feat: add clamped animation

Author: gonuit

lib/custom_refresh_indicator.dart

@@ -1,3 +1,4 @@
 export 'src/data/data.dart';
 export 'src/custom_refresh_indicator.dart';
 export 'src/delegates/delegates.dart';
+export 'src/utils/utils.dart';

lib/src/utils/clamped_animation.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/animation.dart';
+
+/// An animation that clamps the value of another animation within a specified range.
+///
+/// This animation proxies the parent animation but enforces a minimum and a maximum
+/// limit on its value. If the parent animation produces a value outside of this
+/// range, it is clamped to the nearest boundary defined by [min] and [max].
+///
+/// The [min] value should be less than the [max] value.
+///
+/// Example usage:
+/// ```dart
+/// final ClampedAnimation clampedAnimation = ClampedAnimation(
+///   parent: parent,
+///   min: 0.0,
+///   max: 1.0,
+/// );
+/// ```
+/// Here `clampedAnimation.value` will always be between 0.0 and 1.0, inclusive.
+class ClampedAnimation extends Animation<double>
+    with AnimationWithParentMixin<double> {
+  /// Creates a clamped animation with an invariant range.
+  ///
+  /// The [parent] animation is the source of values for this animation.
+  /// The [min] and [max] parameters specify the range within which the
+  /// values of the parent animation should be clamped.
+  /// The constructor asserts that [min] is less than [max].
+  const ClampedAnimation({
+    required this.parent,
+    required this.min,
+    required this.max,
+  }) : assert(min < max, 'The min value must be less than the max value.');
+
+  /// The animation that this clamped animation is based on.
+  @override
+  final Animation<double> parent;
+
+  /// The minimum value of the clamped range.
+  final double min;
+
+  /// The maximum value of the clamped range.
+  final double max;
+
+  /// Gets the current value of the parent animation clamped to the range [min] to [max].
+  ///
+  /// This method overrides the getter for `value` from the parent class and applies
+  /// the clamping logic to the current value of the [parent] animation.
+  @override
+  double get value => parent.value.clamp(min, max);
+
+  @override
+  String toString() => '$parent(min: $min, max: $max)';
+}

lib/src/utils/utils.dart

@@ -0,0 +1 @@
+export 'clamped_animation.dart';