcement script
│   └── pre-commit             # Git pre-commit hook
├── .github/workflows/
│   └── release.yml            # CI/CD pipeline
├── package.json
├── tsconfig.json
├── vite.config.ts
├── CONTRIBUTING.md
├── CODE_OF_CONDUCT.md
└── LICENSE (MIT)

Architecture

Document Model

The score is represented as an immutable data structure. All mutations return new score objects, enabling simple snapshot-based undo/redo with the UndoManager.

Notation Rendering

VexFlow renders musical notation directly in SVG within the browser/Tauri webview. Only visible measures are rendered for performance with large scores.

Playback Engine

Uses the WebAudio API for synthesis. MIDI events are scheduled with deterministic timestamps for accurate playback. The Rust backend provides native MIDI file parsing and writing via the midly crate.

I/O Layer

• MusicXML: Bidirectional conversion targeting lossless round-trip fidelity
• MIDI: Score-to-MIDI and MIDI-to-Score conversion
• Project File: JSON-based .osmproj format preserving full score state
• PDF: Print-quality export via jsPDF
• WAV: Direct audio synthesis export

Keyboard Shortcuts

Key	Action
C-B	Add note (C through B at octave 4)
R	Add rest
1-6	Select duration (whole through 32nd)
Delete/Backspace	Delete selected element
Ctrl+Z	Undo
Ctrl+Shift+Z / Ctrl+Y	Redo
Ctrl+S	Save project
Ctrl+N	New score
Space	Play/Pause
Escape	Stop playback
Arrow Keys	Navigate staves and measures

CI/CD

The GitHub Actions pipeline (.github/workflows/release.yml):

1. Checks for comments in source files
2. Runs unit tests
3. Builds web assets
4. Builds Tauri desktop apps for macOS, Windows, and Linux
5. Creates a GitHub Release with downloadable artifacts (on tag push)

Code Signing

To enable code signing for releases, add these secrets to your GitHub repository:

macOS:

• APPLE_CERTIFICATE: Base64-encoded .p12 certificate
• APPLE_CERTIFICATE_PASSWORD: Certificate password
• APPLE_SIGNING_IDENTITY: Signing identity string
• APPLE_ID: Apple ID for notarization
• APPLE_PASSWORD: App-specific password

Windows:

• WINDOWS_CERTIFICATE: Base64-encoded .pfx certificate
• WINDOWS_CERTIFICATE_PASSWORD: Certificate password

The build will succeed without signing credentials but produce unsigned binaries.

Zero Comments Policy

All source files must contain zero comments. This is enforced by:

1. A CI job that scans all tracked source files
2. A pre-commit hook (tools/pre-commit)
3. The npm run check:comments script

To install the pre-commit hook:

cp tools/pre-commit .git/hooks/pre-commit
chmod +x .git/hooks/pre-commit

Dependencies

All dependencies are open-source:

Dependency	License	Purpose
React	MIT	UI framework
VexFlow	MIT	Music notation rendering
Tauri	MIT/Apache-2.0	Desktop app shell
jsPDF	MIT	PDF generation
uuid	MIT	ID generation
midly (Rust)	MIT	MIDI file parsing
Vite	MIT	Build tool
Vitest	MIT	Test framework

License

MIT License - see LICENSE for details.

Copyright (c) 2026 Zorvia