Two steps to perfect app

This app just turned my education process upside-down: no more tons of paper sheets and copybooks, only iPad. But I really dream about:
1) second mode of rubber to erase only a part of line
2) RULER, im so tired of using my phone/credit card/anything else to draw lines not in "add a picture" mode

Danil T. about Notability: Smarter AI Notes, v6.2.1