Hannun User Guide

Getting started

• Open a file: double-click it in Finder (once Hannun is your default app), press ⌘O, drag a file onto the window, or pick from recent documents in the clock (⏱) menu
• New document: press ⌘N or click + in the tab bar. A scratch document opens right away — no save dialog. It's backed up automatically and is still there after you quit and reopen the app. Press ⌘S to save it as a regular file.
• Default app: in Settings › General › Default App, you can set Hannun as the default for Markdown, text, PDF, and data documents, one type at a time.

The window (Mac)

When there are more tabs than fit, the tab bar scrolls sideways (trackpad swipe or mouse wheel). Drag a tab to reorder it — the new order is kept the next time you open the app.

View modes — ⌘/

Cycles through Preview → Split → Editor.

• Preview: the rendered document, full window. Default for Markdown files
• Split: editor on the left, preview on the right. Drag the divider to resize; each tab remembers its position. Both sides scroll together
• Editor: the editor, full window. Default for .txt
• Data documents (.json .xml .yaml) have no Split view and switch between Preview ⇄ Editor only — see "Data View" below

Zoom

Same everywhere: pinch on the trackpad or ⌘ + scroll.

• Preview: page scale (zoom out to see more of the document at once)
• Editor: font size (10–24 pt)
• PDF: page scale
• Also works inside the image and diagram zoom window
• From the menu: ⌘ + / ⌘ − / ⌘ 0 (remembered separately for preview and editor)

Syntax Palette — hold ⌥ (Mac)

While editing, hold ⌥ (Option) and the palette opens at the bottom right. It's laid out like your keyboard; while you hold ⌥, press a key to apply that format. Every format is a toggle — press the same key again to remove it.

Keyboard shortcuts

Preview features

• Change fonts quickly: Click the "Aa" button in the toolbar to switch the body and heading fonts (serif or sans-serif) and the theme (automatic, light, or dark). It changes the same values as Settings › Preview, so your choice applies to every document and stays the next time you open Hannun.
• Table of contents: ⌘⇧T or the table of contents button — a sidebar on the left; drag to resize. Click an entry to jump to it
• Content width: Full / Wide / Medium / Narrow (the left-right arrow button)
• Zoom into images and diagrams: click to open a larger view. Drag to move, pinch or ⌘ + scroll to zoom, double-click to toggle fit ⇄ 100%, Esc to close. Switching to another tab closes it too
• Links between documents: clicking [doc](./other.md) opens it in a new tab (doc.md#section jumps to that heading). Web links open in your browser
• Supports Mermaid diagrams, math (KaTeX), and front matter cards

Editing features

• Full support for Korean, Japanese, and Chinese input (IME) — formatting never interferes while you compose characters
• Markdown syntax highlighting, line numbers, current line highlight
• Byte-for-byte saving — encoding, BOM, and line endings stay exactly as they were
• If text looks garbled, click the encoding in the status bar to reopen the file with a different encoding

Managing files

• Outside changes: when another app changes an open file, Hannun reloads it automatically. If you were editing, a banner asks what to do
• Unsaved edits are kept: if the app quits before you save, your edits come back — marked with ● — the next time you open it. Closing a tab with unsaved edits asks first
• Session restore: quit and reopen, and your tabs, view modes, and scroll positions are right where you left them
• Reopen a closed window (Mac): if you closed the window with the red button, choose Window › HANNUN in the menu bar
• Allow access to image folders: if a document's images don't show, click "Allow Folder…" in the banner at the top (a macOS security requirement)

PDF

• Page list: click the table of contents button to open page thumbnails — a left panel on Mac and iPad, a sheet on iPhone
• PDF files open in the built-in viewer (it remembers your page)
• Export Markdown to PDF: choose File › Export as PDF…, then in the save dialog, choose the format (one continuous page / A4 pages), scale, and whether to fit wide tables and diagrams to the page

Settings (⌘,)

• General: theme (Auto/Light/Dark) · language (Korean/English/Japanese/Chinese, applies after restart) · detect outside changes · default app · Automatically check for updates (free Mac version from our website only)
  • Default app — for types where Hannun is already the default, you'll see "Default" instead of a button
• Preview: content width · body typeface (Serif/Sans-serif) · heading typeface · font size · Data View (Source/Tree/List)
• Editor: monospaced font · font size

Supported files

• Every type opens the same ways — ⌘O, drag from Finder, the location button (Mac), the Files button (iPhone and iPad), or a link inside a document
• A link like [other doc](./other.md) inside a document also opens in a new Hannun tab, as long as it points to one of the types above

Data View (JSON · XML · YAML)

Data documents are read in the preview with collapsible sections. Choose how they look in Settings › Preview › Data View. Change it with a document open and it redraws on the spot.

• YAML shows in Source only and folds by indentation. Tree and List views for YAML are coming in an update
• Large files (more than 1,000 nodes) open with only the first two levels expanded
• Zoom, Find, PDF export, theme, and content width all work just as they do for Markdown
• Text inside a folded section isn't found by Find — it isn't on screen. Expand it first, then search
• You can't edit values in the preview. To make changes, press ⌘/ to switch to the editor, edit, and save with ⌘S

iPad · iPhone

• Open a file: tap the Files button and pick a document from the Files app. It opens in place, and your edits are saved to the original
• Documents shared to you: files you receive through Mail or a messaging app arrive as copies and open read-only. To edit one, save it to the Files app first and open that file
• Syntax Palette: tap the button at the bottom right of the editor
• Split View (iPad): editor and preview side by side — drag the divider to resize. Both sides scroll together
• Table of contents (iPhone): at the bottom right, above the Files button
• Find & Replace: on iPad, use the menu bar
• Zoom: pinch with two fingers