dart:ui library

Built-in types and core primitives for a Flutter application.

To use, import dart:ui.

This library exposes the lowest-level services that Flutter frameworks use to bootstrap applications, such as classes for driving the input, graphics text, layout, and rendering subsystems.

Classes

Canvas
An interface for recording graphical operations. [...]
Codec
A handle to an image codec.
Color
An immutable 32 bit color value in ARGB format. [...]
ColorFilter
A description of a color filter to apply when drawing a shape or compositing a layer with a particular Paint. A color filter is a function that takes two colors, and outputs one color. When applied during compositing, it is independently applied to each pixel of the layer being drawn before the entire layer is merged with the destination. [...]
FontWeight
The thickness of the glyphs used to draw the text
FrameInfo
Information for a single frame of an animation. [...]
Gradient
A shader (as used by Paint.shader) that renders a color gradient. [...]
Image
Opaque handle to raw decoded image data (pixels). [...]
ImageFilter
A filter operation to apply to a raster image. [...]
ImageShader
A shader (as used by Paint.shader) that tiles an image.
Locale
An identifier used to select a user's language and formatting preferences, consisting of a language and a country. This is a subset of locale identifiers as defined by BCP 47. [...]
MaskFilter
A mask filter to apply to shapes as they are painted. A mask filter is a function that takes a bitmap of color pixels, and returns another bitmap of color pixels. [...]
Offset
An immutable 2D floating-point offset. [...]
OffsetBase
Base class for Size and Offset, which are both ways to describe a distance as a two-dimensional axis-aligned vector.
Paint
A description of the style to use when drawing on a Canvas. [...]
Paragraph
A paragraph of text. [...]
ParagraphBuilder
Builds a Paragraph containing text with the given styling information. [...]
ParagraphConstraints
Layout constraints for Paragraph objects. [...]
ParagraphStyle
An opaque object that determines the configuration used by ParagraphBuilder to position lines within a Paragraph of text.
Path
A complex, one-dimensional subset of a plane. [...]
PathMetric
Utilities for measuring a Path and extracting subpaths. [...]
PathMetricIterator
Tracks iteration from one segment of a path to the next for measurement.
PathMetrics
An iterable collection of PathMetric objects describing a Path. [...]
Picture
An object representing a sequence of recorded graphical operations. [...]
PictureRecorder
Records a Picture containing a sequence of graphical operations. [...]
PointerData
Information about the state of a pointer.
PointerDataPacket
A sequence of reports about the state of pointers.
Radius
A radius for either circular or elliptical shapes.
Rect
An immutable, 2D, axis-aligned, floating-point rectangle whose coordinates are relative to a given origin. [...]
RRect
An immutable rounded rectangle with the custom radii for all four corners.
RSTransform
A transform consisting of a translation, a rotation, and a uniform scale. [...]
Scene
An opaque object representing a composited scene. [...]
SceneBuilder
Builds a Scene containing the given visuals. [...]
SceneHost
(Fuchsia-only) Hosts content provided by another application.
SemanticsAction
The possible actions that can be conveyed from the operating system accessibility APIs to a semantics node.
SemanticsFlag
A Boolean value that can be associated with a semantics node.
SemanticsUpdate
An opaque object representing a batch of semantics updates. [...]
SemanticsUpdateBuilder
An object that creates SemanticsUpdate objects. [...]
Shader
Base class for objects such as Gradient and ImageShader which correspond to shaders as used by Paint.shader.
Size
Holds a 2D floating-point size. [...]
Tangent
The geometric description of a tangent: the angle at a point. [...]
TextBox
A rectangle enclosing a run of text. [...]
TextDecoration
A linear decoration to draw near the text.
TextPosition
A visual position in a string of text.
TextStyle
An opaque object that determines the size, position, and rendering of text.
Vertices
A set of vertex data used by Canvas.drawVertices.
Window
The most basic interface to the host operating system's user interface. [...]
WindowPadding
A representation of distances for each of the four edges of a rectangle, used to encode the view insets and padding that applications should place around their user interface, as exposed by Window.viewInsets and Window.padding. View insets and padding are preferrably read via MediaQuery.of. [...]

Properties

window Window
The Window singleton. This object exposes the size of the display, the core scheduler API, the input event callback, the graphics drawing API, and other such core services.
final

Functions

decodeImageFromList(Uint8List list, ImageDecoderCallback callback) → void
Loads a single image frame from a byte array into an Image object. [...]
hashList(Iterable<Object> arguments) int
Combine the Object.hashCode values of an arbitrary number of objects from an Iterable into one value. This function will return the same value if given null as if given an empty list.
hashValues(Object arg01, Object arg02, [ Object arg03 = _hashEnd, Object arg04 = _hashEnd, Object arg05 = _hashEnd, Object arg06 = _hashEnd, Object arg07 = _hashEnd, Object arg08 = _hashEnd, Object arg09 = _hashEnd, Object arg10 = _hashEnd, Object arg11 = _hashEnd, Object arg12 = _hashEnd, Object arg13 = _hashEnd, Object arg14 = _hashEnd, Object arg15 = _hashEnd, Object arg16 = _hashEnd, Object arg17 = _hashEnd, Object arg18 = _hashEnd, Object arg19 = _hashEnd, Object arg20 = _hashEnd ]) int
Combine up to twenty objects' hash codes into one value. [...]
instantiateImageCodec(Uint8List list) Future<Codec>
Instantiates an image codec Codec object. [...]
lerpDouble(num a, num b, double t) double
Linearly interpolate between two numbers.

Enums

AppLifecycleState
States that an application can be in. [...]
BlendMode
Algorithms to use when painting on the canvas. [...]
BlurStyle
Styles to use for blurs in MaskFilter objects.
ClipOp
Defines how a new clip region should be merged with the existing clip region. [...]
FilterQuality
Quality levels for image filters. [...]
FontStyle
Whether to slant the glyphs in the font
ImageByteFormat
The format in which image bytes should be returned when using Image.toByteData.
PaintingStyle
Strategies for painting shapes and paths on a canvas. [...]
PathFillType
Determines the winding rule that decides how the interior of a Path is calculated. [...]
PathOperation
Strategies for combining paths. [...]
PointerChange
How the pointer has changed since the last report.
PointerDeviceKind
The kind of pointer device.
PointMode
Defines how a list of points is interpreted when drawing a set of points. [...]
StrokeCap
Styles to use for line endings. [...]
StrokeJoin
Styles to use for line joins. [...]
TextAffinity
Whether a TextPosition is visually upstream or downstream of its offset. [...]
TextAlign
Whether and how to align text horizontally.
TextBaseline
A horizontal line used for aligning text.
TextDecorationStyle
The style in which to draw a text decoration
TextDirection
A direction in which text flows. [...]
TileMode
Defines what happens at the edge of the gradient. [...]
VertexMode
Defines how a list of points is interpreted when drawing a set of triangles. [...]

Typedefs

FrameCallback(Duration duration) → void
Signature for Window.onBeginFrame.
ImageDecoderCallback(Image result) → void
Callback signature for decodeImageFromList.
PlatformMessageCallback(String name, ByteData data, PlatformMessageResponseCallback callback) → void
Signature for Window.onPlatformMessage.
PlatformMessageResponseCallback(ByteData data) → void
Signature for responses to platform messages. [...]
PointerDataPacketCallback(PointerDataPacket packet) → void
Signature for Window.onPointerDataPacket.
SemanticsActionCallback(int id, SemanticsAction action, ByteData args) → void
Signature for Window.onSemanticsAction.
VoidCallback() → void
Signature of callbacks that have no arguments and return no data.