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/* creates a gaussian_ring filter.
*
* 02/01/14
* - from gaussian_ring.c
*/
/*
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"
#include "pmask.h"
typedef struct _VipsMaskGaussianRing {
VipsMaskGaussian parent_instance;
double ringwidth;
} VipsMaskGaussianRing;
typedef VipsMaskGaussianClass VipsMaskGaussianRingClass;
G_DEFINE_TYPE(VipsMaskGaussianRing, vips_mask_gaussian_ring,
VIPS_TYPE_MASK_GAUSSIAN);
static double
vips_mask_gaussian_ring_point(VipsMask *mask, double dx, double dy)
{
VipsMaskGaussian *gaussian = (VipsMaskGaussian *) mask;
VipsMaskGaussianRing *gaussian_ring =
(VipsMaskGaussianRing *) mask;
double fc = gaussian->frequency_cutoff;
double ac = gaussian->amplitude_cutoff;
double ringwidth = gaussian_ring->ringwidth;
double df = ringwidth / 2.0;
double df2 = df * df;
double cnst = log(ac);
double dist = sqrt(dx * dx + dy * dy);
return exp(cnst * (dist - fc) * (dist - fc) / df2);
}
static void
vips_mask_gaussian_ring_class_init(VipsMaskGaussianRingClass *class)
{
GObjectClass *gobject_class = G_OBJECT_CLASS(class);
VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS(class);
VipsMaskClass *mask_class = VIPS_MASK_CLASS(class);
gobject_class->set_property = vips_object_set_property;
gobject_class->get_property = vips_object_get_property;
vobject_class->nickname = "mask_gaussian_ring";
vobject_class->description = _("make a gaussian ring filter");
mask_class->point = vips_mask_gaussian_ring_point;
VIPS_ARG_DOUBLE(class, "ringwidth", 20,
_("Ringwidth"),
_("Ringwidth"),
VIPS_ARGUMENT_REQUIRED_INPUT,
G_STRUCT_OFFSET(VipsMaskGaussianRing, ringwidth),
0.0, 1000000.0, 0.5);
}
static void
vips_mask_gaussian_ring_init(VipsMaskGaussianRing *gaussian_ring)
{
gaussian_ring->ringwidth = 0.5;
}
/**
* vips_mask_gaussian_ring:
* @out: (out): output image
* @width: image size
* @height: image size
* @frequency_cutoff: frequency threshold
* @amplitude_cutoff: amplitude threshold
* @ringwidth: ringwidth
* @...: %NULL-terminated list of optional named arguments
*
* Optional arguments:
*
* * @nodc: don't set the DC pixel
* * @reject: invert the filter sense
* * @optical: coordinates in optical space
* * @uchar: output a uchar image
*
* Make a gaussian ring-pass or ring-reject filter, that is, one with a
* variable, smooth transition positioned at @frequency_cutoff of width
* @ringwidth.
*
* See also: vips_mask_ideal().
*
* Returns: 0 on success, -1 on error
*/
int
vips_mask_gaussian_ring(VipsImage **out, int width, int height,
double frequency_cutoff, double amplitude_cutoff, double ringwidth,
...)
{
va_list ap;
int result;
va_start(ap, ringwidth);
result = vips_call_split("mask_gaussian_ring",
ap, out, width, height,
frequency_cutoff, amplitude_cutoff, ringwidth);
va_end(ap);
return result;
}
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