// 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/foundation.dart'; import 'basic.dart'; import 'framework.dart'; import 'icon_theme_data.dart'; import 'inherited_theme.dart'; // Examples can assume: // late BuildContext context; /// Controls the default properties of icons in a widget subtree. /// /// The icon theme is honored by [Icon] and [ImageIcon] widgets. class IconTheme extends InheritedTheme { /// Creates an icon theme that controls properties of descendant widgets. /// /// Both [data] and [child] arguments must not be null. const IconTheme({ super.key, required this.data, required super.child, }) : assert(data != null), assert(child != null); /// Creates an icon theme that controls the properties of /// descendant widgets, and merges in the current icon theme, if any. /// /// The [data] and [child] arguments must not be null. static Widget merge({ Key? key, required IconThemeData data, required Widget child, }) { return Builder( builder: (BuildContext context) { return IconTheme( key: key, data: _getInheritedIconThemeData(context).merge(data), child: child, ); }, ); } /// The set of properties to use for icons in this subtree. final IconThemeData data; /// The data from the closest instance of this class that encloses the given /// context, if any. /// /// If there is no ambient icon theme, defaults to [IconThemeData.fallback]. /// The returned [IconThemeData] is concrete (all values are non-null; see /// [IconThemeData.isConcrete]). Any properties on the ambient icon theme that /// are null get defaulted to the values specified on /// [IconThemeData.fallback]. /// /// The [Theme] widget from the `material` library introduces an [IconTheme] /// widget set to the [ThemeData.iconTheme], so in a Material Design /// application, this will typically default to the icon theme from the /// ambient [Theme]. /// /// Typical usage is as follows: /// /// ```dart /// IconThemeData theme = IconTheme.of(context); /// ``` static IconThemeData of(BuildContext context) { final IconThemeData iconThemeData = _getInheritedIconThemeData(context).resolve(context); return iconThemeData.isConcrete ? iconThemeData : iconThemeData.copyWith( size: iconThemeData.size ?? const IconThemeData.fallback().size, fill: iconThemeData.fill ?? const IconThemeData.fallback().fill, weight: iconThemeData.weight ?? const IconThemeData.fallback().weight, grade: iconThemeData.grade ?? const IconThemeData.fallback().grade, opticalSize: iconThemeData.opticalSize ?? const IconThemeData.fallback().opticalSize, color: iconThemeData.color ?? const IconThemeData.fallback().color, opacity: iconThemeData.opacity ?? const IconThemeData.fallback().opacity, shadows: iconThemeData.shadows ?? const IconThemeData.fallback().shadows, ); } static IconThemeData _getInheritedIconThemeData(BuildContext context) { final IconTheme? iconTheme = context.dependOnInheritedWidgetOfExactType<IconTheme>(); return iconTheme?.data ?? const IconThemeData.fallback(); } @override bool updateShouldNotify(IconTheme oldWidget) => data != oldWidget.data; @override Widget wrap(BuildContext context, Widget child) { return IconTheme(data: data, child: child); } @override void debugFillProperties(DiagnosticPropertiesBuilder properties) { super.debugFillProperties(properties); data.debugFillProperties(properties); } }