/* @(#) Filter functions
* &(#) va_alist is a series of double variables
* @(#)
* @(#) Used to filter image in in the frequency domain, writes
* @(#) the result in image out
* @(#)
* @(#) int im_flt_image_freq( in, out, flag, num_args, va_alist )
* @(#) IMAGE *in, *out;
* @(#) enum mask_type flag;
* @(#) int num_args;
* @(#)
* @(#) Returns 0 on success and -1 on error
* @(#)
* @(#) Creates a filter mask used for filtering in the frequency domain
* @(#) The resultant mask is held by image
* @(#)
* @(#) int im_create_fmask(image, xsize, ysize, flag, num_args, va_alist)
* @(#) IMAGE *image;
* @(#) int xsize, ysize;
* @(#) enum mask_type flag;
* @(#) int num_args;
* @(#)
* @(#) Returns 0 on success and -1 on error
* @(#)
* @(#) Creates a filter mask used for filtering in the frequency domain
* @(#) The resultant mask is held by image
* @(#) Function im_freq_mask() differs from im_create_fmask() in the last
* @(#) argument only: the latter accepts a va_dcl whereas the former
* @(#) accepts a va_list pointer pointing to the read arguments of va_dcl
* @(#)
* @(#) int im_freq_mask(image, xs, ys, flag, num_args, ap)
* @(#) IMAGE *image;
* @(#) int xs, ys;
* @(#) enum mask_type flag;
* @(#) int num_args;
* @(#) va_list ap;
* @(#)
* @(#) Returns 0 on success and -1 on error
* @(#)
* Copyright: N. Dessipris 1991,
* Written on: Nov 1991
* Updated on: Dec 1991
* 20/9/95 JC
* - modernised
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <math.h>
#include <stdarg.h>
#include <vips/vips.h>
#include <vips/fmask.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Create the final mask by copying the 1/4 of the mask held by coeff
* The final mask is written onto image on a line by line basis
* The buffer coeff should hold (xsize/2+1)*(ysize/2+1) elms
* The created mask is not rotated; so the center is at (0, 0)
*/
static int
copy_quarter( IMAGE *out, float *coeff_s )
{
float *line, *cpline;
float *coeff, *cpcoeff;
int x, y;
int hxsplus1;
if( !(line = IM_ARRAY( out, out->Xsize, float )) )
return( -1 );
hxsplus1 = out->Xsize/2 + 1;
coeff = coeff_s;
for( y = 0; y < out->Ysize/2; y++ ) {
cpline = line;
cpcoeff = coeff; coeff += hxsplus1;
for( x = 0; x < out->Xsize/2; x++ )
*cpline++ = *cpcoeff++;
for( x = out->Xsize/2; x < out->Xsize; x++ )
*cpline++ = *cpcoeff--;
if( im_writeline( y, out, (PEL *) line ) )
return( -1 );
}
for( y = out->Ysize/2; y < out->Ysize; y++ ) {
cpline = line;
cpcoeff = coeff; coeff -= hxsplus1;
for( x = 0; x < out->Xsize/2; x++ )
*cpline++ = *cpcoeff++;
for( x = out->Xsize/2; x < out->Xsize; x++ )
*cpline++ = *cpcoeff--;
if( im_writeline( y, out, (PEL *) line ) )
return( -1 );
}
return( 0 );
}
/* Make a mask image.
*/
static int
build_freq_mask( IMAGE *out, int xs, int ys, MaskType flag, va_list ap )
{
float *coeff;
extern float *im__create_quarter( IMAGE *,
int, int, MaskType, va_list );
/* Check sizes and create one quarter of the final mask
*/
if( !im_ispoweroftwo( xs ) || !im_ispoweroftwo( ys ) ) {
im_errormsg( "im_freq_mask: mask sizes power of 2 only" );
return( -1 );
}
/* Create the output image.
*/
im_initdesc( out, xs, ys, 1, IM_BBITS_FLOAT, IM_BANDFMT_FLOAT,
IM_CODING_NONE, IM_TYPE_B_W, 1.0, 1.0, 0, 0 );
if( im_setupout( out ) )
return( -1 );
switch( flag ) {
case MASK_IDEAL_HIGHPASS:
case MASK_IDEAL_LOWPASS:
case MASK_BUTTERWORTH_HIGHPASS:
case MASK_BUTTERWORTH_LOWPASS:
case MASK_GAUSS_HIGHPASS:
case MASK_GAUSS_LOWPASS:
case MASK_IDEAL_RINGPASS:
case MASK_IDEAL_RINGREJECT:
case MASK_BUTTERWORTH_RINGPASS:
case MASK_BUTTERWORTH_RINGREJECT:
case MASK_GAUSS_RINGPASS:
case MASK_GAUSS_RINGREJECT:
case MASK_FRACTAL_FLT:
/* All these are created as a quarter and duplicated.
*/
if( !(coeff = im__create_quarter( out, xs, ys, flag, ap )) ||
copy_quarter( out, coeff ) )
return( -1 );
break;
case MASK_IDEAL_BANDPASS:
case MASK_IDEAL_BANDREJECT:
case MASK_BUTTERWORTH_BANDPASS:
case MASK_BUTTERWORTH_BANDREJECT:
case MASK_GAUSS_BANDPASS:
case MASK_GAUSS_BANDREJECT:
/* Created all in one go.
*/
if( im__fmaskcir( out, flag, ap ) )
return( -1 );
break;
default:
im_errormsg( "im_freq_mask: unimplemented mask type" );
return( -1 );
}
return( 0 );
}
/* Create a mask, and filter an image with it.
*/
int
im_flt_image_freq( IMAGE *in, IMAGE *out, MaskType flag, ... )
{
IMAGE *mask = im_open_local( out, "tempmask", "p" );
va_list ap;
if( !mask )
return( -1 );
/* Generate mask.
*/
va_start( ap, flag );
if( build_freq_mask( mask, in->Xsize, in->Ysize, flag, ap ) )
return( -1 );
va_end( ap );
if( im_freqflt( in, mask, out ) )
return( -1 );
return( 0 );
}
/* Create a filter mask.
*/
int
im_create_fmask( IMAGE *out, int xsize, int ysize, MaskType flag, ... )
{
va_list ap;
va_start( ap, flag );
if( build_freq_mask( out, xsize, ysize, flag, ap ) )
return( -1 );
va_end( ap );
return( 0 );
}