# Core Graphics interoperability Pass image data between the Core Graphics framework and the vImage library. ## Discussion The vImage library uses the class as the main type to consume and produce still images. A instance may originate from or images, or from a drawing destination. A typical Core Graphics-based vImage workflow consists of: 1. Selecting a source image, such as a Core Graphics-backed instance. 2. Initializing a vImage buffer from the image’s bitmap data. 3. Performing an operation on the vImage buffer, such as scaling or adjusting gamma. 4. Creating a destination image from the operation result with the same image format as the source image. vImage provides the following functions that simplify interoperation with Core Graphics: - [`vImageBuffer_InitWithCGImage(_:_:_:_:_:)`](/documentation/Accelerate/vImageBuffer_InitWithCGImage(_:_:_:_:_:)) initializes a vImage buffer with the contents of a Core Graphics image. - [`vImageCreateCGImageFromBuffer(_:_:_:_:_:_:)`](/documentation/Accelerate/vImageCreateCGImageFromBuffer(_:_:_:_:_:_:)) creates a Core Graphics image from a vImage buffer. The following code shows a passthrough function that accepts a image, populates a vImage buffer from the image, and generates a image from the buffer. In this example, the call to [`vImageBuffer_InitWithCGImage(_:_:_:_:_:)`](/documentation/Accelerate/vImageBuffer_InitWithCGImage(_:_:_:_:_:)) populates the [`vImage_CGImageFormat`](/documentation/Accelerate/vImage_CGImageFormat) and the [`vImage_Buffer`](/documentation/Accelerate/vImage_Buffer) variables with the properties of the source image: ```swift static func passThrough(sourceImage: CGImage) -> CGImage? { var format = vImage_CGImageFormat() var buffer = vImage_Buffer() defer { buffer.free() } vImageBuffer_InitWithCGImage( &buffer, &format, nil, sourceImage, vImage_Flags(kvImageNoFlags)) // Perform image-processing operations on `buffer`. let destinationCGImage = vImageCreateCGImageFromBuffer( &buffer, &format, nil, nil, vImage_Flags(kvImageNoFlags), nil) return destinationCGImage?.takeRetainedValue() } ``` Pass a fully initialized [`vImage_CGImageFormat`](/documentation/Accelerate/vImage_CGImageFormat) to specify that [`vImageBuffer_InitWithCGImage(_:_:_:_:_:)`](/documentation/Accelerate/vImageBuffer_InitWithCGImage(_:_:_:_:_:)) converts the source image to the format that `format` describes. The following example converts the source image to a three-channel, 8-bit-per-channel RGB image: ```swift static func passThrough(sourceImage: CGImage) -> CGImage? { var format = vImage_CGImageFormat( bitsPerComponent: 8, bitsPerPixel: 8 * 3, colorSpace: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue), renderingIntent: .defaultIntent)! var buffer = vImage_Buffer() defer { buffer.free() } vImageBuffer_InitWithCGImage( &buffer, &format, nil, sourceImage, vImage_Flags(kvImageNoFlags)) // Perform image-processing operations on RGB888 `buffer`. let destinationCGImage = vImageCreateCGImageFromBuffer( &buffer, &format, nil, nil, vImage_Flags(kvImageNoFlags), nil) return destinationCGImage?.takeRetainedValue() } ``` ## Topics ### Initializing vImage buffers from Core Graphics images [`func vImageBuffer_InitWithCGImage(UnsafeMutablePointer, UnsafeMutablePointer, UnsafePointer!, CGImage, vImage_Flags) -> vImage_Error`](/documentation/Accelerate/vImageBuffer_InitWithCGImage(_:_:_:_:_:)) Initializes a vImage buffer with the contents of a Core Graphics image. ### Creating Core Graphics images from vImage buffers [`func vImageCreateCGImageFromBuffer(UnsafePointer, UnsafePointer, ((UnsafeMutableRawPointer?, UnsafeMutableRawPointer?) -> Void)!, UnsafeMutableRawPointer!, vImage_Flags, UnsafeMutablePointer!) -> Unmanaged!`](/documentation/Accelerate/vImageCreateCGImageFromBuffer(_:_:_:_:_:_:)) Creates a Core Graphics image from a vImage buffer. ### Creating Core Graphics image formats [`struct vImage_CGImageFormat`](/documentation/Accelerate/vImage_CGImageFormat) The description of a Core Graphics image. ### Querying Core Graphics image format attributes [`func vImageCGImageFormat_IsEqual(UnsafePointer!, UnsafePointer!) -> Bool`](/documentation/Accelerate/vImageCGImageFormat_IsEqual(_:_:)) Returns a Boolean value that indicates whether two vImage Core Graphics image formats are equal. [`func vImageCGImageFormat_GetComponentCount(UnsafePointer) -> UInt32`](/documentation/Accelerate/vImageCGImageFormat_GetComponentCount(_:)) Calculates the number of color and alpha channels for a specified image format. ### Creating Core Graphics color spaces [`func vImageCreateRGBColorSpaceWithPrimariesAndTransferFunction(UnsafePointer, UnsafePointer, CGColorRenderingIntent, vImage_Flags, UnsafeMutablePointer!) -> Unmanaged!`](/documentation/Accelerate/vImageCreateRGBColorSpaceWithPrimariesAndTransferFunction(_:_:_:_:_:)) Creates an RGB color space based on primitives from Y’CbCr specifications. [`struct vImageRGBPrimaries`](/documentation/Accelerate/vImageRGBPrimaries) A representation of the chromaticity of primaries that define a color space. [`struct vImageTransferFunction`](/documentation/Accelerate/vImageTransferFunction) A transfer function to convert from linear to nonlinear RGB. [`func vImageCreateMonochromeColorSpaceWithWhitePointAndTransferFunction(UnsafePointer, UnsafePointer, CGColorRenderingIntent, vImage_Flags, UnsafeMutablePointer!) -> Unmanaged!`](/documentation/Accelerate/vImageCreateMonochromeColorSpaceWithWhitePointAndTransferFunction(_:_:_:_:_:)) Creates a monochrome color space based on primitives from Y’CbCr specifications. [`struct vImageWhitePoint`](/documentation/Accelerate/vImageWhitePoint) A representation of a white point according to the CIE 1931 color space. --- 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)