165 lines
3.7 KiB
C
165 lines
3.7 KiB
C
/* @(#) Turn XYZ files into displayable rgb.
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* @(#)
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* @(#) Usage:
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* @(#) int im_XYZ2disp( IMAGE *in, IMAGE *out, struct im_col_display *d )
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* @(#)
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* @(#) Returns: -1 on error, else 0
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*
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* Author: J-P. Laurent
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* Modified:
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* 15/11/94 JC
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* - error message added
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* - out->Type set to IM_TYPE_RGB
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* - memory leak fixed
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* 16/11/94 JC
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* - uses im_wrapone()
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* 15/2/95 JC
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* - oops! now uses PEL, not float for output pointer
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* 2/1/96 JC
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* - sometimes produced incorrect result at extrema
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* - reformatted
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* - now uses IM_RINT() and clip()
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* 18/9/96 JC
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* - some speed-ups ... 3x faster
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* - slightly less accurate, but who cares
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* - added out-of-mem check for table build
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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_XYZ2disp( float *p, PEL *q, int n,
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struct im_col_tab_disp *table, struct im_col_display *d )
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{
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int x;
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float rstep = (d->d_YCR - d->d_Y0R) / 1500.0;
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float gstep = (d->d_YCG - d->d_Y0G) / 1500.0;
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float bstep = (d->d_YCB - d->d_Y0B) / 1500.0;
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for( x = 0; x < n; x++ ) {
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float Yr, Yg, Yb;
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int i;
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int r, g, b;
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float X = p[0];
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float Y = p[1];
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float Z = p[2];
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p += 3;
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/* Multiply through the matrix to get luminosity values.
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*/
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Yr = table->mat_XYZ2lum[0][0] * X
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+ table->mat_XYZ2lum[0][1] * Y
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+ table->mat_XYZ2lum[0][2] * Z;
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Yg = table->mat_XYZ2lum[1][0] * X
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+ table->mat_XYZ2lum[1][1] * Y
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+ table->mat_XYZ2lum[1][2] * Z;
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Yb = table->mat_XYZ2lum[2][0] * X
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+ table->mat_XYZ2lum[2][1] * Y
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+ table->mat_XYZ2lum[2][2] * Z;
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/* Clip -ves.
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*/
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Yr = IM_MAX( Yr, d->d_Y0R );
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Yg = IM_MAX( Yg, d->d_Y0G );
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Yb = IM_MAX( Yb, d->d_Y0B );
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/* Turn luminosity to colour value.
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*/
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i = IM_MIN( 1500, (Yr - d->d_Y0R) / rstep );
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r = table->t_Yr2r[i];
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i = IM_MIN( 1500, (Yg - d->d_Y0G) / gstep );
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g = table->t_Yg2g[i];
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i = IM_MIN( 1500, (Yb - d->d_Y0B) / bstep );
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b = table->t_Yb2b[i];
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/* Clip output.
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*/
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r = IM_MIN( r, d->d_Vrwr );
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g = IM_MIN( g, d->d_Vrwg );
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b = IM_MIN( b, d->d_Vrwb );
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q[0] = r;
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q[1] = g;
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q[2] = b;
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q += 3;
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}
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}
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int
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im_XYZ2disp( IMAGE *in, IMAGE *out, struct im_col_display *d )
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{
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struct im_col_tab_disp *table;
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/* Check input image.
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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_error( "im_XYZ2disp", _( "3-band uncoded float 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->Bbits = IM_BBITS_BYTE;
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out->BandFmt = IM_BANDFMT_UCHAR;
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out->Type = IM_TYPE_RGB;
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/* Build the lookup tables
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*/
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if( !(table = im_col_make_tables_RGB( out, d )) )
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return( -1 );
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/* Do the processing.
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*/
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if( im_wrapone( in, out,
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(im_wrapone_fn) imb_XYZ2disp, table, d ) )
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return( -1 );
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return( 0 );
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}
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