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# Data Types and Constants

Look up type aliases, data types, and constants the vImage library uses.

## Discussion

The vImage library defines data types for planar and interleaved pixel types, a resampling callback filter, and an affine transform. vImage provides constants that specify errors and flags that you pass to a function to specify a variety of processing options.

## Topics

### Pixel Formats

[`typealias Pixel_8`](/documentation/Accelerate/Pixel_8)

A type for a planar, 8-bits-per-channel, unsigned pixel.

[`typealias Pixel_88`](/documentation/Accelerate/Pixel_88)

A type for a two-channel, 8-bits-per-channel, unsigned pixel.

[`typealias Pixel_8888`](/documentation/Accelerate/Pixel_8888)

A type for a four-channel, 8-bits-per-channel, unsigned pixel.

[`typealias Pixel_F`](/documentation/Accelerate/Pixel_F)

A type for a planar, 32-bits-per-channel, floating-point pixel.

[`typealias Pixel_FFFF`](/documentation/Accelerate/Pixel_FFFF)

A type for a four-channel, 32-bits-per-channel, floating-point pixel.

[`typealias Pixel_32U`](/documentation/Accelerate/Pixel_32U)

A type you use for the XRGB2101010 format.

[`typealias Pixel_16U`](/documentation/Accelerate/Pixel_16U)

A type for a planar, 16-bits-per-channel, unsigned pixel.

[`typealias Pixel_ARGB_16U`](/documentation/Accelerate/Pixel_ARGB_16U)

A type for a four-channel, 16-bits-per-channel, unsigned pixel.

[`typealias Pixel_16U16U`](/documentation/Accelerate/Pixel_16U16U)

A type for a two-channel, 16-bits-per-channel, unsigned pixel.

[`typealias Pixel_16Q12`](/documentation/Accelerate/Pixel_16Q12)

A type for a signed 16-bit, fixed-point number with 12 bits of fractional precision.

[`typealias Pixel_16S`](/documentation/Accelerate/Pixel_16S)

A type for a planar, 16-bits-per-channel, signed pixel.

[`typealias Pixel_ARGB_16S`](/documentation/Accelerate/Pixel_ARGB_16S)

A type for a four-channel, 16-bits-per-channel, signed pixel.

[`typealias Pixel_16F`](/documentation/Accelerate/Pixel_16F)

[`typealias Pixel_16F16F`](/documentation/Accelerate/Pixel_16F16F)

[`typealias Pixel_16S16S`](/documentation/Accelerate/Pixel_16S16S)

[`typealias Pixel_ARGB_16F`](/documentation/Accelerate/Pixel_ARGB_16F)

[`typealias Pixel_FF`](/documentation/Accelerate/Pixel_FF)

### Data Types

[`struct vImage_Buffer`](/documentation/Accelerate/vImage_Buffer)

An image buffer that stores an image’s pixel data, dimensions, and row stride.

[`typealias vImagePixelCount`](/documentation/Accelerate/vImagePixelCount)

A type for the number of pixels.

[`struct vImage_AffineTransform`](/documentation/Accelerate/vImage_AffineTransform)

A structure for values that represent an affine transformation.

[`struct vImage_AffineTransform_Double`](/documentation/Accelerate/vImage_AffineTransform_Double)

A structure for values that represent a double-precision affine transformation.

[`typealias vImage_CGAffineTransform`](/documentation/Accelerate/vImage_CGAffineTransform)

A structure for values that represent a Core Graphics–compatible affine transformation.

[`typealias vImage_Error`](/documentation/Accelerate/vImage_Error)

A type for image errors.

[`typealias vImage_Flags`](/documentation/Accelerate/vImage_Flags)

A type for processing options.

[`typealias GammaFunction`](/documentation/Accelerate/GammaFunction)

A type for a gamma function.

[`typealias ResamplingFilter`](/documentation/Accelerate/ResamplingFilter)

A pointer to a resampling filter callback function.

### Constants

  <doc://com.apple.accelerate/documentation/Accelerate/1578972-error-codes>

  <doc://com.apple.accelerate/documentation/Accelerate/1498271-core-video-image-format-errors>

  <doc://com.apple.accelerate/documentation/Accelerate/1578976-processing-flags>

  <doc://com.apple.accelerate/documentation/Accelerate/1533233-dithering-methods>

  <doc://com.apple.accelerate/documentation/Accelerate/availability-flags>

  <doc://com.apple.accelerate/documentation/Accelerate/decode-arrays>

  <doc://com.apple.accelerate/documentation/Accelerate/buffer-types>

[`typealias vImageMatrixType`](/documentation/Accelerate/vImageMatrixType)

An enumeration of RGB -> Y’CbCr conversion matrix types.

[`typealias vImage_WarpInterpolation`](/documentation/Accelerate/vImage_WarpInterpolation)

Constants for selecting the interpolation mode

## See Also

  [vImage Programming Guide](https://developer.apple.com/library/archive/documentation/Performance/Conceptual/vImage/Introduction/Introduction.html#//apple_ref/doc/uid/TP30001001)


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