Ruler Overlay Documentation (Static Index)
This is a lightweight static index for crawlers and no-JavaScript readers. For interactive demos and full step-by-step guides, see the full documentation.
Installation & First Launch
Install Ruler Overlay from the Mac App Store or Microsoft Store, launch it, and start in
px mode for digital work. Use Compact Mode to reduce visual chrome on dense screens.
Linear Mode
Classic horizontal ruler for spacing, margins, and alignment. Drag edges to resize, drag the body to move.
Zero-Point Adjustment
Hover near the tick/delimiter area, then drag or scroll to shift where measurement starts without resizing. Snaps to left edge, center, and right edge.
EKE Set-Square Mode
Orthogonal alignment guides with x/y coordinate readouts and vertical guide lines for layout work.
Grid Mode
Adaptive grid overlay for spacing rhythm checks and proportional alignment verification.
Two-Point Calibration
Click two points on screen, enter the known real-world distance, and the app derives the exact scale factor for cm/inch accuracy.
Display Diagonal Entry
Enter your monitor diagonal (e.g. 27 in) to derive PPI from screen resolution — ideal for external monitors with incorrect OS DPI. Known-object chips (credit card 85.6 mm, A4 210 mm) can pre-fill the reference distance.
Rotating the Ruler
Smooth 360-degree rotation via the rotation handle for diagonal alignment work.
Magnetic Snapping
Rotation snaps magnetically around 15-degree increments with fine control between snap points.
Placing Measurement Points
Place points A and B to read straight-line distance in the current unit. Arrow keys nudge (1 px in px mode), Shift for ×10, Alt/Option for ×0.1. A third click starts a new measurement.
Keyboard Shortcuts
Built-in shortcut overlay covers starting/stopping measurements, cancelling with Esc, nudging points,
and adjusting opacity with [ and ].
Adjustable Opacity & Color
Toolbar slider adjusts opacity in 1% steps; a combined color control tunes ruler foreground and background. Preferences persist across restarts.
Instant Patch Updates
Shorebird OTA patches download in the background; restart from the toolbar to apply. No store wait for minor patches.