LinearGradient class
A 2D linear gradient.
This class is used by BoxDecoration to represent linear gradients. This
abstracts out the arguments to the ui.Gradient.linear constructor from
the dart:ui
library.
A gradient has two anchor points, begin and end. The begin point corresponds to 0.0, and the end point corresponds to 1.0. These points are expressed in fractions, so that the same gradient can be reused with varying sized boxes without changing the parameters. (This contrasts with ui.Gradient.linear, whose arguments are expressed in logical pixels.)
The colors are described by a list of Color objects. There must be at least two colors. 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 begin and after end is colored according to tileMode.
Typically this class is used with BoxDecoration, which does the painting. To use a LinearGradient to paint on a canvas directly, see createShader.
To create a local project with this code sample, run:
flutter create --sample=painting.LinearGradient.1 mysample
See also:
- RadialGradient, which displays a gradient in concentric circles, and has an example which shows a different way to use Gradient objects.
- SweepGradient, which displays a gradient in a sweeping arc around a center point.
- BoxDecoration, which can take a LinearGradient in its BoxDecoration.gradient property.
Constructors
-
LinearGradient({AlignmentGeometry begin = Alignment.centerLeft, AlignmentGeometry end = Alignment.centerRight, required List<
Color> colors, List<double> ? stops, TileMode tileMode = TileMode.clamp, GradientTransform? transform}) -
Creates a linear gradient.
const
Properties
- begin → AlignmentGeometry
-
The offset at which stop 0.0 of the gradient is placed.
final
-
colors
→ List<
Color> -
The colors the gradient should obtain at each of the stops.
finalinherited
- end → AlignmentGeometry
-
The offset at which stop 1.0 of the gradient 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
-
stops
→ List<
double> ? -
A list of values from 0.0 to 1.0 that denote fractions along the gradient.
finalinherited
- tileMode → TileMode
-
How this gradient should tile the plane beyond in the region before
begin and after end.
final
- transform → GradientTransform?
-
The transform, if any, to apply to the gradient.
finalinherited
Methods
-
createShader(
Rect rect, {TextDirection? textDirection}) → Shader -
Creates a Shader for this gradient to fill the given rect.
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) → LinearGradient -
Returns a new LinearGradient with its colors scaled by the given factor.
override
-
toString(
) → String -
A string representation of this object.
override
-
withOpacity(
double opacity) → LinearGradient -
Returns a new Gradient with each color set to the given opacity.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
override
Static Methods
-
lerp(
LinearGradient? a, LinearGradient? b, double t) → LinearGradient? -
Linearly interpolate between two LinearGradients.
override