---
title: apl
framework: metrickit
role: symbol
role_heading: Type Property
path: metrickit/mxunitaveragepixelluminance/apl
---

# apl

The average number of powered pixels on a OLED display.

## Declaration

```swift
@NSCopying class var apl: MXUnitAveragePixelLuminance { get }
```

## Discussion

Discussion The value of apl is a whole number ranging from 0 to 100. 0 means the display is black with no illuminated pixels. A value of 100 means the display is white with all red, green, and blue components of all pixels illuminated.