libvips/libvips/arithmetic/sign.c
2011-11-18 14:34:33 +00:00

188 lines
4.2 KiB
C

/* im_sign.c
*
* 9/7/02 JC
* - from im_cmulnorm
* 9/9/09
* - gtkdoc, tidies
* 6/11/11
* - redone as a class
*/
/*
Copyright (C) 1991-2005 The National Gallery
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU 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
*/
/*
#define DEBUG
*/
#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>
#include "unary.h"
typedef VipsUnary VipsSign;
typedef VipsUnaryClass VipsSignClass;
G_DEFINE_TYPE( VipsSign, vips_sign, VIPS_TYPE_UNARY );
#define CSIGN( TYPE ) { \
TYPE *p = (TYPE *) in; \
TYPE *q = (TYPE *) out; \
int x; \
\
for( x = 0; x < sz; x++ ) { \
TYPE re = p[0]; \
TYPE im = p[1]; \
double fac = sqrt( re * re + im * im ); \
\
p += 2; \
\
if( fac == 0.0 ) { \
q[0] = 0.0; \
q[1] = 0.0; \
} \
else { \
q[0] = re / fac; \
q[1] = im / fac; \
} \
\
q += 2; \
} \
}
#define SIGN( TYPE ) { \
TYPE *p = (TYPE *) in; \
signed char *q = (signed char *) out; \
int x; \
\
for( x = 0; x < sz; x++ ) { \
TYPE v = p[x]; \
\
if( v > 0 ) \
q[x] = 1; \
else if( v == 0 ) \
q[x] = 0; \
else \
q[x] = -1; \
} \
}
static void
vips_sign_buffer( VipsArithmetic *arithmetic, PEL *out, PEL **in, int width )
{
VipsUnary *unary = VIPS_UNARY( arithmetic );
const int bands = vips_image_get_bands( unary->in );
int sz = width * bands;
switch( vips_image_get_format( unary->in ) ) {
case VIPS_FORMAT_UCHAR: SIGN( unsigned char ); break;
case VIPS_FORMAT_CHAR: SIGN( signed char ); break;
case VIPS_FORMAT_USHORT: SIGN( unsigned short ); break;
case VIPS_FORMAT_SHORT: SIGN( signed short ); break;
case VIPS_FORMAT_UINT: SIGN( unsigned int ); break;
case VIPS_FORMAT_INT: SIGN( signed int ); break;
case VIPS_FORMAT_FLOAT: SIGN( float ); break;
case VIPS_FORMAT_DOUBLE: SIGN( double ); break;
case VIPS_FORMAT_COMPLEX: CSIGN( float ); break;
case VIPS_FORMAT_DPCOMPLEX: CSIGN( double ); break;
default:
g_assert( 0 );
}
}
/* Save a bit of typing.
*/
#define UC VIPS_FORMAT_UCHAR
#define C VIPS_FORMAT_CHAR
#define US VIPS_FORMAT_USHORT
#define S VIPS_FORMAT_SHORT
#define UI VIPS_FORMAT_UINT
#define I VIPS_FORMAT_INT
#define F VIPS_FORMAT_FLOAT
#define X VIPS_FORMAT_COMPLEX
#define D VIPS_FORMAT_DOUBLE
#define DX VIPS_FORMAT_DPCOMPLEX
static const VipsBandFormat vips_bandfmt_sign[10] = {
/* UC C US S UI I F X D DX */
C, C, C, C, C, C, C, X, C, DX
};
static void
vips_sign_class_init( VipsSignClass *class )
{
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsArithmeticClass *aclass = VIPS_ARITHMETIC_CLASS( class );
object_class->nickname = "sign";
object_class->description = _( "unit vector of pixel" );
vips_arithmetic_set_format_table( aclass, vips_bandfmt_sign );
aclass->process_line = vips_sign_buffer;
}
static void
vips_sign_init( VipsSign *sign )
{
}
/**
* vips_sign:
* @in: input image
* @out: output image
*
* Finds the unit vector in the direction of the pixel value. For non-complex
* images, it returns a signed char image with values -1, 0, and 1 for negative,
* zero and positive pixels. For complex images, it returns a
* complex normalised to length 1.
*
* See also: vips_abs().
*
* Returns: 0 on success, -1 on error
*/
int
vips_sign( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "sign", ap, in, out );
va_end( ap );
return( result );
}