Issue by Hixie
Wednesday Oct 21, 2015 at 16:51 GMT
Originally opened as https://github.com/flutter/engine/issues/1709

Rather than AnimatedValue being mutable, it should just represent a begin/end range and have an API that, given a value 0.0..1.0, returns a lerp over that range.

Alternatively, we could make AnimatedValue take an object that represents 0..1, a direction, and a change notification API, and exposes a value in the range begin..end and a change notification API. That way you would just plug AnimatedValues straight into the things they were animated by.