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  "identifier" : "/documentation/CoreImage/CIFilter-swift.class/sourceOutCompositing()",
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# sourceOutCompositing()

Subtracts overlapping area of two images to create the output image.

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

## Return Value

The modified image.

## Discussion

This method applies the source-out compositing filter to an image. The effect creates the result by overlaying the input image over the background image. The filter then removes the overlapping area of the background image from the result.

The source-out compositing filter uses the following properties:

- `inputImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).
- `backgroundImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).

The following code creates a filter that results in an output image that shows the portion of the background image that doesn’t overlap with the input image:

```swift
func sourceOutCompositing(inputImage: CIImage, backgroundImage: CIImage) -> CIImage {
    let colorBlendFilter = CIFilter.sourceOutCompositing()
    colorBlendFilter.inputImage = inputImage
    colorBlendFilter.backgroundImage = backgroundImage
    return colorBlendFilter.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 a source-out compositing filter. The filter removes the overlapping area of the beach image from the gradient image, leaving only the top corner of the gradient image.](images/com.apple.coreimage/media-3546394@2x.png)

---

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