Markdown Previewer Extension

A VSCode extension that provides enhanced markdown preview functionality with GitHub-style rendering, auto-preview capabilities, and intuitive mode switching.

Latest Update: Version 1.1.5 adds keyboard shortcut support (Alt+M / Option+M) for seamless mode switching.

✨ Features

🚀 Auto-Preview System

• Smart File Opening: Click any .md file in the file browser
  • "Preview First" mode: Opens as rendered preview
  • "Code First" mode: Opens as raw markdown
• Seamless Mode Switching: Toggle between preview ↔ code in the same panel

✅ Interactive Elements

• Live Checkboxes: Click checkboxes in preview to update source markdown automatically
• Save from Preview: Press Ctrl+S (Cmd+S on Mac) to save directly from preview mode
• Mermaid.js Diagrams: Full support for flowcharts, sequence diagrams, and more
• GIF Support: Full animated GIF rendering for both local and remote images
• Position Sync: Bidirectional scroll synchronization between preview and code editor
• Smart Mode Switching: Preview closure automatically switches to code-first mode

🎨 Beautiful Themes

• GitHub Light Theme: Clean, professional styling matching GitHub's markdown rendering
• Dracula Dark Theme: Beautiful dark mode with authentic Dracula colors
• Instant Theme Switching: Right-click in preview to toggle themes
• Persistent Preferences: Theme choice saved across VSCode sessions

🎬 Image & GIF Support

• Animated GIFs: Full support for animated GIF rendering with proper animation
• Local & Remote: Support for both local files and remote URLs
• All Formats: GIF, PNG, JPG, JPEG, SVG, WebP with responsive sizing
• Theme Compatible: Images display in both light and dark themes

🖱️ Intuitive Context Menus

• Right-click in Preview:
  • Toggle Mode (Preview ↔ Code)
  • Toggle Theme (Light/Dark)
• Right-click in Markdown Editor:
  • Toggle Mode (Preview ↔ Code)
  • Open Preview

⌨️ Keyboard Shortcuts & Commands

• Alt+M / Option+M: Quick toggle between Preview ↔ Code modes
• Command Palette via Cmd+Shift+P (Mac) / Ctrl+Shift+P (Windows):
  • "Markdown Previewer: Open Preview"
  • "Markdown Previewer: Toggle Mode (Preview ↔ Code)"
  • "Markdown Previewer: Toggle Theme (Light/Dark)"

🛠️ Installation & Usage

Development Mode

1. Clone this repository
2. Open in VSCode
3. Run npm install to install dependencies
4. Press F5 to launch in Extension Development Host
5. Open any .md file to see the extension in action!

Using the Extension

1. Open a markdown file - It will automatically open in preview mode (if "Preview First" is set)
2. Right-click for options:
   • In preview: Toggle to code view or switch themes
   • In editor: Toggle to preview or open preview panel
3. Use keyboard shortcuts: Press Alt+M (Windows/Linux) or Option+M (Mac) to toggle modes
4. Use Command Palette: Cmd+Shift+P → "Markdown Previewer" commands

📁 Project Structure

├── src/
│   ├── extension-standalone.ts  # Complete extension implementation
│   ├── previewManager.ts        # Preview panel management (legacy)
│   ├── themeManager.ts          # Theme handling (legacy)
│   ├── statusBarManager.ts      # Status bar integration (legacy)
│   └── *.test.ts               # Comprehensive test suite
├── dist/
│   └── extension-standalone.js  # Compiled extension bundle
├── package.json                 # Extension manifest & configuration
├── webpack.config.js           # Build configuration
├── tsconfig.json               # TypeScript configuration
└── markdown-previewer-enhanced.vsix  # Final extension package

🧪 Development Commands

• npm run compile - Compile with webpack
• npm run watch - Watch mode compilation
• npm run package - Production build
• npm test - Run test suite
• npm run lint - Run ESLint
• npx vsce package - Create VSIX extension package

🎯 Configuration

The extension provides these settings:

• markdownPreviewer.defaultMode: Set default mode ("preview-first" or "code-first")
• markdownPreviewer.defaultTheme: Set default theme ("light" or "dark")
• markdownPreviewer.showModeNotifications: Show status messages when switching modes

🚀 What Makes This Special

• Zero Configuration: Works out of the box with sensible defaults
• GitHub-Style Rendering: Authentic GitHub markdown styling with Dracula dark theme
• Interactive Elements: Live checkboxes and Mermaid.js diagram support
• Position Sync: Bidirectional scroll synchronization between preview and editor
• Smart Workflow: Automatic mode switching and persistent preferences
• Intuitive UX: Right-click context menus make everything discoverable
• Performance Optimized: Efficient rendering and memory management
• Seamless Integration: Works perfectly with VSCode's existing markdown ecosystem
• Production Ready: Thoroughly tested and debugged for reliability

🤝 Contributing

The core functionality is complete, but contributions for additional features are welcome:

• PDF export functionality
• Custom CSS themes
• Additional markdown extensions
• Performance improvements

📄 License

This project is open source and available under the MIT License.

🎉 Enjoy your beautiful markdown previewing experience!