103 lines
2.0 KiB
C
103 lines
2.0 KiB
C
/* @(#) Turn Yxy to XYZ colourspace.
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* @(#)
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* @(#) Usage:
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* @(#) im_Yxy2XYZ( imagein, imageout )
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* @(#) IMAGE *imagein, *imageout;
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* @(#)
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* @(#) Float in, float out.
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* @(#)
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* @(#) Returns: -1 on error, else 0
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* Modified:
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* 29/5/02 JC
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* - from lab2xyz
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <math.h>
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#include <vips/vips.h>
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif /*WITH_DMALLOC*/
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/* Process a buffer of data.
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*/
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void
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imb_Yxy2XYZ( float *p, float *q, int n )
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{
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int i;
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for( i = 0; i < n; i++ ) {
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float Y = p[0];
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float x = p[1];
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float y = p[2];
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double total;
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float X, Z;
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p += 3;
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total = Y / y;
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X = x * total;
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Z = (X - x * X - x * Y) / x;
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q[0] = X;
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q[1] = Y;
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q[2] = Z;
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q += 3;
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}
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}
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int
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im_Yxy2XYZ( IMAGE *in, IMAGE *out )
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{
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if( in->Bands != 3 || in->BandFmt != IM_BANDFMT_FLOAT ||
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in->Coding != IM_CODING_NONE ) {
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im_errormsg( "im_Yxy2XYZ: 3-band uncoded float input only" );
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return( -1 );
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}
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if( im_cp_desc( out, in ) )
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return( -1 );
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out->Type = IM_TYPE_XYZ;
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if( im_wrapone( in, out,
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(im_wrapone_fn) imb_Yxy2XYZ, NULL, NULL ) )
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return( -1 );
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return( 0 );
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}
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