BoxDecoration class

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 example uses the Container widget from the widgets layer to draw an image with a border:
Container(
  decoration: BoxDecoration(
    color: const Color(0xff7c94b6),
    image: DecorationImage(
      image: ExactAssetImage('images/flowers.jpeg'),
      fit: BoxFit.cover,
    ),
    border: Border.all(
      color: Colors.black,
      width: 8.0,
    ),
  ),
)

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. See also:

Inheritance

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-only, override
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-only, override
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-only, override
shape BoxShape
The shape to fill the background color, gradient, and image into and to cast as the boxShadow. [...]
final
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

createBoxPainter([VoidCallback onChanged ]) → _BoxDecorationPainter
Returns a BoxPainter that will paint this decoration. [...]
override
debugAssertIsValid() bool
In checked 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
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
scale(double factor) BoxDecoration
Returns a new box decoration that is scaled by the given factor.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
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.debug }) String
Returns 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 ==(dynamic other) bool
The equality operator. [...]
override

Static Methods

lerp(BoxDecoration a, BoxDecoration b, double t) BoxDecoration
Linearly interpolate between two box decorations. [...]
override