fps-meter.md

title
FPS Meter

FPS Meter allows you capture the frames-per-second metrics of your application.

Using FPS Meter

Measuring FPS

Register a callback that will receive the FPS metrics using the addCallBack method. Then call the start method to begin measuring.

import {
  removeCallback,
  start,
  stop,
  addCallback,
  running,
} from '@nativescript/core/fps-meter'

let callbackId: number

export function startFPSMeter(args: EventData) {
  callbackId = addCallback((fps: number, minFps: number | undefined) => {
    console.log(`Frames per seconds: ${fps.toFixed(2)}`)
    console.log(minFps?.toFixed(2))
  })

  start()
  console.log('Is running: ', running())
}

Stop measuring FPS

Remove the registered callback using its id and then call the stop method.

export function stopFPSMeter(args: EventData) {
  removeCallback(callbackId)

  stop()
}

FPS Meter API

addCallback

const callbackId = addCallback(callback: (fps: number, minFps?: number) => void): number

Implement a callback function that will be executed whenever FPS data becomes available. Assign a unique identifier (number) to this callback, facilitating its future removal, if needed.

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start

start()

Starts the frames-per-second meter.

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stop

stop()

Stops the frames-per-second meter.

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removeCallback

removeCallback(callbackId)

Removes the callback with the specified id.

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running

running()

Returns a boolean value indicating whether the frames-per-second meter is currently running.

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Additional Resources

Native Component

• Android: android.view.Choreographer
• iOS: CADisplayLink