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

# maskToAlpha()

Converts an image to a white image with an alpha component.

## Declaration

```swift
class func maskToAlpha() -> any CIFilter & CIMaskToAlpha
```

## Return Value

Return Value The modified image.

## Discussion

Discussion This method applies the mask-to-alpha filter to an image. The value of the alpha component is determined by the grayscale value of the input image. Black pixels become completely transparent, white pixels are completely solid. The mask-to-alpha filter uses the following properties: The following code creates a filter that makes the input image’s background transparent: func maskToAlpha(inputImage: CIImage) -> CIImage {     let maskToAlphaFilter = CIFilter.maskToAlpha()     maskToAlphaFilter.inputImage = inputImage     return maskToAlphaFilter.outputImage! }

## See Also

### Color Effect Filters

- [colorCrossPolynomial()](coreimage/cifilter-swift.class/colorcrosspolynomial().md)
- [colorCube()](coreimage/cifilter-swift.class/colorcube().md)
- [colorCubeWithColorSpace()](coreimage/cifilter-swift.class/colorcubewithcolorspace().md)
- [colorCubesMixedWithMask()](coreimage/cifilter-swift.class/colorcubesmixedwithmask().md)
- [colorCurves()](coreimage/cifilter-swift.class/colorcurves().md)
- [colorInvert()](coreimage/cifilter-swift.class/colorinvert().md)
- [colorMap()](coreimage/cifilter-swift.class/colormap().md)
- [colorMonochrome()](coreimage/cifilter-swift.class/colormonochrome().md)
- [colorPosterize()](coreimage/cifilter-swift.class/colorposterize().md)
- [convertLabToRGB()](coreimage/cifilter-swift.class/convertlabtorgb().md)
- [convertRGBtoLab()](coreimage/cifilter-swift.class/convertrgbtolab().md)
- [dither()](coreimage/cifilter-swift.class/dither().md)
- [documentEnhancer()](coreimage/cifilter-swift.class/documentenhancer().md)
- [falseColor()](coreimage/cifilter-swift.class/falsecolor().md)
- [labDeltaE()](coreimage/cifilter-swift.class/labdeltae().md)