Linearly interpolates from
this to another Decoration (which may be of
a different class).
This is called if
b's lerpTo did not know how to handle this class.
When implementing this method in subclasses, return null if this class
cannot interpolate from
b. In that case, lerp will apply a default
Supporting interpolating to null is recommended as the Decoration.lerp method uses this as a fallback when two classes can't interpolate between each other.
t argument represents position on the timeline, with 0.0 meaning
that the interpolation has not started, returning
this (or something
this), 1.0 meaning that the interpolation has finished,
b (or something equivalent to
b), and values in between
meaning that the interpolation is at the relevant point on the timeline
b. The interpolation can be extrapolated beyond 0.0
and 1.0, so negative values and values greater than 1.0 are valid (and can
easily be generated by curves such as Curves.elasticInOut).
Instead of calling this directly, use Decoration.lerp.
@protected Decoration lerpTo(Decoration b, double t) => null;