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/* labelregions.c
*
* 5/11/09
* - renamed from im_segment()
* 11/2/14
* - redo as a class
*/
/*
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 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 <vips/vips.h>
#include <vips/internal.h>
#include "pmorphology.h"
typedef struct _VipsLabelregions {
VipsMorphology parent_instance;
VipsImage *mask;
int segments;
} VipsLabelregions;
typedef VipsMorphologyClass VipsLabelregionsClass;
G_DEFINE_TYPE( VipsLabelregions, vips_labelregions, VIPS_TYPE_MORPHOLOGY );
static int
vips_labelregions_build( VipsObject *object )
{
VipsMorphology *morphology = VIPS_MORPHOLOGY( object );
VipsImage *in = morphology->in;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 2 );
VipsImage *mask;
int segments;
int *m;
int x, y;
if( VIPS_OBJECT_CLASS( vips_labelregions_parent_class )->
build( object ) )
return( -1 );
/* Create the zero mask image in memory.
*/
mask = vips_image_new_memory();
g_object_set( object,
"mask", mask,
NULL );
if( vips_black( &t[0], in->Xsize, in->Ysize, NULL ) ||
vips_cast( t[0], &t[1], VIPS_FORMAT_INT, NULL ) ||
vips_image_write( t[1], mask ) )
return( -1 );
segments = 1;
m = (int *) mask->data;
for( y = 0; y < mask->Ysize; y++ ) {
for( x = 0; x < mask->Xsize; x++ ) {
if( !m[x] ) {
/* Use a direct path for speed.
*/
if( vips__draw_flood_direct( mask, in,
segments, x, y ) )
return( -1 );
segments += 1;
}
}
m += mask->Xsize;
}
g_object_set( object,
"segments", segments,
NULL );
return( 0 );
}
static void
vips_labelregions_class_init( VipsLabelregionsClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "labelregions";
vobject_class->description = _( "label regions in an image" );
vobject_class->build = vips_labelregions_build;
VIPS_ARG_IMAGE( class, "mask", 2,
_( "Mask" ),
_( "Mask of region labels" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsLabelregions, mask ) );
VIPS_ARG_INT( class, "segments", 3,
_( "Segments" ),
_( "Number of discrete contigious regions" ),
VIPS_ARGUMENT_OPTIONAL_OUTPUT,
G_STRUCT_OFFSET( VipsLabelregions, segments ),
0, 1000000000, 0 );
}
static void
vips_labelregions_init( VipsLabelregions *labelregions )
{
}
/**
* vips_labelregions:
* @in: image to test
* @mask: write labelled regions here
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @segments: return number of regions found here
*
* Repeatedly scans @in for regions of 4-connected pixels
* with the same pixel value. Every time a region is discovered, those
* pixels are marked in @mask with a unique serial number. Once all pixels
* have been labelled, the operation returns, setting @segments to the number
* of discrete regions which were detected.
*
* @mask is always a 1-band #VIPS_FORMAT_INT image of the same dimensions as
* @in.
*
* This operation is useful for, for example, blob counting. You can use the
* morphological operators to detect and isolate a series of objects, then use
* vips_labelregions() to number them all.
*
* Use vips_hist_find_indexed() to (for example) find blob coordinates.
*
* See also: vips_hist_find_indexed().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_labelregions( VipsImage *in, VipsImage **mask, ... )
{
va_list ap;
int result;
va_start( ap, mask );
result = vips_call_split( "labelregions", ap, in, mask );
va_end( ap );
return( result );
}
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