ContextPainterObject class abstract

Inheritance

• Object
• Listenable
• CustomPainter
• ContextPainterObject

Mixed-in types

• ChangeNotifier

Constructors

ContextPainterObject({Listenable? repaint})

Properties

ctxAccessor → ContextAccessor?

no setter

hashCode → int

The hash code for this object.

no setter, inherited

hasListeners → bool

Whether any listeners are currently registered.

no setter, inherited

paintRect → Rect?

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

semanticsBuilder → SemanticsBuilderCallback?

Returns a function that builds semantic information for the picture drawn by this painter.

no setter, inherited

Methods

addListener(VoidCallback listener) → void

Register a closure to be called when the object changes.

inherited

asBackground({Widget? child}) → CustomPaint

asForeground({Widget? child}) → CustomPaint

delegatePaint(Canvas canvas, Size size) → void

dispose() → void

Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).

inherited

givePainterCall(ContextAccessor? ctxAccessor) → PainterCall?

该方法使得绘图方法只依赖一次 ctx 并缓存以来的计算数据，比如大小位置信息等。

hitTest(Offset position) → bool?

Called whenever a hit test is being performed on an object that is using this custom paint delegate.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notifyListeners() → void

Call all the registered listeners.

inherited

paint(Canvas canvas, Size size) → void

Called whenever the object needs to paint. The given Canvas has its coordinate space configured such that the origin is at the top left of the box. The area of the box is the size of the size argument.

override

paintContext(ContextAccessor? ctxAccessor, Canvas ctxCanvas, Size ctxSize) → void

该方法使得绘图方法次次依赖实时的 ctx 数据，可能造成性能影响

removeListener(VoidCallback listener) → void

Remove a previously registered closure from the list of closures that are notified when the object changes.

inherited

shouldRebuildSemantics(covariant CustomPainter oldDelegate) → bool

Called whenever a new instance of the custom painter delegate class is provided to the RenderCustomPaint object, or any time that a new CustomPaint object is created with a new instance of the custom painter delegate class (which amounts to the same thing, because the latter is implemented in terms of the former).

inherited

shouldRepaint(covariant CustomPainter oldDelegate) → bool

Called whenever a new instance of the custom painter delegate class is provided to the RenderCustomPaint object, or any time that a new CustomPaint object is created with a new instance of the custom painter delegate class (which amounts to the same thing, because the latter is implemented in terms of the former).

override

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited