A lightweight screen magnifier and annotation overlay for Windows, inspired by Sysinternals ZoomIt, but with smoother zooming and a few extra presentation tools (laser ink, step badges, blur, timer).
Written in pure C++ (Win32 API + GDI+), no third-party dependencies.
- Cursor-centered Magnifier: Uses the Windows Magnification API (
MagSetFullscreenTransform) for hardware-accelerated zoom without lag. - On-screen Drawing: Freehand lines, arrows, rectangles, and highlighters.
- Step Badges: Numbered markers (1, 2, 3...) to guide walkthroughs or tutorials.
- Privacy Blur: Quickly redact tokens, passwords, or credentials on screen.
- Break Timer: A fullscreen overlay with a countdown clock for talks, webinars, or study sessions.
- Click-through Pin Mode: Keeps annotations on screen while letting you interact with underlying windows.
- Spotlight & Laser Ink: Dim everything except the cursor area, or draw strokes that fade out automatically after a second.
The default trigger key is Alt. Hold it down to access shortcuts:
| Action | Hotkey |
|---|---|
| Zoom in / out | Alt + Mouse Wheel |
| Draw Line | Alt + Left Click + Drag |
| Draw Arrow | Alt + Right Click + Drag |
| Snap angle (0° / 45° / 90°) | Alt + Shift + Drag |
| Draw Rectangle | Alt + Shift + Left Click |
| Drop Step Badge (1, 2...) | Alt + Middle Click |
| Text on screen | Alt + X (Enter to finish, Esc to cancel) |
| Toggle Highlighter | Alt + H |
| Toggle Blur Redaction | Alt + O |
| Laser Ink (auto-fade) | Alt + V |
| Spotlight mode | Alt + S |
| Whiteboard / Blackboard | Alt + W (cycles White -> Dark -> Off) |
| Keystroke HUD | Alt + K |
| Break Timer | Alt + T |
| Color Switch | Alt + R (Red) / G (Green) / B (Blue) / Y (Yellow) |
| Undo last stroke | Alt + Z |
| Full Screenshot | Alt + C |
| Crop Screenshot | Alt + Shift + C |
| Pin drawings | Alt + P (prevents clearing on release) |
| Reset / Exit active tool | Esc |
The trigger key and rectangle modifier can be rebound in Settings (right-click the tray icon).
- Scroll Wheel or
↑/↓adjusts time by ±1 minute. - Shift + Scroll or
Shift + ↑/↓adjusts by ±5 seconds. - Click the clock to type time directly (
3:50,10, etc.). - Space toggles pause, Esc dismisses the timer.
- Exclusive Fullscreen: LensIt uses a layered desktop window (
UpdateLayeredWindow) combined with the Windows Magnification engine. It will not render over games running in true exclusive fullscreen. If you need it over a game, switch the game to Borderless Windowed.
Requires Visual Studio 2022+ with the Desktop development with C++ workload.
- Clone the repo:
git clone https://github.com/akywaa/LensIt.git cd LensIt - Open
LensIt.vcxprojin Visual Studio. - Select Release / x64 and build (
Ctrl + Shift + B).
All linked libraries (magnification.lib, gdiplus.lib, dwmapi.lib) are included in the default Windows SDK.
MIT