libvips/libvips/arithmetic/im_divide.c

275 lines
6.8 KiB
C

/* im_divide.c
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on:
* 29/4/93 JC
* - now works for partial images
* 1/7/93 JC
* - adapted for partial v2
* - ANSIfied
* 19/10/93 JC
* - coredump-inducing bug in complex*complex fixed
* 13/12/93
* - char*short bug fixed
* 12/6/95 JC
* - new im_multiply adapted to make new im_divide
* 27/9/04
* - updated for 1 band $op n band image -> n band image case
* 8/12/06
* - add liboil support
* 18/8/08
* - revise upcasting system
* - add gtkdoc comments
* 31/7/10
* - remove liboil support
* - avoid /0
*/
/*
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 <assert.h>
#include <vips/vips.h>
#include <vips/internal.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Complex divide.
*/
#ifdef USE_MODARG_DIV
/* This is going to be much slower */
#define CLOOP( TYPE ) { \
TYPE *X = (TYPE *) in[0]; \
TYPE *Y = (TYPE *) in[1]; \
TYPE *Z = (TYPE *) out; \
int i; \
\
for( i = 0; i < sz; i++ ) { \
double arg = atan2( X[1], X[0] ) - atan2( Y[1], Y[0] ); \
double mod = hypot( X[1], X[0] ) / hypot( Y[1], Y[0] ); \
\
Z[0] = mod * cos( arg ); \
Z[1] = mod * sin( arg ); \
\
X += 2; \
Y += 2; \
Z += 2; \
} \
}
#else /* USE_MODARG_DIV */
#define CLOOP( TYPE ) { \
TYPE *X = (TYPE *) in[0]; \
TYPE *Y = (TYPE *) in[1]; \
TYPE *Z = (TYPE *) out; \
int i; \
\
for( i = 0; i < sz; i++ ) { \
if( fabs( Y[0] ) > fabs( Y[1] ) ) { \
double a = Y[1] / Y[0]; \
double b = Y[0] + Y[1] * a; \
\
Z[0] = (X[0] + X[1] * a) / b; \
Z[1] = (X[1] - X[0] * a) / b; \
} \
else { \
double a = Y[0] / Y[1]; \
double b = Y[1] + Y[0] * a; \
\
Z[0] = (X[0] * a + X[1]) / b; \
Z[1] = (X[1] * a - X[0]) / b; \
} \
\
X += 2; \
Y += 2; \
Z += 2; \
} \
}
#endif /* USE_MODARG_DIV */
/* Real divide.
*/
#define RLOOP( IN, OUT ) { \
IN *p1 = (IN *) in[0]; \
IN *p2 = (IN *) in[1]; \
OUT *q = (OUT *) out; \
\
for( x = 0; x < sz; x++ ) \
if( p2[x] == 0.0 ) \
q[x] = 0; \
else \
q[x] = p1[x] / p2[x]; \
}
static void
divide_buffer( PEL **in, PEL *out, int width, IMAGE *im )
{
int x;
int sz = width * im->Bands;
/* Divide all input types.
*/
switch( im->BandFmt ) {
case IM_BANDFMT_CHAR: RLOOP( signed char, float ); break;
case IM_BANDFMT_UCHAR: RLOOP( unsigned char, float ); break;
case IM_BANDFMT_SHORT: RLOOP( signed short, float ); break;
case IM_BANDFMT_USHORT: RLOOP( unsigned short, float ); break;
case IM_BANDFMT_INT: RLOOP( signed int, float ); break;
case IM_BANDFMT_UINT: RLOOP( unsigned int, float ); break;
case IM_BANDFMT_FLOAT: RLOOP( float, float ); break;
case IM_BANDFMT_DOUBLE: RLOOP( double, double ); break;
case IM_BANDFMT_COMPLEX:CLOOP( float ); break;
case IM_BANDFMT_DPCOMPLEX:CLOOP( double ); break;
default:
assert( 0 );
}
}
/* Save a bit of typing.
*/
#define F IM_BANDFMT_FLOAT
#define X IM_BANDFMT_COMPLEX
#define D IM_BANDFMT_DOUBLE
#define DX IM_BANDFMT_DPCOMPLEX
/* Type promotion for division. Sign and value preserving. Make sure
* these match the case statement in divide_buffer() above.
*/
static int bandfmt_divide[10] = {
/* UC C US S UI I F X D DX */
F, F, F, F, F, F, F, X, D, DX
};
/**
* im_divide:
* @in1: input #IMAGE 1
* @in2: input #IMAGE 2
* @out: output #IMAGE
*
* This operation calculates @in1 / @in2 and writes the result to @out. If any
* pixels in @in2 are zero, the corresponding pixel in @out is also zero.
*
* If the images differ in size, the smaller image is enlarged to match the
* larger by adding zero pixels along the bottom and right.
*
* If the number of bands differs, one of the images
* must have one band. In this case, an n-band image is formed from the
* one-band image by joining n copies of the one-band image together, and then
* the two n-band images are operated upon.
*
* The two input images are cast up to the smallest common type (see table
* Smallest common format in
* <link linkend="VIPS-arithmetic">arithmetic</link>), then the
* following table is used to determine the output type:
*
* <table>
* <title>im_divide() type promotion</title>
* <tgroup cols='2' align='left' colsep='1' rowsep='1'>
* <thead>
* <row>
* <entry>input type</entry>
* <entry>output type</entry>
* </row>
* </thead>
* <tbody>
* <row>
* <entry>uchar</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>char</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>ushort</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>short</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>uint</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>int</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>float</entry>
* <entry>float</entry>
* </row>
* <row>
* <entry>double</entry>
* <entry>double</entry>
* </row>
* <row>
* <entry>complex</entry>
* <entry>complex</entry>
* </row>
* <row>
* <entry>double complex</entry>
* <entry>double complex</entry>
* </row>
* </tbody>
* </tgroup>
* </table>
*
* In other words, the output type is just large enough to hold the whole
* range of possible values.
*
* See also: im_multiply(), im_lintra().
*
* Returns: 0 on success, -1 on error
*/
int
im_divide( IMAGE *in1, IMAGE *in2, IMAGE *out )
{
return( im__arith_binary( "im_divide",
in1, in2, out,
bandfmt_divide,
(im_wrapmany_fn) divide_buffer, NULL ) );
}