DFTInitAlloc

Allocates memory and fills in context data needed for the image DFT functions to operate.

Syntax

IppStatus ippiDFTInitAlloc_R_32s (IppiDFTSpec_R_32s** ppDFTSpec, IppiSize roiSize, int flag, IppHintAlgorithm hint);

IppStatus ippiDFTInitAlloc_R_32f (IppiDFTSpec_R_32f** ppDFTSpec, IppiSize roiSize, int flag, IppHintAlgorithm hint);

IppStatus ippiDFTInitAlloc_C_32fc (IppiDFTSpec_C_32fc** ppDFTSpec, IppiSize roiSize, int flag, IppHintAlgorithm hint);

Parameters

ppDFTSpec	Pointer to pointer to the DFT context structure being initialized.
roiSize	Size of the source and destination ROI in pixels.
flag	Flag to choose the results normalization option.
hint	Option to select the algorithmic implementation of the transform function (see Table “Hint Arguments for Linear Transform Functions”).

Description

The function ippiDFTInitAlloc is declared in the ippi.h file. This function allocates memory and initializes the context structure pDFTSpec needed to compute the forward and inverse DFT of a two-dimensional image data.

The ippiDFTFwd and ippiDFTInv functions called with the pointer to the initialized pDFTSpec structure as an argument will compute the discrete Fourier transform for points in the ROI of size roiSize, with results normalization mode set according to flag (see Table “Normalization Factors for Fourier Transform Results”), and computation algorithm indicated by hint.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr	Indicates an error condition if pDFTSpec pointer is NULL.
ippStsSizeErr	Indicates an error condition if roiSize has a field with zero or negative value.
ippStsFFTFlagErr	Indicates an error condition if flag has an illegal value.
ippStsMemAllocErr	Indicates an error condition if memory allocation fails.