packages/flutter/lib/src/material/menu_style.dart - mirrors/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 'dart:ui' show lerpDouble;

 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

 import 'button_style.dart';
 import 'material_state.dart';
 import 'menu_anchor.dart';
 import 'theme.dart';
 import 'theme_data.dart';

 // Examples can assume:
 // late Widget child;
 // late BuildContext context;
 // late MenuStyle style;
 // @immutable
 // class MyAppHome extends StatelessWidget {
 //   const MyAppHome({super.key});
 //   @override
 //   Widget build(BuildContext context) => const SizedBox();
 // }

 /// The visual properties that menus have in common.
 ///
 /// Menus created by [MenuBar] and [MenuAnchor] and their themes have a
 /// [MenuStyle] property which defines the visual properties whose default
 /// values are to be overridden. The default values are defined by the
 /// individual menu widgets and are typically based on overall theme's
 /// [ThemeData.colorScheme] and [ThemeData.textTheme].
 ///
 /// All of the [MenuStyle] properties are null by default.
 ///
 /// Many of the [MenuStyle] properties are [MaterialStateProperty] objects which
 /// resolve to different values depending on the menu's state. For example the
 /// [Color] properties are defined with `MaterialStateProperty<Color>` and can
 /// resolve to different colors depending on if the menu is pressed, hovered,
 /// focused, disabled, etc.
 ///
 /// These properties can override the default value for just one state or all of
 /// them. For example to create a [SubmenuButton] whose background color is the
 /// color scheme’s primary color with 50% opacity, but only when the menu is
 /// pressed, one could write:
 ///
 /// ```dart
 /// SubmenuButton(
 ///   menuStyle: MenuStyle(
 ///     backgroundColor: MaterialStateProperty.resolveWith<Color?>(
 ///       (Set<MaterialState> states) {
 ///         if (states.contains(MaterialState.focused)) {
 ///           return Theme.of(context).colorScheme.primary.withOpacity(0.5);
 ///         }
 ///         return null; // Use the component's default.
 ///       },
 ///     ),
 ///   ),
 ///   menuChildren: const <Widget>[ /* ... */ ],
 ///   child: const Text('Fly me to the moon'),
 /// ),
 /// ```
 ///
 /// In this case the background color for all other menu states would fall back
 /// to the [SubmenuButton]'s default values. To unconditionally set the menu's
 /// [backgroundColor] for all states one could write:
 ///
 /// ```dart
 /// const SubmenuButton(
 ///   menuStyle: MenuStyle(
 ///     backgroundColor: MaterialStatePropertyAll<Color>(Colors.green),
 ///   ),
 ///   menuChildren: <Widget>[ /* ... */ ],
 ///   child: Text('Let me play among the stars'),
 /// ),
 /// ```
 ///
 /// To configure all of the application's menus in the same way, specify the
 /// overall theme's `menuTheme`:
 ///
 /// ```dart
 /// MaterialApp(
 ///   theme: ThemeData(
 ///     menuTheme: const MenuThemeData(
 ///       style: MenuStyle(backgroundColor: MaterialStatePropertyAll<Color>(Colors.red)),
 ///     ),
 ///   ),
 ///   home: const MyAppHome(),
 /// ),
 /// ```
 ///
 /// See also:
 ///
 /// * [MenuAnchor], a widget which hosts cascading menus.
 /// * [MenuBar], a widget which defines a menu bar of buttons hosting cascading
 ///   menus.
 /// * [MenuButtonTheme], the theme for [SubmenuButton]s and [MenuItemButton]s.
 /// * [ButtonStyle], a similar configuration object for button styles.
 @immutable
 class MenuStyle with Diagnosticable {
   /// Create a [MenuStyle].
   const MenuStyle({
     this.backgroundColor,
     this.shadowColor,
     this.surfaceTintColor,
     this.elevation,
     this.padding,
     this.minimumSize,
     this.fixedSize,
     this.maximumSize,
     this.side,
     this.shape,
     this.mouseCursor,
     this.visualDensity,
     this.alignment,
   });

   /// The menu's background fill color.
   final MaterialStateProperty<Color?>? backgroundColor;

   /// The shadow color of the menu's [Material].
   ///
   /// The material's elevation shadow can be difficult to see for dark themes,
   /// so by default the menu classes add a semi-transparent overlay to indicate
   /// elevation. See [ThemeData.applyElevationOverlayColor].
   final MaterialStateProperty<Color?>? shadowColor;

   /// The surface tint color of the menu's [Material].
   ///
   /// See [Material.surfaceTintColor] for more details.
   final MaterialStateProperty<Color?>? surfaceTintColor;

   /// The elevation of the menu's [Material].
   final MaterialStateProperty<double?>? elevation;

   /// The padding between the menu's boundary and its child.
   final MaterialStateProperty<EdgeInsetsGeometry?>? padding;

   /// The minimum size of the menu itself.
   ///
   /// This value must be less than or equal to [maximumSize].
   final MaterialStateProperty<Size?>? minimumSize;

   /// The menu's size.
   ///
   /// This size is still constrained by the style's [minimumSize] and
   /// [maximumSize]. Fixed size dimensions whose value is [double.infinity] are
   /// ignored.
   ///
   /// To specify menus with a fixed width and the default height use `fixedSize:
   /// Size.fromWidth(320)`. Similarly, to specify a fixed height and the default
   /// width use `fixedSize: Size.fromHeight(100)`.
   final MaterialStateProperty<Size?>? fixedSize;

   /// The maximum size of the menu itself.
   ///
   /// A [Size.infinite] or null value for this property means that the menu's
   /// maximum size is not constrained.
   ///
   /// This value must be greater than or equal to [minimumSize].
   final MaterialStateProperty<Size?>? maximumSize;

   /// The color and weight of the menu's outline.
   ///
   /// This value is combined with [shape] to create a shape decorated with an
   /// outline.
   final MaterialStateProperty<BorderSide?>? side;

   /// The shape of the menu's underlying [Material].
   ///
   /// This shape is combined with [side] to create a shape decorated with an
   /// outline.
   final MaterialStateProperty<OutlinedBorder?>? shape;

   /// The cursor for a mouse pointer when it enters or is hovering over this
   /// menu's [InkWell].
   final MaterialStateProperty<MouseCursor?>? mouseCursor;

   /// Defines how compact the menu's layout will be.
   ///
   /// {@macro flutter.material.themedata.visualDensity}
   ///
   /// See also:
   ///
   ///  * [ThemeData.visualDensity], which specifies the [visualDensity] for all
   ///    widgets within a [Theme].
   final VisualDensity? visualDensity;

   /// Determines the desired alignment of the submenu when opened relative to
   /// the button that opens it.
   ///
   /// If there isn't sufficient space to open the menu with the given alignment,
   /// and there's space on the other side of the button, then the alignment is
   /// swapped to it's opposite (1 becomes -1, etc.), and the menu will try to
   /// appear on the other side of the button. If there isn't enough space there
   /// either, then the menu will be pushed as far over as necessary to display
   /// as much of itself as possible, possibly overlapping the parent button.
   final AlignmentGeometry? alignment;

   @override
   int get hashCode {
     final List<Object?> values = <Object?>[
       backgroundColor,
       shadowColor,
       surfaceTintColor,
       elevation,
       padding,
       minimumSize,
       fixedSize,
       maximumSize,
       side,
       shape,
       mouseCursor,
       visualDensity,
       alignment,
     ];
     return Object.hashAll(values);
   }

   @override
   bool operator ==(Object other) {
     if (identical(this, other)) {
       return true;
     }
     if (other.runtimeType != runtimeType) {
       return false;
     }
     return other is MenuStyle
         && other.backgroundColor == backgroundColor
         && other.shadowColor == shadowColor
         && other.surfaceTintColor == surfaceTintColor
         && other.elevation == elevation
         && other.padding == padding
         && other.minimumSize == minimumSize
         && other.fixedSize == fixedSize
         && other.maximumSize == maximumSize
         && other.side == side
         && other.shape == shape
         && other.mouseCursor == mouseCursor
         && other.visualDensity == visualDensity
         && other.alignment == alignment;
   }

   /// Returns a copy of this MenuStyle with the given fields replaced with
   /// the new values.
   MenuStyle copyWith({
     MaterialStateProperty<Color?>? backgroundColor,
     MaterialStateProperty<Color?>? shadowColor,
     MaterialStateProperty<Color?>? surfaceTintColor,
     MaterialStateProperty<double?>? elevation,
     MaterialStateProperty<EdgeInsetsGeometry?>? padding,
     MaterialStateProperty<Size?>? minimumSize,
     MaterialStateProperty<Size?>? fixedSize,
     MaterialStateProperty<Size?>? maximumSize,
     MaterialStateProperty<BorderSide?>? side,
     MaterialStateProperty<OutlinedBorder?>? shape,
     MaterialStateProperty<MouseCursor?>? mouseCursor,
     VisualDensity? visualDensity,
     AlignmentGeometry? alignment,
   }) {
     return MenuStyle(
       backgroundColor: backgroundColor ?? this.backgroundColor,
       shadowColor: shadowColor ?? this.shadowColor,
       surfaceTintColor: surfaceTintColor ?? this.surfaceTintColor,
       elevation: elevation ?? this.elevation,
       padding: padding ?? this.padding,
       minimumSize: minimumSize ?? this.minimumSize,
       fixedSize: fixedSize ?? this.fixedSize,
       maximumSize: maximumSize ?? this.maximumSize,
       side: side ?? this.side,
       shape: shape ?? this.shape,
       mouseCursor: mouseCursor ?? this.mouseCursor,
       visualDensity: visualDensity ?? this.visualDensity,
       alignment: alignment ?? this.alignment,
     );
   }

   /// Returns a copy of this MenuStyle where the non-null fields in [style]
   /// have replaced the corresponding null fields in this MenuStyle.
   ///
   /// In other words, [style] is used to fill in unspecified (null) fields
   /// this MenuStyle.
   MenuStyle merge(MenuStyle? style) {
     if (style == null) {
       return this;
     }
     return copyWith(
       backgroundColor: backgroundColor ?? style.backgroundColor,
       shadowColor: shadowColor ?? style.shadowColor,
       surfaceTintColor: surfaceTintColor ?? style.surfaceTintColor,
       elevation: elevation ?? style.elevation,
       padding: padding ?? style.padding,
       minimumSize: minimumSize ?? style.minimumSize,
       fixedSize: fixedSize ?? style.fixedSize,
       maximumSize: maximumSize ?? style.maximumSize,
       side: side ?? style.side,
       shape: shape ?? style.shape,
       mouseCursor: mouseCursor ?? style.mouseCursor,
       visualDensity: visualDensity ?? style.visualDensity,
       alignment: alignment ?? style.alignment,
     );
   }

   /// Linearly interpolate between two [MenuStyle]s.
   static MenuStyle? lerp(MenuStyle? a, MenuStyle? b, double t) {
     if (identical(a, b)) {
       return a;
     }
     return MenuStyle(
       backgroundColor: MaterialStateProperty.lerp<Color?>(a?.backgroundColor, b?.backgroundColor, t, Color.lerp),
       shadowColor: MaterialStateProperty.lerp<Color?>(a?.shadowColor, b?.shadowColor, t, Color.lerp),
       surfaceTintColor: MaterialStateProperty.lerp<Color?>(a?.surfaceTintColor, b?.surfaceTintColor, t, Color.lerp),
       elevation: MaterialStateProperty.lerp<double?>(a?.elevation, b?.elevation, t, lerpDouble),
       padding:  MaterialStateProperty.lerp<EdgeInsetsGeometry?>(a?.padding, b?.padding, t, EdgeInsetsGeometry.lerp),
       minimumSize: MaterialStateProperty.lerp<Size?>(a?.minimumSize, b?.minimumSize, t, Size.lerp),
       fixedSize: MaterialStateProperty.lerp<Size?>(a?.fixedSize, b?.fixedSize, t, Size.lerp),
       maximumSize: MaterialStateProperty.lerp<Size?>(a?.maximumSize, b?.maximumSize, t, Size.lerp),
       side: _LerpSides(a?.side, b?.side, t),
       shape: MaterialStateProperty.lerp<OutlinedBorder?>(a?.shape, b?.shape, t, OutlinedBorder.lerp),
       mouseCursor: t < 0.5 ? a?.mouseCursor : b?.mouseCursor,
       visualDensity: t < 0.5 ? a?.visualDensity : b?.visualDensity,
       alignment: AlignmentGeometry.lerp(a?.alignment, b?.alignment, t),
     );
   }

   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
     properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('backgroundColor', backgroundColor, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('shadowColor', shadowColor, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('surfaceTintColor', surfaceTintColor, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<double?>>('elevation', elevation, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<EdgeInsetsGeometry?>>('padding', padding, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('minimumSize', minimumSize, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('fixedSize', fixedSize, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('maximumSize', maximumSize, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<BorderSide?>>('side', side, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<OutlinedBorder?>>('shape', shape, defaultValue: null));
     properties.add(DiagnosticsProperty<MaterialStateProperty<MouseCursor?>>('mouseCursor', mouseCursor, defaultValue: null));
     properties.add(DiagnosticsProperty<VisualDensity>('visualDensity', visualDensity, defaultValue: null));
     properties.add(DiagnosticsProperty<AlignmentGeometry>('alignment', alignment, defaultValue: null));
   }
 }

 /// A required helper class because [BorderSide.lerp] doesn't support passing or
 /// returning null values.
 class _LerpSides implements MaterialStateProperty<BorderSide?> {
   const _LerpSides(this.a, this.b, this.t);

   final MaterialStateProperty<BorderSide?>? a;
   final MaterialStateProperty<BorderSide?>? b;
   final double t;

   @override
   BorderSide? resolve(Set<MaterialState> states) {
     final BorderSide? resolvedA = a?.resolve(states);
     final BorderSide? resolvedB = b?.resolve(states);
     if (resolvedA == null && resolvedB == null) {
       return null;
     }
     if (resolvedA == null) {
       return BorderSide.lerp(BorderSide(width: 0, color: resolvedB!.color.withAlpha(0)), resolvedB, t);
     }
     if (resolvedB == null) {
       return BorderSide.lerp(resolvedA, BorderSide(width: 0, color: resolvedA.color.withAlpha(0)), t);
     }
     return BorderSide.lerp(resolvedA, resolvedB, t);
   }
 }
	// 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 'dart:ui' show lerpDouble;

	import 'package:flutter/foundation.dart';
	import 'package:flutter/widgets.dart';

	import 'button_style.dart';
	import 'material_state.dart';
	import 'menu_anchor.dart';
	import 'theme.dart';
	import 'theme_data.dart';

	// Examples can assume:
	// late Widget child;
	// late BuildContext context;
	// late MenuStyle style;
	// @immutable
	// class MyAppHome extends StatelessWidget {
	// const MyAppHome({super.key});
	// @override
	// Widget build(BuildContext context) => const SizedBox();
	// }

	/// The visual properties that menus have in common.
	///
	/// Menus created by [MenuBar] and [MenuAnchor] and their themes have a
	/// [MenuStyle] property which defines the visual properties whose default
	/// values are to be overridden. The default values are defined by the
	/// individual menu widgets and are typically based on overall theme's
	/// [ThemeData.colorScheme] and [ThemeData.textTheme].
	///
	/// All of the [MenuStyle] properties are null by default.
	///
	/// Many of the [MenuStyle] properties are [MaterialStateProperty] objects which
	/// resolve to different values depending on the menu's state. For example the
	/// [Color] properties are defined with `MaterialStateProperty<Color>` and can
	/// resolve to different colors depending on if the menu is pressed, hovered,
	/// focused, disabled, etc.
	///
	/// These properties can override the default value for just one state or all of
	/// them. For example to create a [SubmenuButton] whose background color is the
	/// color scheme’s primary color with 50% opacity, but only when the menu is
	/// pressed, one could write:
	///
	/// ```dart
	/// SubmenuButton(
	/// menuStyle: MenuStyle(
	/// backgroundColor: MaterialStateProperty.resolveWith<Color?>(
	/// (Set<MaterialState> states) {
	/// if (states.contains(MaterialState.focused)) {
	/// return Theme.of(context).colorScheme.primary.withOpacity(0.5);
	/// }
	/// return null; // Use the component's default.
	/// },
	/// ),
	/// ),
	/// menuChildren: const <Widget>[ /* ... */ ],
	/// child: const Text('Fly me to the moon'),
	/// ),
	/// ```
	///
	/// In this case the background color for all other menu states would fall back
	/// to the [SubmenuButton]'s default values. To unconditionally set the menu's
	/// [backgroundColor] for all states one could write:
	///
	/// ```dart
	/// const SubmenuButton(
	/// menuStyle: MenuStyle(
	/// backgroundColor: MaterialStatePropertyAll<Color>(Colors.green),
	/// ),
	/// menuChildren: <Widget>[ /* ... */ ],
	/// child: Text('Let me play among the stars'),
	/// ),
	/// ```
	///
	/// To configure all of the application's menus in the same way, specify the
	/// overall theme's `menuTheme`:
	///
	/// ```dart
	/// MaterialApp(
	/// theme: ThemeData(
	/// menuTheme: const MenuThemeData(
	/// style: MenuStyle(backgroundColor: MaterialStatePropertyAll<Color>(Colors.red)),
	/// ),
	/// ),
	/// home: const MyAppHome(),
	/// ),
	/// ```
	///
	/// See also:
	///
	/// * [MenuAnchor], a widget which hosts cascading menus.
	/// * [MenuBar], a widget which defines a menu bar of buttons hosting cascading
	/// menus.
	/// * [MenuButtonTheme], the theme for [SubmenuButton]s and [MenuItemButton]s.
	/// * [ButtonStyle], a similar configuration object for button styles.
	@immutable
	class MenuStyle with Diagnosticable {
	/// Create a [MenuStyle].
	const MenuStyle({
	this.backgroundColor,
	this.shadowColor,
	this.surfaceTintColor,
	this.elevation,
	this.padding,
	this.minimumSize,
	this.fixedSize,
	this.maximumSize,
	this.side,
	this.shape,
	this.mouseCursor,
	this.visualDensity,
	this.alignment,
	});

	/// The menu's background fill color.
	final MaterialStateProperty<Color?>? backgroundColor;

	/// The shadow color of the menu's [Material].
	///
	/// The material's elevation shadow can be difficult to see for dark themes,
	/// so by default the menu classes add a semi-transparent overlay to indicate
	/// elevation. See [ThemeData.applyElevationOverlayColor].
	final MaterialStateProperty<Color?>? shadowColor;

	/// The surface tint color of the menu's [Material].
	///
	/// See [Material.surfaceTintColor] for more details.
	final MaterialStateProperty<Color?>? surfaceTintColor;

	/// The elevation of the menu's [Material].
	final MaterialStateProperty<double?>? elevation;

	/// The padding between the menu's boundary and its child.
	final MaterialStateProperty<EdgeInsetsGeometry?>? padding;

	/// The minimum size of the menu itself.
	///
	/// This value must be less than or equal to [maximumSize].
	final MaterialStateProperty<Size?>? minimumSize;

	/// The menu's size.
	///
	/// This size is still constrained by the style's [minimumSize] and
	/// [maximumSize]. Fixed size dimensions whose value is [double.infinity] are
	/// ignored.
	///
	/// To specify menus with a fixed width and the default height use `fixedSize:
	/// Size.fromWidth(320)`. Similarly, to specify a fixed height and the default
	/// width use `fixedSize: Size.fromHeight(100)`.
	final MaterialStateProperty<Size?>? fixedSize;

	/// The maximum size of the menu itself.
	///
	/// A [Size.infinite] or null value for this property means that the menu's
	/// maximum size is not constrained.
	///
	/// This value must be greater than or equal to [minimumSize].
	final MaterialStateProperty<Size?>? maximumSize;

	/// The color and weight of the menu's outline.
	///
	/// This value is combined with [shape] to create a shape decorated with an
	/// outline.
	final MaterialStateProperty<BorderSide?>? side;

	/// The shape of the menu's underlying [Material].
	///
	/// This shape is combined with [side] to create a shape decorated with an
	/// outline.
	final MaterialStateProperty<OutlinedBorder?>? shape;

	/// The cursor for a mouse pointer when it enters or is hovering over this
	/// menu's [InkWell].
	final MaterialStateProperty<MouseCursor?>? mouseCursor;

	/// Defines how compact the menu's layout will be.
	///
	/// {@macro flutter.material.themedata.visualDensity}
	///
	/// See also:
	///
	/// * [ThemeData.visualDensity], which specifies the [visualDensity] for all
	/// widgets within a [Theme].
	final VisualDensity? visualDensity;

	/// Determines the desired alignment of the submenu when opened relative to
	/// the button that opens it.
	///
	/// If there isn't sufficient space to open the menu with the given alignment,
	/// and there's space on the other side of the button, then the alignment is
	/// swapped to it's opposite (1 becomes -1, etc.), and the menu will try to
	/// appear on the other side of the button. If there isn't enough space there
	/// either, then the menu will be pushed as far over as necessary to display
	/// as much of itself as possible, possibly overlapping the parent button.
	final AlignmentGeometry? alignment;

	@override
	int get hashCode {
	final List<Object?> values = <Object?>[
	backgroundColor,
	shadowColor,
	surfaceTintColor,
	elevation,
	padding,
	minimumSize,
	fixedSize,
	maximumSize,
	side,
	shape,
	mouseCursor,
	visualDensity,
	alignment,
	];
	return Object.hashAll(values);
	}

	@override
	bool operator ==(Object other) {
	if (identical(this, other)) {
	return true;
	}
	if (other.runtimeType != runtimeType) {
	return false;
	}
	return other is MenuStyle
	&& other.backgroundColor == backgroundColor
	&& other.shadowColor == shadowColor
	&& other.surfaceTintColor == surfaceTintColor
	&& other.elevation == elevation
	&& other.padding == padding
	&& other.minimumSize == minimumSize
	&& other.fixedSize == fixedSize
	&& other.maximumSize == maximumSize
	&& other.side == side
	&& other.shape == shape
	&& other.mouseCursor == mouseCursor
	&& other.visualDensity == visualDensity
	&& other.alignment == alignment;
	}

	/// Returns a copy of this MenuStyle with the given fields replaced with
	/// the new values.
	MenuStyle copyWith({
	MaterialStateProperty<Color?>? backgroundColor,
	MaterialStateProperty<Color?>? shadowColor,
	MaterialStateProperty<Color?>? surfaceTintColor,
	MaterialStateProperty<double?>? elevation,
	MaterialStateProperty<EdgeInsetsGeometry?>? padding,
	MaterialStateProperty<Size?>? minimumSize,
	MaterialStateProperty<Size?>? fixedSize,
	MaterialStateProperty<Size?>? maximumSize,
	MaterialStateProperty<BorderSide?>? side,
	MaterialStateProperty<OutlinedBorder?>? shape,
	MaterialStateProperty<MouseCursor?>? mouseCursor,
	VisualDensity? visualDensity,
	AlignmentGeometry? alignment,
	}) {
	return MenuStyle(
	backgroundColor: backgroundColor ?? this.backgroundColor,
	shadowColor: shadowColor ?? this.shadowColor,
	surfaceTintColor: surfaceTintColor ?? this.surfaceTintColor,
	elevation: elevation ?? this.elevation,
	padding: padding ?? this.padding,
	minimumSize: minimumSize ?? this.minimumSize,
	fixedSize: fixedSize ?? this.fixedSize,
	maximumSize: maximumSize ?? this.maximumSize,
	side: side ?? this.side,
	shape: shape ?? this.shape,
	mouseCursor: mouseCursor ?? this.mouseCursor,
	visualDensity: visualDensity ?? this.visualDensity,
	alignment: alignment ?? this.alignment,
	);
	}

	/// Returns a copy of this MenuStyle where the non-null fields in [style]
	/// have replaced the corresponding null fields in this MenuStyle.
	///
	/// In other words, [style] is used to fill in unspecified (null) fields
	/// this MenuStyle.
	MenuStyle merge(MenuStyle? style) {
	if (style == null) {
	return this;
	}
	return copyWith(
	backgroundColor: backgroundColor ?? style.backgroundColor,
	shadowColor: shadowColor ?? style.shadowColor,
	surfaceTintColor: surfaceTintColor ?? style.surfaceTintColor,
	elevation: elevation ?? style.elevation,
	padding: padding ?? style.padding,
	minimumSize: minimumSize ?? style.minimumSize,
	fixedSize: fixedSize ?? style.fixedSize,
	maximumSize: maximumSize ?? style.maximumSize,
	side: side ?? style.side,
	shape: shape ?? style.shape,
	mouseCursor: mouseCursor ?? style.mouseCursor,
	visualDensity: visualDensity ?? style.visualDensity,
	alignment: alignment ?? style.alignment,
	);
	}

	/// Linearly interpolate between two [MenuStyle]s.
	static MenuStyle? lerp(MenuStyle? a, MenuStyle? b, double t) {
	if (identical(a, b)) {
	return a;
	}
	return MenuStyle(
	backgroundColor: MaterialStateProperty.lerp<Color?>(a?.backgroundColor, b?.backgroundColor, t, Color.lerp),
	shadowColor: MaterialStateProperty.lerp<Color?>(a?.shadowColor, b?.shadowColor, t, Color.lerp),
	surfaceTintColor: MaterialStateProperty.lerp<Color?>(a?.surfaceTintColor, b?.surfaceTintColor, t, Color.lerp),
	elevation: MaterialStateProperty.lerp<double?>(a?.elevation, b?.elevation, t, lerpDouble),
	padding: MaterialStateProperty.lerp<EdgeInsetsGeometry?>(a?.padding, b?.padding, t, EdgeInsetsGeometry.lerp),
	minimumSize: MaterialStateProperty.lerp<Size?>(a?.minimumSize, b?.minimumSize, t, Size.lerp),
	fixedSize: MaterialStateProperty.lerp<Size?>(a?.fixedSize, b?.fixedSize, t, Size.lerp),
	maximumSize: MaterialStateProperty.lerp<Size?>(a?.maximumSize, b?.maximumSize, t, Size.lerp),
	side: _LerpSides(a?.side, b?.side, t),
	shape: MaterialStateProperty.lerp<OutlinedBorder?>(a?.shape, b?.shape, t, OutlinedBorder.lerp),
	mouseCursor: t < 0.5 ? a?.mouseCursor : b?.mouseCursor,
	visualDensity: t < 0.5 ? a?.visualDensity : b?.visualDensity,
	alignment: AlignmentGeometry.lerp(a?.alignment, b?.alignment, t),
	);
	}

	@override
	void debugFillProperties(DiagnosticPropertiesBuilder properties) {
	super.debugFillProperties(properties);
	properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('backgroundColor', backgroundColor, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('shadowColor', shadowColor, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<Color?>>('surfaceTintColor', surfaceTintColor, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<double?>>('elevation', elevation, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<EdgeInsetsGeometry?>>('padding', padding, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('minimumSize', minimumSize, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('fixedSize', fixedSize, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<Size?>>('maximumSize', maximumSize, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<BorderSide?>>('side', side, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<OutlinedBorder?>>('shape', shape, defaultValue: null));
	properties.add(DiagnosticsProperty<MaterialStateProperty<MouseCursor?>>('mouseCursor', mouseCursor, defaultValue: null));
	properties.add(DiagnosticsProperty<VisualDensity>('visualDensity', visualDensity, defaultValue: null));
	properties.add(DiagnosticsProperty<AlignmentGeometry>('alignment', alignment, defaultValue: null));
	}
	}

	/// A required helper class because [BorderSide.lerp] doesn't support passing or
	/// returning null values.
	class _LerpSides implements MaterialStateProperty<BorderSide?> {
	const _LerpSides(this.a, this.b, this.t);

	final MaterialStateProperty<BorderSide?>? a;
	final MaterialStateProperty<BorderSide?>? b;
	final double t;

	@override
	BorderSide? resolve(Set<MaterialState> states) {
	final BorderSide? resolvedA = a?.resolve(states);
	final BorderSide? resolvedB = b?.resolve(states);
	if (resolvedA == null && resolvedB == null) {
	return null;
	}
	if (resolvedA == null) {
	return BorderSide.lerp(BorderSide(width: 0, color: resolvedB!.color.withAlpha(0)), resolvedB, t);
	}
	if (resolvedB == null) {
	return BorderSide.lerp(resolvedA, BorderSide(width: 0, color: resolvedA.color.withAlpha(0)), t);
	}
	return BorderSide.lerp(resolvedA, resolvedB, t);
	}
	}