---
title: "vImageBuffer_Init(_:_:_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/vimagebuffer_init(_:_:_:_:_:)"
---

# vImageBuffer_Init(_:_:_:_:_:)

Initializes a vImage buffer with a specified width, height, and bits per pixel.

## Declaration

```swift
func vImageBuffer_Init(_ buf: UnsafeMutablePointer<vImage_Buffer>, _ height: vImagePixelCount, _ width: vImagePixelCount, _ pixelBits: UInt32, _ flags: vImage_Flags) -> vImage_Error
```

## Parameters

- `buf`: A valid empty doc://com.apple.accelerate/documentation/Accelerate/vImage_Buffer structure.
- `height`: The height of the image.
- `width`: The width of the image.
- `pixelBits`: The number of bits in a pixel of image data. If pixelBits isn’t divisible by 8, doc://com.apple.accelerate/documentation/Accelerate/vImageBuffer_Init(_:_:_:_:_:) pads each row of pixels to a multiple of a byte. This ensures that two rows don’t share the same byte, and all rows start at the beginning of a byte.
- `flags`: The options to use when performing this operation.

## Return Value

Return Value kvImageNoError; otherwise, one of the error codes in Data Types and Constants.

## Discussion

Discussion This function provides two different operations, depending on whether you pass the kvImageNoAllocate flag. Without the kvImageNoAllocate flag, this function initializes a vImage_Buffer structure with memory that the vImage library sizes and aligns for the best performance. For example, the following code initializes a vImage buffer with the optimal memory size and alignment for a 10 x 5 image: var buffer = vImage_Buffer()

vImageBuffer_Init(     &buffer,     5,    // height     10,   // width     8,    // bits per pixel     vImage_Flags(kvImageNoFlags))

// Prints "vImage_Buffer(data: Optional(...), height: 5, width: 10, rowBytes: 16)". print(buffer) With the kvImageNoAllocate flag, the function returns the memory alignment and overwrites the buffer’s rowBytes property with values that provide the best performance. For example, the following code calls vImageBuffer_Init(_:_:_:_:_:) and uses the computed values to allocate an UnsafeMutableRawPointer: let width = 10 let height = 5

var buffer = vImage_Buffer()

let alignment = vImageBuffer_Init(     &buffer,     vImagePixelCount(height),     vImagePixelCount(width),     8,     vImage_Flags(kvImageNoAllocate))

guard alignment > 0 else {     // A negative value indicates an error.     fatalError() }

let data = UnsafeMutableRawPointer.allocate(     byteCount: buffer.rowBytes * height,     alignment: alignment)

buffer.data = data

// Prints "vImage_Buffer(data: Optional(...), height: 5, width: 10, rowBytes: 16)". print(buffer) In both cases, this function sets the buffer’s width, height, and row bytes properties.

## See Also

### Initializing vImage buffers

- [vImage_Buffer](accelerate/vimage_buffer.md)