/* im_c2imag ... get imaginary part
 *
 * Copyright: 1990, N. Dessipris.
 *
 * Author: Nicos Dessipris
 * Written on: 12/02/1990
 * Modified on : 09/05/1990
 * 21/12/94 JC
 *	- im_c2amph() adapted to make im_c2real() and im_c2imag()
 * 27/1/10
 * 	- modernised
 * 	- gtk-doc
 */

/*

    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 <stdlib.h>
#include <math.h>

#include <vips/vips.h>

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/

#define loop(TYPE) { \
	TYPE *p = (TYPE *) in + 1; \
	TYPE *q = (TYPE *) out; \
	int x; \
	\
	for( x = 0; x < n; x++ ) { \
		q[x] = *p; \
		p += 2; \
	} \
}

/* c2imag buffer processor.
 */
static void
buffer_c2imag( void *in, void *out, int w, IMAGE *im )
{
	int n = w * im->Bands;

	switch( im->BandFmt ) {
		case IM_BANDFMT_DPCOMPLEX:      loop(double); break; 
		case IM_BANDFMT_COMPLEX:        loop(float); break;
		default:
			g_assert( 0 );
	}
}

/**
 * im_c2imag:
 * @in: input image
 * @out: output image
 *
 * Extract the imaginary part of a complex image.
 *
 * See also: im_c2real().
 *
 * Returns: 0 on success, -1 on error
 */
int 
im_c2imag( IMAGE *in, IMAGE *out )
{
	if( im_check_uncoded( "im_c2imag", in ) ||
		im_check_complex( "im_c2imag", in ) ||
		im_cp_desc( out, in ) )
                return( -1 );

	/* Output will be float or double.
	 */
	if( in->BandFmt == IM_BANDFMT_DPCOMPLEX ) 
		out->BandFmt = IM_BANDFMT_DOUBLE;
	else 
		out->BandFmt = IM_BANDFMT_FLOAT;

        if( im_wrapone( in, out,
                (im_wrapone_fn) buffer_c2imag, in, NULL ) )
                return( -1 );

	return( 0 );
}