// 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 'package:flutter/rendering.dart'; import 'package:flutter/widgets.dart'; import 'constants.dart'; import 'elevation_overlay.dart'; import 'theme.dart'; /// Signature for the callback used by ink effects to obtain the rectangle for the effect. /// /// Used by [InkHighlight] and [InkSplash], for example. typedef RectCallback = Rect Function(); /// The various kinds of material in material design. Used to /// configure the default behavior of [Material] widgets. /// /// See also: /// /// * [Material], in particular [Material.type]. /// * [kMaterialEdges] enum MaterialType { /// Rectangle using default theme canvas color. canvas, /// Rounded edges, card theme color. card, /// A circle, no color by default (used for floating action buttons). circle, /// Rounded edges, no color by default (used for [MaterialButton] buttons). button, /// A transparent piece of material that draws ink splashes and highlights. /// /// While the material metaphor describes child widgets as printed on the /// material itself and do not hide ink effects, in practice the [Material] /// widget draws child widgets on top of the ink effects. /// A [Material] with type transparency can be placed on top of opaque widgets /// to show ink effects on top of them. /// /// Prefer using the [Ink] widget for showing ink effects on top of opaque /// widgets. transparency } /// The border radii used by the various kinds of material in material design. /// /// See also: /// /// * [MaterialType] /// * [Material] const Map<MaterialType, BorderRadius?> kMaterialEdges = <MaterialType, BorderRadius?>{ MaterialType.canvas: null, MaterialType.card: BorderRadius.all(Radius.circular(2.0)), MaterialType.circle: null, MaterialType.button: BorderRadius.all(Radius.circular(2.0)), MaterialType.transparency: null, }; /// An interface for creating [InkSplash]s and [InkHighlight]s on a material. /// /// Typically obtained via [Material.of]. abstract class MaterialInkController { /// The color of the material. Color? get color; /// The ticker provider used by the controller. /// /// Ink features that are added to this controller with [addInkFeature] should /// use this vsync to drive their animations. TickerProvider get vsync; /// Add an [InkFeature], such as an [InkSplash] or an [InkHighlight]. /// /// The ink feature will paint as part of this controller. void addInkFeature(InkFeature feature); /// Notifies the controller that one of its ink features needs to repaint. void markNeedsPaint(); } /// A piece of material. /// /// The Material widget is responsible for: /// /// 1. Clipping: If [clipBehavior] is not [Clip.none], Material clips its widget /// sub-tree to the shape specified by [shape], [type], and [borderRadius]. /// By default, [clipBehavior] is [Clip.none] for performance considerations. /// 2. Elevation: Material elevates its widget sub-tree on the Z axis by /// [elevation] pixels, and draws the appropriate shadow. /// 3. Ink effects: Material shows ink effects implemented by [InkFeature]s /// like [InkSplash] and [InkHighlight] below its children. /// /// ## The Material Metaphor /// /// Material is the central metaphor in material design. Each piece of material /// exists at a given elevation, which influences how that piece of material /// visually relates to other pieces of material and how that material casts /// shadows. /// /// Most user interface elements are either conceptually printed on a piece of /// material or themselves made of material. Material reacts to user input using /// [InkSplash] and [InkHighlight] effects. To trigger a reaction on the /// material, use a [MaterialInkController] obtained via [Material.of]. /// /// In general, the features of a [Material] should not change over time (e.g. a /// [Material] should not change its [color], [shadowColor] or [type]). /// Changes to [elevation] and [shadowColor] are animated for [animationDuration]. /// Changes to [shape] are animated if [type] is not [MaterialType.transparency] /// and [ShapeBorder.lerp] between the previous and next [shape] values is /// supported. Shape changes are also animated for [animationDuration]. /// /// ## Shape /// /// The shape for material is determined by [shape], [type], and [borderRadius]. /// /// - If [shape] is non null, it determines the shape. /// - If [shape] is null and [borderRadius] is non null, the shape is a /// rounded rectangle, with corners specified by [borderRadius]. /// - If [shape] and [borderRadius] are null, [type] determines the /// shape as follows: /// - [MaterialType.canvas]: the default material shape is a rectangle. /// - [MaterialType.card]: the default material shape is a rectangle with /// rounded edges. The edge radii is specified by [kMaterialEdges]. /// - [MaterialType.circle]: the default material shape is a circle. /// - [MaterialType.button]: the default material shape is a rectangle with /// rounded edges. The edge radii is specified by [kMaterialEdges]. /// - [MaterialType.transparency]: the default material shape is a rectangle. /// /// ## Border /// /// If [shape] is not null, then its border will also be painted (if any). /// /// ## Layout change notifications /// /// If the layout changes (e.g. because there's a list on the material, and it's /// been scrolled), a [LayoutChangedNotification] must be dispatched at the /// relevant subtree. This in particular means that transitions (e.g. /// [SlideTransition]) should not be placed inside [Material] widgets so as to /// move subtrees that contain [InkResponse]s, [InkWell]s, [Ink]s, or other /// widgets that use the [InkFeature] mechanism. Otherwise, in-progress ink /// features (e.g., ink splashes and ink highlights) won't move to account for /// the new layout. /// /// ## Painting over the material /// /// Material widgets will often trigger reactions on their nearest material /// ancestor. For example, [ListTile.hoverColor] triggers a reaction on the /// tile's material when a pointer is hovering over it. These reactions will be /// obscured if any widget in between them and the material paints in such a /// way as to obscure the material (such as setting a [BoxDecoration.color] on /// a [DecoratedBox]). To avoid this behavior, use [InkDecoration] to decorate /// the material itself. /// /// See also: /// /// * [MergeableMaterial], a piece of material that can split and re-merge. /// * [Card], a wrapper for a [Material] of [type] [MaterialType.card]. /// * <https://material.io/design/> class Material extends StatefulWidget { /// Creates a piece of material. /// /// The [type], [elevation], [shadowColor], [borderOnForeground], /// [clipBehavior], and [animationDuration] arguments must not be null. /// Additionally, [elevation] must be non-negative. /// /// If a [shape] is specified, then the [borderRadius] property must be /// null and the [type] property must not be [MaterialType.circle]. If the /// [borderRadius] is specified, then the [type] property must not be /// [MaterialType.circle]. In both cases, these restrictions are intended to /// catch likely errors. const Material({ Key? key, this.type = MaterialType.canvas, this.elevation = 0.0, this.color, this.shadowColor, this.textStyle, this.borderRadius, this.shape, this.borderOnForeground = true, this.clipBehavior = Clip.none, this.animationDuration = kThemeChangeDuration, this.child, }) : assert(type != null), assert(elevation != null && elevation >= 0.0), assert(!(shape != null && borderRadius != null)), assert(animationDuration != null), assert(!(identical(type, MaterialType.circle) && (borderRadius != null || shape != null))), assert(borderOnForeground != null), assert(clipBehavior != null), super(key: key); /// The widget below this widget in the tree. /// /// {@macro flutter.widgets.ProxyWidget.child} final Widget? child; /// The kind of material to show (e.g., card or canvas). This /// affects the shape of the widget, the roundness of its corners if /// the shape is rectangular, and the default color. final MaterialType type; /// {@template flutter.material.material.elevation} /// The z-coordinate at which to place this material relative to its parent. /// /// This controls the size of the shadow below the material and the opacity /// of the elevation overlay color if it is applied. /// /// If this is non-zero, the contents of the material are clipped, because the /// widget conceptually defines an independent printed piece of material. /// /// Defaults to 0. Changing this value will cause the shadow and the elevation /// overlay to animate over [Material.animationDuration]. /// /// The value is non-negative. /// /// See also: /// /// * [ThemeData.applyElevationOverlayColor] which controls the whether /// an overlay color will be applied to indicate elevation. /// * [Material.color] which may have an elevation overlay applied. /// /// {@endtemplate} final double elevation; /// The color to paint the material. /// /// Must be opaque. To create a transparent piece of material, use /// [MaterialType.transparency]. /// /// To support dark themes, if the surrounding /// [ThemeData.applyElevationOverlayColor] is true and [ThemeData.brightness] /// is [Brightness.dark] then a semi-transparent overlay color will be /// composited on top of this color to indicate the elevation. /// /// By default, the color is derived from the [type] of material. final Color? color; /// The color to paint the shadow below the material. /// /// If null, [ThemeData.shadowColor] is used, which defaults to fully opaque black. /// /// Shadows can be difficult to see in a dark theme, so the elevation of a /// surface should be portrayed with an "overlay" in addition to the shadow. /// As the elevation of the component increases, the overlay increases in /// opacity. /// /// See also: /// /// * [ThemeData.applyElevationOverlayColor], which turns elevation overlay /// on or off for dark themes. final Color? shadowColor; /// The typographical style to use for text within this material. final TextStyle? textStyle; /// Defines the material's shape as well its shadow. /// /// If shape is non null, the [borderRadius] is ignored and the material's /// clip boundary and shadow are defined by the shape. /// /// A shadow is only displayed if the [elevation] is greater than /// zero. final ShapeBorder? shape; /// Whether to paint the [shape] border in front of the [child]. /// /// The default value is true. /// If false, the border will be painted behind the [child]. final bool borderOnForeground; /// {@template flutter.material.Material.clipBehavior} /// The content will be clipped (or not) according to this option. /// /// See the enum [Clip] for details of all possible options and their common /// use cases. /// {@endtemplate} /// /// Defaults to [Clip.none], and must not be null. final Clip clipBehavior; /// Defines the duration of animated changes for [shape], [elevation], /// [shadowColor] and the elevation overlay if it is applied. /// /// The default value is [kThemeChangeDuration]. final Duration animationDuration; /// If non-null, the corners of this box are rounded by this /// [BorderRadiusGeometry] value. /// /// Otherwise, the corners specified for the current [type] of material are /// used. /// /// If [shape] is non null then the border radius is ignored. /// /// Must be null if [type] is [MaterialType.circle]. final BorderRadiusGeometry? borderRadius; /// The ink controller from the closest instance of this class that /// encloses the given context. /// /// Typical usage is as follows: /// /// ```dart /// MaterialInkController inkController = Material.of(context); /// ``` /// /// This method can be expensive (it walks the element tree). static MaterialInkController? of(BuildContext context) { return context.findAncestorRenderObjectOfType<_RenderInkFeatures>(); } @override State<Material> createState() => _MaterialState(); @override void debugFillProperties(DiagnosticPropertiesBuilder properties) { super.debugFillProperties(properties); properties.add(EnumProperty<MaterialType>('type', type)); properties.add(DoubleProperty('elevation', elevation, defaultValue: 0.0)); properties.add(ColorProperty('color', color, defaultValue: null)); properties.add(ColorProperty('shadowColor', shadowColor, defaultValue: null)); textStyle?.debugFillProperties(properties, prefix: 'textStyle.'); properties.add(DiagnosticsProperty<ShapeBorder>('shape', shape, defaultValue: null)); properties.add(DiagnosticsProperty<bool>('borderOnForeground', borderOnForeground, defaultValue: true)); properties.add(DiagnosticsProperty<BorderRadiusGeometry>('borderRadius', borderRadius, defaultValue: null)); } /// The default radius of an ink splash in logical pixels. static const double defaultSplashRadius = 35.0; } class _MaterialState extends State<Material> with TickerProviderStateMixin { final GlobalKey _inkFeatureRenderer = GlobalKey(debugLabel: 'ink renderer'); Color? _getBackgroundColor(BuildContext context) { final ThemeData theme = Theme.of(context); Color? color = widget.color; if (color == null) { switch (widget.type) { case MaterialType.canvas: color = theme.canvasColor; break; case MaterialType.card: color = theme.cardColor; break; default: break; } } return color; } @override Widget build(BuildContext context) { final Color? backgroundColor = _getBackgroundColor(context); assert( backgroundColor != null || widget.type == MaterialType.transparency, 'If Material type is not MaterialType.transparency, a color must ' 'either be passed in through the `color` property, or be defined ' 'in the theme (ex. canvasColor != null if type is set to ' 'MaterialType.canvas)', ); Widget? contents = widget.child; if (contents != null) { contents = AnimatedDefaultTextStyle( style: widget.textStyle ?? Theme.of(context).textTheme.bodyText2!, duration: widget.animationDuration, child: contents, ); } contents = NotificationListener<LayoutChangedNotification>( onNotification: (LayoutChangedNotification notification) { final _RenderInkFeatures renderer = _inkFeatureRenderer.currentContext!.findRenderObject()! as _RenderInkFeatures; renderer._didChangeLayout(); return false; }, child: _InkFeatures( key: _inkFeatureRenderer, absorbHitTest: widget.type != MaterialType.transparency, color: backgroundColor, vsync: this, child: contents, ), ); // PhysicalModel has a temporary workaround for a performance issue that // speeds up rectangular non transparent material (the workaround is to // skip the call to ui.Canvas.saveLayer if the border radius is 0). // Until the saveLayer performance issue is resolved, we're keeping this // special case here for canvas material type that is using the default // shape (rectangle). We could go down this fast path for explicitly // specified rectangles (e.g shape RoundedRectangleBorder with radius 0, but // we choose not to as we want the change from the fast-path to the // slow-path to be noticeable in the construction site of Material. if (widget.type == MaterialType.canvas && widget.shape == null && widget.borderRadius == null) { return AnimatedPhysicalModel( curve: Curves.fastOutSlowIn, duration: widget.animationDuration, shape: BoxShape.rectangle, clipBehavior: widget.clipBehavior, borderRadius: BorderRadius.zero, elevation: widget.elevation, color: ElevationOverlay.applyOverlay(context, backgroundColor!, widget.elevation), shadowColor: widget.shadowColor ?? Theme.of(context).shadowColor, animateColor: false, child: contents, ); } final ShapeBorder shape = _getShape(); if (widget.type == MaterialType.transparency) { return _transparentInterior( context: context, shape: shape, clipBehavior: widget.clipBehavior, contents: contents, ); } return _MaterialInterior( curve: Curves.fastOutSlowIn, duration: widget.animationDuration, shape: shape, borderOnForeground: widget.borderOnForeground, clipBehavior: widget.clipBehavior, elevation: widget.elevation, color: backgroundColor!, shadowColor: widget.shadowColor ?? Theme.of(context).shadowColor, child: contents, ); } static Widget _transparentInterior({ required BuildContext context, required ShapeBorder shape, required Clip clipBehavior, required Widget contents, }) { final _ShapeBorderPaint child = _ShapeBorderPaint( shape: shape, child: contents, ); if (clipBehavior == Clip.none) { return child; } return ClipPath( clipper: ShapeBorderClipper( shape: shape, textDirection: Directionality.maybeOf(context), ), clipBehavior: clipBehavior, child: child, ); } // Determines the shape for this Material. // // If a shape was specified, it will determine the shape. // If a borderRadius was specified, the shape is a rounded // rectangle. // Otherwise, the shape is determined by the widget type as described in the // Material class documentation. ShapeBorder _getShape() { if (widget.shape != null) return widget.shape!; if (widget.borderRadius != null) return RoundedRectangleBorder(borderRadius: widget.borderRadius!); switch (widget.type) { case MaterialType.canvas: case MaterialType.transparency: return const RoundedRectangleBorder(); case MaterialType.card: case MaterialType.button: return RoundedRectangleBorder( borderRadius: widget.borderRadius ?? kMaterialEdges[widget.type]!, ); case MaterialType.circle: return const CircleBorder(); } } } class _RenderInkFeatures extends RenderProxyBox implements MaterialInkController { _RenderInkFeatures({ RenderBox? child, required this.vsync, required this.absorbHitTest, this.color, }) : assert(vsync != null), super(child); // This class should exist in a 1:1 relationship with a MaterialState object, // since there's no current support for dynamically changing the ticker // provider. @override final TickerProvider vsync; // This is here to satisfy the MaterialInkController contract. // The actual painting of this color is done by a Container in the // MaterialState build method. @override Color? color; bool absorbHitTest; List<InkFeature>? _inkFeatures; @override void addInkFeature(InkFeature feature) { assert(!feature._debugDisposed); assert(feature._controller == this); _inkFeatures ??= <InkFeature>[]; assert(!_inkFeatures!.contains(feature)); _inkFeatures!.add(feature); markNeedsPaint(); } void _removeFeature(InkFeature feature) { assert(_inkFeatures != null); _inkFeatures!.remove(feature); markNeedsPaint(); } void _didChangeLayout() { if (_inkFeatures != null && _inkFeatures!.isNotEmpty) markNeedsPaint(); } @override bool hitTestSelf(Offset position) => absorbHitTest; @override void paint(PaintingContext context, Offset offset) { if (_inkFeatures != null && _inkFeatures!.isNotEmpty) { final Canvas canvas = context.canvas; canvas.save(); canvas.translate(offset.dx, offset.dy); canvas.clipRect(Offset.zero & size); for (final InkFeature inkFeature in _inkFeatures!) inkFeature._paint(canvas); canvas.restore(); } super.paint(context, offset); } } class _InkFeatures extends SingleChildRenderObjectWidget { const _InkFeatures({ Key? key, this.color, required this.vsync, required this.absorbHitTest, Widget? child, }) : super(key: key, child: child); // This widget must be owned by a MaterialState, which must be provided as the vsync. // This relationship must be 1:1 and cannot change for the lifetime of the MaterialState. final Color? color; final TickerProvider vsync; final bool absorbHitTest; @override _RenderInkFeatures createRenderObject(BuildContext context) { return _RenderInkFeatures( color: color, absorbHitTest: absorbHitTest, vsync: vsync, ); } @override void updateRenderObject(BuildContext context, _RenderInkFeatures renderObject) { renderObject..color = color ..absorbHitTest = absorbHitTest; assert(vsync == renderObject.vsync); } } /// A visual reaction on a piece of [Material]. /// /// To add an ink feature to a piece of [Material], obtain the /// [MaterialInkController] via [Material.of] and call /// [MaterialInkController.addInkFeature]. abstract class InkFeature { /// Initializes fields for subclasses. InkFeature({ required MaterialInkController controller, required this.referenceBox, this.onRemoved, }) : assert(controller != null), assert(referenceBox != null), _controller = controller as _RenderInkFeatures; /// The [MaterialInkController] associated with this [InkFeature]. /// /// Typically used by subclasses to call /// [MaterialInkController.markNeedsPaint] when they need to repaint. MaterialInkController get controller => _controller; final _RenderInkFeatures _controller; /// The render box whose visual position defines the frame of reference for this ink feature. final RenderBox referenceBox; /// Called when the ink feature is no longer visible on the material. final VoidCallback? onRemoved; bool _debugDisposed = false; /// Free up the resources associated with this ink feature. @mustCallSuper void dispose() { assert(!_debugDisposed); assert(() { _debugDisposed = true; return true; }()); _controller._removeFeature(this); onRemoved?.call(); } void _paint(Canvas canvas) { assert(referenceBox.attached); assert(!_debugDisposed); // find the chain of renderers from us to the feature's referenceBox final List<RenderObject> descendants = <RenderObject>[referenceBox]; RenderObject node = referenceBox; while (node != _controller) { node = node.parent! as RenderObject; descendants.add(node); } // determine the transform that gets our coordinate system to be like theirs final Matrix4 transform = Matrix4.identity(); assert(descendants.length >= 2); for (int index = descendants.length - 1; index > 0; index -= 1) descendants[index].applyPaintTransform(descendants[index - 1], transform); paintFeature(canvas, transform); } /// Override this method to paint the ink feature. /// /// The transform argument gives the coordinate conversion from the coordinate /// system of the canvas to the coordinate system of the [referenceBox]. @protected void paintFeature(Canvas canvas, Matrix4 transform); @override String toString() => describeIdentity(this); } /// An interpolation between two [ShapeBorder]s. /// /// This class specializes the interpolation of [Tween] to use [ShapeBorder.lerp]. class ShapeBorderTween extends Tween<ShapeBorder?> { /// Creates a [ShapeBorder] tween. /// /// the [begin] and [end] properties may be null; see [ShapeBorder.lerp] for /// the null handling semantics. ShapeBorderTween({ShapeBorder? begin, ShapeBorder? end}) : super(begin: begin, end: end); /// Returns the value this tween has at the given animation clock value. @override ShapeBorder? lerp(double t) { return ShapeBorder.lerp(begin, end, t); } } /// The interior of non-transparent material. /// /// Animates [elevation], [shadowColor], and [shape]. class _MaterialInterior extends ImplicitlyAnimatedWidget { /// Creates a const instance of [_MaterialInterior]. /// /// The [child], [shape], [clipBehavior], [color], and [shadowColor] arguments /// must not be null. The [elevation] must be specified and greater than or /// equal to zero. const _MaterialInterior({ Key? key, required this.child, required this.shape, this.borderOnForeground = true, this.clipBehavior = Clip.none, required this.elevation, required this.color, required this.shadowColor, Curve curve = Curves.linear, required Duration duration, }) : assert(child != null), assert(shape != null), assert(clipBehavior != null), assert(elevation != null && elevation >= 0.0), assert(color != null), assert(shadowColor != null), super(key: key, curve: curve, duration: duration); /// The widget below this widget in the tree. /// /// {@macro flutter.widgets.ProxyWidget.child} final Widget child; /// The border of the widget. /// /// This border will be painted, and in addition the outer path of the border /// determines the physical shape. final ShapeBorder shape; /// Whether to paint the border in front of the child. /// /// The default value is true. /// If false, the border will be painted behind the child. final bool borderOnForeground; /// {@macro flutter.material.Material.clipBehavior} /// /// Defaults to [Clip.none], and must not be null. final Clip clipBehavior; /// The target z-coordinate at which to place this physical object relative /// to its parent. /// /// The value is non-negative. final double elevation; /// The target background color. final Color color; /// The target shadow color. final Color shadowColor; @override _MaterialInteriorState createState() => _MaterialInteriorState(); @override void debugFillProperties(DiagnosticPropertiesBuilder description) { super.debugFillProperties(description); description.add(DiagnosticsProperty<ShapeBorder>('shape', shape)); description.add(DoubleProperty('elevation', elevation)); description.add(ColorProperty('color', color)); description.add(ColorProperty('shadowColor', shadowColor)); } } class _MaterialInteriorState extends AnimatedWidgetBaseState<_MaterialInterior> { Tween<double>? _elevation; ColorTween? _shadowColor; ShapeBorderTween? _border; @override void forEachTween(TweenVisitor<dynamic> visitor) { _elevation = visitor( _elevation, widget.elevation, (dynamic value) => Tween<double>(begin: value as double), ) as Tween<double>?; _shadowColor = visitor( _shadowColor, widget.shadowColor, (dynamic value) => ColorTween(begin: value as Color), ) as ColorTween?; _border = visitor( _border, widget.shape, (dynamic value) => ShapeBorderTween(begin: value as ShapeBorder), ) as ShapeBorderTween?; } @override Widget build(BuildContext context) { final ShapeBorder shape = _border!.evaluate(animation)!; final double elevation = _elevation!.evaluate(animation); return PhysicalShape( clipper: ShapeBorderClipper( shape: shape, textDirection: Directionality.maybeOf(context), ), clipBehavior: widget.clipBehavior, elevation: elevation, color: ElevationOverlay.applyOverlay(context, widget.color, elevation), shadowColor: _shadowColor!.evaluate(animation)!, child: _ShapeBorderPaint( shape: shape, borderOnForeground: widget.borderOnForeground, child: widget.child, ), ); } } class _ShapeBorderPaint extends StatelessWidget { const _ShapeBorderPaint({ required this.child, required this.shape, this.borderOnForeground = true, }); final Widget child; final ShapeBorder shape; final bool borderOnForeground; @override Widget build(BuildContext context) { return CustomPaint( painter: borderOnForeground ? null : _ShapeBorderPainter(shape, Directionality.maybeOf(context)), foregroundPainter: borderOnForeground ? _ShapeBorderPainter(shape, Directionality.maybeOf(context)) : null, child: child, ); } } class _ShapeBorderPainter extends CustomPainter { _ShapeBorderPainter(this.border, this.textDirection); final ShapeBorder border; final TextDirection? textDirection; @override void paint(Canvas canvas, Size size) { border.paint(canvas, Offset.zero & size, textDirection: textDirection); } @override bool shouldRepaint(_ShapeBorderPainter oldDelegate) { return oldDelegate.border != border; } }