1// Copyright 2014 The Flutter Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5/// @docImport 'package:flutter/material.dart';
6library;
7
8import 'package:flutter/foundation.dart';
9
10import 'curves.dart';
11import 'tween.dart';
12
13/// Used to override the default parameters of an animation.
14///
15/// Currently, this class is used by the following widgets:
16/// - [ExpansionTile]
17/// - [MaterialApp]
18/// - [PopupMenuButton]
19/// - [ScaffoldMessengerState.showSnackBar]
20/// - [showBottomSheet]
21/// - [showModalBottomSheet]
22///
23/// If [duration] and [reverseDuration] are set to [Duration.zero], the
24/// corresponding animation will be disabled.
25///
26/// All of the parameters are optional. If no parameters are specified,
27/// the default animation will be used.
28@immutable
29class AnimationStyle with Diagnosticable {
30 /// Creates an instance of Animation Style class.
31 const AnimationStyle({this.curve, this.duration, this.reverseCurve, this.reverseDuration});
32
33 /// Creates an instance of Animation Style class with no animation.
34 static const AnimationStyle noAnimation = AnimationStyle(
35 duration: Duration.zero,
36 reverseDuration: Duration.zero,
37 );
38
39 /// When specified, the animation will use this curve.
40 final Curve? curve;
41
42 /// When specified, the animation will use this duration.
43 final Duration? duration;
44
45 /// When specified, the reverse animation will use this curve.
46 final Curve? reverseCurve;
47
48 /// When specified, the reverse animation will use this duration.
49 final Duration? reverseDuration;
50
51 /// Creates a new [AnimationStyle] based on the current selection, with the
52 /// provided parameters overridden.
53 AnimationStyle copyWith({
54 final Curve? curve,
55 final Duration? duration,
56 final Curve? reverseCurve,
57 final Duration? reverseDuration,
58 }) {
59 return AnimationStyle(
60 curve: curve ?? this.curve,
61 duration: duration ?? this.duration,
62 reverseCurve: reverseCurve ?? this.reverseCurve,
63 reverseDuration: reverseDuration ?? this.reverseDuration,
64 );
65 }
66
67 /// Linearly interpolate between two animation styles.
68 static AnimationStyle? lerp(AnimationStyle? a, AnimationStyle? b, double t) {
69 if (identical(a, b)) {
70 return a;
71 }
72 return AnimationStyle(
73 curve: t < 0.5 ? a?.curve : b?.curve,
74 duration: t < 0.5 ? a?.duration : b?.duration,
75 reverseCurve: t < 0.5 ? a?.reverseCurve : b?.reverseCurve,
76 reverseDuration: t < 0.5 ? a?.reverseDuration : b?.reverseDuration,
77 );
78 }
79
80 @override
81 bool operator ==(Object other) {
82 if (identical(this, other)) {
83 return true;
84 }
85 if (other.runtimeType != runtimeType) {
86 return false;
87 }
88 return other is AnimationStyle &&
89 other.curve == curve &&
90 other.duration == duration &&
91 other.reverseCurve == reverseCurve &&
92 other.reverseDuration == reverseDuration;
93 }
94
95 @override
96 int get hashCode => Object.hash(curve, duration, reverseCurve, reverseDuration);
97
98 @override
99 void debugFillProperties(DiagnosticPropertiesBuilder properties) {
100 super.debugFillProperties(properties);
101 properties.add(DiagnosticsProperty<Curve>('curve', curve, defaultValue: null));
102 properties.add(DiagnosticsProperty<Duration>('duration', duration, defaultValue: null));
103 properties.add(DiagnosticsProperty<Curve>('reverseCurve', reverseCurve, defaultValue: null));
104 properties.add(
105 DiagnosticsProperty<Duration>('reverseDuration', reverseDuration, defaultValue: null),
106 );
107 }
108}
109