# Flattening data Perform an alpha composite of a four-channel image over a solid background color. ## Topics ### Flattening 4-channel, 8-bit images [`func vImageFlatten_ARGB8888(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGB8888(_:_:_:_:_:)) Performs an alpha composite of an 8-bit-per-channel, 4-channel ARGB buffer over a solid background color. [`func vImageFlatten_RGBA8888(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBA8888(_:_:_:_:_:)) Performs an alpha composite of an 8-bit-per-channel, 4-channel RGBA buffer over a solid background color. ### Flattening 4-channel, 8-bit images to three channels [`func vImageFlatten_ARGB8888ToRGB888(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGB8888ToRGB888(_:_:_:_:_:)) Flattens an 8-bit-per-channel ARGB buffer against a solid background to produce an 8-bit-per-channel RGB result. [`func vImageFlatten_BGRA8888ToRGB888(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_BGRA8888ToRGB888(_:_:_:_:_:)) Flattens an 8-bit-per-channel BGRA buffer against a solid background to produce an 8-bit-per-channel RGB result. [`#define vImageFlatten_BGRA8888ToBGR888(_bgra8888Src, _bgr888Dest, _backgroundColor, _isImagePremultiplied, _flags)`](/documentation/Accelerate/vImageFlatten_BGRA8888ToBGR888) Flattens an 8-bit-per-channel BGRA buffer against a solid background to produce an 8-bit-per-channel BGR result. [`func vImageFlatten_RGBA8888ToRGB888(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBA8888ToRGB888(_:_:_:_:_:)) Flattens an 8-bit-per-channel RGBA buffer against a solid background to produce an 8-bit-per-channel RGB result. [`#define vImageFlatten_RGBA8888ToBGR888(_rgba8888Src, _bgr888Dest, _backgroundColor, _isImagePremultiplied, _flags)`](/documentation/Accelerate/vImageFlatten_RGBA8888ToBGR888) Flattens an 8-bit-per-channel RGBA buffer against a solid background to produce an 8-bit-per-channel BGR result. ### Flattening 4-channel,16-bit images [`func vImageFlatten_ARGB16U(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGB16U(_:_:_:_:_:)) Performs an alpha composite of an unsigned 16-bit-per-channel, 4-channel ARGB buffer over a solid background color. [`func vImageFlatten_RGBA16U(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBA16U(_:_:_:_:_:)) Performs an alpha composite of an unsigned 16-bit-per-channel, 4-channel RGBA buffer over a solid background color. [`func vImageFlatten_RGBA16Q12(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBA16Q12(_:_:_:_:_:)) Performs an alpha composite of a fixed-point 16-bit-per-channel, 4-channel RGBA buffer over a solid background color. [`func vImageFlatten_ARGB16Q12(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGB16Q12(_:_:_:_:_:)) Performs an alpha composite of a fixed-point 16-bit-per-channel, 4-channel ARGB buffer over a solid background color. ### Flattening 4-channel, 32-bit images [`func vImageFlatten_ARGBFFFF(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGBFFFF(_:_:_:_:_:)) Performs an alpha composite of a 32-bit-per-channel, 4-channel ARGB buffer over a solid background color. [`func vImageFlatten_RGBAFFFF(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBAFFFF(_:_:_:_:_:)) Performs an alpha composite of a 32-bit-per-channel, 4-channel RGBA buffer over a solid background color. ### Flattening 4-channel, 32-bit images to three channels [`func vImageFlatten_ARGBFFFFToRGBFFF(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_ARGBFFFFToRGBFFF(_:_:_:_:_:)) Flattens a 32-bit-per-channel ARGB buffer against a solid background to produce a 32-bit-per-channel RGB result. [`func vImageFlatten_BGRAFFFFToRGBFFF(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_BGRAFFFFToRGBFFF(_:_:_:_:_:)) Flattens a 32-bit-per-channel BGRA buffer against a solid background to produce a 32-bit-per-channel RGB result. [`func vImageFlatten_RGBAFFFFToRGBFFF(UnsafePointer, UnsafePointer, UnsafePointer, Bool, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageFlatten_RGBAFFFFToRGBFFF(_:_:_:_:_:)) Flattens a 32-bit-per-channel RGBA buffer against a solid background to produce a 32-bit-per-channel RGB result. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)