MarkdownView

A native, blazing-fast macOS Markdown editor built with SwiftUI and NSTextView. Designed for developers who appreciate clean code, native performance, and modern macOS architecture.

✨ Features

• Extreme Performance: Direct NSTextView integration via NSViewRepresentable for maximum editing performance
• Native Document Architecture: DocumentGroup with FileDocument protocol for native document handling
• Split View Layout: Editor on left, preview on right with draggable divider
• Manual Preview Toggle: No live preview overhead - toggle when needed for performance
• Large File Support: Handles files up to 10MB effortlessly with native text engine
• Zero Dependencies: Pure Apple frameworks (SwiftUI, AppKit, Foundation)
• File Associations: Native support for .md, .markdown, .mdown extensions
• Dark Mode: Automatic system appearance support

🚀 Quick Start

# Clone the repository
git clone https://github.com/duhman/markdownview.git
cd markdownview

# Build the app
./build_app.sh

# Or build and install in one command
./build_app.sh release --install

# Launch MarkdownView
open MarkdownView.app

📋 Requirements

• macOS: 15.0+ (Sequoia)
• Swift: 6.1+
• Xcode: 16.0+ (Command Line Tools)

🛠️ Building from Source

One-Command Build

./build_app.sh

This creates MarkdownView.app in the project directory, ready to use.

Build and Install

./build_app.sh release --install

This builds a release version and copies it to /Applications/.

Manual Build

# Development build
swift build

# Release build
swift build -c release

# Run directly (for testing)
swift run

🎯 Setting as Default Markdown App

Option 1: Right-Click (Per File)

1. Right-click any Markdown file (.md, .markdown, .mdown)
2. Select Get Info (⌘+I)
3. Under Open with:, select MarkdownView
4. Click Change All... to apply to all Markdown files

Option 2: Command Line (All Markdown Files)

# Install duti if not already installed
brew install duti

# Set MarkdownView as default for all Markdown files
duti -s com.bigmac.markdownview net.daringfireball.markdown all

Option 3: System Settings

1. Open System Settings
2. Navigate to Desktop & Dock
3. Scroll to Default web browser (macOS uses this for document handlers too)
4. Select MarkdownView

🏗️ Architecture

Design Decisions

Component	Technology	Rationale
Build System	Swift Package Manager	No Xcode project, CI/CD friendly, reproducible builds
UI Framework	SwiftUI + DocumentGroup	Native document-based architecture, modern declarative UI
Text Engine	NSTextView via NSViewRepresentable	Maximum performance, handles large files effortlessly
Preview Engine	AttributedString with Markdown	Native SwiftUI rendering, no web views
Document Model	FileDocument	SwiftUI's native document protocol, automatic save/open
Layout	HSplitView	Native macOS split view with draggable divider

Project Structure

markdownview/
├── Package.swift                    # Swift Package Manager manifest
├── build_app.sh                     # App bundling & installation script
├── README.md                        # This file
├── .gitignore                       # Git ignore rules
├── Sources/
│   ├── MarkdownViewApp/
│   │   ├── MarkdownViewApp.swift    # @main App entry point
│   │   └── MarkdownDocument.swift   # FileDocument implementation
│   └── Views/
│       ├── ContentView.swift        # Main split view interface
│       ├── MarkdownEditorView.swift # NSTextView NSViewRepresentable bridge
│       └── MarkdownPreviewView.swift # AttributedString markdown preview
└── MarkdownView.app                 # Built app bundle

⌨️ Keyboard Shortcuts

Shortcut	Action
⌘+O	Open Markdown file
⌘+S	Save document
⌘+W	Close window
⌘+Q	Quit app
⌘+N	New document
Toolbar Eye Icon	Toggle preview pane

📦 Distribution

Local Installation

# Build and install to Applications
./build_app.sh release --install

# Or manually copy
cp -R MarkdownView.app /Applications/

# Or create symlink
ln -s $(pwd)/MarkdownView.app /Applications/MarkdownView.app

Sharing the App

The built MarkdownView.app is self-contained and can be:

• Copied to other Macs running macOS 15+
• Shared via AirDrop, Dropbox, etc.
• Installed by simply dragging to /Applications

Note: Since the app is ad-hoc signed, users may need to:

1. Right-click the app and select Open (first launch only)
2. Or run: xattr -cr MarkdownView.app to remove quarantine

🐛 Troubleshooting

App Won't Open

# Remove quarantine attribute
xattr -cr MarkdownView.app

# Or allow in System Settings > Privacy & Security

Markdown Files Not Opening

1. Check System Settings > Privacy & Security > Files and Folders
2. Ensure MarkdownView has access to the folder containing your files
3. Try opening via File > Open menu instead of double-click

Build Errors

# Clean build
swift package clean
rm -rf .build/

# Rebuild
./build_app.sh

📝 License

MIT License - See LICENSE file for details.

This is a personal project by @duhman.

🙏 Acknowledgments

• Built with Apple's AppKit and SwiftUI frameworks
• Uses native NSTextView for extreme editing performance
• Inspired by the macOS document-based app paradigm

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Made with ❤️ for macOS — Fast, native, no Electron, no bloat.