Draw a line as a reference length on the image. Once the reference is set you can measure any place on the image as relative length based on the reference.

Usage examples)
- Measuring arbitrary part of neighbour's car from blueprint
- Measuring the bath room size from floor plan
- Measuring the height of a celebrity who falsely claiming to be taller than he/she is.

The app is for 2D image, but you can transform perspective image into a plane so you can measure them (in that case you need to have TWO known lengths as vertical and horizontal as the reference)

FAQ
Q: Line length changes on scaling
A: Before setting a reference the line length is the same as screen pixel size. Please set the reference.

Q: I can't specify unit!!
A: You should know the unit because you type the reference. You can convert the length as centi-meter or percec whatever you want.

Q: After transforming the image flew away from the screen
A: It is because of the calcutation. Please try tweaking the transform shape.

Q: After transforming the lines shifted from the image
A: Transforming doesnot effect to lines. Draw lines after transforming.