## NAME

         nonfft_xformfilter - arrange frequency filter for  use  with
         various transforms

## SYNOPSIS

          #include <stdio.h>
          #include <stdlib.h>
          #include "CVIPdef.h"
          #include "CVIPimage.h"
          #include "CVIPxformfilter.h"

         Image *nonfft_xformfilter(Image *imgP, int  block_size,  int
         dc, FILTER_TYPE filtertype, int p1, float p2, int order)

          <imgP> - pointer to an image
          <block_size> - block size used in transform
          <dc> - 1 = keep DC, 2 = discard DC
          <filtertype> - one of:
                     IDEAL_LOW
                     BUTTER_LOW
                     IDEAL_HIGH
                     BUTTER_HIGH
                     IDEAL_BAND
                     BUTTER_BAND
                     IDEAL_REJECT
                     BUTTER_REJECT
                     HIGH_FREQ_EMPHASIS
          <p1> - for IDEAL_LOW, BUTTER_LOW, IDEAL_HIGH,
                 BUTTER_HIGH: cutoff frequency
               - for IDEAL_BAND, BUTTER_BAND, IDEAL_REJECT,
                 BUTTER_REJECT: inner cutoff frequency
          <p2> - for IDEAL_LOW, BUTTER_LOW, IDEAL_HIGH,
                 BUTTER_HIGH: set to -1
               - for IDEAL_BAND, BUTTER_BAND, IDEAL_REJECT,
                 BUTTER_REJECT: outer cutoff frequency
               - for HIGH_FREQ_EMPHASIS: emphasis offset
          <order> - Butterworth filter order, otherwise -1

## PATH

         $CVIPHOME/XFORMFILTER/nonfft_filter.c

## DESCRIPTION

         This function is an internal function called  by  frequency-
         domain  filters  to  arrange frequency filter values for use
         with various transforms. For example, the dc  value  of  the
         FFT  transform  is  placed in the center of the image, while
         the dc value of the DCT transform is placed  in  the  upper-
         left  corner  of  the image. The nonfft_xformfilter function
         places the center of the filter in the appropriate location.

         Not normally called directly by a user.

## TYPES AND CONSTANTS

          typedef enum {
              IDEAL_LOW = 1,
              BUTTER_LOW = 2,
              IDEAL_HIGH =3 ,
              BUTTER_HIGH = 4,
              IDEAL_BAND = 5,
              BUTTER_BAND = 6,
              IDEAL_REJECT = 7,
              BUTTER_REJECT = 8,
              HIGH_FREQ_EMPHASIS = 9
          } FILTER_TYPE;

## RETURN VALUES

         Pointer to an appropriate filter image

## HISTORY

         History information recorded: None

## SEE ALSO

         libxformfilter

## AUTHOR

         Copyright (C) 1996 SIUE - by Scott Umbaugh, Simon  Low,  and
         Greg Hance.