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BroadcastFrameClock

class BroadcastFrameClock : MonotonicFrameClock
kotlin.Any
   ↳ androidx.compose.runtime.dispatch.BroadcastFrameClock

A simple frame clock.

This implementation is intended for low-contention environments involving low total numbers of threads in a pool on the order of ~number of CPU cores available for UI recomposition work, while avoiding additional allocation where possible.

onNewAwaiters will be invoked whenever the number of awaiters has changed from 0 to 1. If onNewAwaiters fails by throwing an exception it will permanently fail this BroadcastFrameClock; all current and future awaiters will resume with the thrown exception.

Summary

Public constructors
<init>(onNewAwaiters: () -> Unit = null)

A simple frame clock.

Public methods
Unit
cancel(cancellationException: CancellationException = CancellationException("clock cancelled"))

Permanently cancel this BroadcastFrameClock and cancel all current and future awaiters with cancellationException.

Unit
sendFrame(timeNanos: Long)

suspend R
withFrameNanos(onFrame: (Long) -> R)

Suspends until a new frame is requested, immediately invokes onFrame with the frame time in nanoseconds in the calling context of frame dispatch, then resumes with the result from onFrame.

Inherited extension functions
From androidx.compose.runtime.dispatch
suspend R
MonotonicFrameClock.withFrameMillis(crossinline onFrame: (frameTimeMillis: Long) -> R)

Suspends until a new frame is requested, immediately invokes onFrame with the frame time in nanoseconds in the calling context of frame dispatch, then resumes with the result from onFrame.

Properties
Boolean

Inherited properties

Public constructors

<init>

BroadcastFrameClock(onNewAwaiters: () -> Unit = null)

A simple frame clock.

This implementation is intended for low-contention environments involving low total numbers of threads in a pool on the order of ~number of CPU cores available for UI recomposition work, while avoiding additional allocation where possible.

onNewAwaiters will be invoked whenever the number of awaiters has changed from 0 to 1. If onNewAwaiters fails by throwing an exception it will permanently fail this BroadcastFrameClock; all current and future awaiters will resume with the thrown exception.

Public methods

cancel

fun cancel(cancellationException: CancellationException = CancellationException("clock cancelled")): Unit

Permanently cancel this BroadcastFrameClock and cancel all current and future awaiters with cancellationException.

sendFrame

fun sendFrame(timeNanos: Long): Unit

withFrameNanos

suspend fun <R> withFrameNanos(onFrame: (Long) -> R): R

Suspends until a new frame is requested, immediately invokes onFrame with the frame time in nanoseconds in the calling context of frame dispatch, then resumes with the result from onFrame.

frameTimeNanos should be used when calculating animation time deltas from frame to frame as it may be normalized to the target time for the frame, not necessarily a direct, "now" value.

The time base of the value provided by withFrameNanos is implementation defined. Time values provided are monotonically increasing; after a call to withFrameNanos completes it must not provide the same value again for a subsequent call.

Properties

hasAwaiters

val hasAwaiters: Boolean