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libvips/libvips/arithmetic/linear.c

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/* im_lintra.c -- linear transform
*
* Copyright: 1990, N. Dessipris, based on im_powtra()
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on:
* 23/4/93 JC
* - adapted to work with partial images
* 1/7/93 JC
* - adapted for partial v2
* 7/10/94 JC
* - new IM_NEW()
* - more typedefs
* 9/2/95 JC
* - adapted for im_wrap...
* - operations on complex images now just transform the real channel
* 29/9/95 JC
* - complex was broken
* 15/4/97 JC
* - return(0) missing from generate, arrgh!
* 1/7/98 JC
* - im_lintra_vec added
* 3/8/02 JC
* - fall back to im_copy() for a == 1, b == 0
* 10/10/02 JC
* - auug, failing to multiply imag for complex! (thanks matt)
* 10/12/02 JC
* - removed im_copy() fallback ... meant that output format could change
* with value :-( very confusing
* 30/6/04
* - added 1 band image * n band vector case
* 8/12/06
* - add liboil support
* 9/9/09
* - gtkdoc comment, minor reformat
* 31/7/10
* - remove liboil
* 31/10/11
* - rework as a class
* - removed the 1-ary constant path, no faster
*/
/*
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"
/**
* VipsLinear:
* @in: image to transform
* @out: output image
* @a: array of constants for multiplication
* @b: array of constants for addition
*
* Pass an image through a linear transform, ie. (@out = @in * @a + @b). Output
* is always float for integer input, double for double input, complex for
* complex input and double complex for double complex input.
*
* If the arrays of constants have just one element, that constant is used for
* all image bands. If the arrays have more than one element and they have
* the same number of elements as there are bands in the image, then
* one array element is used for each band. If the arrays have more than one
* element and the image only has a single band, the result is a many-band
* image where each band corresponds to one array element.
*
* See also: #VipsAdd.
*
* Returns: 0 on success, -1 on error
*/
typedef struct _VipsLinear {
VipsUnary parent_instance;
/* Our constants: multiply by a, add b.
*/
VipsArea *a;
VipsArea *b;
/* Our constants expanded to match arith->ready in size.
*/
int n;
double *a_ready;
double *b_ready;
} VipsLinear;
typedef VipsUnaryClass VipsLinearClass;
G_DEFINE_TYPE( VipsLinear, vips_linear, VIPS_TYPE_UNARY );
static int
vips_linear_build( VipsObject *object )
{
VipsArithmetic *arithmetic = VIPS_ARITHMETIC( object );
VipsUnary *unary = (VipsUnary *) object;
VipsLinear *linear = (VipsLinear *) object;
int i;
/* If we have a three-element vector we need to bandup the image to
* match.
*/
linear->n = 1;
if( linear->a )
linear->n = VIPS_MAX( linear->n, linear->b->n );
if( linear->b )
linear->n = VIPS_MAX( linear->n, linear->b->n );
if( unary->in )
linear->n = VIPS_MAX( linear->n, unary->in->Bands );
arithmetic->base_bands = linear->n;
if( unary->in && linear->a && linear->b ) {
if( vips_check_vector( "VipsLinear",
linear->a->n, unary->in ) ||
vips_check_vector( "VipsLinear",
linear->b->n, unary->in ) )
return( -1 );
}
/* Make up-banded versions of our constants.
*/
linear->a_ready = g_new( double, linear->n );
linear->b_ready = g_new( double, linear->n );
for( i = 0; i < linear->n; i++ ) {
if( linear->a ) {
double *ary = (double *) linear->a->data;
int j = VIPS_MIN( i, linear->a->n - 1 );
linear->a_ready[i] = ary[j];
}
if( linear->b ) {
double *ary = (double *) linear->b->data;
int j = VIPS_MIN( i, linear->b->n - 1 );
linear->b_ready[i] = ary[j];
}
}
if( VIPS_OBJECT_CLASS( vips_linear_parent_class )->build( object ) )
return( -1 );
return( 0 );
}
/* Non-complex input, any output.
*/
#define LOOPN( IN, OUT ) { \
IN *p = (IN *) in[0]; \
OUT *q = (OUT *) out; \
\
for( i = 0, x = 0; x < width; x++ ) \
for( k = 0; k < nb; k++, i++ ) \
q[i] = a[k] * (OUT) p[i] + b[k]; \
}
/* Complex input, complex output.
*/
#define LOOPCMPLXN( IN, OUT ) { \
IN *p = (IN *) in[0]; \
OUT *q = (OUT *) out; \
\
for( x = 0; x < width; x++ ) \
for( k = 0; k < nb; k++ ) { \
q[0] = a[k] * p[0] + b[k]; \
q[1] = a[k] * p[1]; \
q += 2; \
p += 2; \
} \
}
/* Lintra a buffer, n set of scale/offset.
*/
static void
vips_linear_buffer( VipsArithmetic *arithmetic, PEL *out, PEL **in, int width )
{
VipsImage *im = arithmetic->ready[0];
VipsLinear *linear = (VipsLinear *) arithmetic;
double *a = linear->a_ready;
double *b = linear->b_ready;
int nb = im->Bands;
int i, x, k;
switch( vips_image_get_format( im ) ) {
case VIPS_FORMAT_UCHAR: LOOPN( unsigned char, float ); break;
case VIPS_FORMAT_CHAR: LOOPN( signed char, float ); break;
case VIPS_FORMAT_USHORT: LOOPN( unsigned short, float ); break;
case VIPS_FORMAT_SHORT: LOOPN( signed short, float ); break;
case VIPS_FORMAT_UINT: LOOPN( unsigned int, float ); break;
case VIPS_FORMAT_INT: LOOPN( signed int, float ); break;
case VIPS_FORMAT_FLOAT: LOOPN( float, float ); break;
case VIPS_FORMAT_DOUBLE: LOOPN( double, double ); break;
case VIPS_FORMAT_COMPLEX: LOOPCMPLXN( float, float ); break;
case VIPS_FORMAT_DPCOMPLEX: LOOPCMPLXN( double, 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
/* Format doesn't change with linear.
*/
static const VipsBandFormat vips_bandfmt_linear[10] = {
/* UC C US S UI I F X D DX */
F, F, F, F, F, F, F, X, D, DX
};
static void
vips_linear_class_init( VipsLinearClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsArithmeticClass *aclass = VIPS_ARITHMETIC_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
object_class->nickname = "linear";
object_class->description = _( "calculate (a * in + b)" );
object_class->build = vips_linear_build;
vips_arithmetic_set_format_table( aclass, vips_bandfmt_linear );
aclass->process_line = vips_linear_buffer;
VIPS_ARG_BOXED( class, "a", 110,
_( "a" ),
_( "Multiply by this" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsLinear, a ),
VIPS_TYPE_ARRAY_DOUBLE );
VIPS_ARG_BOXED( class, "b", 111,
_( "b" ),
_( "Add this" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsLinear, b ),
VIPS_TYPE_ARRAY_DOUBLE );
}
static void
vips_linear_init( VipsLinear *linear )
{
}
int
vips_linear( VipsImage *in, VipsImage **out, double *a, double *b, int n, ... )
{
va_list ap;
VipsArea *area_a;
VipsArea *area_b;
double *array;
int result;
int i;
area_a = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n );
array = (double *) area_a->data;
for( i = 0; i < n; i++ )
array[i] = a[i];
area_b = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n );
array = (double *) area_b->data;
for( i = 0; i < n; i++ )
array[i] = b[i];
va_start( ap, n );
result = vips_call_split( "linear", ap, in, out, area_a, area_b );
va_end( ap );
vips_area_unref( area_a );
vips_area_unref( area_b );
return( result );
}
int
vips_linear1( VipsImage *in, VipsImage **out, double a, double b, ... )
{
va_list ap;
VipsArea *area_a;
VipsArea *area_b;
double *array;
int result;
area_a = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), 1 );
array = (double *) area_a->data;
array[0] = a;
area_b = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), 1 );
array = (double *) area_b->data;
array[0] = b;
va_start( ap, b );
result = vips_call_split( "linear", ap, in, out, area_a, area_b );
va_end( ap );
vips_area_unref( area_a );
vips_area_unref( area_b );
return( result );
}
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