libvips/libsrc/conversion/im_slice.c

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2007-08-29 18:23:50 +02:00
/* @(#) Slices an image using two thresholds. Works for any non-complex type.
* @(#) Output has three levels 0 128 and 255. Values below or = t1 are 0,
* @(#) above t2 are 255 and the remaining are 128.
* @(#) Input is either memory mapped or in a buffer.
* @(#) It is implied that t1 is less than t2; however the program checks
* @(#) if they are the wrong way and swaps them
* @(#)
* @(#) int im_slice(in, out, t1, t2)
* @(#) IMAGE *in, *out;
* @(#) double t1, t2;
* @(#)
* @(#) Returns 0 on success and -1 on error
*
* Copyright: 1991, N. Dessipris
*
* Author: N. Dessipris
* 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., 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 <stdlib.h>
#include <math.h>
#include <vips/vips.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
#define BRIGHT 255
#define GREY 128
#define DARK 0
/* Useful: Call a macro with the name, type pairs for all VIPS functions.
*/
#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;
/* Replacement for im_slice */
int
im_slice( in, out, t1, t2 )
IMAGE *in, *out;
double t1, t2;
{
int x, y, z;
PEL *bu; /* Buffer we write to */
int s, epl; /* Size and els per line */
double thresh1, thresh2;
/* Check our args. */
if( im_iocheck( in, out ) )
{
im_errormsg("im_slice: im_iocheck failed");
return( -1 );
}
if( in->Coding != IM_CODING_NONE )
{
im_errormsg("im_slice: input should be uncoded");
return( -1 );
}
/* Set up the output header. */
if( im_cp_desc( out, in ) )
{
im_errormsg("im_slice: im_cp_desc failed");
return( -1 );
}
out->BandFmt = IM_BANDFMT_UCHAR;
out->Bbits = IM_BBITS_BYTE;
if( im_setupout( out ) )
{
im_errormsg("im_slice: im_setupout failed");
return( -1 );
}
if ( t1 <= t2 )
{ thresh1 = t1; thresh2 = t2; }
else
{ thresh1 = t2; thresh2 = t1; }
/* 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_slice_loop(TYPE)\
{ TYPE *a = (TYPE *) in->data;\
\
for( y = 0; y < in->Ysize; y++ ) {\
PEL *b = bu;\
\
for( x = 0; x < in->Xsize; x++ )\
for( z = 0; z < in->Bands; z++ ) {\
double f = (double) *a++;\
if ( f <= thresh1)\
*b++ = (PEL)DARK;\
else if ( f > thresh2 )\
*b++ = (PEL)BRIGHT;\
else \
*b++ = (PEL)GREY;\
}\
\
if( im_writeline( y, out, bu ) )\
return( -1 );\
}\
}
/* Do the above for all image types. */
switch( in->BandFmt ) {
im_for_all_types( im_slice_loop );
default:
im_errormsg("im_slice: Unknown input format");
return( -1 );
}
return( 0 );
}