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/* make a test pattern to show the eye's frequency response
*
* Copyright: 1990, 1991, N.Dessipris.
*
* Author N. Dessipris
* Written on 30/05/1990
* Updated on: 27/01/1991, 07/03/1991,
* 22/7/93 JC
* - im_outcheck() added
* 30/8/95 JC
* - modernized
* 1/2/11
* - gtk-doc
* 13/6/13
* - redo as a class
*/
/*
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
*/
/*
#define VIPS_DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <glib/gi18n-lib.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <vips/vips.h>
#include "pcreate.h"
#include "point.h"
typedef struct _VipsEye {
VipsPoint parent_instance;
double factor;
} VipsEye;
typedef VipsPointClass VipsEyeClass;
G_DEFINE_TYPE( VipsEye, vips_eye, VIPS_TYPE_POINT );
static float
vips_eye_point( VipsPoint *point, int x, int y )
{
VipsEye *eye = (VipsEye *) point;
/* VIPS_MAX to prevent /0.
*/
int max_x = VIPS_MAX( point->width - 1, 1 );
int max_y = VIPS_MAX( point->height - 1, 1 );
double c = eye->factor * VIPS_PI / (2 * max_x);
double h = max_y * max_y;
return( y * y * cos( c * x * x ) / h );
}
static void
vips_eye_class_init( VipsEyeClass *class )
{
GObjectClass *gobject_class = G_OBJECT_CLASS( class );
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
VipsPointClass *point_class = VIPS_POINT_CLASS( class );
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "eye";
vobject_class->description =
_( "make an image showing the eye's spatial response" );
point_class->point = vips_eye_point;
VIPS_ARG_DOUBLE( class, "factor", 6,
_( "Factor" ),
_( "Maximum spatial frequency" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsEye, factor ),
0.0, 1.0, 0.5 );
}
static void
vips_eye_init( VipsEye *eye )
{
eye->factor = 0.5;
}
/**
* vips_eye:
* @out: (out): output image
* @width: image size
* @height: image size
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @factor: maximum spatial frequency
* * @uchar: output a uchar image
*
* Create a test pattern with increasing spatial frequence in X and
* amplitude in Y. @factor should be between 0 and 1 and determines the
* maximum spatial frequency.
*
* Set @uchar to output a uchar image.
*
* See also: vips_zone().
*
* Returns: 0 on success, -1 on error
*/
int
vips_eye( VipsImage **out, int width, int height, ... )
{
va_list ap;
int result;
va_start( ap, height );
result = vips_call_split( "eye", ap, out, width, height );
va_end( ap );
return( result );
}
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