vImageClip_PlanarF(_:_:_:_:_:)

Declaration

func vImageClip_PlanarF(_ src: UnsafePointer<vImage_Buffer>, _ dest: UnsafePointer<vImage_Buffer>, _ maxFloat: Pixel_F, _ minFloat: Pixel_F, _ flags: vImage_Flags) -> vImage_Error

Parameters

• src:

  The source vImage buffer.

• dest:

  A pointer to the destination vImage buffer structure. You’re responsible for filling out the Height, Width, and Rowbytes fields of this structure, and for allocating a data buffer of the appropriate size. On return, the data buffer this structure points to contains the destination image data. When you no longer need the data buffer, deallocate the memory to prevent memory leaks.

• maxFloat:

  The maximum pixel value. The function sets source values that are greater than this value to this value.

• minFloat:

  The minimum pixel value. The function sets source values that are less than this value to this value.

• flags:

  The options to use when performing the operation. If your code implements its own tiling or its own multithreading, pass Kvimagedonottile; otherwise, pass Kvimagenoflags.

Return Value

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

Discussion

This function performs the following calculation for each pixel:

 if (pixel > maxFloat)
   pixel = maxFloat;
if (pixel < minFloat)
   pixel = minFloat;

The following code clamps the pixel values [-0.5, -0.25, 0, 0.25, 0.5, 0.75, 1, 1.25, 1.5] to the range 0...1:

let pixelBuffer = vImage.PixelBuffer<vImage.PlanarF>(
    pixelValues: [-0.5, -0.25, 0, 0.25, 0.5, 0.75, 1, 1.25, 1.5],
    size: .init(width: 9, height: 1))

pixelBuffer.withUnsafePointerToVImageBuffer { buf in
    _ = vImageClip_PlanarF(buf,
                           buf,
                           1.0,
                           0.0,
                           vImage_Flags(kvImageNoFlags))
}

// Prints "[0.0, 0.0, 0.0, 0.25, 0.5, 0.75, 1.0, 1.0, 1.0]".
print(pixelBuffer.array)