FluentBoxDecoration class

A BoxDecoration whose boxShadow paints the way CSS box-shadow does: outside the box only.

BoxDecoration draws each shadow as a blurred, filled copy of the box under the box. An opaque color hides that, which is why a menu or a card never shows it. A transparent or translucent box does: light-theme shadow16 on a box with no fill washes its whole inside to about 76% of whatever is behind it. Upstream writes boxShadow: tokens.shadow16 on elements with no background all the time, and the browser shows the page through them untouched.

Use this wherever upstream shadows an element that has no opaque background. Everything except the shadows is painted exactly as BoxDecoration paints it. The shadows follow CSS rather than BoxShadow.toPaint:

• they are clipped to outside the decoration's shape, the border box;
• the blur's standard deviation is half of BoxShadow.blurRadius, as the CSS spec defines it, not Shadow.convertRadiusToSigma; and
• the first shadow in the list paints on top, as in CSS, where BoxDecoration puts the last one on top.

BoxShadow.spreadRadius inflates the box without growing its corner radii, as BoxDecoration does, whereas CSS grows them by the spread. BoxShadow.blurStyle is ignored, because CSS has no equivalent.

Inheritance

• Object
• Decoration
• BoxDecoration
• FluentBoxDecoration

Constructors

FluentBoxDecoration({Color? color, DecorationImage? image, BoxBorder? border, BorderRadiusGeometry? borderRadius, List<BoxShadow>? boxShadow, Gradient? gradient, BlendMode? backgroundBlendMode, BoxShape shape = BoxShape.rectangle})

Creates a decoration whose shadows stay outside the box.

const

Properties

backgroundBlendMode → BlendMode?

The blend mode applied to the color or gradient background of the box.

final, inherited

border → BoxBorder?

A border to draw above the background color, gradient, or image.

final, inherited

borderRadius → BorderRadiusGeometry?

If non-null, the corners of this box are rounded by this BorderRadius.

final, inherited

boxShadow → List<BoxShadow>?

A list of shadows cast by this box behind the box.

final, inherited

color → Color?

The color to fill in the background of the box.

final, inherited

gradient → Gradient?

A gradient to use when filling the box.

final, inherited

hashCode → int

The hash code for this object.

no setter, inherited

image → DecorationImage?

An image to paint above the background color or gradient.

final, inherited

isComplex → bool

Whether this decoration is complex enough to benefit from caching its painting.

no setter, inherited

padding → EdgeInsetsGeometry

Returns the insets to apply when using this decoration on a box that has contents, so that the contents do not overlap the edges of the decoration. For example, if the decoration draws a frame around its edge, the padding would return the distance by which to inset the children so as to not overlap the frame.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

shape → BoxShape

The shape to fill the background color, gradient, and image into and to cast as the boxShadow.

final, inherited

Methods

copyWith({Color? color, DecorationImage? image, BoxBorder? border, BorderRadiusGeometry? borderRadius, List<BoxShadow>? boxShadow, Gradient? gradient, BlendMode? backgroundBlendMode, BoxShape? shape}) → BoxDecoration

Creates a copy of this object but with the given fields replaced with the new values.

inherited

createBoxPainter([VoidCallback? onChanged]) → BoxPainter

Returns a BoxPainter that will paint this decoration.

override

debugAssertIsValid() → bool

In debug mode, throws an exception if the object is not in a valid configuration. Otherwise, returns true.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

getClipPath(Rect rect, TextDirection textDirection) → Path

Returns a closed Path that describes the outer edge of this decoration.

inherited

hitTest(Size size, Offset position, {TextDirection? textDirection}) → bool

Tests whether the given point, on a rectangle of a given size, would be considered to hit the decoration or not. For example, if the decoration only draws a circle, this function might return true if the point was inside the circle and false otherwise.

inherited

lerpFrom(Decoration? a, double t) → BoxDecoration?

Linearly interpolates from another Decoration (which may be of a different class) to this.

inherited

lerpTo(Decoration? b, double t) → BoxDecoration?

Linearly interpolates from this to another Decoration (which may be of a different class).

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

scale(double factor) → BoxDecoration

Returns a new box decoration that is scaled by the given factor.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringShort() → String

A brief description of this object, usually just the runtimeType and the hashCode.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited