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
- AccessibilityFeatures
- Additional accessibility features that may be enabled by the platform. [...]
- BackdropFilterEngineLayer
- An opaque handle to a backdrop filter engine layer. [...]
- CallbackHandle
- A wrapper for a raw callback handle. [...]
- Canvas
- An interface for recording graphical operations. [...]
- ChannelBuffers
- Storage of channel messages until the channels are completely routed, i.e. when a message handler is attached to the channel on the framework side. [...]
- ClipPathEngineLayer
- An opaque handle to a clip path engine layer. [...]
- ClipRectEngineLayer
- An opaque handle to a clip rect engine layer. [...]
- ClipRRectEngineLayer
- An opaque handle to a clip rounded rect engine layer. [...]
- 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. [...]
- ColorFilterEngineLayer
- An opaque handle to a color filter engine layer. [...]
- EngineLayer
- A handle for the framework to hold and retain an engine layer across frames.
- FontFeature
- A feature tag and value that affect the selection of glyphs in a font. [...]
- FontWeight
- The thickness of the glyphs used to draw the text
- FrameInfo
- Information for a single frame of an animation. [...]
- FrameTiming
- Time-related performance metrics of a frame. [...]
- 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. [...]
- ImageFilterEngineLayer
- An opaque handle to an image filter engine layer. [...]
- ImageShader
- A shader (as used by Paint.shader) that tiles an image.
- IsolateNameServer
- Static methods to allow for simple sharing of SendPorts across Isolates. [...]
- LineMetrics
- LineMetrics stores the measurements and statistics of a single line in the paragraph. [...]
- Locale
- An identifier used to select a user's language and formatting preferences. [...]
- 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.
- OffsetEngineLayer
- An opaque handle to an offset engine layer. [...]
- OpacityEngineLayer
- An opaque handle to an opacity engine layer. [...]
- 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 sub-paths. [...]
- PathMetricIterator
- Used by PathMetrics to track iteration from one segment of a path to the next for measurement.
- PathMetrics
- An iterable collection of PathMetric objects describing a Path. [...]
- PhysicalShapeEngineLayer
- An opaque handle to a physical shape engine layer. [...]
- Picture
- An object representing a sequence of recorded graphical operations. [...]
- PictureRecorder
- Records a Picture containing a sequence of graphical operations. [...]
- PluginUtilities
- Functionality for Flutter plugin authors. [...]
- 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.
- ShaderMaskEngineLayer
- An opaque handle to a shader mask engine layer. [...]
- Shadow
- A single shadow. [...]
- Size
- Holds a 2D floating-point size. [...]
- StrutStyle
- See also: [...]
- 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.
- TextHeightBehavior
-
Defines how the paragraph will apply
TextStyle.heightto the ascent of the first line and descent of the last line. [...] - TextPosition
- A position in a string of text. [...]
- TextRange
- A range of characters in a string of text.
- TextStyle
- An opaque object that determines the size, position, and rendering of text. [...]
- TransformEngineLayer
- An opaque handle to a transform engine layer. [...]
- 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 preferably read via
MediaQuery.of. [...]
Constants
- keepToString → const _KeepToString
-
Annotation used by Flutter's Dart compiler to indicate that an
Object.toString override should not be replaced with a supercall. [...]
const _KeepToString()
Properties
- channelBuffers → ChannelBuffers
-
ChannelBuffers that allow the storage of messages between the Engine and the Framework. Typically messages that can't be delivered are stored here until the Framework is able to process them. [...]final - window → Window
-
The Window singleton. [...]
final
Functions
-
decodeImageFromList(
Uint8List list, ImageDecoderCallback callback) → void - Loads a single image frame from a byte array into an Image object. [...]
-
decodeImageFromPixels(
Uint8List pixels, int width, int height, PixelFormat format, ImageDecoderCallback callback, { int rowBytes int targetWidth int targetHeight }) → void - Convert an array of pixel values 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, { int targetWidth int targetHeight }) → Future< Codec> - Instantiates an image codec Codec object. [...]
-
lerpDouble(
num a, num b, double t) → double - Linearly interpolate between two numbers.
-
loadFontFromList(
Uint8List list, { String fontFamily }) → Future< void> - Loads a font from a buffer and makes it available for rendering text. [...]
-
saveCompilationTrace(
) → List< int> - Returns runtime Dart compilation trace as a UTF-8 encoded memory buffer. [...]
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.
- BoxHeightStyle
- Defines various ways to vertically bound the boxes returned by Paragraph.getBoxesForRange. [...]
- BoxWidthStyle
- Defines various ways to horizontally bound the boxes returned by Paragraph.getBoxesForRange. [...]
- Brightness
- Describes the contrast of a theme or color palette.
- Clip
- Different ways to clip a widget's content.
- 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
- FramePhase
- Various important time points in the lifetime of a frame. [...]
- 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. [...]
- PixelFormat
- The format of pixel data given to decodeImageFromPixels.
- PlaceholderAlignment
- Where to vertically align the placeholder relative to the surrounding text. [...]
- PointerChange
- How the pointer has changed since the last report.
- PointerDeviceKind
- The kind of pointer device.
- PointerSignalKind
-
The kind of
PointerDeviceKind.signal. - 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 segment joins. [...]
- TextAffinity
- A way to disambiguate a TextPosition when its offset could match two different locations in the rendered string. [...]
- 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
-
DrainChannelCallback(
ByteData, PlatformMessageResponseCallback ) → Future< void> - Signature for ChannelBuffers.drain.
-
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.
-
TimingsCallback(
List< FrameTiming> timings) → void - Signature for Window.onReportTimings. [...]
-
VoidCallback(
) → void - Signature of callbacks that have no arguments and return no data.