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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 <glib/gi18n-lib.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(IMAGE *in, IMAGE *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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