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/* @(#) Thresholds an image. Works for any non-complex type.
* @(#) Output is a binary image with 0 and 255 only
* @(#) Input is either memory mapped or in a buffer.
* @(#)
* @(#) int im_thresh(imin, imout, threshold)
* @(#) IMAGE *imin, *imout;
* @(#) double threshold;
* @(#)
* @(#) Returns 0 on success and -1 on error
*
* Copyright: 1991, N. Dessipris, J Cupitt
*
* Author: N. Dessipris, J. Cupitt
* Written on: 15/03/1991
* Modified on :
*/
/*
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 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 <stdlib.h>
#include <vips/vips.h>
/* Useful: Call a macro with the name, type pairs for all VIPS functions. */
#define BRIGHT 255
#define DARK 0
#define im_for_all_types(A) \
case IM_BANDFMT_UCHAR: A(unsigned char); break; \
case IM_BANDFMT_CHAR: A(signed char); break; \
case IM_BANDFMT_USHORT: A(unsigned short); break; \
case IM_BANDFMT_SHORT: A(signed short); break; \
case IM_BANDFMT_UINT: A(unsigned int); break; \
case IM_BANDFMT_INT: A(signed int); break; \
case IM_BANDFMT_FLOAT: A(float); break; \
case IM_BANDFMT_DOUBLE: A(double); break;
/* Replacement for im_thresh */
int
im_thresh( in, out, threshold )
IMAGE *in, *out;
double threshold;
{
int x, y;
PEL *bu; /* Buffer we write to */
int s, epl; /* Size and els per line */
/* Check our args. */
if( im_iocheck( in, out ) )
return( -1 );
if( in->Coding != IM_CODING_NONE ) {
im_error( "im_thresh", "%s", _( "input should be uncoded") );
return(-1);
}
/* Set up the output header. */
if( im_cp_desc( out, in ) )
return( -1 );
out->BandFmt = IM_BANDFMT_UCHAR;
if( im_setupout( out ) )
return( -1 );
/* Make buffer for building o/p in. */
epl = in->Xsize * in->Bands;
s = epl * sizeof( PEL );
if( (bu = (PEL *) im_malloc( out, (unsigned)s )) == NULL )
return( -1 );
/* Define what we do for each band element type. */
#define im_thresh_loop(TYPE)\
{ TYPE *a = (TYPE *) in->data;\
\
for( y = 0; y < in->Ysize; y++ ) {\
PEL *b = bu;\
\
for( x = 0; x < epl; x++ ) {\
double f = (double) *a++;\
if ( f >= threshold)\
*b++ = (PEL)BRIGHT;\
else\
*b++ = (PEL)DARK;\
}\
\
if( im_writeline( y, out, bu ) ) \
return( -1 );\
}\
}
/* Do the above for all image types. */
switch( in->BandFmt ) {
im_for_all_types( im_thresh_loop );
default:
im_error( "im_thresh", "%s", _( "Unknown input format") );
return( -1 );
}
return( 0 );
}
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