MarkerOn

Lightweight screen annotation tool — press a hotkey to instantly draw, highlight, and annotate anywhere on your desktop.

中文

Download

Download Latest Release — pick the installer for your platform from the assets list.

After launching, the app runs silently in the system tray with no window shown.

Features

• Annotate anywhere — draw over any app, including the taskbar
• 8 tools — pen, highlighter, arrow, rectangle, ellipse, line, eraser, text
• Intuitive panel — press Space to toggle tools, colors, and stroke widths
• Full keyboard control — every action has a shortcut, no menus needed
• Preserve drawings — optionally keep annotations in memory after exiting, so you can resume where you left off

Lightweight & Fast

Built with Rust + Canvas, MarkerOn has an installer of just ~1.5 MB and a minimal memory footprint — no background daemons, no bloat. It responds instantly to your hotkey and renders annotations at full frame rate while consuming nearly zero system resources.

Keyboard Shortcuts

On macOS, use Command (⌘) in place of Ctrl, and Option (⌥) in place of Alt.

Global Shortcuts

Action	Windows	macOS
Toggle annotation mode	Ctrl + Shift + D	Command + Shift + D
Clear all annotations	Ctrl + Shift + C	Command + Shift + C

Tool Switching

Key	Tool	Key	Tool
1	Pen	5	Ellipse
2	Highlighter	6	Line
3	Arrow	7	Eraser
4	Rectangle	T	Text

Common Actions

Action	Windows	macOS
Settings panel	Space	Space
Copy screen	Ctrl + C	Command + C
Undo / Redo	Ctrl + Z / Y	Command + Z / Y
Stroke width	Ctrl + Scroll	Command + Scroll
Clear all	Delete	Delete
Exit	Esc	Esc

All shortcuts

Drawing with Modifier Keys

Draws	Windows	macOS
Current tool (default: pen)	Drag	Drag
Line	Alt + Drag	Option + Drag
Rectangle	Ctrl + Drag	Command + Drag
Square	Ctrl + Alt + Drag	Command + Option + Drag
Ellipse	Shift + Drag	Shift + Drag
Circle	Shift + Alt + Drag	Shift + Option + Drag
Arrow	Ctrl + Shift + Drag	Command + Shift + Drag

Edit & Move

Action	Effect
Hover over an element and drag	Move the element (enable "Allow dragging existing elements" in settings)
Double-click existing text	Re-enter edit mode for that text
Double-click empty area in T mode	Create a new text input at cursor position

Color Switching

Action	Effect
Q / E	Previous / Next color
Right-click	Open quick color picker at cursor

Other

Action	Windows	macOS
Stroke width	Ctrl + Scroll	Command + Scroll
Redo (alt)	Ctrl + Shift + Z	Command + Shift + Z
Switch window & exit	Alt + Tab	Command + Tab

Development

npm install
npm run dev
npm run build

Tech Stack

Technology	Role
Tauri v2	Desktop framework — Rust backend, system tray, global shortcuts, transparent always-on-top window
Vue 3	Frontend UI framework
Vite	Fast bundling and HMR
TypeScript	Full type safety
Canvas API	High-performance drawing engine

Project structure

markeron/
├── src-tauri/
│   ├── src/
│   │   └── lib.rs               # Rust backend — window management, shortcuts, tray
│   └── tauri.conf.json          # Tauri configuration
│
├── src/
│   ├── components/
│   │   ├── DrawingOverlay.vue   # Drawing overlay (Canvas + interactions)
│   │   ├── SettingsPanel.vue    # Annotation toolbar (tool / color / stroke)
│   │   ├── SettingsView.vue     # Settings window (shortcut config / sidebar layout)
│   │   └── TextBox.vue          # Inline text input
│   ├── composables/
│   │   └── useDrawing.ts        # Drawing engine (pen, shapes, text, undo/redo)
│   ├── types/
│   │   └── app.d.ts             # TypeScript type declarations
│   ├── App.vue                  # Root component
│   ├── main.ts                  # Renderer entry point
│   └── style.css                # Global styles
│
├── index.html                   # HTML entry
├── vite.config.ts               # Vite configuration
└── package.json

License

MIT