packages/flutter/lib/src/material/toggleable.dart - external/github.com/flutter/flutter - Git at Google

 // Copyright 2014 The Flutter 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 'package:flutter/animation.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';

 import 'constants.dart';

 // Duration of the animation that moves the toggle from one state to another.
 const Duration _kToggleDuration = Duration(milliseconds: 200);

 // Duration of the fade animation for the reaction when focus and hover occur.
 const Duration _kReactionFadeDuration = Duration(milliseconds: 50);

 /// A base class for material style toggleable controls with toggle animations.
 ///
 /// This class handles storing the current value, dispatching ValueChanged on a
 /// tap gesture and driving a changed animation. Subclasses are responsible for
 /// painting.
 abstract class RenderToggleable extends RenderConstrainedBox {
   /// Creates a toggleable render object.
   ///
   /// The [activeColor], and [inactiveColor] arguments must not be
   /// null. The [value] can only be null if tristate is true.
   RenderToggleable({
     required bool? value,
     bool tristate = false,
     required Color activeColor,
     required Color inactiveColor,
     Color? hoverColor,
     Color? focusColor,
     Color? reactionColor,
     Color? inactiveReactionColor,
     required double splashRadius,
     ValueChanged<bool?>? onChanged,
     required BoxConstraints additionalConstraints,
     required TickerProvider vsync,
     bool hasFocus = false,
     bool hovering = false,
   }) : assert(tristate != null),
        assert(tristate || value != null),
        assert(activeColor != null),
        assert(inactiveColor != null),
        assert(vsync != null),
        _value = value,
        _tristate = tristate,
        _activeColor = activeColor,
        _inactiveColor = inactiveColor,
        _hoverColor = hoverColor ?? activeColor.withAlpha(kRadialReactionAlpha),
        _focusColor = focusColor ?? activeColor.withAlpha(kRadialReactionAlpha),
        _reactionColor = reactionColor ?? activeColor.withAlpha(kRadialReactionAlpha),
        _inactiveReactionColor = inactiveReactionColor ?? activeColor.withAlpha(kRadialReactionAlpha),
        _splashRadius = splashRadius,
        _onChanged = onChanged,
        _hasFocus = hasFocus,
        _hovering = hovering,
        _vsync = vsync,
        super(additionalConstraints: additionalConstraints) {
     _tap = TapGestureRecognizer()
       ..onTapDown = _handleTapDown
       ..onTap = _handleTap
       ..onTapUp = _handleTapUp
       ..onTapCancel = _handleTapCancel;
     _positionController = AnimationController(
       duration: _kToggleDuration,
       value: value == false ? 0.0 : 1.0,
       vsync: vsync,
     );
     _position = CurvedAnimation(
       parent: _positionController,
       curve: Curves.linear,
     )..addListener(markNeedsPaint);
     _reactionController = AnimationController(
       duration: kRadialReactionDuration,
       vsync: vsync,
     );
     _reaction = CurvedAnimation(
       parent: _reactionController,
       curve: Curves.fastOutSlowIn,
     )..addListener(markNeedsPaint);
     _reactionHoverFadeController = AnimationController(
       duration: _kReactionFadeDuration,
       value: hovering || hasFocus ? 1.0 : 0.0,
       vsync: vsync,
     );
     _reactionHoverFade = CurvedAnimation(
       parent: _reactionHoverFadeController,
       curve: Curves.fastOutSlowIn,
     )..addListener(markNeedsPaint);
     _reactionFocusFadeController = AnimationController(
       duration: _kReactionFadeDuration,
       value: hovering || hasFocus ? 1.0 : 0.0,
       vsync: vsync,
     );
     _reactionFocusFade = CurvedAnimation(
       parent: _reactionFocusFadeController,
       curve: Curves.fastOutSlowIn,
     )..addListener(markNeedsPaint);
   }

   /// Used by subclasses to manipulate the visual value of the control.
   ///
   /// Some controls respond to user input by updating their visual value. For
   /// example, the thumb of a switch moves from one position to another when
   /// dragged. These controls manipulate this animation controller to update
   /// their [position] and eventually trigger an [onChanged] callback when the
   /// animation reaches either 0.0 or 1.0.
   @protected
   AnimationController get positionController => _positionController;
   late AnimationController _positionController;

   /// The visual value of the control.
   ///
   /// When the control is inactive, the [value] is false and this animation has
   /// the value 0.0. When the control is active, the value either true or tristate
   /// is true and the value is null. When the control is active the animation
   /// has a value of 1.0. When the control is changing from inactive
   /// to active (or vice versa), [value] is the target value and this animation
   /// gradually updates from 0.0 to 1.0 (or vice versa).
   CurvedAnimation get position => _position;
   late CurvedAnimation _position;

   /// Used by subclasses to control the radial reaction animation.
   ///
   /// Some controls have a radial ink reaction to user input. This animation
   /// controller can be used to start or stop these ink reactions.
   ///
   /// Subclasses should call [paintRadialReaction] to actually paint the radial
   /// reaction.
   @protected
   AnimationController get reactionController => _reactionController;
   late AnimationController _reactionController;
   late Animation<double> _reaction;

   /// Used by subclasses to control the radial reaction's opacity animation for
   /// [hasFocus] changes.
   ///
   /// Some controls have a radial ink reaction to focus. This animation
   /// controller can be used to start or stop these ink reaction fade-ins and
   /// fade-outs.
   ///
   /// Subclasses should call [paintRadialReaction] to actually paint the radial
   /// reaction.
   @protected
   AnimationController get reactionFocusFadeController => _reactionFocusFadeController;
   late AnimationController _reactionFocusFadeController;
   late Animation<double> _reactionFocusFade;

   /// Used by subclasses to control the radial reaction's opacity animation for
   /// [hovering] changes.
   ///
   /// Some controls have a radial ink reaction to pointer hover. This animation
   /// controller can be used to start or stop these ink reaction fade-ins and
   /// fade-outs.
   ///
   /// Subclasses should call [paintRadialReaction] to actually paint the radial
   /// reaction.
   @protected
   AnimationController get reactionHoverFadeController => _reactionHoverFadeController;
   late AnimationController _reactionHoverFadeController;
   late Animation<double> _reactionHoverFade;

   /// True if this toggleable has the input focus.
   bool get hasFocus => _hasFocus;
   bool _hasFocus;
   set hasFocus(bool value) {
     assert(value != null);
     if (value == _hasFocus)
       return;
     _hasFocus = value;
     if (_hasFocus) {
       _reactionFocusFadeController.forward();
     } else {
       _reactionFocusFadeController.reverse();
     }
     markNeedsPaint();
   }

   /// True if this toggleable is being hovered over by a pointer.
   bool get hovering => _hovering;
   bool _hovering;
   set hovering(bool value) {
     assert(value != null);
     if (value == _hovering)
       return;
     _hovering = value;
     if (_hovering) {
       _reactionHoverFadeController.forward();
     } else {
       _reactionHoverFadeController.reverse();
     }
     markNeedsPaint();
   }

   /// The [TickerProvider] for the [AnimationController]s that run the animations.
   TickerProvider get vsync => _vsync;
   TickerProvider _vsync;
   set vsync(TickerProvider value) {
     assert(value != null);
     if (value == _vsync)
       return;
     _vsync = value;
     positionController.resync(vsync);
     reactionController.resync(vsync);
   }

   /// False if this control is "inactive" (not checked, off, or unselected).
   ///
   /// If value is true then the control "active" (checked, on, or selected). If
   /// tristate is true and value is null, then the control is considered to be
   /// in its third or "indeterminate" state.
   ///
   /// When the value changes, this object starts the [positionController] and
   /// [position] animations to animate the visual appearance of the control to
   /// the new value.
   bool? get value => _value;
   bool? _value;
   set value(bool? value) {
     assert(tristate || value != null);
     if (value == _value)
       return;
     _value = value;
     markNeedsSemanticsUpdate();
     _position
       ..curve = Curves.easeIn
       ..reverseCurve = Curves.easeOut;
     if (tristate) {
       if (value == null)
         _positionController.value = 0.0;
       if (value != false)
         _positionController.forward();
       else
         _positionController.reverse();
     } else {
       if (value == true)
         _positionController.forward();
       else
         _positionController.reverse();
     }
   }

   /// If true, [value] can be true, false, or null, otherwise [value] must
   /// be true or false.
   ///
   /// When [tristate] is true and [value] is null, then the control is
   /// considered to be in its third or "indeterminate" state.
   bool get tristate => _tristate;
   bool _tristate;
   set tristate(bool value) {
     assert(tristate != null);
     if (value == _tristate)
       return;
     _tristate = value;
     markNeedsSemanticsUpdate();
   }

   /// The color that should be used in the active state (i.e., when [value] is true).
   ///
   /// For example, a checkbox should use this color when checked.
   Color get activeColor => _activeColor;
   Color _activeColor;
   set activeColor(Color value) {
     assert(value != null);
     if (value == _activeColor)
       return;
     _activeColor = value;
     markNeedsPaint();
   }

   /// The color that should be used in the inactive state (i.e., when [value] is false).
   ///
   /// For example, a checkbox should use this color when unchecked.
   Color get inactiveColor => _inactiveColor;
   Color _inactiveColor;
   set inactiveColor(Color value) {
     assert(value != null);
     if (value == _inactiveColor)
       return;
     _inactiveColor = value;
     markNeedsPaint();
   }

   /// The color that should be used for the reaction when [hovering] is true.
   ///
   /// Used when the toggleable needs to change the reaction color/transparency,
   /// when it is being hovered over.
   ///
   /// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
   Color get hoverColor => _hoverColor;
   Color _hoverColor;
   set hoverColor(Color value) {
     assert(value != null);
     if (value == _hoverColor)
       return;
     _hoverColor = value;
     markNeedsPaint();
   }

   /// The color that should be used for the reaction when [hasFocus] is true.
   ///
   /// Used when the toggleable needs to change the reaction color/transparency,
   /// when it has focus.
   ///
   /// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
   Color get focusColor => _focusColor;
   Color _focusColor;
   set focusColor(Color value) {
     assert(value != null);
     if (value == _focusColor)
       return;
     _focusColor = value;
     markNeedsPaint();
   }

   /// The color that should be used for the reaction when the toggleable is
   /// active.
   ///
   /// Used when the toggleable needs to change the reaction color/transparency
   /// that is displayed when the toggleable is active and tapped.
   ///
   /// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
   Color? get reactionColor => _reactionColor;
   Color? _reactionColor;
   set reactionColor(Color? value) {
     assert(value != null);
     if (value == _reactionColor)
       return;
     _reactionColor = value;
     markNeedsPaint();
   }

   /// The color that should be used for the reaction when the toggleable is
   /// inactive.
   ///
   /// Used when the toggleable needs to change the reaction color/transparency
   /// that is displayed when the toggleable is inactive and tapped.
   ///
   /// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
   Color? get inactiveReactionColor => _inactiveReactionColor;
   Color? _inactiveReactionColor;
   set inactiveReactionColor(Color? value) {
     assert(value != null);
     if (value == _inactiveReactionColor)
       return;
     _inactiveReactionColor = value;
     markNeedsPaint();
   }

   /// The splash radius for the radial reaction.
   double get splashRadius => _splashRadius;
   double _splashRadius;
   set splashRadius(double value) {
     if (value == _splashRadius)
       return;
     _splashRadius = value;
     markNeedsPaint();
   }

   /// Called when the control changes value.
   ///
   /// If the control is tapped, [onChanged] is called immediately with the new
   /// value.
   ///
   /// The control is considered interactive (see [isInteractive]) if this
   /// callback is non-null. If the callback is null, then the control is
   /// disabled, and non-interactive. A disabled checkbox, for example, is
   /// displayed using a grey color and its value cannot be changed.
   ValueChanged<bool?>? get onChanged => _onChanged;
   ValueChanged<bool?>? _onChanged;
   set onChanged(ValueChanged<bool?>? value) {
     if (value == _onChanged)
       return;
     final bool wasInteractive = isInteractive;
     _onChanged = value;
     if (wasInteractive != isInteractive) {
       markNeedsPaint();
       markNeedsSemanticsUpdate();
     }
   }

   /// Whether [value] of this control can be changed by user interaction.
   ///
   /// The control is considered interactive if the [onChanged] callback is
   /// non-null. If the callback is null, then the control is disabled, and
   /// non-interactive. A disabled checkbox, for example, is displayed using a
   /// grey color and its value cannot be changed.
   bool get isInteractive => onChanged != null;

   late TapGestureRecognizer _tap;
   Offset? _downPosition;

   @override
   void attach(PipelineOwner owner) {
     super.attach(owner);
     if (value == false)
       _positionController.reverse();
     else
       _positionController.forward();
     if (isInteractive) {
       switch (_reactionController.status) {
         case AnimationStatus.forward:
           _reactionController.forward();
           break;
         case AnimationStatus.reverse:
           _reactionController.reverse();
           break;
         case AnimationStatus.dismissed:
         case AnimationStatus.completed:
           // nothing to do
           break;
       }
     }
   }

   @override
   void detach() {
     _positionController.stop();
     _reactionController.stop();
     _reactionHoverFadeController.stop();
     _reactionFocusFadeController.stop();
     super.detach();
   }

   void _handleTapDown(TapDownDetails details) {
     if (isInteractive) {
       _downPosition = globalToLocal(details.globalPosition);
       _reactionController.forward();
     }
   }

   void _handleTap() {
     if (!isInteractive)
       return;
     switch (value) {
       case false:
         onChanged!(true);
         break;
       case true:
         onChanged!(tristate ? null : false);
         break;
       case null:
         onChanged!(false);
         break;
     }
     sendSemanticsEvent(const TapSemanticEvent());
   }

   void _handleTapUp(TapUpDetails details) {
     _downPosition = null;
     if (isInteractive)
       _reactionController.reverse();
   }

   void _handleTapCancel() {
     _downPosition = null;
     if (isInteractive)
       _reactionController.reverse();
   }

   @override
   bool hitTestSelf(Offset position) => true;

   @override
   void handleEvent(PointerEvent event, BoxHitTestEntry entry) {
     assert(debugHandleEvent(event, entry));
     if (event is PointerDownEvent && isInteractive)
       _tap.addPointer(event);
   }

   /// Used by subclasses to paint the radial ink reaction for this control.
   ///
   /// The reaction is painted on the given canvas at the given offset. The
   /// origin is the center point of the reaction (usually distinct from the
   /// point at which the user interacted with the control, which is handled
   /// automatically).
   void paintRadialReaction(Canvas canvas, Offset offset, Offset origin) {
     if (!_reaction.isDismissed || !_reactionFocusFade.isDismissed || !_reactionHoverFade.isDismissed) {
       final Paint reactionPaint = Paint()
         ..color = Color.lerp(
           Color.lerp(
             Color.lerp(inactiveReactionColor, reactionColor, _position.value),
             hoverColor,
             _reactionHoverFade.value,
           ),
           focusColor,
           _reactionFocusFade.value,
         )!;
       final Offset center = Offset.lerp(_downPosition ?? origin, origin, _reaction.value)!;
       final Animatable<double> radialReactionRadiusTween = Tween<double>(
         begin: 0.0,
         end: splashRadius,
       );
       final double reactionRadius = hasFocus || hovering
           ? splashRadius
           : radialReactionRadiusTween.evaluate(_reaction);
       if (reactionRadius > 0.0) {
         canvas.drawCircle(center + offset, reactionRadius, reactionPaint);
       }
     }
   }

   @override
   void describeSemanticsConfiguration(SemanticsConfiguration config) {
     super.describeSemanticsConfiguration(config);

     config.isEnabled = isInteractive;
     if (isInteractive)
       config.onTap = _handleTap;
   }

   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
     properties.add(FlagProperty('value', value: value, ifTrue: 'checked', ifFalse: 'unchecked', showName: true));
     properties.add(FlagProperty('isInteractive', value: isInteractive, ifTrue: 'enabled', ifFalse: 'disabled', defaultValue: true));
   }
 }
	// Copyright 2014 The Flutter 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 'package:flutter/animation.dart';
	import 'package:flutter/foundation.dart';
	import 'package:flutter/gestures.dart';
	import 'package:flutter/rendering.dart';
	import 'package:flutter/scheduler.dart';

	import 'constants.dart';

	// Duration of the animation that moves the toggle from one state to another.
	const Duration _kToggleDuration = Duration(milliseconds: 200);

	// Duration of the fade animation for the reaction when focus and hover occur.
	const Duration _kReactionFadeDuration = Duration(milliseconds: 50);

	/// A base class for material style toggleable controls with toggle animations.
	///
	/// This class handles storing the current value, dispatching ValueChanged on a
	/// tap gesture and driving a changed animation. Subclasses are responsible for
	/// painting.
	abstract class RenderToggleable extends RenderConstrainedBox {
	/// Creates a toggleable render object.
	///
	/// The [activeColor], and [inactiveColor] arguments must not be
	/// null. The [value] can only be null if tristate is true.
	RenderToggleable({
	required bool? value,
	bool tristate = false,
	required Color activeColor,
	required Color inactiveColor,
	Color? hoverColor,
	Color? focusColor,
	Color? reactionColor,
	Color? inactiveReactionColor,
	required double splashRadius,
	ValueChanged<bool?>? onChanged,
	required BoxConstraints additionalConstraints,
	required TickerProvider vsync,
	bool hasFocus = false,
	bool hovering = false,
	}) : assert(tristate != null),
	assert(tristate \|\| value != null),
	assert(activeColor != null),
	assert(inactiveColor != null),
	assert(vsync != null),
	_value = value,
	_tristate = tristate,
	_activeColor = activeColor,
	_inactiveColor = inactiveColor,
	_hoverColor = hoverColor ?? activeColor.withAlpha(kRadialReactionAlpha),
	_focusColor = focusColor ?? activeColor.withAlpha(kRadialReactionAlpha),
	_reactionColor = reactionColor ?? activeColor.withAlpha(kRadialReactionAlpha),
	_inactiveReactionColor = inactiveReactionColor ?? activeColor.withAlpha(kRadialReactionAlpha),
	_splashRadius = splashRadius,
	_onChanged = onChanged,
	_hasFocus = hasFocus,
	_hovering = hovering,
	_vsync = vsync,
	super(additionalConstraints: additionalConstraints) {
	_tap = TapGestureRecognizer()
	..onTapDown = _handleTapDown
	..onTap = _handleTap
	..onTapUp = _handleTapUp
	..onTapCancel = _handleTapCancel;
	_positionController = AnimationController(
	duration: _kToggleDuration,
	value: value == false ? 0.0 : 1.0,
	vsync: vsync,
	);
	_position = CurvedAnimation(
	parent: _positionController,
	curve: Curves.linear,
	)..addListener(markNeedsPaint);
	_reactionController = AnimationController(
	duration: kRadialReactionDuration,
	vsync: vsync,
	);
	_reaction = CurvedAnimation(
	parent: _reactionController,
	curve: Curves.fastOutSlowIn,
	)..addListener(markNeedsPaint);
	_reactionHoverFadeController = AnimationController(
	duration: _kReactionFadeDuration,
	value: hovering \|\| hasFocus ? 1.0 : 0.0,
	vsync: vsync,
	);
	_reactionHoverFade = CurvedAnimation(
	parent: _reactionHoverFadeController,
	curve: Curves.fastOutSlowIn,
	)..addListener(markNeedsPaint);
	_reactionFocusFadeController = AnimationController(
	duration: _kReactionFadeDuration,
	value: hovering \|\| hasFocus ? 1.0 : 0.0,
	vsync: vsync,
	);
	_reactionFocusFade = CurvedAnimation(
	parent: _reactionFocusFadeController,
	curve: Curves.fastOutSlowIn,
	)..addListener(markNeedsPaint);
	}

	/// Used by subclasses to manipulate the visual value of the control.
	///
	/// Some controls respond to user input by updating their visual value. For
	/// example, the thumb of a switch moves from one position to another when
	/// dragged. These controls manipulate this animation controller to update
	/// their [position] and eventually trigger an [onChanged] callback when the
	/// animation reaches either 0.0 or 1.0.
	@protected
	AnimationController get positionController => _positionController;
	late AnimationController _positionController;

	/// The visual value of the control.
	///
	/// When the control is inactive, the [value] is false and this animation has
	/// the value 0.0. When the control is active, the value either true or tristate
	/// is true and the value is null. When the control is active the animation
	/// has a value of 1.0. When the control is changing from inactive
	/// to active (or vice versa), [value] is the target value and this animation
	/// gradually updates from 0.0 to 1.0 (or vice versa).
	CurvedAnimation get position => _position;
	late CurvedAnimation _position;

	/// Used by subclasses to control the radial reaction animation.
	///
	/// Some controls have a radial ink reaction to user input. This animation
	/// controller can be used to start or stop these ink reactions.
	///
	/// Subclasses should call [paintRadialReaction] to actually paint the radial
	/// reaction.
	@protected
	AnimationController get reactionController => _reactionController;
	late AnimationController _reactionController;
	late Animation<double> _reaction;

	/// Used by subclasses to control the radial reaction's opacity animation for
	/// [hasFocus] changes.
	///
	/// Some controls have a radial ink reaction to focus. This animation
	/// controller can be used to start or stop these ink reaction fade-ins and
	/// fade-outs.
	///
	/// Subclasses should call [paintRadialReaction] to actually paint the radial
	/// reaction.
	@protected
	AnimationController get reactionFocusFadeController => _reactionFocusFadeController;
	late AnimationController _reactionFocusFadeController;
	late Animation<double> _reactionFocusFade;

	/// Used by subclasses to control the radial reaction's opacity animation for
	/// [hovering] changes.
	///
	/// Some controls have a radial ink reaction to pointer hover. This animation
	/// controller can be used to start or stop these ink reaction fade-ins and
	/// fade-outs.
	///
	/// Subclasses should call [paintRadialReaction] to actually paint the radial
	/// reaction.
	@protected
	AnimationController get reactionHoverFadeController => _reactionHoverFadeController;
	late AnimationController _reactionHoverFadeController;
	late Animation<double> _reactionHoverFade;

	/// True if this toggleable has the input focus.
	bool get hasFocus => _hasFocus;
	bool _hasFocus;
	set hasFocus(bool value) {
	assert(value != null);
	if (value == _hasFocus)
	return;
	_hasFocus = value;
	if (_hasFocus) {
	_reactionFocusFadeController.forward();
	} else {
	_reactionFocusFadeController.reverse();
	}
	markNeedsPaint();
	}

	/// True if this toggleable is being hovered over by a pointer.
	bool get hovering => _hovering;
	bool _hovering;
	set hovering(bool value) {
	assert(value != null);
	if (value == _hovering)
	return;
	_hovering = value;
	if (_hovering) {
	_reactionHoverFadeController.forward();
	} else {
	_reactionHoverFadeController.reverse();
	}
	markNeedsPaint();
	}

	/// The [TickerProvider] for the [AnimationController]s that run the animations.
	TickerProvider get vsync => _vsync;
	TickerProvider _vsync;
	set vsync(TickerProvider value) {
	assert(value != null);
	if (value == _vsync)
	return;
	_vsync = value;
	positionController.resync(vsync);
	reactionController.resync(vsync);
	}

	/// False if this control is "inactive" (not checked, off, or unselected).
	///
	/// If value is true then the control "active" (checked, on, or selected). If
	/// tristate is true and value is null, then the control is considered to be
	/// in its third or "indeterminate" state.
	///
	/// When the value changes, this object starts the [positionController] and
	/// [position] animations to animate the visual appearance of the control to
	/// the new value.
	bool? get value => _value;
	bool? _value;
	set value(bool? value) {
	assert(tristate \|\| value != null);
	if (value == _value)
	return;
	_value = value;
	markNeedsSemanticsUpdate();
	_position
	..curve = Curves.easeIn
	..reverseCurve = Curves.easeOut;
	if (tristate) {
	if (value == null)
	_positionController.value = 0.0;
	if (value != false)
	_positionController.forward();
	else
	_positionController.reverse();
	} else {
	if (value == true)
	_positionController.forward();
	else
	_positionController.reverse();
	}
	}

	/// If true, [value] can be true, false, or null, otherwise [value] must
	/// be true or false.
	///
	/// When [tristate] is true and [value] is null, then the control is
	/// considered to be in its third or "indeterminate" state.
	bool get tristate => _tristate;
	bool _tristate;
	set tristate(bool value) {
	assert(tristate != null);
	if (value == _tristate)
	return;
	_tristate = value;
	markNeedsSemanticsUpdate();
	}

	/// The color that should be used in the active state (i.e., when [value] is true).
	///
	/// For example, a checkbox should use this color when checked.
	Color get activeColor => _activeColor;
	Color _activeColor;
	set activeColor(Color value) {
	assert(value != null);
	if (value == _activeColor)
	return;
	_activeColor = value;
	markNeedsPaint();
	}

	/// The color that should be used in the inactive state (i.e., when [value] is false).
	///
	/// For example, a checkbox should use this color when unchecked.
	Color get inactiveColor => _inactiveColor;
	Color _inactiveColor;
	set inactiveColor(Color value) {
	assert(value != null);
	if (value == _inactiveColor)
	return;
	_inactiveColor = value;
	markNeedsPaint();
	}

	/// The color that should be used for the reaction when [hovering] is true.
	///
	/// Used when the toggleable needs to change the reaction color/transparency,
	/// when it is being hovered over.
	///
	/// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
	Color get hoverColor => _hoverColor;
	Color _hoverColor;
	set hoverColor(Color value) {
	assert(value != null);
	if (value == _hoverColor)
	return;
	_hoverColor = value;
	markNeedsPaint();
	}

	/// The color that should be used for the reaction when [hasFocus] is true.
	///
	/// Used when the toggleable needs to change the reaction color/transparency,
	/// when it has focus.
	///
	/// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
	Color get focusColor => _focusColor;
	Color _focusColor;
	set focusColor(Color value) {
	assert(value != null);
	if (value == _focusColor)
	return;
	_focusColor = value;
	markNeedsPaint();
	}

	/// The color that should be used for the reaction when the toggleable is
	/// active.
	///
	/// Used when the toggleable needs to change the reaction color/transparency
	/// that is displayed when the toggleable is active and tapped.
	///
	/// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
	Color? get reactionColor => _reactionColor;
	Color? _reactionColor;
	set reactionColor(Color? value) {
	assert(value != null);
	if (value == _reactionColor)
	return;
	_reactionColor = value;
	markNeedsPaint();
	}

	/// The color that should be used for the reaction when the toggleable is
	/// inactive.
	///
	/// Used when the toggleable needs to change the reaction color/transparency
	/// that is displayed when the toggleable is inactive and tapped.
	///
	/// Defaults to the [activeColor] at alpha [kRadialReactionAlpha].
	Color? get inactiveReactionColor => _inactiveReactionColor;
	Color? _inactiveReactionColor;
	set inactiveReactionColor(Color? value) {
	assert(value != null);
	if (value == _inactiveReactionColor)
	return;
	_inactiveReactionColor = value;
	markNeedsPaint();
	}

	/// The splash radius for the radial reaction.
	double get splashRadius => _splashRadius;
	double _splashRadius;
	set splashRadius(double value) {
	if (value == _splashRadius)
	return;
	_splashRadius = value;
	markNeedsPaint();
	}

	/// Called when the control changes value.
	///
	/// If the control is tapped, [onChanged] is called immediately with the new
	/// value.
	///
	/// The control is considered interactive (see [isInteractive]) if this
	/// callback is non-null. If the callback is null, then the control is
	/// disabled, and non-interactive. A disabled checkbox, for example, is
	/// displayed using a grey color and its value cannot be changed.
	ValueChanged<bool?>? get onChanged => _onChanged;
	ValueChanged<bool?>? _onChanged;
	set onChanged(ValueChanged<bool?>? value) {
	if (value == _onChanged)
	return;
	final bool wasInteractive = isInteractive;
	_onChanged = value;
	if (wasInteractive != isInteractive) {
	markNeedsPaint();
	markNeedsSemanticsUpdate();
	}
	}

	/// Whether [value] of this control can be changed by user interaction.
	///
	/// The control is considered interactive if the [onChanged] callback is
	/// non-null. If the callback is null, then the control is disabled, and
	/// non-interactive. A disabled checkbox, for example, is displayed using a
	/// grey color and its value cannot be changed.
	bool get isInteractive => onChanged != null;

	late TapGestureRecognizer _tap;
	Offset? _downPosition;

	@override
	void attach(PipelineOwner owner) {
	super.attach(owner);
	if (value == false)
	_positionController.reverse();
	else
	_positionController.forward();
	if (isInteractive) {
	switch (_reactionController.status) {
	case AnimationStatus.forward:
	_reactionController.forward();
	break;
	case AnimationStatus.reverse:
	_reactionController.reverse();
	break;
	case AnimationStatus.dismissed:
	case AnimationStatus.completed:
	// nothing to do
	break;
	}
	}
	}

	@override
	void detach() {
	_positionController.stop();
	_reactionController.stop();
	_reactionHoverFadeController.stop();
	_reactionFocusFadeController.stop();
	super.detach();
	}

	void _handleTapDown(TapDownDetails details) {
	if (isInteractive) {
	_downPosition = globalToLocal(details.globalPosition);
	_reactionController.forward();
	}
	}

	void _handleTap() {
	if (!isInteractive)
	return;
	switch (value) {
	case false:
	onChanged!(true);
	break;
	case true:
	onChanged!(tristate ? null : false);
	break;
	case null:
	onChanged!(false);
	break;
	}
	sendSemanticsEvent(const TapSemanticEvent());
	}

	void _handleTapUp(TapUpDetails details) {
	_downPosition = null;
	if (isInteractive)
	_reactionController.reverse();
	}

	void _handleTapCancel() {
	_downPosition = null;
	if (isInteractive)
	_reactionController.reverse();
	}

	@override
	bool hitTestSelf(Offset position) => true;

	@override
	void handleEvent(PointerEvent event, BoxHitTestEntry entry) {
	assert(debugHandleEvent(event, entry));
	if (event is PointerDownEvent && isInteractive)
	_tap.addPointer(event);
	}

	/// Used by subclasses to paint the radial ink reaction for this control.
	///
	/// The reaction is painted on the given canvas at the given offset. The
	/// origin is the center point of the reaction (usually distinct from the
	/// point at which the user interacted with the control, which is handled
	/// automatically).
	void paintRadialReaction(Canvas canvas, Offset offset, Offset origin) {
	if (!_reaction.isDismissed \|\| !_reactionFocusFade.isDismissed \|\| !_reactionHoverFade.isDismissed) {
	final Paint reactionPaint = Paint()
	..color = Color.lerp(
	Color.lerp(
	Color.lerp(inactiveReactionColor, reactionColor, _position.value),
	hoverColor,
	_reactionHoverFade.value,
	),
	focusColor,
	_reactionFocusFade.value,
	)!;
	final Offset center = Offset.lerp(_downPosition ?? origin, origin, _reaction.value)!;
	final Animatable<double> radialReactionRadiusTween = Tween<double>(
	begin: 0.0,
	end: splashRadius,
	);
	final double reactionRadius = hasFocus \|\| hovering
	? splashRadius
	: radialReactionRadiusTween.evaluate(_reaction);
	if (reactionRadius > 0.0) {
	canvas.drawCircle(center + offset, reactionRadius, reactionPaint);
	}
	}
	}

	@override
	void describeSemanticsConfiguration(SemanticsConfiguration config) {
	super.describeSemanticsConfiguration(config);

	config.isEnabled = isInteractive;
	if (isInteractive)
	config.onTap = _handleTap;
	}

	@override
	void debugFillProperties(DiagnosticPropertiesBuilder properties) {
	super.debugFillProperties(properties);
	properties.add(FlagProperty('value', value: value, ifTrue: 'checked', ifFalse: 'unchecked', showName: true));
	properties.add(FlagProperty('isInteractive', value: isInteractive, ifTrue: 'enabled', ifFalse: 'disabled', defaultValue: true));
	}
	}