156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
/* make a test pattern to show the eye's frequency response
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*
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* Copyright: 1990, 1991, N.Dessipris.
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*
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* Author N. Dessipris
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* Written on 30/05/1990
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* Updated on: 27/01/1991, 07/03/1991,
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* 22/7/93 JC
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* - im_outcheck() added
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* 30/8/95 JC
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* - modernized
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* 1/2/11
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* - gtk-doc
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* 13/6/13
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* - redo as a class
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define VIPS_DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <glib/gi18n-lib.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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#include "pcreate.h"
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#include "point.h"
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typedef struct _VipsEye {
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VipsPoint parent_instance;
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double factor;
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} VipsEye;
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typedef VipsPointClass VipsEyeClass;
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G_DEFINE_TYPE( VipsEye, vips_eye, VIPS_TYPE_POINT );
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static float
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vips_eye_point( VipsPoint *point, int x, int y )
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{
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VipsEye *eye = (VipsEye *) point;
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/* VIPS_MAX to prevent /0.
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*/
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int max_x = VIPS_MAX( point->width - 1, 1 );
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int max_y = VIPS_MAX( point->height - 1, 1 );
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double c = eye->factor * VIPS_PI / (2 * max_x);
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double h = max_y * max_y;
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return( y * y * cos( c * x * x ) / h );
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}
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static void
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vips_eye_class_init( VipsEyeClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
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VipsPointClass *point_class = VIPS_POINT_CLASS( class );
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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vobject_class->nickname = "eye";
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vobject_class->description =
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_( "make an image showing the eye's spatial response" );
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point_class->point = vips_eye_point;
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VIPS_ARG_DOUBLE( class, "factor", 6,
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_( "Factor" ),
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_( "Maximum spatial frequency" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsEye, factor ),
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0.0, 1.0, 0.5 );
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}
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static void
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vips_eye_init( VipsEye *eye )
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{
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eye->factor = 0.5;
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}
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/**
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* vips_eye:
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* @out: (out): output image
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* @width: image size
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* @height: image size
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* * @factor: maximum spatial frequency
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* * @uchar: output a uchar image
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*
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* Create a test pattern with increasing spatial frequence in X and
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* amplitude in Y. @factor should be between 0 and 1 and determines the
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* maximum spatial frequency.
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*
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* Set @uchar to output a uchar image.
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*
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* See also: vips_zone().
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*
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* Returns: 0 on success, -1 on error
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*/
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int
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vips_eye( VipsImage **out, int width, int height, ... )
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{
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va_list ap;
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int result;
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va_start( ap, height );
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result = vips_call_split( "eye", ap, out, width, height );
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va_end( ap );
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return( result );
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}
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