Lightweight open-source screen annotation tool with click-through mode
MarkerOn
Lightweight screen annotation tool (~1.5 MB) β press a hotkey (keyboard-first) to instantly draw, highlight, and annotate anywhere on your desktop. Built for demos, teaching, meetings, and screen recording.Free & open source. If MarkerOn saves you time in demos, teaching, or meetings, sponsor on Afdian β every contribution helps keep the project maintained.
Contents: Download Β· Quick Start Β· Features Β· Shortcuts Β· Feedback Β· Development
Download
Download Latest Release β pick the installer for your platform from the assets list.
Windows users can also install the Microsoft Store version with WinGet:
winget install --id 9N6623X973JV --source msstoreOfficial downloads are GitHub Releases and Microsoft Store. Third-party mirrors may be outdated or repackaged.
Quick Start
- Install and launch β MarkerOn runs in the system tray; no window appears.
- Enter annotation mode β press Ctrl + Shift + D (Command + Shift + D on macOS).
- Draw, then click through β use number keys for tools; press X to interact with apps below while keeping annotations visible; press Esc to exit.
New here? Press Space for the toolbar. See Keyboard Shortcuts for the full list.
Features
- Lightweight & fast β ~1.5 MB installer (Rust + Canvas), minimal memory, no background daemons
- Annotate anywhere β draw over any app, including the taskbar
- 8 tools β pen, highlighter, arrow, rectangle, ellipse, line, eraser, text
- Flexible toolbar β press Space to toggle, or enable always-on in Settings; compact panel with More to expand, undo, copy, and whiteboard actions in-panel; independent floating window with drawing / click-through toggles
- Click-through mode β interact with apps below while staying in the session; toggle via toolbar buttons, Ctrl+Shift+X (global), or X while drawing; disabled in whiteboard mode
- Full keyboard control β every action has a shortcut, no menus needed
- Preserve drawings β enable Keep after exit under Whiteboard & content to resume on re-enter
- Whiteboard mode β set default entry to whiteboard, or press W to toggle; content rules are in Whiteboard & content settings
- Whiteboard copy β copy the whiteboard as an image with Ctrl/Command + C
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Keyboard Shortcuts
On macOS, use Command (β) in place of Ctrl, and Option (β₯) 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 | | Toggle click-through mode | Ctrl + Shift + X | Command + Shift + X |
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 | | :--- | :--- | :--- | | Toolbar (toggle) | Space | Space | | Click-through (while drawing) | X | X | | Toolbar always-on / layout | Settings β General | Settings β General | | Copy screen / whiteboard | Ctrl + C | Command + C | | Whiteboard toggle | W | W | | Undo / Redo | Ctrl + Z / Y | Command + Z / Y | | Stroke width | Ctrl + Scroll | Command + Scroll (pen & shapes share; highlighter/eraser/text separate) | | 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 | | :--- | :--- | | Element dragging | In General settings: Off / Hover drag / Hold Ctrl to drag | | 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 | | :--- | :--- | :--- | | Redo (alt) | Ctrl + Shift + Z | Command + Shift + Z |
Advanced settings
In Settings β General (toolbar display, click-through, and stroke width β see Features):
- Whiteboard & content β default entry (screen / whiteboard), keep after exit, keep on W toggle
- Element dragging β off, hover to drag, or hold Ctrl/Command to drag (disabled while eraser is selected)
- Eraser mode β stroke (local erase) or object (delete whole elements when passing over)
- Angle snap step β snap interval for straight lines drawn with Alt
- Auto start β launch the app automatically at system startup
Feedback & Issues
- Bug reports: Settings β Diagnostics β export a report, then open a GitHub Issue
- Privacy: PRIVACY.md
Development
See CONTRIBUTING.md for prerequisites, setup, and the full workflow. Stack: Tauri v2 Β· Vue 3 Β· Vite Β· TypeScript Β· Canvas API
