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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:math' as math;
import 'package:flutter/foundation.dart';
/// An easing curve, i.e. a mapping of the unit interval to the unit interval.
///
/// Easing curves are used to adjust the rate of change of an animation over
/// time, allowing them to speed up and slow down, rather than moving at a
/// constant rate.
///
/// A curve must map t=0.0 to 0.0 and t=1.0 to 1.0.
///
/// See also:
///
/// * [Curves], a collection of common animation easing curves.
/// * [CurveTween], which can be used to apply a [Curve] to an [Animation].
/// * [Canvas.drawArc], which draws an arc, and has nothing to do with easing
/// curves.
/// * [Animatable], for a more flexible interface that maps fractions to
/// arbitrary values.
@immutable
abstract class Curve {
/// Abstract const constructor. This constructor enables subclasses to provide
/// const constructors so that they can be used in const expressions.
const Curve();
/// Returns the value of the curve at point `t`.
///
/// This function must ensure the following:
/// - The value of `t` must be between 0.0 and 1.0
/// - Values of `t`=0.0 and `t`=1.0 must be mapped to 0.0 and 1.0,
/// respectively.
///
/// It is recommended that subclasses override [transformInternal] instead of
/// this function, as the above cases are already handled in the default
/// implementation of [transform], which delegates the remaining logic to
/// [transformInternal].
double transform(double t) {
assert(t >= 0.0 && t <= 1.0);
if (t == 0.0 || t == 1.0) {
return t;
}
return transformInternal(t);
}
/// Returns the value of the curve at point `t`, in cases where
/// 1.0 > `t` > 0.0.
@protected
double transformInternal(double t) {
throw UnimplementedError();
}
/// Returns a new curve that is the reversed inversion of this one.
///
/// This is often useful with [CurvedAnimation.reverseCurve].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_flipped.mp4}
///
/// See also:
///
/// * [FlippedCurve], the class that is used to implement this getter.
/// * [ReverseAnimation], which reverses an [Animation] rather than a [Curve].
/// * [CurvedAnimation], which can take a separate curve and reverse curve.
Curve get flipped => FlippedCurve(this);
@override
String toString() {
return '$runtimeType';
}
}
/// The identity map over the unit interval.
///
/// See [Curves.linear] for an instance of this class.
class _Linear extends Curve {
const _Linear._();
@override
double transformInternal(double t) => t;
}
/// A sawtooth curve that repeats a given number of times over the unit interval.
///
/// The curve rises linearly from 0.0 to 1.0 and then falls discontinuously back
/// to 0.0 each iteration.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_sawtooth.mp4}
class SawTooth extends Curve {
/// Creates a sawtooth curve.
///
/// The [count] argument must not be null.
const SawTooth(this.count) : assert(count != null);
/// The number of repetitions of the sawtooth pattern in the unit interval.
final int count;
@override
double transformInternal(double t) {
t *= count;
return t - t.truncateToDouble();
}
@override
String toString() {
return '$runtimeType($count)';
}
}
/// A curve that is 0.0 until [begin], then curved (according to [curve]) from
/// 0.0 at [begin] to 1.0 at [end], then remains 1.0 past [end].
///
/// An [Interval] can be used to delay an animation. For example, a six second
/// animation that uses an [Interval] with its [begin] set to 0.5 and its [end]
/// set to 1.0 will essentially become a three-second animation that starts
/// three seconds later.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_interval.mp4}
class Interval extends Curve {
/// Creates an interval curve.
///
/// The arguments must not be null.
const Interval(this.begin, this.end, { this.curve = Curves.linear })
: assert(begin != null),
assert(end != null),
assert(curve != null);
/// The largest value for which this interval is 0.0.
///
/// From t=0.0 to t=`begin`, the interval's value is 0.0.
final double begin;
/// The smallest value for which this interval is 1.0.
///
/// From t=`end` to t=1.0, the interval's value is 1.0.
final double end;
/// The curve to apply between [begin] and [end].
final Curve curve;
@override
double transformInternal(double t) {
assert(begin >= 0.0);
assert(begin <= 1.0);
assert(end >= 0.0);
assert(end <= 1.0);
assert(end >= begin);
t = ((t - begin) / (end - begin)).clamp(0.0, 1.0);
if (t == 0.0 || t == 1.0)
return t;
return curve.transform(t);
}
@override
String toString() {
if (curve is! _Linear)
return '$runtimeType($begin\u22EF$end)\u27A9$curve';
return '$runtimeType($begin\u22EF$end)';
}
}
/// A curve that is 0.0 until it hits the threshold, then it jumps to 1.0.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_threshold.mp4}
class Threshold extends Curve {
/// Creates a threshold curve.
///
/// The [threshold] argument must not be null.
const Threshold(this.threshold) : assert(threshold != null);
/// The value before which the curve is 0.0 and after which the curve is 1.0.
///
/// When t is exactly [threshold], the curve has the value 1.0.
final double threshold;
@override
double transformInternal(double t) {
assert(threshold >= 0.0);
assert(threshold <= 1.0);
return t < threshold ? 0.0 : 1.0;
}
}
/// A cubic polynomial mapping of the unit interval.
///
/// The [Curves] class contains some commonly used cubic curves:
///
/// * [Curves.ease]
/// * [Curves.easeIn]
/// * [Curves.easeOut]
/// * [Curves.easeInOut]
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out.mp4}
///
/// The [Cubic] class implements third-order Bézier curves.
class Cubic extends Curve {
/// Creates a cubic curve.
///
/// Rather than creating a new instance, consider using one of the common
/// cubic curves in [Curves].
///
/// The [a], [b], [c], and [d] arguments must not be null.
const Cubic(this.a, this.b, this.c, this.d)
: assert(a != null),
assert(b != null),
assert(c != null),
assert(d != null);
/// The x coordinate of the first control point.
///
/// The line through the point (0, 0) and the first control point is tangent
/// to the curve at the point (0, 0).
final double a;
/// The y coordinate of the first control point.
///
/// The line through the point (0, 0) and the first control point is tangent
/// to the curve at the point (0, 0).
final double b;
/// The x coordinate of the second control point.
///
/// The line through the point (1, 1) and the second control point is tangent
/// to the curve at the point (1, 1).
final double c;
/// The y coordinate of the second control point.
///
/// The line through the point (1, 1) and the second control point is tangent
/// to the curve at the point (1, 1).
final double d;
static const double _cubicErrorBound = 0.001;
double _evaluateCubic(double a, double b, double m) {
return 3 * a * (1 - m) * (1 - m) * m +
3 * b * (1 - m) * m * m +
m * m * m;
}
@override
double transformInternal(double t) {
double start = 0.0;
double end = 1.0;
while (true) {
final double midpoint = (start + end) / 2;
final double estimate = _evaluateCubic(a, c, midpoint);
if ((t - estimate).abs() < _cubicErrorBound)
return _evaluateCubic(b, d, midpoint);
if (estimate < t)
start = midpoint;
else
end = midpoint;
}
}
@override
String toString() {
return '$runtimeType(${a.toStringAsFixed(2)}, ${b.toStringAsFixed(2)}, ${c.toStringAsFixed(2)}, ${d.toStringAsFixed(2)})';
}
}
/// A curve that is the reversed inversion of its given curve.
///
/// This curve evaluates the given curve in reverse (i.e., from 1.0 to 0.0 as t
/// increases from 0.0 to 1.0) and returns the inverse of the given curve's
/// value (i.e., 1.0 minus the given curve's value).
///
/// This is the class used to implement the [flipped] getter on curves.
///
/// This is often useful with [CurvedAnimation.reverseCurve].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_flipped.mp4}
///
/// See also:
///
/// * [Curve.flipped], which provides the [FlippedCurve] of a [Curve].
/// * [ReverseAnimation], which reverses an [Animation] rather than a [Curve].
/// * [CurvedAnimation], which can take a separate curve and reverse curve.
class FlippedCurve extends Curve {
/// Creates a flipped curve.
///
/// The [curve] argument must not be null.
const FlippedCurve(this.curve) : assert(curve != null);
/// The curve that is being flipped.
final Curve curve;
@override
double transformInternal(double t) => 1.0 - curve.transform(1.0 - t);
@override
String toString() {
return '$runtimeType($curve)';
}
}
/// A curve where the rate of change starts out quickly and then decelerates; an
/// upside-down `f(t) = t²` parabola.
///
/// This is equivalent to the Android `DecelerateInterpolator` class with a unit
/// factor (the default factor).
///
/// See [Curves.decelerate] for an instance of this class.
class _DecelerateCurve extends Curve {
const _DecelerateCurve._();
@override
double transformInternal(double t) {
// Intended to match the behavior of:
// https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/view/animation/DecelerateInterpolator.java
// ...as of December 2016.
t = 1.0 - t;
return 1.0 - t * t;
}
}
// BOUNCE CURVES
double _bounce(double t) {
if (t < 1.0 / 2.75) {
return 7.5625 * t * t;
} else if (t < 2 / 2.75) {
t -= 1.5 / 2.75;
return 7.5625 * t * t + 0.75;
} else if (t < 2.5 / 2.75) {
t -= 2.25 / 2.75;
return 7.5625 * t * t + 0.9375;
}
t -= 2.625 / 2.75;
return 7.5625 * t * t + 0.984375;
}
/// An oscillating curve that grows in magnitude.
///
/// See [Curves.bounceIn] for an instance of this class.
class _BounceInCurve extends Curve {
const _BounceInCurve._();
@override
double transformInternal(double t) {
return 1.0 - _bounce(1.0 - t);
}
}
/// An oscillating curve that shrink in magnitude.
///
/// See [Curves.bounceOut] for an instance of this class.
class _BounceOutCurve extends Curve {
const _BounceOutCurve._();
@override
double transformInternal(double t) {
return _bounce(t);
}
}
/// An oscillating curve that first grows and then shrink in magnitude.
///
/// See [Curves.bounceInOut] for an instance of this class.
class _BounceInOutCurve extends Curve {
const _BounceInOutCurve._();
@override
double transformInternal(double t) {
if (t < 0.5)
return (1.0 - _bounce(1.0 - t * 2.0)) * 0.5;
else
return _bounce(t * 2.0 - 1.0) * 0.5 + 0.5;
}
}
// ELASTIC CURVES
/// An oscillating curve that grows in magnitude while overshooting its bounds.
///
/// An instance of this class using the default period of 0.4 is available as
/// [Curves.elasticIn].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in.mp4}
class ElasticInCurve extends Curve {
/// Creates an elastic-in curve.
///
/// Rather than creating a new instance, consider using [Curves.elasticIn].
const ElasticInCurve([this.period = 0.4]);
/// The duration of the oscillation.
final double period;
@override
double transformInternal(double t) {
final double s = period / 4.0;
t = t - 1.0;
return -math.pow(2.0, 10.0 * t) * math.sin((t - s) * (math.pi * 2.0) / period);
}
@override
String toString() {
return '$runtimeType($period)';
}
}
/// An oscillating curve that shrinks in magnitude while overshooting its bounds.
///
/// An instance of this class using the default period of 0.4 is available as
/// [Curves.elasticOut].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_out.mp4}
class ElasticOutCurve extends Curve {
/// Creates an elastic-out curve.
///
/// Rather than creating a new instance, consider using [Curves.elasticOut].
const ElasticOutCurve([this.period = 0.4]);
/// The duration of the oscillation.
final double period;
@override
double transformInternal(double t) {
final double s = period / 4.0;
return math.pow(2.0, -10 * t) * math.sin((t - s) * (math.pi * 2.0) / period) + 1.0;
}
@override
String toString() {
return '$runtimeType($period)';
}
}
/// An oscillating curve that grows and then shrinks in magnitude while
/// overshooting its bounds.
///
/// An instance of this class using the default period of 0.4 is available as
/// [Curves.elasticInOut].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in_out.mp4}
class ElasticInOutCurve extends Curve {
/// Creates an elastic-in-out curve.
///
/// Rather than creating a new instance, consider using [Curves.elasticInOut].
const ElasticInOutCurve([this.period = 0.4]);
/// The duration of the oscillation.
final double period;
@override
double transformInternal(double t) {
final double s = period / 4.0;
t = 2.0 * t - 1.0;
if (t < 0.0)
return -0.5 * math.pow(2.0, 10.0 * t) * math.sin((t - s) * (math.pi * 2.0) / period);
else
return math.pow(2.0, -10.0 * t) * math.sin((t - s) * (math.pi * 2.0) / period) * 0.5 + 1.0;
}
@override
String toString() {
return '$runtimeType($period)';
}
}
// PREDEFINED CURVES
/// A collection of common animation curves.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_decelerate.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_sine.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quad.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_cubic.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quart.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quint.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_expo.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_circ.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_back.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_sine.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quad.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_cubic.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quart.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quint.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_expo.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_circ.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_back.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_sine.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quad.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_cubic.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quart.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quint.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_expo.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_circ.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_back.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_out.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_fast_out_slow_in.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_slow_middle.mp4}
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_linear.mp4}
///
/// See also:
///
/// * [Curve], the interface implemented by the constants available from the
/// [Curves] class.
class Curves {
Curves._();
/// A linear animation curve.
///
/// This is the identity map over the unit interval: its [Curve.transform]
/// method returns its input unmodified. This is useful as a default curve for
/// cases where a [Curve] is required but no actual curve is desired.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_linear.mp4}
static const Curve linear = _Linear._();
/// A curve where the rate of change starts out quickly and then decelerates; an
/// upside-down `f(t) = t²` parabola.
///
/// This is equivalent to the Android `DecelerateInterpolator` class with a unit
/// factor (the default factor).
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_decelerate.mp4}
static const Curve decelerate = _DecelerateCurve._();
/// A curve that is very steep and linear at the beginning, but quickly flattens out
/// and very slowly eases in.
///
/// By default is the curve used to animate pages on iOS back to their original
/// position if a swipe gesture is ended midway through a swipe.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/fast_linear_to_slow_ease_in.mp4}
static const Cubic fastLinearToSlowEaseIn = Cubic(0.18, 1.0, 0.04, 1.0);
/// A cubic animation curve that speeds up quickly and ends slowly.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease.mp4}
static const Cubic ease = Cubic(0.25, 0.1, 0.25, 1.0);
/// A cubic animation curve that starts slowly and ends quickly.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in.mp4}
static const Cubic easeIn = Cubic(0.42, 0.0, 1.0, 1.0);
/// A cubic animation curve that starts starts slowly and ends linearly.
///
/// The symmetric animation to [linearToEaseOut].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_to_linear.mp4}
static const Cubic easeInToLinear = Cubic(0.67, 0.03, 0.65, 0.09);
/// A cubic animation curve that starts slowly and ends quickly. This is
/// similar to [Curves.easeIn], but with sinusoidal easing for a slightly less
/// abrupt beginning and end. Nonetheless, the result is quite gentle and is
/// hard to distinguish from [Curves.linear] at a glance.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_sine.mp4}
static const Cubic easeInSine = Cubic(0.47, 0.0, 0.745, 0.715);
/// A cubic animation curve that starts slowly and ends quickly. Based on a
/// quadratic equation where `f(t) = t²`, this is effectively the inverse of
/// [Curves.decelerate].
///
/// Compared to [Curves.easeInSine], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quad.mp4}
static const Cubic easeInQuad = Cubic(0.55, 0.085, 0.68, 0.53);
/// A cubic animation curve that starts slowly and ends quickly. This curve is
/// based on a cubic equation where `f(t) = t³`. The result is a safe sweet
/// spot when choosing a curve for widgets animating off the viewport.
///
/// Compared to [Curves.easeInQuad], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_cubic.mp4}
static const Cubic easeInCubic = Cubic(0.55, 0.055, 0.675, 0.19);
/// A cubic animation curve that starts slowly and ends quickly. This curve is
/// based on a quartic equation where `f(t) = t⁴`.
///
/// Animations using this curve or steeper curves will benefit from a longer
/// duration to avoid motion feeling unnatural.
///
/// Compared to [Curves.easeInCubic], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quart.mp4}
static const Cubic easeInQuart = Cubic(0.895, 0.03, 0.685, 0.22);
/// A cubic animation curve that starts slowly and ends quickly. This curve is
/// based on a quintic equation where `f(t) = t⁵`.
///
/// Compared to [Curves.easeInQuart], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_quint.mp4}
static const Cubic easeInQuint = Cubic(0.755, 0.05, 0.855, 0.06);
/// A cubic animation curve that starts slowly and ends quickly. This curve is
/// based on an exponential equation where `f(t) = 2¹⁰⁽ᵗ⁻¹⁾`.
///
/// Using this curve can give your animations extra flare, but a longer
/// duration may need to be used to compensate for the steepness of the curve.
///
/// Compared to [Curves.easeInQuint], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_expo.mp4}
static const Cubic easeInExpo = Cubic(0.95, 0.05, 0.795, 0.035);
/// A cubic animation curve that starts slowly and ends quickly. This curve is
/// effectively the bottom-right quarter of a circle.
///
/// Like [Curves.easeInExpo], this curve is fairly dramatic and will reduce
/// the clarity of an animation if not given a longer duration.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_circ.mp4}
static const Cubic easeInCirc = Cubic(0.6, 0.04, 0.98, 0.335);
/// A cubic animation curve that starts slowly and ends quickly. This curve
/// is similar to [Curves.elasticIn] in that it overshoots its bounds before
/// reaching its end. Instead of repeated swinging motions before ascending,
/// though, this curve overshoots once, then continues to ascend.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_back.mp4}
static const Cubic easeInBack = Cubic(0.6, -0.28, 0.735, 0.045);
/// A cubic animation curve that starts quickly and ends slowly.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out.mp4}
static const Cubic easeOut = Cubic(0.0, 0.0, 0.58, 1.0);
/// A cubic animation curve that starts linearly and ends slowly.
///
/// A symmetric animation to [easeInToLinear].
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/linear_to_ease_out.mp4}
static const Cubic linearToEaseOut = Cubic(0.35, 0.91, 0.33, 0.97);
/// A cubic animation curve that starts quickly and ends slowly. This is
/// similar to [Curves.easeOut], but with sinusoidal easing for a slightly
/// less abrupt beginning and end. Nonetheless, the result is quite gentle and
/// is hard to distinguish from [Curves.linear] at a glance.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_sine.mp4}
static const Cubic easeOutSine = Cubic(0.39, 0.575, 0.565, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This is
/// effectively the same as [Curves.decelerate], only simulated using a cubic
/// bezier function.
///
/// Compared to [Curves.easeOutSine], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quad.mp4}
static const Cubic easeOutQuad = Cubic(0.25, 0.46, 0.45, 0.94);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// a flipped version of [Curves.easeInCubic].
///
/// The result is a safe sweet spot when choosing a curve for animating a
/// widget's position entering or already inside the viewport.
///
/// Compared to [Curves.easeOutQuad], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_cubic.mp4}
static const Cubic easeOutCubic = Cubic(0.215, 0.61, 0.355, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// a flipped version of [Curves.easeInQuart].
///
/// Animations using this curve or steeper curves will benefit from a longer
/// duration to avoid motion feeling unnatural.
///
/// Compared to [Curves.easeOutCubic], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quart.mp4}
static const Cubic easeOutQuart = Cubic(0.165, 0.84, 0.44, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// a flipped version of [Curves.easeInQuint].
///
/// Compared to [Curves.easeOutQuart], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_quint.mp4}
static const Cubic easeOutQuint = Cubic(0.23, 1.0, 0.32, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// a flipped version of [Curves.easeInExpo]. Using this curve can give your
/// animations extra flare, but a longer duration may need to be used to
/// compensate for the steepness of the curve.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_expo.mp4}
static const Cubic easeOutExpo = Cubic(0.19, 1.0, 0.22, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// effectively the top-left quarter of a circle.
///
/// Like [Curves.easeOutExpo], this curve is fairly dramatic and will reduce
/// the clarity of an animation if not given a longer duration.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_circ.mp4}
static const Cubic easeOutCirc = Cubic(0.075, 0.82, 0.165, 1.0);
/// A cubic animation curve that starts quickly and ends slowly. This curve is
/// similar to [Curves.elasticOut] in that it overshoots its bounds before
/// reaching its end. Instead of repeated swinging motions after ascending,
/// though, this curve only overshoots once.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_out_back.mp4}
static const Cubic easeOutBack = Cubic(0.175, 0.885, 0.32, 1.275);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out.mp4}
static const Cubic easeInOut = Cubic(0.42, 0.0, 0.58, 1.0);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This is similar to [Curves.easeInOut], but with sinusoidal easing
/// for a slightly less abrupt beginning and end.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_sine.mp4}
static const Cubic easeInOutSine = Cubic(0.445, 0.05, 0.55, 0.95);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInQuad] as the first
/// half, and [Curves.easeOutQuad] as the second.
///
/// Compared to [Curves.easeInOutSine], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quad.mp4}
static const Cubic easeInOutQuad = Cubic(0.455, 0.03, 0.515, 0.955);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInCubic] as the first
/// half, and [Curves.easeOutCubic] as the second.
///
/// The result is a safe sweet spot when choosing a curve for a widget whose
/// initial and final positions are both within the viewport.
///
/// Compared to [Curves.easeInOutQuad], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_cubic.mp4}
static const Cubic easeInOutCubic = Cubic(0.645, 0.045, 0.355, 1.0);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInQuart] as the first
/// half, and [Curves.easeOutQuart] as the second.
///
/// Animations using this curve or steeper curves will benefit from a longer
/// duration to avoid motion feeling unnatural.
///
/// Compared to [Curves.easeInOutCubic], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quart.mp4}
static const Cubic easeInOutQuart = Cubic(0.77, 0.0, 0.175, 1.0);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInQuint] as the first
/// half, and [Curves.easeOutQuint] as the second.
///
/// Compared to [Curves.easeInOutQuart], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_quint.mp4}
static const Cubic easeInOutQuint = Cubic(0.86, 0.0, 0.07, 1.0);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly.
///
/// Since this curve is arrived at with an exponential function, the midpoint
/// is exceptionally steep. Extra consideration should be taken when designing
/// an animation using this.
///
/// Compared to [Curves.easeInOutQuint], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_expo.mp4}
static const Cubic easeInOutExpo = Cubic(1.0, 0.0, 0.0, 1.0);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInCirc] as the first
/// half, and [Curves.easeOutCirc] as the second.
///
/// Like [Curves.easeInOutExpo], this curve is fairly dramatic and will reduce
/// the clarity of an animation if not given a longer duration.
///
/// Compared to [Curves.easeInOutExpo], this curve is slightly steeper.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_circ.mp4}
static const Cubic easeInOutCirc = Cubic(0.785, 0.135, 0.15, 0.86);
/// A cubic animation curve that starts slowly, speeds up, and then ends
/// slowly. This curve can be imagined as [Curves.easeInBack] as the first
/// half, and [Curves.easeOutBack] as the second.
///
/// Since two curves are used as a basis for this curve, the resulting
/// animation will overshoot its bounds twice before reaching its end - first
/// by exceeding its lower bound, then exceeding its upper bound and finally
/// descending to its final position.
///
/// Derived from Robert Penner’s easing functions.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_ease_in_out_back.mp4}
static const Cubic easeInOutBack = Cubic(0.68, -0.55, 0.265, 1.55);
/// A curve that starts quickly and eases into its final position.
///
/// Over the course of the animation, the object spends more time near its
/// final destination. As a result, the user isn’t left waiting for the
/// animation to finish, and the negative effects of motion are minimized.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_fast_out_slow_in.mp4}
static const Cubic fastOutSlowIn = Cubic(0.4, 0.0, 0.2, 1.0);
/// A cubic animation curve that starts quickly, slows down, and then ends
/// quickly.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_slow_middle.mp4}
static const Cubic slowMiddle = Cubic(0.15, 0.85, 0.85, 0.15);
/// An oscillating curve that grows in magnitude.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in.mp4}
static const Curve bounceIn = _BounceInCurve._();
/// An oscillating curve that first grows and then shrink in magnitude.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_out.mp4}
static const Curve bounceOut = _BounceOutCurve._();
/// An oscillating curve that first grows and then shrink in magnitude.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_bounce_in_out.mp4}
static const Curve bounceInOut = _BounceInOutCurve._();
/// An oscillating curve that grows in magnitude while overshooting its bounds.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in.mp4}
static const ElasticInCurve elasticIn = ElasticInCurve();
/// An oscillating curve that shrinks in magnitude while overshooting its bounds.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_out.mp4}
static const ElasticOutCurve elasticOut = ElasticOutCurve();
/// An oscillating curve that grows and then shrinks in magnitude while overshooting its bounds.
///
/// {@animation 464 192 https://flutter.github.io/assets-for-api-docs/assets/animation/curve_elastic_in_out.mp4}
static const ElasticInOutCurve elasticInOut = ElasticInOutCurve();
}
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