feat: add transform and normalize methods

Author: gonuit

lib/custom_refresh_indicator.dart

@@ -1,6 +1,5 @@
 export 'src/data/data.dart';
 export 'src/custom_refresh_indicator.dart';
-export 'src/delegates/delegates.dart';
 export 'src/widgets/widgets.dart';
 export 'src/physics/physics.dart';
 export 'src/utils/utils.dart';

lib/src/custom_refresh_indicator.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:meta/meta.dart';
 
-part 'controller.dart';
+part 'indicator_controller.dart';
 
 typedef IndicatorBuilder = Widget Function(
   BuildContext context,

lib/src/controller.dart renamed to lib/src/indicator_controller.dart

@@ -8,6 +8,12 @@ class IndicatorController extends Animation<double>
         ClampingWithOverscrollPhysicsState {
   double _value;
 
+  /// Represents the **minimum** value that an indicator can have.
+  static double get minValue => 0.0;
+
+  /// Represents the **maximum** value that an indicator can have.
+  static double get maxValue => 1.5;
+
   /// Current indicator value / progress
   @override
   double get value => _value;
@@ -211,7 +217,7 @@ class IndicatorController extends Animation<double>
   @override
   AnimationStatus get status => state.isIdle ? AnimationStatus.dismissed : AnimationStatus.forward;
 
-  /// Returns a [ClampedAnimation] that constrains the animation value of its parent
+  /// Returns [ClampedAnimation] that constrains the animation value of its parent
   /// within the given [min] and [max] range.
   ///
   /// - [min] represents the smallest value the animation can have. If the parent
@@ -223,4 +229,22 @@ class IndicatorController extends Animation<double>
         min: min,
         max: max,
       );
+
+  /// Returns [TransformedAnimation], which transforms the animation value of its parent
+  /// to the specified [min] and [max] range.
+  ///
+  /// - [min] represents the smallest value the animation can have.
+  /// - [max] represents the largest value the animation can have.
+  /// 
+  /// If instead of transforming the entire range of controller values, you want to use only a specific range, see the [clamp] method.
+  Animation<double> transform(double min, double max) => TransformedAnimation(
+        parent: this,
+        fromMin: minValue,
+        fromMax: maxValue,
+        toMin: min,
+        toMax: max,
+      );
+
+  /// Returns a new animation with the controller value transformed to the range from `0.0` to `1.0` inclusive.
+  Animation<double> normalize() => transform(0.0, 1.0);
 }