277 lines
7.1 KiB
C
277 lines
7.1 KiB
C
/* generate gaussian images
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*
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* Written on: 30/11/1989 by Nicos
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* Updated on: 6/12/1991
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* 7/8/96 JC
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* - ansified, mem leaks plugged
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* 20/11/98 JC
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* - mask too large check added
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* 18/3/09
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* - bumped max mask size *40
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* - added _sep variant
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* 30/3/09
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* - set scale in _sep variant, why not
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* 21/10/10
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* - gtkdoc
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* 20/10/13
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* - redone as a class
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* 16/12/14
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* - default to int output to match vips_conv()
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* - use @precision, not @integer
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* 10/3/16
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* - allow 1x1 masks
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* - better size calc
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define VIPS_DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <glib/gi18n-lib.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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#include "pcreate.h"
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typedef struct _VipsGaussmat {
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VipsCreate parent_instance;
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double sigma;
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double min_ampl;
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gboolean separable;
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gboolean integer; /* Deprecated */
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VipsPrecision precision;
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} VipsGaussmat;
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typedef struct _VipsGaussmatClass {
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VipsCreateClass parent_class;
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} VipsGaussmatClass;
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G_DEFINE_TYPE( VipsGaussmat, vips_gaussmat, VIPS_TYPE_CREATE );
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/* Don't allow mask radius to go over this.
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*/
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#define MASK_SANITY (5000)
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static int
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vips_gaussmat_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsCreate *create = VIPS_CREATE( object );
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VipsGaussmat *gaussmat = (VipsGaussmat *) object;
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double sig2 = 2. * gaussmat->sigma * gaussmat->sigma;
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int max_x = VIPS_CLIP( 0, 8 * gaussmat->sigma, MASK_SANITY );
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int x, y;
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int width, height;
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double sum;
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if( VIPS_OBJECT_CLASS( vips_gaussmat_parent_class )->build( object ) )
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return( -1 );
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/* The old, deprecated @integer property has been deliberately set to
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* FALSE and they've not used the new @precision property ... switch
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* to float to help them out.
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*/
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if( vips_object_argument_isset( object, "integer" ) &&
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!vips_object_argument_isset( object, "precision" ) &&
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!gaussmat->integer )
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gaussmat->precision = VIPS_PRECISION_FLOAT;
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/* Find the size of the mask. Limit the mask size to 10k x 10k for
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* sanity. We allow x == 0, meaning a 1x1 mask.
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*/
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for( x = 0; x < max_x; x++ ) {
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double v = exp( - ((double)(x * x)) / sig2 );
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if( v < gaussmat->min_ampl )
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break;
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}
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if( x >= MASK_SANITY ) {
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vips_error( class->nickname, "%s", _( "mask too large" ) );
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return( -1 );
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}
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width = 2 * VIPS_MAX( x - 1, 0 ) + 1;
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height = gaussmat->separable ? 1 : width;
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vips_image_init_fields( create->out,
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width, height, 1,
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VIPS_FORMAT_DOUBLE, VIPS_CODING_NONE,
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VIPS_INTERPRETATION_MULTIBAND,
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1.0, 1.0 );
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if( vips_image_pipelinev( create->out, VIPS_DEMAND_STYLE_ANY, NULL ) ||
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vips_image_write_prepare( create->out ) )
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return( -1 );
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sum = 0.0;
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for( y = 0; y < height; y++ ) {
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for( x = 0; x < width; x++ ) {
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int xo = x - width / 2;
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int yo = y - height / 2;
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double distance = xo * xo + yo * yo;
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double v = exp( -distance / sig2 );
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if( gaussmat->precision != VIPS_PRECISION_FLOAT )
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v = VIPS_RINT( 20 * v );
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*VIPS_MATRIX( create->out, x, y ) = v;
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sum += v;
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}
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}
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/* Make sure we can't make sum == 0: it'd certainly cause /0 later.
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*/
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if( sum == 0 )
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sum = 1;
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vips_image_set_double( create->out, "scale", sum );
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vips_image_set_double( create->out, "offset", 0.0 );
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return( 0 );
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}
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static void
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vips_gaussmat_class_init( VipsGaussmatClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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vobject_class->nickname = "gaussmat";
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vobject_class->description = _( "make a gaussian image" );
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vobject_class->build = vips_gaussmat_build;
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VIPS_ARG_DOUBLE( class, "sigma", 2,
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_( "Sigma" ),
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_( "Sigma of Gaussian" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsGaussmat, sigma ),
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0.000001, 10000.0, 1.0 );
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VIPS_ARG_DOUBLE( class, "min_ampl", 3,
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_( "Minimum amplitude" ),
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_( "Minimum amplitude of Gaussian" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsGaussmat, min_ampl ),
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0.000001, 10000.0, 0.1 );
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VIPS_ARG_BOOL( class, "separable", 4,
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_( "Separable" ),
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_( "Generate separable Gaussian" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsGaussmat, separable ),
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FALSE );
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VIPS_ARG_BOOL( class, "integer", 5,
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_( "Integer" ),
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_( "Generate integer Gaussian" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
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G_STRUCT_OFFSET( VipsGaussmat, integer ),
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FALSE );
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VIPS_ARG_ENUM( class, "precision", 6,
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_( "Precision" ),
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_( "Generate with this precision" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsGaussmat, precision ),
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VIPS_TYPE_PRECISION, VIPS_PRECISION_INTEGER );
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}
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static void
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vips_gaussmat_init( VipsGaussmat *gaussmat )
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{
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gaussmat->sigma = 1;
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gaussmat->min_ampl = 0.1;
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gaussmat->precision = VIPS_PRECISION_INTEGER;
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}
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/**
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* vips_gaussmat:
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* @out: (out): output image
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* @sigma: standard deviation of mask
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* @min_ampl: minimum amplitude
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* * @separable: generate a separable gaussian
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* * @precision: #VipsPrecision for @out
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*
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* Creates a circularly symmetric Gaussian image of radius
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* @sigma. The size of the mask is determined by the variable @min_ampl;
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* if for instance the value .1 is entered this means that the produced mask
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* is clipped at values less than 10 percent of the maximum amplitude.
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*
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* The program uses the following equation:
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*
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* H(r) = exp( -(r * r) / (2 * @sigma * @sigma) )
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*
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* The generated image has odd size and its maximum value is normalised to
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* 1.0, unless @precision is #VIPS_PRECISION_INTEGER.
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*
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* If @separable is set, only the centre horizontal is generated. This is
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* useful for separable convolutions.
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*
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* If @precision is #VIPS_PRECISION_INTEGER, an integer gaussian is generated.
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* This is useful for integer convolutions.
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*
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* "scale" is set to the sum of all the mask elements.
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*
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* See also: vips_logmat(), vips_conv().
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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vips_gaussmat( VipsImage **out, double sigma, double min_ampl, ... )
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{
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va_list ap;
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int result;
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va_start( ap, min_ampl );
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result = vips_call_split( "gaussmat", ap, out, sigma, min_ampl );
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va_end( ap );
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return( result );
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}
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