126 lines
2.7 KiB
C
126 lines
2.7 KiB
C
/* @(#) im_LabQ2LabS() - convert IM_CODING_LABQ format to three band signed short.
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* @(#) Justify to get msb in bit 15.
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* @(#)
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* @(#) int im_LabQ2LabS( IMAGE *in, IMAGE *out )
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* @(#)
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* @(#)
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*
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* 17/11/93 JC
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* - adapted from im_LabQ2Lab()
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* 16/11/94 JC
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* - uses new im_wrap_oneonebuf() fn
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* 9/2/95 JC
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* - new im_wrapone function
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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 <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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/* CONVERT n pels from packed 32bit Lab to signed short.
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*/
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void
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imb_LabQ2LabS( unsigned char *in, signed short *out, int n )
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{
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int c;
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unsigned char *p = in;
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unsigned char ext;
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signed short *q = out;
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signed short l, a, b;
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for( c = 0; c < n; c++ ) {
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/* Get most significant 8 bits of lab.
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*/
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l = p[0] << 7;
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a = p[1] << 8;
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b = p[2] << 8;
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/* Get x-tra bits.
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*/
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ext = p[3];
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p += 4;
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/* Shift and mask in to lab.
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*/
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l |= (unsigned char) (ext & 0xc0) >> 1;
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a |= (ext & 0x38) << 2;
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b |= (ext & 0x7) << 5;
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/* Write!
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*/
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q[0] = l;
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q[1] = a;
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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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/* unpack a Lab32 ie 10,11,11 Lab image into signed short image
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this is a wrapper around the buffer processing function
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(C) K.Martinez 2/5/93
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*/
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int
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im_LabQ2LabS( IMAGE *labim, IMAGE *outim )
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{
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/* check for coded Lab type
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*/
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if( labim->Coding != IM_CODING_LABQ ) {
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im_errormsg( "im_LabQ2LabS: not a packed Lab image" );
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return( -1 );
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}
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/* set up output image
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*/
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if( im_cp_desc( outim, labim ) )
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return( -1 );
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outim->Bands = 3;
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outim->Type = IM_TYPE_LABS;
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outim->BandFmt = IM_BANDFMT_SHORT;
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outim->Bbits = IM_BBITS_SHORT;
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outim->Coding = IM_CODING_NONE;
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/* Produce output.
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*/
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if( im_wrapone( labim, outim,
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(im_wrapone_fn) imb_LabQ2LabS, NULL, NULL ) )
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return( -1 );
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return( 0 );
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}
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