Support

Contact

For help or feedback, email xxyyyue@gmail.com.

Please include your device model, operating system version, app version, and steps to reproduce the issue. For measurement questions, include the ruler direction, reference length, and any display scaling changes. Avoid sending personal information unrelated to the issue.

Measure an object

1. Choose centimeters or inches.
2. Choose a horizontal or vertical ruler layout.
3. Move the green start guide and red end guide to the two ends of the object.
4. Read the distance and lock the guides if you want to keep them in place.
5. Use reset to return the start to 0 and the end to 40 mm, limited to the visible ruler range.

Measure from the zero mark on the screen, not the device edge. The object must fit within the visible ruler range.

Calibrate the ruler

1. Select the direction you want to calibrate, then open calibration using the control at the bottom right.
2. Choose a known length on a physical ruler. The default reference is 50 mm; you can enter another length.
3. Place the reference line parallel to your physical ruler. Use the slider and plus/minus buttons to align both ends with the known length.
4. Save calibration.
5. Switch direction and calibrate it separately.

Restoring the default clears manual calibration for the current display and direction only. Other saved directions and display modes are unaffected.

Why does the app ask for calibration?

Some devices and display configurations do not provide reliable physical dimensions. Simulator dimensions also do not represent physical device measurements. Use a physical ruler to calibrate when needed.

Leave full-screen mode

Use the collapse control on the ruler. You can still move both measurement guides and view the readout in full-screen mode.

Change displays

Check the scale after changing display scaling, switching screens, or noticing a mismatch. Use a physical ruler to check the scale and calibrate each direction when needed.

Calibration storage

Calibration settings are stored in local app preferences. TrueRuler does not provide cloud sync for calibration. System backup and restore may be controlled by your device settings. The current version does not save measurement history.

Measurement accuracy

Decimal places in the readout do not indicate certified accuracy. Actual accuracy depends on the device, display settings, reference, and calibration. Check results for your intended use.