A Real Bubble Level
iOS iPhone Productivity
Seems that you want to fix your crooked picture frames.
This application turns your device into an amazing Bubble Level. Can be used also as a clinometer/inclinometer. We are giving this app for free, enjoy!
A spirit level or bubble level is an instrument designed to indicate whether a surface is level or plumb. Different types of spirit levels are used by carpenters, stone masons, bricklayers, other building trades workers, surveyors, millwrights and other metalworkers, and serious videographers.