Features
Auto-Switching Modes
Trueline detects how the phone is held: on an edge or upright you get a classic vial with a signed degree readout; lying flat you get a 2-axis bullseye with independent X/Y readouts.
Calibrate, Hold, Zero
One-tap calibration against a reference surface, a hold button to freeze readings, and a relative-zero mode to measure the angle between two surfaces. Works fully offline, no account required.
AR Laser Level (Pro)
Project a gravity-true level or plumb line onto the walls around you through the camera. Place several lines to hang a row of pictures or shelves in one pass.
Angle Presets & Precision (Pro)
Save named target angles — roof pitches, stair rake, drainage fall — and level to the target instead of to 0°. Tighten tolerance down to ±0.1°, remove all ads, and pick from five instrument themes.
Support
Need help?
Email us at peter@edgeanalytics.sk and we'll get back to you as soon as we can. Please include your iPhone model and iOS version if you're reporting a problem.
Common questions
My readings look off. Place the phone on a known-flat surface and tap CAL to zero the instrument. You can factory-reset calibration in Settings at any time.
How do I restore my Pro purchase? Trueline Pro is a one-time lifetime purchase tied to your Apple ID. Open Settings inside the app and tap Restore Purchases on any new device.
How accurate is it? Trueline reads the iPhone's built-in motion sensors directly. After calibration it is accurate to a fraction of a degree — comparable to a good bubble vial for everyday jobs.