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/* creates a pattern showing the similtaneous constrast effect
*
* Copyright: 1990, N. Dessipris.
*
* Author: Nicos Dessipris
* Written on: 19/07/1991
* Modified on:
* 22/7/93 JC
* - externs removed
* - im_outcheck() added
* 1/2/11
* - gtk-doc
*/
/*
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 <math.h>
#include <vips/vips.h>
/**
* im_simcontr:
* @out: output image
* @xsize: image size
* @ysize: image size
*
* Creates a pattern showing the similtaneous constrast effect.
*
* See also: im_eye().
*
* Returns: 0 on success, -1 on error
*/
int
im_simcontr( IMAGE *out, int xsize, int ysize )
{
int x, y;
unsigned char *line1, *line2, *cpline;
/* Check input args */
if( im_outcheck( out ) )
return( -1 );
/* Set now image properly */
im_initdesc(out, xsize, ysize, 1, IM_BBITS_BYTE, IM_BANDFMT_UCHAR,
IM_CODING_NONE, IM_TYPE_B_W, 1.0, 1.0, 0, 0 );
/* Set up image checking whether the output is a buffer or a file */
if (im_setupout( out ) == -1 )
return( -1 );
/* Create data */
line1 = (unsigned char *)calloc((unsigned)xsize, sizeof(char));
line2 = (unsigned char *)calloc((unsigned)xsize, sizeof(char));
if ( (line1 == NULL) || (line2 == NULL) ) {
im_error( "im_simcontr", "%s", _( "calloc failed") );
return(-1); }
cpline = line1;
for (x=0; x<xsize; x++)
*cpline++ = (PEL)255;
cpline = line1;
for (x=0; x<xsize/2; x++)
*cpline++ = (PEL)0;
cpline = line2;
for (x=0; x<xsize; x++)
*cpline++ = (PEL)255;
cpline = line2;
for (x=0; x<xsize/8; x++)
*cpline++ = (PEL)0;
for (x=0; x<xsize/4; x++)
*cpline++ = (PEL)128;
for (x=0; x<xsize/8; x++)
*cpline++ = (PEL)0;
for (x=0; x<xsize/8; x++)
*cpline++ = (PEL)255;
for (x=0; x<xsize/4; x++)
*cpline++ = (PEL)128;
for (y=0; y<ysize/4; y++)
{
if ( im_writeline( y, out, (PEL *)line1 ) == -1 )
{
free ( (char *)line1 ); free ( (char *)line2 );
return( -1 );
}
}
for (y=ysize/4; y<(ysize/4+ysize/2); y++)
{
if ( im_writeline( y, out, (PEL *)line2 ) == -1 )
{
free ( (char *)line1 ); free ( (char *)line2 );
return( -1 );
}
}
for (y=(ysize/4 + ysize/2); y<ysize; y++)
{
if ( im_writeline( y, out, (PEL *)line1 ) == -1 )
{
free ( (char *)line1 ); free ( (char *)line2 );
return( -1 );
}
}
free ( (char *)line1 ); free ( (char *)line2 );
return(0);
}
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