Processing Flags

Set flags on vImage operations to specify processing options.


You can pass multiple flags to a function by adding the flag values together. For example, to leave alpha unchanged and turn off tiling, you can pass:

kvImageLeaveAlphaUnchanged + kvImageDoNotTile

Three of the flags are mutually exclusive: kvImageCopyInPlace, kvImageBackgroundColorFill, and kvImageEdgeExtend. Never pass more than one of these flag values in the same flag parameter.

When passing flags to a function, do not set values for flags that are not used by the function. If the function requires you to set certain flag values, do so. For example, for the convolution function, you must set exactly one of kvImageCopyInPlace, kvImageBackgroundColorFill, and kvImageEdgeExtend. Otherwise the function may return an error. If you don’t want to set flag values, pass kvImageNoFlags.



struct vImage.Options

Set flags on vImage operations to specify processing options.

var kvImageNoFlags: Int

A flag that sets the behavior to the default.

var kvImageLeaveAlphaUnchanged: Int

A flag that restricts the operation to red, green, and blue channels only.

var kvImageDoNotTile: Int

A flag that disables vImage internal tiling routines.

var kvImageHighQualityResampling: Int

A flag that uses a higher quality, slower resampling filter for geometry operations.

var kvImageGetTempBufferSize: Int

A flag that returns the minimum temporary buffer size for the operation, given the parameters provided.

var kvImagePrintDiagnosticsToConsole: Int

A flag that prints a debug message if the operation fails.

var kvImageNoAllocate: Int

A flag that prevents vImage from allocating additional storage.

var kvImageHDRContent: Int

A flag that uses HDR-aware methods.

var kvImageDoNotClamp: Int

A flag that disables clamping in some conversions to floating-point formats.

Edging Modes

var kvImageCopyInPlace: Int

A flag that copies the value of the edge pixel in the source to the destination.

var kvImageBackgroundColorFill: Int

A flag that uses the background color for missing pixels.

var kvImageEdgeExtend: Int

A flag that extends the edges of the image infinitely.

var kvImageTruncateKernel: Int

A flag that uses only the part of the kernel that overlaps the image.