lerp static method
- FlutterLogoDecoration? a,
- FlutterLogoDecoration? b,
- double t
Linearly interpolate between two Flutter logo descriptions.
Interpolates both the color and the style in a continuous fashion.
If both values are null, this returns null. Otherwise, it returns a non-null value. If one of the values is null, then the result is obtained by scaling the other value's opacity and margin.
The t
argument represents position on the timeline, with 0.0 meaning
that the interpolation has not started, returning a
(or something
equivalent to a
), 1.0 meaning that the interpolation has finished,
returning b
(or something equivalent to b
), and values in between
meaning that the interpolation is at the relevant point on the timeline
between a
and 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).
Values for t
are usually obtained from an Animation<double>, such as
an AnimationController.
See also:
- Decoration.lerp, which interpolates between arbitrary decorations.
Implementation
static FlutterLogoDecoration? lerp(FlutterLogoDecoration? a, FlutterLogoDecoration? b, double t) {
assert(a == null || a.debugAssertIsValid());
assert(b == null || b.debugAssertIsValid());
if (identical(a, b)) {
return a;
}
if (a == null) {
return FlutterLogoDecoration._(
b!.textColor,
b.style,
b.margin * t,
b._position,
b._opacity * clampDouble(t, 0.0, 1.0),
);
}
if (b == null) {
return FlutterLogoDecoration._(
a.textColor,
a.style,
a.margin * t,
a._position,
a._opacity * clampDouble(1.0 - t, 0.0, 1.0),
);
}
if (t == 0.0) {
return a;
}
if (t == 1.0) {
return b;
}
return FlutterLogoDecoration._(
Color.lerp(a.textColor, b.textColor, t)!,
t < 0.5 ? a.style : b.style,
EdgeInsets.lerp(a.margin, b.margin, t)!,
a._position + (b._position - a._position) * t,
clampDouble(a._opacity + (b._opacity - a._opacity) * t, 0.0, 1.0),
);
}