MarkdownRender

A native macOS command-line tool that renders Markdown files in a beautiful window with support for Mermaid diagrams and Graphviz graphs.

Features

• Native macOS window - Lightweight AppKit window with WebKit rendering
• Mermaid diagrams - Flowcharts, sequence diagrams, state diagrams, and more
• Graphviz/DOT support - Full DOT language support including colors, shapes, clusters, and styling
• Syntax highlighting - Code blocks with language-aware highlighting
• Dark/light mode - Follows system appearance or manual override
• Live reload - Watch mode for automatic refresh on file changes
• PDF export - Export rendered documents to PDF (Cmd+E)
• Keyboard shortcuts - Cmd+R (reload), Cmd+W (close), Cmd+±0 (zoom)

Installation

Build from source

Requires Xcode command-line tools and Swift 5.9+.

# Clone and build
git clone <repo-url>
cd MarkdownRender
swift build -c release

# Copy to your bin directory
cp .build/release/MarkdownRender ~/bin/

Usage

# Basic usage
MarkdownRender path/to/file.md

# Watch for changes (live reload)
MarkdownRender --watch path/to/file.md

# Force dark or light theme
MarkdownRender --theme dark path/to/file.md
MarkdownRender --theme light path/to/file.md

# Show help
MarkdownRender --help

Markdown Features

Standard CommonMark syntax is supported, plus:

Mermaid Diagrams

```mermaid
flowchart TD
    A[Start] --> B{Decision}
    B -->|Yes| C[OK]
    B -->|No| D[Cancel]
```

Graphviz/DOT Graphs

```dot
digraph G {
    rankdir=LR;
    node [shape=box, style="rounded,filled", fillcolor="#e8f4f8"];

    A -> B -> C;
}
```

Or use graphviz as the language identifier:

```graphviz
digraph G {
    A -> B;
}
```

Supported Graphviz Features

• All node shapes (box, circle, diamond, cylinder, etc.)
• Cluster subgraphs with custom styling
• Edge styles (solid, dashed, dotted, bold)
• Colors (fill, border, font)
• HTML-like labels with tables
• Multiple layout engines

Project Structure

MarkdownRender/
├── Package.swift                 # Swift Package Manager manifest
├── Sources/MarkdownRender/
│   ├── main.swift               # CLI entry point
│   ├── App/
│   │   └── AppDelegate.swift    # Window and app lifecycle
│   └── Rendering/
│       ├── MarkdownParser.swift # Markdown to HTML conversion
│       └── HTMLGenerator.swift  # HTML template and CSS
└── sample.md                    # Example markdown file

Dependencies

• swift-markdown - Apple's CommonMark parser
• swift-argument-parser - CLI argument parsing
• Mermaid.js - Diagram rendering (CDN)
• Viz.js - Graphviz rendering (CDN)
• Highlight.js - Syntax highlighting (CDN)

Requirements

• macOS 13.0 (Ventura) or later
• Internet connection (for CDN-hosted JavaScript libraries)

License

MIT