MkDown

A minimal macOS Markdown editor with live split-pane preview, multi-tab support, dark mode, and pinch-to-zoom — inspired by MacDown.

Features

• Split-pane layout — edit Markdown on the left, see the rendered result on the right in real time
• Multi-tab — open multiple files simultaneously; ⌘T new tab, ⌘W close tab, ⌘1–⌘9 / ⌘⇧[ / ⌘⇧] to switch
• Drag & drop — drag .md files directly into the window to open them in a new tab
• Syntax highlighting — headers, bold, italic, code blocks, links highlighted in the editor; colours adapt to light/dark theme automatically
• Dark / Light / Auto theme — follows macOS system appearance, or set manually via the View menu
• Pinch-to-zoom — use a two-finger trackpad gesture to zoom the preview
• Chinese-friendly font — preview uses PingFang TC (蘋方-繁) for comfortable Traditional Chinese reading
• Code block highlighting — fenced code blocks are syntax-coloured via Pygments (friendly / monokai styles for light / dark mode)
• WCAG AAA contrast — all foreground/background colour pairs meet WCAG AA/AAA contrast requirements in both themes
• Export to PDF — full-fidelity PDF output via Qt's print engine
• Export to HTML — self-contained HTML file with all styles embedded
• Open from CLI — python3 main.py README.md
• GFM support — tables, task lists, footnotes, definition lists, admonitions

Screenshots

Light mode	Dark mode

Requirements

• macOS 11 or later
• Python 3.10+

Quick start

git clone https://github.com/AndyJuang/mkdown.git
cd mkdown
pip install -r requirements.txt
python3 main.py

Install as a native .app

Build a self-contained macOS application bundle with PyInstaller:

pip install pyinstaller pillow
python3 make_icon.py          # generates MkDown.icns
pyinstaller MkDown.spec --clean -y
open dist/MkDown.app

The resulting dist/MkDown.app can be copied to /Applications.

First-launch note: macOS may show an "unidentified developer" warning because the binary is not notarised.
Right-click → Open → Open to bypass it, or go to System Settings → Privacy & Security and click Open Anyway.

Keyboard shortcuts

Action	Shortcut
New tab	⌘T
Close tab	⌘W
Open file	⌘O
Save	⌘S
Save As	⌘⇧S
Export PDF	⌘⇧P
Export HTML	⌘⇧H
Toggle preview	⌘⇧M
Switch to tab N	⌘1 – ⌘9
Previous tab	⌘⇧[
Next tab	⌘⇧]
Zoom in	⌘=
Zoom out	⌘–
Reset zoom	⌘0

Project structure

mkdown/
├── main.py          # Entry point + macOS Apple Event handler
├── window.py        # Main window, tab management, menus, file operations
├── editor.py        # Code editor widget with line numbers & syntax highlight
├── highlighter.py   # QSyntaxHighlighter for Markdown (theme-aware)
├── preview.py       # Live preview widget (QTextBrowser + Pygments)
├── theme.py         # Light / dark / auto theme manager
├── wcag_fix.py      # WCAG contrast audit & colour adjustment script
├── requirements.txt
└── MkDown.spec      # PyInstaller build spec

Dependencies

Package	Purpose
PyQt5	GUI framework
Markdown	Markdown → HTML rendering
Pygments	Syntax highlighting for code blocks

License

MIT