libvips/libsrc/arithmetic/im_powtra.c

236 lines
5.6 KiB
C

/* @(#) Finds the power of an image
* @(#) Function im_powtra() assumes that the imin file
* @(#) is either memory mapped or in a buffer.
* @(#) Output image pow(imin, exponent) depends on input
* @(#) If input is up to float, output is float
* @(#) else input is the same as output
* @(#) Works on any number of bands.
* @(#)
* @(#) int im_powtra( in, out, e )
* @(#) IMAGE *in, *out;
* @(#) double e;
* @(#)
* @(#) Returns 0 on success and -1 on error
* @(#)
*
* Copyright: 1990, N. Dessipris
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on:
* 10/12/93 JC
* - now reports total number of x/0, rather than each one.
* 1/2/95 JC
* - rewritten for PIO with im_wrapone()
* - incorrect complex code removed
* - /0 reporting removed for ease of programming
* 15/4/97 JC
* - return( 0 ) missing, oops!
* 6/7/98 JC
* - _vec form added
*/
/*
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 <assert.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Parameters saved here.
*/
typedef struct {
int n;
double *e; /* Exponent value */
} PowtraInfo;
/* Define what we do for each band element type. Single constant.
*/
#define loop1(IN, OUT)\
{\
IN *p = (IN *) in;\
OUT *q = (OUT *) out;\
\
for( x = 0; x < sz; x++ ) {\
double f = (double) p[x];\
\
if( f == 0.0 && e < 0.0 ) {\
/* Division by zero! Difficult to report tho'\
*/\
q[x] = 0.0;\
}\
else\
q[x] = pow( f, e );\
}\
}
/* Powtra a buffer.
*/
static int
powtra1_gen( PEL *in, PEL *out, int width, IMAGE *im, PowtraInfo *inf )
{
int sz = width * im->Bands;
double e = inf->e[0];
int x;
/* Powtra all non-complex input types.
*/
switch( im->BandFmt ) {
case IM_BANDFMT_UCHAR: loop1(unsigned char, float); break;
case IM_BANDFMT_CHAR: loop1(signed char, float); break;
case IM_BANDFMT_USHORT: loop1(unsigned short, float); break;
case IM_BANDFMT_SHORT: loop1(signed short, float); break;
case IM_BANDFMT_UINT: loop1(unsigned int, float); break;
case IM_BANDFMT_INT: loop1(signed int, float); break;
case IM_BANDFMT_FLOAT: loop1(float, float); break;
case IM_BANDFMT_DOUBLE: loop1(double, double); break;
default:
assert( 0 );
}
return( 0 );
}
/* Define what we do for each band element type. One constant per band.
*/
#define loopn(IN, OUT)\
{\
IN *p = (IN *) in;\
OUT *q = (OUT *) out;\
\
for( i = 0, x = 0; x < width; x++ )\
for( k = 0; k < im->Bands; k++, i++ ) {\
double e = inf->e[k];\
double f = (double) p[i];\
\
if( f == 0.0 && e < 0.0 ) {\
q[i] = 0.0;\
}\
else\
q[i] = pow( f, e );\
}\
}
/* Powtra a buffer.
*/
static int
powtran_gen( PEL *in, PEL *out, int width, IMAGE *im, PowtraInfo *inf )
{
int x, k, i;
/* Powtra all non-complex input types.
*/
switch( im->BandFmt ) {
case IM_BANDFMT_UCHAR: loopn(unsigned char, float); break;
case IM_BANDFMT_CHAR: loopn(signed char, float); break;
case IM_BANDFMT_USHORT: loopn(unsigned short, float); break;
case IM_BANDFMT_SHORT: loopn(signed short, float); break;
case IM_BANDFMT_UINT: loopn(unsigned int, float); break;
case IM_BANDFMT_INT: loopn(signed int, float); break;
case IM_BANDFMT_FLOAT: loopn(float, float); break;
case IM_BANDFMT_DOUBLE: loopn(double, double); break;
default:
assert( 0 );
}
return( 0 );
}
int
im_powtra_vec( IMAGE *in, IMAGE *out, int n, double *e )
{
PowtraInfo *inf;
int i;
/* Check args.
*/
if( in->Coding != IM_CODING_NONE ) {
im_error( "im_powtra_vec", "%s", _( "not uncoded" ) );
return( -1 );
}
if( im_iscomplex( in ) ) {
im_error( "im_powtra_vec", "%s", _( "not non-complex" ) );
return( -1 );
}
if( n != 1 && n != in->Bands ) {
im_error( "im_powtra_vec",
_( "not 1 or %d elements in vector" ), in->Bands );
return( -1 );
}
/* Prepare output header.
*/
if( im_cp_desc( out, in ) )
return( -1 );
if( im_isint( in ) ) {
out->Bbits = IM_BBITS_FLOAT;
out->BandFmt = IM_BANDFMT_FLOAT;
}
/* Make space for a little buffer.
*/
if( !(inf = IM_NEW( out, PowtraInfo )) ||
!(inf->e = IM_ARRAY( out, n, double )) )
return( -1 );
for( i = 0; i < n; i++ )
inf->e[i] = e[i];
inf->n = n;
/* Generate!
*/
if( n == 1 ) {
if( im_wrapone( in, out,
(im_wrapone_fn) powtra1_gen, in, inf ) )
return( -1 );
}
else {
if( im_wrapone( in, out,
(im_wrapone_fn) powtran_gen, in, inf ) )
return( -1 );
}
return( 0 );
}
int
im_powtra( IMAGE *in, IMAGE *out, double e )
{
return( im_powtra_vec( in, out, 1, &e ) );
}