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.

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) → void

Signature for Window.onSemanticsAction.

VoidCallback() → void

Signature of callbacks that have no arguments and return no data.

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.

read-only

Functions

decodeImageFromList(Uint8List list, ImageDecoderCallback callback) → void

Convert an image file from a byte array into an Image object.

hashList(Iterable<Object> args) int

Combine the hashCodes of an arbitrary number of values 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 values' hashCodes into one value.

lerpDouble(num a, num b, double t) double

Linearly interpolate between two numbers.

Enums

AppLifecycleState

States that an application can be in.

BlurStyle

Styles to use for blurs in MaskFilter objects.

FilterQuality

Quality levels for image filters.

FontStyle

Whether to slant the glyphs in the font

PaintingStyle

Strategies for painting shapes and paths on a canvas.

PathFillType

Determines how the interior of a Path is calculated.

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.

TextAffinity

Whether a TextPosition is visually upstream or downstream of its offset.

TextAlign

Whether 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.

TransferMode

Algorithms to use when painting on the canvas.

VertexMode

Defines how a list of points is interpreted when drawing a set of triangles.

Classes

Canvas

An interface for recording graphical operations.

Color

An immutable 32 bit color value in ARGB

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

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 position of lines within a paragraph of text.

Path

A complex, one-dimensional subset of a plane.

Picture

An object representing a sequence of recorded graphical operations.

PictureRecorder

Records a Picture containing a sequence of graphical operations.

Point

An immutable 2D floating-point x,y coordinate pair.

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 an origin point.

RRect

A 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.

SemanticsAction

The possible actions that can be conveyed from the operating system accessibility APIs to a semantics node.

SemanticsFlags

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.

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.

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 padding that applications should place around their user interface, as exposed by Window.padding.