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

# areaHistogram()

Returns a histogram of a specified area of the image.

## Declaration

```swift
class func areaHistogram() -> any CIFilter & CIAreaHistogram
```

## Return Value

Return Value A 1 pixel high image containing the calculated histogram.

## Discussion

Discussion This filter calculates histograms of the red, green, blue, and alpha colors in the region defined by extent. The count property controls the number of bins (or width) of the histogram. The filter scales the histogram so that the total of all the counts in the bins equals scale. The area histogram filter uses the following properties: The following code creates a filter that results in an image that has a height of 1 pixel and a width of 256 pixels. The pixel color components contain the histogram values. func areaHistogram(inputImage: CIImage) -> CIImage {     let filter = CIFilter.areaHistogram()     filter.inputImage = inputImage     filter.count = 256     filter.scale = 50     filter.extent = CGRect(         x: inputImage.extent.width/2-250,         y: inputImage.extent.height/2-250,         width: 500,         height: 500)     return filter.outputImage! } To display the histogram, you can use the histogramDisplay() filter: func histogramDisplay(inputImage: CIImage) -> CIImage {     let filter = CIFilter.histogramDisplay()     filter.inputImage = areaHistogram(inputImage: inputImage)     filter.highLimit = 1     filter.height = 100     filter.lowLimit = 0     return filter.outputImage! }

## See Also

### Filters

- [areaAverage()](coreimage/cifilter-swift.class/areaaverage().md)
- [areaLogarithmicHistogram()](coreimage/cifilter-swift.class/arealogarithmichistogram().md)
- [areaMaximum()](coreimage/cifilter-swift.class/areamaximum().md)
- [areaMaximumAlpha()](coreimage/cifilter-swift.class/areamaximumalpha().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)