I would love the ruler tool much more, if there were measurements in it. In order to create sketches with more realism, I would suggest to add centimeters/inches, to the ruler and degrees to the elipse. The feature of seeing the angle in which the ruler is located, is already really cool and useful. But now adding the measurements, whether you decide them to be an option can turn them on/off, or just plain out adding them permanently, would be really useful and appreciated.
Love the app, and I hope you consider my suggestion.
Thank you.