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/* im_LCh2Lab
*
* 15/11/94 JC
* - error messages added
* - memory leak fixed
* 16/11/94 JC
* - uses im_wrap_oneonebuf() now
* 8/2/95 JC
* - im_wrap v2
* 2/11/09
* - gtkdoc
* 19/9/12
* - 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 <stdio.h>
#include <math.h>
#include <vips/vips.h>
#include "pcolour.h"
typedef VipsColourTransform VipsLCh2Lab;
typedef VipsColourTransformClass VipsLCh2LabClass;
G_DEFINE_TYPE( VipsLCh2Lab, vips_LCh2Lab, VIPS_TYPE_COLOUR_TRANSFORM );
/* Process a buffer of data.
*/
static void
vips_LCh2Lab_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
{
float * restrict p = (float *) in[0];
float * restrict q = (float *) out;
int x;
for( x = 0; x < width; x++ ) {
float L = p[0];
float C = p[1];
float h = p[2];
float a, b;
p += 3;
a = C * cos( VIPS_RAD( h ) );
b = C * sin( VIPS_RAD( h ) );
q[0] = L;
q[1] = a;
q[2] = b;
q += 3;
}
}
/**
* vips_col_Ch2ab:
* @C: Chroma
* @h: Hue angle (degrees)
* @a: return CIE a* value
* @b: return CIE b* value
*
* Calculate ab from Ch, h in degrees.
*/
void
vips_col_Ch2ab( float C, float h, float *a, float *b )
{
float in[3];
float out[3];
float *x;
in[1] = C;
in[2] = h;
x = &in[0];
vips_LCh2Lab_line( NULL, (VipsPel *) out, (VipsPel **) &x, 1 );
*a = out[1];
*b = out[2];
}
static void
vips_LCh2Lab_class_init( VipsLCh2LabClass *class )
{
VipsObjectClass *object_class = (VipsObjectClass *) class;
VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
object_class->nickname = "LCh2Lab";
object_class->description = _( "transform LCh to Lab" );
colour_class->process_line = vips_LCh2Lab_line;
}
static void
vips_LCh2Lab_init( VipsLCh2Lab *LCh2Lab )
{
VipsColour *colour = VIPS_COLOUR( LCh2Lab );
colour->interpretation = VIPS_INTERPRETATION_LAB;
}
/**
* vips_LCh2Lab:
* @in: input image
* @out: output image
* @...: %NULL-terminated list of optional named arguments
*
* Turn LCh to Lab.
*
* Returns: 0 on success, -1 on error
*/
int
vips_LCh2Lab( VipsImage *in, VipsImage **out, ... )
{
va_list ap;
int result;
va_start( ap, out );
result = vips_call_split( "LCh2Lab", ap, in, out );
va_end( ap );
return( result );
}
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