---
title: "init(cgImage:cgImageFormat:pixelFormat:)"
framework: accelerate
role: symbol
role_heading: Initializer
path: "accelerate/vimage/pixelbuffer/init(cgimage:cgimageformat:pixelformat:)"
---

# init(cgImage:cgImageFormat:pixelFormat:)

Returns a new pixel buffer initialized from a Core Graphics image.

## Declaration

```swift
init(cgImage: CGImage, cgImageFormat: inout vImage_CGImageFormat, pixelFormat: Format.Type = Format.self) throws
```

## Parameters

- `cgImage`: The source image.
- `cgImageFormat`: The format of the image. Pass an empty doc://com.apple.accelerate/documentation/Accelerate/vImage_CGImageFormat to specify that the function populates cgImageFormat with the properties of the image. Pass a populated doc://com.apple.accelerate/documentation/Accelerate/vImage_CGImageFormat to specify that the function converts the image data to the format you specify.
- `pixelFormat`: The pixel format of the initialized buffer.

## Mentioned in

Converting bitmap data between Core Graphics images and vImage buffers Optimizing image-processing performance

## Discussion

Discussion For example, the following code creates a single-channel, 8-bit per pixel buffer from a CGImage of unknown bit depth. When you pass a populated cgImageFormat, the init(cgImage:cgImageFormat:pixelFormat:) initializer performs the conversion from the CGImage instance’s format to the vImage_CGImageFormat that you specify. Note the bitsPerComponent, bitsPerPixel, colorSpace, and bitmapInfo.  let cgImage = [ ... ]

let pixelFormat = vImage.Planar8.self

var imageFormat = vImage_CGImageFormat(      bitsPerComponent: pixelFormat.bitsPerComponent, // 8      bitsPerPixel: pixelFormat.bitsPerPixel,         // 8      colorSpace: CGColorSpaceCreateDeviceGray(),      bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue))!

let buffer = vImage.PixelBuffer(     cgImage: cgImage,     cgImageFormat: &imageFormat,     pixelFormat: pixelFormat) The following code shows a similar workflow, but it creates a 32-bit per channel RGBA buffer:  let cgImage = [ ... ]

let pixelFormat = vImage.InterleavedFx4.self

var imageFormat = vImage_CGImageFormat(      bitsPerComponent: pixelFormat.bitsPerComponent, // 32      bitsPerPixel: pixelFormat.bitsPerPixel,         // 32 * 4      colorSpace: CGColorSpaceCreateDeviceRGB(),      bitmapInfo: CGBitmapInfo(rawValue:                                  kCGBitmapByteOrder32Host.rawValue |                                  CGBitmapInfo.floatComponents.rawValue |                                  CGImageAlphaInfo.noneSkipLast.rawValue))

let buffer = vImage.PixelBuffer(      cgImage: cgImage,      cgImageFormat: &imageFormat,      pixelFormat: pixelFormat) If you pass an empty cgImageFormat, the init(cgImage:cgImageFormat:pixelFormat:) initializer populates the vImage_CGImageFormat with the properties of the CGImage instance. For example, the following code initializes a pixel buffer from a 8-bit-per-channel, 4-channel RGB image: let cgImage = [ ... ]

var cgImageFormat = vImage_CGImageFormat()

let buffer = try vImage.PixelBuffer(     cgImage: cgImage,     cgImageFormat: &cgImageFormat,     pixelFormat: vImage.Interleaved8x4.self)

// Prints "8  32  1 (`CGColorSpaceModel.rgb.rawValue`)". print(cgImageFormat.bitsPerComponent,       cgImageFormat.bitsPerPixel,       cgImageFormat.colorSpace.takeRetainedValue().model.rawValue) important: If you specify a populated vImage_CGImageFormat, its bits per component and bits per pixel must match those of the buffer’s pixelFormat. If you specify an empty vImage_CGImageFormat, the bits per component and bits per pixel of the CGImage must match those of the buffer’s pixelFormat. important: If you provide a populated vImage_CGImageFormat with properties (such as bit-depth, color space, and channel ordering) that are different from those of the CGImage instance, vImage uses any-to-any conversion as part of the operation. If your app is latency-sensitive, provide either an empty vImage_CGImageFormat or a vImage_CGImageFormat with properties that match the source image to ensure that the operation avoids the conversion step.