lerpTo method Null safety
Linearly interpolates from
this to another Gradient.
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
b is null, this must not return null. The base class implements this
by deferring to scale.
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 Gradient.lerp.
@override Gradient? lerpTo(Gradient? b, double t) => (b == null || (b is SweepSteps)) ? SweepSteps.lerp(this, b as SweepSteps?, t) : super.lerpTo(b, t);