145 lines
3.0 KiB
C
145 lines
3.0 KiB
C
|
/* @(#) Turn Lab to XYZ colourspace.
|
||
|
|
* @(#)
|
||
|
|
* @(#) Usage:
|
||
|
|
* @(#) im_Lab2XYZ( imagein, imageout )
|
||
|
|
* @(#) IMAGE *imagein, *imageout;
|
||
|
|
* @(#)
|
||
|
|
* @(#) Float in, float out.
|
||
|
|
* @(#)
|
||
|
|
* @(#) Returns: -1 on error, else 0
|
||
|
|
* Modified:
|
||
|
|
* 15/11/94 JC
|
||
|
|
* - ANSIfied
|
||
|
|
* - sets Type of output
|
||
|
|
* - better error messages
|
||
|
|
* 16/11/94 JC
|
||
|
|
* - partialed
|
||
|
|
* - in-line conversion
|
||
|
|
* 8/2/95 JC
|
||
|
|
* - new im_wrapone 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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>
|
||
|
|
|
||
|
|
#ifdef WITH_DMALLOC
|
||
|
|
#include <dmalloc.h>
|
||
|
|
#endif /*WITH_DMALLOC*/
|
||
|
|
|
||
|
|
/* Process a buffer of data.
|
||
|
|
*/
|
||
|
|
void
|
||
|
|
imb_Lab2XYZ( float *p, float *q, int n, im_colour_temperature *temp )
|
||
|
|
{
|
||
|
|
int x;
|
||
|
|
|
||
|
|
for( x = 0; x < n; x++ ) {
|
||
|
|
float L = p[0];
|
||
|
|
float a = p[1];
|
||
|
|
float b = p[2];
|
||
|
|
float X, Y, Z;
|
||
|
|
double cby, tmp;
|
||
|
|
p += 3;
|
||
|
|
|
||
|
|
if( L < 8.0 ) {
|
||
|
|
Y = (L * temp->Y0) / 903.3;
|
||
|
|
cby = 7.787 * (Y / temp->Y0) + 16.0 / 116.0;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
cby = (L + 16.0) / 116.0;
|
||
|
|
Y = temp->Y0 * cby * cby * cby;
|
||
|
|
}
|
||
|
|
|
||
|
|
tmp = a / 500.0 + cby;
|
||
|
|
if( tmp < 0.2069 )
|
||
|
|
X = temp->X0 * (tmp - 0.13793) / 7.787;
|
||
|
|
else
|
||
|
|
X = temp->X0 * tmp * tmp * tmp;
|
||
|
|
|
||
|
|
tmp = cby - b / 200.0;
|
||
|
|
if( tmp < 0.2069 )
|
||
|
|
Z = temp->Z0 * (tmp - 0.13793) / 7.787;
|
||
|
|
else
|
||
|
|
Z = temp->Z0 * tmp * tmp * tmp;
|
||
|
|
|
||
|
|
/* Write.
|
||
|
|
*/
|
||
|
|
q[0] = X;
|
||
|
|
q[1] = Y;
|
||
|
|
q[2] = Z;
|
||
|
|
q += 3;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
im_Lab2XYZ_temp( IMAGE *in, IMAGE *out, double X0, double Y0, double Z0 )
|
||
|
|
{
|
||
|
|
im_colour_temperature *temp = IM_NEW( out, im_colour_temperature );
|
||
|
|
|
||
|
|
/* Check input image.
|
||
|
|
*/
|
||
|
|
if( !temp )
|
||
|
|
return( -1 );
|
||
|
|
if( in->Bands != 3 || in->BandFmt != IM_BANDFMT_FLOAT ||
|
||
|
|
in->Coding != IM_CODING_NONE ) {
|
||
|
|
im_errormsg( "im_Lab2XYZ: 3-band uncoded float input only" );
|
||
|
|
return( -1 );
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Prepare the output image.
|
||
|
|
*/
|
||
|
|
if( im_cp_desc( out, in ) )
|
||
|
|
return( -1 );
|
||
|
|
out->Type = IM_TYPE_XYZ;
|
||
|
|
|
||
|
|
/* Process!
|
||
|
|
*/
|
||
|
|
temp->X0 = X0;
|
||
|
|
temp->Y0 = Y0;
|
||
|
|
temp->Z0 = Z0;
|
||
|
|
if( im_wrapone( in, out,
|
||
|
|
(im_wrapone_fn) imb_Lab2XYZ, temp, NULL ) )
|
||
|
|
return( -1 );
|
||
|
|
|
||
|
|
return( 0 );
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
im_Lab2XYZ( IMAGE *in, IMAGE *out )
|
||
|
|
{
|
||
|
|
return( im_Lab2XYZ_temp( in, out, IM_D65_X0, IM_D65_Y0, IM_D65_Z0 ) );
|
||
|
|
}
|