SweepSteps class

A 2D stepping sweep "gradient".

This class represents sweep steps, abstracting out the arguments to the new ui.Gradient.sweep constructor from dart:ui.

A SweepSteps has a center, a startAngle, and an endAngle. The startAngle corresponds to 0.0, and endAngle corresponds to 1.0. These angles are expressed in radians.

The colors are described by a List<Color>. The stops list, if specified, must have the same length as colors. It specifies fractions of the vector from start to end, between 0.0 and 1.0, for each color. If it is null, a uniform distribution is assumed.

The region of the canvas before startAngle and after endAngle is painted according to tileMode.

Typically this class is used with BoxDecoration, which does the painting. To use a SweepSteps to paint directly on a canvas, see createShader.

{@tool snippet}

The left-most example is this `SweepSteps`

the left-most example is this SweepSteps

final stepBowSweep = Container(
  decoration: BoxDecoration(
    gradient: SweepSteps(
      tileMode: TileMode.repeated,
      startAngle: 0.0,
      endAngle: math.pi * 0.5, // ¼ rotation + TileMode.repeated
      // endAngle: math.pi * 2, // full rotation
      colors: [
        Colors.red, Colors.orange, Colors.yellow, Colors.green,
        Colors.blue, Colors.indigo, Colors.purple, Colors.pink,
      ],
    ),
  )
);

{@end-tool}

Constructors

SweepSteps({AlignmentGeometry center = Alignment.center, double startAngle = 0.0, double endAngle = math.pi * 2, required List<Color> colors, List<double>? stops, TileMode tileMode = TileMode.clamp, GradientTransform? transform}): Construct a new SweepSteps type Gradient.
const

Properties

center → AlignmentGeometry: The center of this SweepSteps, as an offset into the (-1.0, -1.0) x (1.0, 1.0) square describing the Gradient which will be mapped onto the paint box.
final
colors → List<Color>: The colors the gradient should obtain at each of the stops.
finalinherited
endAngle → double: The angle in radians at which stop 1.0 of this SweepSteps is placed.
final
hashCode → int: The hash code for this object.
no setteroverride
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
startAngle → double: The angle in radians at which stop 0.0 of this SweepSteps is placed.
final
stops → List<double>?: A list of values from 0.0 to 1.0 that denote fractions along the gradient.
finalinherited
tileMode → TileMode: How this SweepSteps should tile the plane beyond the region before startAngle and after endAngle.
final
transform → GradientTransform?: The transform, if any, to apply to the gradient.
finalinherited

Methods

copyWith({List<Color>? colors, List<double>? stops, AlignmentGeometry? center, double? startAngle, double? endAngle, TileMode? tileMode, GradientTransform? transform}) → SweepSteps: 📋 Returns a new copy of this SweepSteps with any provided optional parameters overriding those of this.
copyWith({List<Color>? colors, List<double>? stops, GradientTransform? transform, TileMode? tileMode, AlignmentGeometry? begin, AlignmentGeometry? end, AlignmentGeometry? center, double? radius, AlignmentGeometry? focal, double? focalRadius, double? startAngle, double? endAngle}) → Gradient: Available on Gradient, provided by the GradientUtils extension
📋 Returns a new copy of this Gradient with any appropriate optional parameters overriding those of this.
createShader(Rect rect, {TextDirection? textDirection}) → Shader: Creates a ui.Gradient.sweep with duplicated colors and stops.
override
lerpFrom(Gradient? a, double t) → Gradient?: Linearly interpolates from another Gradient to this.
override
lerpTo(Gradient? b, double t) → Gradient?: Linearly interpolates from this to another Gradient.
override
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
scale(double factor) → SweepSteps: Returns a new SweepSteps with its colors scaled by the given factor. Since the alpha channel is what receives the scale factor, 0.0 or less results in a gradient that is fully transparent.
override
toString() → String: A string representation of this object.
override
withOpacity(double opacity) → Gradient: Returns a new Gradient with each color set to the given opacity.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
override

Static Methods

lerp(SweepSteps? a, SweepSteps? b, double t) → SweepSteps?: Copied from SweepGradient.
Linearly interpolate between two SweepStepss.
override