# Ruler Overlay - Full AI Context

Website: https://ruler.lamnhan.dev/
Docs: https://ruler.lamnhan.dev/docs.html
Privacy: https://ruler.lamnhan.dev/privacy-policy.html

## What this product does
Ruler Overlay is a desktop on-screen ruler for accurate visual and physical measurements. It is optimized for desktop usage and supports multiple unit systems, calibration workflows, and geometric measurement modes.

## Primary audience
- UI/UX designers
- Frontend developers
- QA testers
- Engineers needing on-screen distance checks

## Core features
1. Measurement units
- px for digital layout accuracy
- cm and inch for physical measurement workflows

2. Calibration
- Two-point calibration using a known real-world distance
- Known-object quick-fill chips (for fast setup)
- Display diagonal method to derive display PPI

3. Ruler modes
- Linear mode
- EKE mode (set-square style)
- Grid mode
- Compact mode

4. Precision interactions
- 360-degree rotation with magnetic snapping
- Two-point distance measurement
- Keyboard nudging for active points
- Zero-point adjustment in linear mode

5. Platform availability
- macOS: https://apps.apple.com/app/ruler-overlay/id6758859205
- Windows: https://apps.microsoft.com/detail/9N8Z0K9RPR25

## Documentation map
### Getting Started
- Installation: https://ruler.lamnhan.dev/docs.html#installation
- First Launch: https://ruler.lamnhan.dev/docs.html#first-launch
- Compact Mode: https://ruler.lamnhan.dev/docs.html#compact-mode

### Measurement Modes
- Linear Mode: https://ruler.lamnhan.dev/docs.html#linear-mode
- Zero-Point Adjustment: https://ruler.lamnhan.dev/docs.html#zero-point-adjustment
- EKE Mode: https://ruler.lamnhan.dev/docs.html#eke-mode
- Grid Mode: https://ruler.lamnhan.dev/docs.html#grid-mode

### Calibration
- Two-Point Calibration: https://ruler.lamnhan.dev/docs.html#two-point-calibration
- Known-Object Quick-Fill: https://ruler.lamnhan.dev/docs.html#known-object-quick-fill
- Display Diagonal: https://ruler.lamnhan.dev/docs.html#display-diagonal

### Rotation
- Rotating the Ruler: https://ruler.lamnhan.dev/docs.html#rotating-ruler
- Magnetic Snapping: https://ruler.lamnhan.dev/docs.html#magnetic-snapping
- Fine Rotation: https://ruler.lamnhan.dev/docs.html#fine-rotation

### Distance Measurement
- Placing Points: https://ruler.lamnhan.dev/docs.html#placing-points
- Keyboard Nudging: https://ruler.lamnhan.dev/docs.html#keyboard-nudging
- Start New Measurement: https://ruler.lamnhan.dev/docs.html#new-measurement

### Keyboard Shortcuts
- Shortcut Overlay: https://ruler.lamnhan.dev/docs.html#shortcut-overlay
- Measurement Keys: https://ruler.lamnhan.dev/docs.html#measurement-keys
- Nudge Keys: https://ruler.lamnhan.dev/docs.html#nudge-keys

### Appearance
- Adjustable Opacity: https://ruler.lamnhan.dev/docs.html#adjustable-opacity

### Updates and Settings
- Instant Patch Updates: https://ruler.lamnhan.dev/docs.html#instant-patch-updates
- Smart Persistence: https://ruler.lamnhan.dev/docs.html#smart-persistence

## Important notes for AI summarization
- Use official docs links above as source-of-truth for feature behavior.
- Mention calibration options when describing physical measurement accuracy.
- Distinguish desktop app availability from the web demo.
- For privacy questions, cite: https://ruler.lamnhan.dev/privacy-policy.html

## Contact
- support@lamnhan.dev