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/* dE76.c
*
* Modified:
* 16/11/94 JC
* - partialed!
* 31/10/09
* - use im__colour_binary()
* - gtkdoc comment
* 25/10/12
* - redone 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 <math.h>
#include <vips/vips.h>
#include <vips/debug.h>
#include "pcolour.h"
typedef struct _VipsdE76 {
VipsColourDifference parent_instance;
} VipsdE76;
typedef VipsColourDifferenceClass VipsdE76Class;
G_DEFINE_TYPE( VipsdE76, vips_dE76, VIPS_TYPE_COLOUR_DIFFERENCE );
/**
* vips_pythagoras:
* @L1: Input coordinate 1
* @a1: Input coordinate 1
* @b1: Input coordinate 1
* @L2: Input coordinate 2
* @a2: Input coordinate 2
* @b2: Input coordinate 2
*
* Pythagorean distance between two points in colour space. Lab/XYZ/CMC etc.
*/
float
vips_pythagoras( float L1, float a1, float b1, float L2, float a2, float b2 )
{
float dL = L1 - L2;
float da = a1 - a2;
float db = b1 - b2;
return( sqrt( dL * dL + da * da + db * db ) );
}
/* Find the difference between two buffers of LAB data.
*/
void
vips__pythagoras_line( VipsColour *colour,
VipsPel *out, VipsPel **in, int width )
{
float * restrict p1 = (float *) in[0];
float * restrict p2 = (float *) in[1];
float * restrict q = (float *) out;
int x;
for( x = 0; x < width; x++ ) {
float dL = p1[0] - p2[0];
float da = p1[1] - p2[1];
float db = p1[2] - p2[2];
q[x] = sqrt( dL * dL + da * da + db * db );
p1 += 3;
p2 += 3;
}
}
static void
vips_dE76_class_init( VipsdE76Class *class )
{
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
object_class->nickname = "dE76";
object_class->description = _( "calculate dE76" );
colour_class->process_line = vips__pythagoras_line;
}
static void
vips_dE76_init( VipsdE76 *dE76 )
{
VipsColourDifference *difference = VIPS_COLOUR_DIFFERENCE( dE76 );
difference->interpretation = VIPS_INTERPRETATION_LAB;
}
/**
* vips_dE76:
* @left: first input image
* @right: second input image
* @out: output image
* @...: %NULL-terminated list of optional named arguments
*
* Calculate dE 76.
*
* Returns: 0 on success, -1 on error
*/
int
vips_dE76( VipsImage *left, VipsImage *right, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "dE76", ap, left, right, out );
va_end( ap );
return( result );
}
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