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# additionCompositing()

Blends colors from two images by addition.

```
class func additionCompositing() -> any CIFilter & CICompositeOperation
```

## Return Value

The modified image.

## Discussion

The filter calculates the sum of color components in the two input images to produce a brightening effect. People typically use this filter to add highlights and lens flares.

The addition compositing filter uses the following properties:

- `inputImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).
- `backgroundImage`: An image that the filter applies the effect on with the type [`CIImage`](/documentation/CoreImage/CIImage).

The following code creates a filter that combines the images’ colors to produce one image:

```swift
func additionCompositing(inputImage: CIImage, backgroundImage: CIImage) -> CIImage {
    let additionCompositeFilter = CIFilter.additionCompositing()
    additionCompositeFilter.inputImage = inputImage
    additionCompositeFilter.backgroundImage = backgroundImage
    return additionCompositeFilter.outputImage!
}
```

![The image on the top left shows a beach with multiple palm trees and a rainbow arching across the blue sky.  The image below is a gradient image displaying a gradual color shift from purple to a dark orange. The image on the right shows the output from applying the addition compositing filter. This displays a mix of colors from both images and is brighter.](images/com.apple.coreimage/media-3546408@2x.png)

---

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