BoxDecoration class Null safety

An immutable description of how to paint a box.

The BoxDecoration class provides a variety of ways to draw a box.

The box has a border, a body, and may cast a boxShadow.

The shape of the box can be a circle or a rectangle. If it is a rectangle, then the borderRadius property controls the roundness of the corners.

The body of the box is painted in layers. The bottom-most layer is the color, which fills the box. Above that is the gradient, which also fills the box. Finally there is the image, the precise alignment of which is controlled by the DecorationImage class.

The border paints over the body; the boxShadow, naturally, paints below it.

The following applies a BoxDecoration to a Container widget to draw an image of an owl with a thick black border and rounded corners.

Container(
  decoration: BoxDecoration(
    color: const Color(0xff7c94b6),
    image: const DecorationImage(
      image: NetworkImage('https://flutter.github.io/assets-for-api-docs/assets/widgets/owl-2.jpg'),
      fit: BoxFit.cover,
    ),
    border: Border.all(
      width: 8,
    ),
    borderRadius: BorderRadius.circular(12),
  ),
)

The shape or the borderRadius won't clip the children of the decorated Container. If the clip is required, insert a clip widget (e.g., ClipRect, ClipRRect, ClipPath) as the child of the Container. Be aware that clipping may be costly in terms of performance.

Constructors

BoxDecoration({Color? color, DecorationImage? image, BoxBorder? border, BorderRadiusGeometry? borderRadius, List<BoxShadow>? boxShadow, Gradient? gradient, BlendMode? backgroundBlendMode, BoxShape shape = BoxShape.rectangle}): Creates a box decoration.
const

Properties

backgroundBlendMode → BlendMode?: The blend mode applied to the color or gradient background of the box.
final
border → BoxBorder?: A border to draw above the background color, gradient, or image.
final
borderRadius → BorderRadiusGeometry?: If non-null, the corners of this box are rounded by this BorderRadius.
final
boxShadow → List<BoxShadow>?: A list of shadows cast by this box behind the box.
final
color → Color?: The color to fill in the background of the box.
final
gradient → Gradient?: A gradient to use when filling the box.
final
hashCode → int: The hash code for this object.
read-onlyoverride
image → DecorationImage?: An image to paint above the background color or gradient.
final
isComplex → bool: Whether this decoration is complex enough to benefit from caching its painting.
read-onlyoverride
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.
read-onlyoverride
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited
shape → BoxShape: The shape to fill the background color, gradient, and image into and to cast as the boxShadow.
final

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.
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.
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
override
getClipPath(Rect rect, TextDirection textDirection) → Path: Returns a closed Path that describes the outer edge of this decoration.
override
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.
override
lerpFrom(Decoration? a, double t) → BoxDecoration?: Linearly interpolates from another Decoration (which may be of a different class) to this.
override
lerpTo(Decoration? b, double t) → BoxDecoration?: Linearly interpolates from this to another Decoration (which may be of a different class).
override
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed.
inherited
scale(double factor) → BoxDecoration: Returns a new box decoration that is scaled by the given factor.
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.
override

Static Methods

lerp(BoxDecoration? a, BoxDecoration? b, double t) → BoxDecoration?: Linearly interpolate between two box decorations.
override