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Tina5/tina-libs/tina/image/imgPrc_spiral.c

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  1 /**********
  2  *
  3  * Copyright (c) 2003, Division of Imaging Science and Biomedical Engineering,
  4  * University of Manchester, UK.  All rights reserved.
  5  * 
  6  * Redistribution and use in source and binary forms, with or without modification, 
  7  * are permitted provided that the following conditions are met:
  8  * 
  9  *   . Redistributions of source code must retain the above copyright notice, 
 10  *     this list of conditions and the following disclaimer.
 11  *    
 12  *   . Redistributions in binary form must reproduce the above copyright notice,
 13  *     this list of conditions and the following disclaimer in the documentation 
 14  *     and/or other materials provided with the distribution.
 15  * 
 16  *   . Neither the name of the University of Manchester nor the names of its
 17  *     contributors may be used to endorse or promote products derived from this 
 18  *     software without specific prior written permission.
 19  * 
 20  * 
 21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 31  * POSSIBILITY OF SUCH DAMAGE.
 32  *
 33  **********
 34  *
 35  * Program :    TINA
 36  * File    :  $Source: /home/tina/cvs/tina-libs/tina/image/imgPrc_spiral.c,v $
 37  * Date    :  $Date: 2005/01/23 19:10:21 $
 38  * Version :  $Revision: 1.7 $
 39  * CVS Id  :  $Id: imgPrc_spiral.c,v 1.7 2005/01/23 19:10:21 paul Exp $
 40  *
 41  * Author  : Legacy TINA
 42  */
 43 
 44 /** 
 45  *  @file
 46  *  @brief Generate spiral test images.
 47  *
 48  * Angle is measured with reference to the positive x-axis from the centre.
 49  * This is version 3, discrete solution.  PAB 17 / 5 / 2001.
 50  *
 51  */
 52 
 53 #include "imgPrc_spiral.h"
 54 
 55 #if HAVE_CONFIG_H
 56 #include <config.h>
 57 #endif
 58 
 59 #include <math.h>
 60 #include <tina/sys/sysDef.h>
 61 #include <tina/sys/sysPro.h>
 62 #include <tina/math/mathDef.h>
 63 #include <tina/math/mathPro.h>
 64 #include <tina/image/img_GenDef.h>
 65 #include <tina/image/img_GenPro.h>
 66 
 67 
 68 Imrect         *imf_spiral(int x_centre, int y_centre, int height, int width,
 69                                            double overtake, double loops)
 70 {
 71 
 72 
 73 
 74         Imrect         *im;
 75         Imregion       *roi;
 76         float          *row = fvector_alloc(0, width);
 77         float           radius, radius_a, radius_b, theta, x, y;
 78         float           k_a, k_b;
 79         int             i, j, flag;
 80 
 81         if (loops < 0 || overtake < 0)
 82         {
 83                 error("Positive parameters only", warning);
 84                 fvector_free(row, 0);
 85                 return (NULL);
 86         }
 87         im = im_alloc(height, width, (Imregion *) NULL, float_v);
 88         if (im == NULL)
 89         {
 90                 return (NULL);
 91         }
 92         roi = im->region;
 93 
 94         k_a = exp(log(width / 2) / (TWOPI * loops));
 95         k_b = pow(k_a, ((overtake + 1) / overtake));
 96 
 97         for (i = roi->ly; i < roi->uy; i++)
 98         {
 99                 for (j = roi->lx; j < roi->ux; j++)
100                 {
101                         x = j - x_centre;
102                         y = y_centre - i;
103                         radius = sqrt(sqr(x) + sqr(y));
104                         theta = atan2(y, x);
105                         if (y < 0)
106                                 theta = TWOPI + theta;
107 
108                         flag = 0;
109                         while (flag == 0)
110                         {
111                                 radius_a = (pow(k_a, theta));
112                                 radius_b = (pow(k_b, theta)) + 1;
113 
114                                 /*
115                                  * Note: the plus one in the previous line is
116                                  * used to get the inner parts of the spiral
117                                  * fully painted, by ensuring that there is
118                                  * always at least a one pixel gap between
119                                  * the two radii: equivalent to an angular
120                                  * offset on the outer spiral
121                                  */
122 
123                                 if (radius_a <= radius && radius_b >= radius)
124                                 {
125                                         row[j] = 255.0;
126                                         flag = 1;
127                                 }
128                                 if (radius < radius_a && radius < radius_b)
129                                 {
130                                         row[j] = 0.0;
131                                         flag = 1;
132                                 }
133                                 if (radius > radius_a && radius > radius_b)
134                                 {
135                                         theta += TWOPI;
136                                 }
137                         }
138                 }
139                 im_put_rowf(row, im, i, 0, width);
140         }
141 
142         fvector_free(row, 0);
143         return (im);
144 }
145 

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