Absolutely awesome!

If you need quick and simple but precise measurements, or if you need to check alignment in a web page or PDF while creating it in code, whether on the desktop or in an app displayed full screen with mission control — this is the best there is!

Most ruler apps don’t work when what you need to measure is displayed full screen using mission control. Euclid does!

JBR 2012 about Euclid, v1.3