PulsePainter class

Pulsing ring around the primary target (Material feature-discovery pattern). Opt-in via HintTheme.showPulse; the animation runs only while a step is active with the flag on.

The painter lives in the global overlay layer (full-screen canvas), painted ABOVE the scrim — including the blur scrim, which is a global BackdropFilter layer of its own (a pulse inside the target's follower would end up under the blur). The ring is anchored at the resolver's global translation, so it follows the target while the picture repaints (the animation tick repaints every frame, reading the compositor transform live — no rebuilds, no extra lag).

Inheritance

Constructors

PulsePainter({required Animation<double>? animation, required HintPositionResolver? resolver, required Color color})

Properties

animation → Animation<double>?: The repeating phase in 0..1; null — a static ring at phase 0 (not used in practice: the engine starts the controller only when pulsing).
final
color → Color: final
hashCode → int: The hash code for this object.
no setterinherited
resolver → HintPositionResolver?: The primary target's resolver (hole size at paint time).
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
semanticsBuilder → SemanticsBuilderCallback?: Returns a function that builds semantic information for the picture drawn by this painter.
no setterinherited

Methods

addListener(VoidCallback listener) → void: Register a closure to be notified when it is time to repaint.
inherited
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
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
removeListener(VoidCallback listener) → void: Remove a previously registered closure from the list of closures that the object notifies when it is time to repaint.
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 PulsePainter 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

Static Methods

pulseRing(double phase, Size size, {double expansion = 24}) → (Rect, double): The expanding ring for a pulse phase in 0..1 around a hole of size: (rect, opacity). The rect inflates from the hole by up to expansion (in each direction); the opacity holds for the first half of the phase and fades linearly to zero by the end. Pure — unit-tested directly.