[**CameraKit Web SDK v1.15.0**](../README.md)

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[CameraKit Web SDK](../globals.md) / LensPerformanceMetrics

# Class: LensPerformanceMetrics

Use to measure lens rendering performance.

The [LensPerformanceMetrics.beginMeasurement](LensPerformanceMetrics.md#beginmeasurement) method is used to start measuring rendering performance. After
a measurement has begun, performance metrics can be read using [LensPerformanceMeasurement](LensPerformanceMeasurement.md).

## Example

```ts
const measurement = cameraKitSession.metrics.beginMeasurement()
// some time later
console.log(measurement.measure())
```

## Methods

### beginMeasurement()

> **beginMeasurement**(): [`LensPerformanceMeasurement`](LensPerformanceMeasurement.md)

Begin a measurement window, during which time rendering metrics will be gathered.

#### Returns

[`LensPerformanceMeasurement`](LensPerformanceMeasurement.md)

A [LensPerformanceMeasurement](LensPerformanceMeasurement.md) representing an ongoing measurement of aggregated rendering
metrics, from which specific metrics can be obtained.

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### destroy()

> **destroy**(): `void`

#### Returns

`void`