MarkLens

View Markdown documents on iOS and macOS, with a Quick Look extension for fast previews in Finder.

Features

• GitHub Flavored Markdown rendering with syntax highlighting and copy buttons for code blocks.
• LaTeX math rendering with KaTeX and Mermaid diagram rendering for fenced code blocks.
• Raw Markdown editing with toolbar shortcuts, search, and synchronized preview/source scrolling.
• Local links and images, plus wiki-style links and in-app wiki navigation on macOS.
• Customizable preview typography, content width, and CSS on macOS.
• PDF and portable HTML export bundling app resources and local images on macOS, plus direct paginated review in Preview; remote content remains linked.
• Printing and page setup on macOS.
• Quick Look previews in Finder.

Requirements

Development requires Xcode 26 running on a compatible version of macOS.

MarkLens supports:

• macOS 15.6 or later
• iOS 17.6 or later

Build

Open the project:

open MarkLens.xcodeproj

Build the app from the command line:

xcodebuild -project MarkLens.xcodeproj -scheme MarkLens -configuration Debug build

Build the Quick Look extension:

xcodebuild -project MarkLens.xcodeproj -scheme QuickLookPreview_macOS -configuration Debug build

Test

Run the Markdown pipeline tests on any supported Swift development platform:

swift test --package-path MarkdownPipeline

Run the app unit and UI tests on macOS:

xcodebuild -project MarkLens.xcodeproj -scheme MarkLens -destination 'platform=macOS' test

Project Layout

• MarkLens/ contains the SwiftUI app and app-specific web resources.
• QuickLookPreview_macOS/ contains the macOS Quick Look extension.
• MarkdownPipeline/ contains the shared Markdown renderer, bundled web assets, and pipeline tests.
• Shared/ contains Swift code shared by the app and extension.
• MarkLensTests/ and MarkLensUITests/ contain app integration and UI tests.

Future Tasks

• Consider adding a custom print panel accessory for header/footer toggles and margin presets.

License

MIT. See LICENSE.

Third-Party Notices

See THIRD_PARTY_NOTICES.