---
title: areaMaximumAlpha()
framework: coreimage
role: symbol
role_heading: Type Method
path: coreimage/cifilter-swift.class/areamaximumalpha()
---

# areaMaximumAlpha()

Finds the pixel with the highest alpha value.

## Declaration

```swift
class func areaMaximumAlpha() -> any CIFilter & CIAreaMaximumAlpha
```

## Return Value

Return Value A 1 x 1 size image containing the pixel with the maximum alpha value.

## Discussion

Discussion This filter returns the pixel with highest alpha value in the region defined by extent. The area maximum alpha filter uses the following properties: The following code creates a filter that results in a single pixel image containing the pixel with the highest alpha value: func areaMaximumAlpha(inputImage: CIImage) -> CIImage {     let filter = CIFilter.areaMaximumAlpha()     filter.inputImage = inputImage     filter.extent = CGRect(         x: inputImage.extent.width/2-250,         y: inputImage.extent.height/2-250,         width: 500,         height: 500)     return filter.outputImage! }

## See Also

### Filters

- [areaAverage()](coreimage/cifilter-swift.class/areaaverage().md)
- [areaHistogram()](coreimage/cifilter-swift.class/areahistogram().md)
- [areaLogarithmicHistogram()](coreimage/cifilter-swift.class/arealogarithmichistogram().md)
- [areaMaximum()](coreimage/cifilter-swift.class/areamaximum().md)
- [areaMinimum()](coreimage/cifilter-swift.class/areaminimum().md)
- [areaMinimumAlpha()](coreimage/cifilter-swift.class/areaminimumalpha().md)
- [areaMinMax()](coreimage/cifilter-swift.class/areaminmax().md)
- [areaMinMaxRed()](coreimage/cifilter-swift.class/areaminmaxred().md)
- [columnAverage()](coreimage/cifilter-swift.class/columnaverage().md)
- [histogramDisplay()](coreimage/cifilter-swift.class/histogramdisplay().md)
- [kMeans()](coreimage/cifilter-swift.class/kmeans().md)
- [rowAverage()](coreimage/cifilter-swift.class/rowaverage().md)