d2/image_zero.h

   1 // Copyright 2002, 2003, 2004 David Hilvert <dhilvert@auricle.dyndns.org>,
   2 //                                          <dhilvert@ugcs.caltech.edu>
   3
   4 /*  This file is part of the Anti-Lamenessing Engine.
   5
   6     The Anti-Lamenessing Engine is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     The Anti-Lamenessing Engine is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with the Anti-Lamenessing Engine; if not, write to the Free Software
  18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20
  21 /*
  22  * zero_image.h: Image that is zero everywhere.
  23  */
  24
  25 #ifndef __image_zero_h__
  26 #define __image_zero_h__
  27
  28 #include "point.h"
  29 #include "pixel.h"
  30 #include "exposure/exposure.h"
  31
  32 class image_zero : public image_weighted_avg {
  33 public:
  34
  35         pixel get_pixel(unsigned int y, unsigned int x) const {
  36                 return pixel::zero();
  37         }
  38
  39         ale_real maxval() const {
  40                 return 0;
  41         }
  42
  43         ale_real minval() const {
  44                 return 0;
  45         }
  46
  47         /*
  48          * Get a color value at a given position using bilinear interpolation between the
  49          * four nearest pixels.  Result values:
  50          *
  51          * result[0] == pixel value
  52          * result[1] == pixel confidence
  53          */
  54         void get_bl(point x, pixel result[2]) const {
  55                 result[0] = pixel::zero();
  56                 result[1] = pixel::zero();
  57         }
  58
  59         pixel get_bl(point x) const {
  60                 pixel result[2];
  61
  62                 get_bl(x, result);
  63
  64                 return result[0];
  65         }
  66
  67         pixel get_scaled_bl(point x, ale_pos f) const {
  68                 return pixel::zero();
  69         }
  70
  71
  72         /*
  73          * Make a new image suitable for receiving scaled values.
  74          */
  75         virtual image *scale_generator(int height, int width, int depth, char *name) const {
  76
  77                 image *is = new image_zero(height, width, depth, name);
  78
  79                 assert(is);
  80
  81                 return is;
  82         }
  83
  84         /*
  85          * Return an image scaled by some factor >= 1.0
  86          */
  87         image *scale(ale_pos f, char *name) const {
  88
  89                 image *is = new image_zero(
  90                         (int) floor(height() * f),
  91                         (int) floor(width()  * f), depth());
  92
  93                 assert(is);
  94
  95                 return is;
  96         }
  97
  98         /*
  99          * Scale by half.  We use the following filter:
 100          *
 101          *      1/16    1/8     1/16
 102          *      1/8     1/4     1/8
 103          *      1/16    1/8     1/16
 104          *
 105          * At the edges, these values are normalized so that the sum of
 106          * contributing pixels is 1.
 107          */
 108         image *scale_by_half(char *name) const {
 109                 ale_pos f = 0.5;
 110
 111                 image *result = new image_zero(
 112                         (int) floor(height() * f),
 113                         (int) floor(width()  * f), depth());
 114
 115                 assert(result);
 116
 117                 return result;
 118         }
 119
 120         /*
 121          * Scale an image definition array by 1/2.
 122          *
 123          * ALE considers an image definition array as a special kind of image
 124          * weight array (typedefs of which should appear below the definition
 125          * of this class).  ALE uses nonzero pixel values to mean 'defined' and
 126          * zero values to mean 'undefined'.  Through this interpretation, the
 127          * image weight array implementation that ALE uses allows image weight
 128          * arrays to also serve as image definition arrays.
 129          *
 130          * Whereas scaling of image weight arrays is not generally obvious in
 131          * either purpose or method, ALE requires that image definition arrays
 132          * be scalable, and the method we implement here is a fairly obvious
 133          * one.  In particular, if any source pixel contributing to the value of
 134          * a scaled target pixel has an undefined value, then the scaled target
 135          * pixel is undefined (zero).  Otherwise, it is defined (non-zero).
 136          *
 137          * Since there are many possible ways of implementing this function, we
 138          * choose an easy way and simply multiply the numerical values of the
 139          * source pixels to obtain the value of the scaled target pixel.
 140          *
 141          * XXX: we consider all pixels within a 9-pixel square to contribute.
 142          * There are other approaches.  For example, edge pixels could be
 143          * considered to have six contributing pixels and corner pixels four
 144          * contributing pixels.  To use this convention, change the ': 0' text
 145          * in the code below to ': 1'.
 146          */
 147
 148         image *defined_scale_by_half(char *name) const {
 149                 ale_pos f = 0.5;
 150
 151                 image *result = new image_zero(
 152                         (int) floor(height() * f),
 153                         (int) floor(width()  * f), depth());
 154
 155                 assert(result);
 156
 157                 return result;
 158         }
 159
 160         /*
 161          * Extend the image area to the top, bottom, left, and right,
 162          * initializing the new image areas with black pixels.
 163          */
 164         virtual void extend(int top, int bottom, int left, int right) {
 165                 _dimy += top + bottom;
 166                 _dimx += left + right;
 167                 _offset[0] -= top;
 168                 _offset[1] -= left;
 169         }
 170
 171         /*
 172          * Clone
 173          */
 174         image *clone(char *name) const {
 175                 return new image_zero(_dimy, _dimx, _depth, name);
 176         }
 177
 178         /*
 179          * Calculate the average (mean) clamped magnitude of a channel across
 180          * all pixels in an image.  The magnitude is clamped to the range of
 181          * real inputs.
 182          */
 183         ale_real avg_channel_clamped_magnitude(unsigned int k) const {
 184                 return 0;
 185         }
 186
 187         pixel avg_channel_clamped_magnitude() const {
 188                 return pixel::zero();
 189         }
 190
 191         /*
 192          * Calculate the average (mean) magnitude of a channel across all
 193          * pixels in an image.
 194          */
 195         ale_real avg_channel_magnitude(unsigned int k) const {
 196                 return 0;
 197         }
 198
 199         pixel avg_channel_magnitude() const {
 200                 return pixel::zero();
 201         }
 202
 203         /*
 204          * Calculate the average (mean) magnitude of a pixel (where magnitude
 205          * is defined as the mean of the channel values).
 206          */
 207         ale_real avg_pixel_magnitude() const {
 208                 return 0;
 209         }
 210
 211         image_zero(unsigned int dimy, unsigned int dimx, unsigned int depth,
 212                         char *name = "anonymous") : image_weighted_avg(dimy, dimx, depth, name) {
 213         }
 214
 215         int accumulate_norender(int i, int j) {
 216                 return 1;
 217         }
 218
 219         void accumulate(int i, int j, int f, pixel new_value, pixel new_weight) {
 220                 assert(0);
 221         }
 222
 223         image *get_colors() {
 224                 return this;
 225         }
 226
 227         image *get_weights() {
 228                 return this;
 229         }
 230 };
 231
 232 #endif