multiply(by:divisor:preBias:postBias:destination:)

Declaration

func multiply(by factor: Int, divisor: Int, preBias: Int, postBias: Int, destination: vImage.PixelBuffer<vImage.Planar8>)

Parameters

• factor:

  The multiplication factor.

• divisor:

  A value that the function divides the result by. The function treats 0 as 1.

• preBias:

  A value that the function adds to the source before multiplication.

• postBias:

  A value that the function adds to the result after multiplication.

• destination:

  The destination pixel buffer.

Discussion

This function applies the following operation to each pixel:

destination = (((source + preBias) * factor) + postBias) / divisor

For example, the following code multiplies each pixel value in an 8-bit planar buffer by 2 and adds 5:

  let buffer = vImage.PixelBuffer<vImage.Planar8>(
       pixelValues: [10, 20, 30, 40,
                     50, 60, 70, 80],
       size: vImage.Size(width: 4,
                         height: 2))

   buffer.multiply(by: 2,
                   divisor: 1,
                   preBias: 0, postBias: 5,
                   destination: buffer)

   // Prints
   // [  25,  45,  65,  85,
   //   105, 125, 145, 165 ]
   print(buffer.array)

See Also

Scalar Multiplication

• multiply(by:preBias:postBias:destination:)