MacOSScrollViewFlingVelocityTracker class

A VelocityTracker subclass that provides a close approximation of macOS scroll view's velocity estimation strategy.

The estimated velocity reported by this class is a close approximation of the velocity a macOS scroll view would report with the same PointerMoveEvents, when the touch that initiates a fling is released.

This class differs from the VelocityTracker class in that it uses weighted average of the latest few velocity samples of the tracked pointer, instead of doing a linear regression on a relatively large amount of data points, to estimate the velocity of the tracked pointer. Adding data points and estimating the velocity are both cheap.

To obtain a velocity, call getVelocity or getVelocityEstimate. The estimated velocity is typically used as the initial flinging velocity of a Scrollable, when its drag gesture ends.

Inheritance

Constructors

MacOSScrollViewFlingVelocityTracker(PointerDeviceKind kind)
Create a new MacOSScrollViewFlingVelocityTracker.

Properties

hashCode → int
The hash code for this object.
no setterinherited
kind → PointerDeviceKind
The kind of pointer this tracker is for.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

addPosition(Duration time, Offset position) → void
Adds a position as the given time to the tracker.
inherited
getVelocity() → Velocity
Computes the velocity of the pointer at the time of the last provided data point.
inherited
getVelocityEstimate() → VelocityEstimate
Returns an estimate of the velocity of the object being tracked by the tracker given the current information available to the tracker.
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited