libvips/libvips/morphology/countlines.c

190 lines
4.7 KiB
C

/* count lines
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 02/05/1990
* Modified on :
*
* 19/9/95 JC
* - tidied up
* 23/10/10
* - gtk-doc
* 17/1/14
* - redone as a class, now just a convenience function
*/
/*
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
*/
/*
#define VIPS_DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <vips/vips.h>
#include <vips/internal.h>
#include <vips/debug.h>
#include "pmorphology.h"
typedef struct _VipsCountlines {
VipsMorphology parent_instance;
double nolines;
VipsDirection direction;
} VipsCountlines;
typedef VipsMorphologyClass VipsCountlinesClass;
G_DEFINE_TYPE( VipsCountlines, vips_countlines, VIPS_TYPE_MORPHOLOGY );
static int
vips_countlines_build( VipsObject *object )
{
VipsMorphology *morphology = VIPS_MORPHOLOGY( object );
VipsCountlines *countlines = (VipsCountlines *) object;
VipsImage *in = morphology->in;
VipsImage **t = (VipsImage **) vips_object_local_array( object, 7 );
double nolines;
if( VIPS_OBJECT_CLASS( vips_countlines_parent_class )->build( object ) )
return( -1 );
/* Compiler warnings.
*/
nolines = 1;
switch( countlines->direction ) {
case VIPS_DIRECTION_HORIZONTAL:
if( !(t[0] = vips_image_new_matrixv( 1, 2, -1.0, 1.0 )) ||
vips_moreeq_const1( in, &t[1], 128, NULL ) ||
vips_conv( t[1], &t[2], t[0],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ||
vips_project( t[2], &t[3], &t[4], NULL ) ||
vips_avg( t[3], &nolines, NULL ) )
return( -1 );
break;
case VIPS_DIRECTION_VERTICAL:
if( !(t[0] = vips_image_new_matrixv( 2, 1, -1.0, 1.0 )) ||
vips_moreeq_const1( in, &t[1], 128, NULL ) ||
vips_conv( t[1], &t[2], t[0],
"precision", VIPS_PRECISION_INTEGER,
NULL ) ||
vips_project( t[2], &t[3], &t[4], NULL ) ||
vips_avg( t[4], &nolines, NULL ) )
return( -1 );
break;
default:
g_assert_not_reached();
}
g_object_set( object, "nolines", nolines / 255.0, NULL );
return( 0 );
}
static void
vips_countlines_class_init( VipsCountlinesClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
VIPS_DEBUG_MSG( "vips_countlines_class_init\n" );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "countlines";
vobject_class->description = _( "count lines in an image" );
vobject_class->build = vips_countlines_build;
VIPS_ARG_DOUBLE( class, "nolines", 2,
_( "Nolines" ),
_( "Number of lines" ),
VIPS_ARGUMENT_REQUIRED_OUTPUT,
G_STRUCT_OFFSET( VipsCountlines, nolines ),
0, 10000000, 0.0 );
VIPS_ARG_ENUM( class, "direction", 3,
_( "direction" ),
_( "Countlines left-right or up-down" ),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET( VipsCountlines, direction ),
VIPS_TYPE_DIRECTION, VIPS_DIRECTION_HORIZONTAL );
}
static void
vips_countlines_init( VipsCountlines *countlines )
{
}
/**
* vips_countlines: (method)
* @in: input image
* @nolines: (out): output average number of lines
* @direction: count lines horizontally or vertically
* @...: %NULL-terminated list of optional named arguments
*
* Function which calculates the number of transitions
* between black and white for the horizontal or the vertical
* direction of an image. black<128 , white>=128
* The function calculates the number of transitions for all
* Xsize or Ysize and returns the mean of the result
* Input should be one band, 8-bit.
*
* See also: vips_morph(), vips_conv().
*
* Returns: 0 on success, -1 on error.
*/
int
vips_countlines( VipsImage *in, double *nolines,
VipsDirection direction, ... )
{
va_list ap;
int result;
va_start( ap, direction );
result = vips_call_split( "countlines", ap, in, nolines, direction );
va_end( ap );
return( result );
}