libvips/libsrc/colour/im_XYZ2disp.c

166 lines
3.8 KiB
C

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