lqr/lqr_carver_bias.c

   1 /* LiquidRescaling Library
   2  * Copyright (C) 2007-2009 Carlo Baldassi (the "Author") <carlobaldassi@gmail.com>.
   3  * All Rights Reserved.
   4  *
   5  * This library implements the algorithm described in the paper
   6  * "Seam Carving for Content-Aware Image Resizing"
   7  * by Shai Avidan and Ariel Shamir
   8  * which can be found at http://www.faculty.idc.ac.il/arik/imret.pdf
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; version 3 dated June, 2007.
  13
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU Lesser General Public License for more details.
  18
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>
  21  */
  22
  23 #include <lqr/lqr_all.h>
  24
  25 #ifdef __LQR_DEBUG__
  26 #include <assert.h>
  27 #endif
  28
  29 /**** LQR_CARVER_BIAS STRUCT FUNTIONS ****/
  30
  31 LQR_PUBLIC
  32 LqrRetVal
  33 lqr_carver_bias_add_area(LqrCarver *r, gdouble *buffer, gint bias_factor, gint width, gint height, gint x_off, gint y_off)
  34 {
  35   gint x, y;
  36   gint x1, y1, x2, y2;
  37   gfloat bias;
  38
  39   if (bias_factor == 0)
  40     {
  41       return LQR_OK;
  42     }
  43
  44   CATCH_CANC (r);
  45   CATCH_F (r->active);
  46   if ((r->w != r->w0) || (r->w_start != r->w0) ||
  47       (r->h != r->h0) || (r->h_start != r->h0))
  48     {
  49       CATCH (lqr_carver_flatten(r));
  50     }
  51   if (r->transposed)
  52     {
  53       CATCH (lqr_carver_transpose(r));
  54     }
  55
  56   x1 = MAX (0, x_off);
  57   y1 = MAX (0, y_off);
  58   x2 = MIN (r->w, width + x_off);
  59   y2 = MIN (r->h, height + y_off);
  60
  61   for (y = 0; y < y2 - y1; y++)
  62     {
  63       for (x = 0; x < x2 - x1; x++)
  64         {
  65           bias = (gfloat) ((gdouble) bias_factor * buffer[y * width + x] / 2);
  66
  67           r->bias[(y + y1) * r->w0 + (x + x1)] += bias;
  68
  69         }
  70
  71     }
  72
  73   return LQR_OK;
  74 }
  75
  76
  77 LQR_PUBLIC
  78 LqrRetVal
  79 lqr_carver_bias_add(LqrCarver *r, gdouble *buffer, gint bias_factor)
  80 {
  81   return lqr_carver_bias_add_area(r, buffer, bias_factor, r->w0, r->h0, 0, 0);
  82 }
  83
  84 LQR_PUBLIC
  85 LqrRetVal
  86 lqr_carver_bias_add_rgb_area(LqrCarver *r, guchar *rgb, gint bias_factor, gint channels, gint width, gint height, gint x_off, gint y_off)
  87 {
  88   gint x, y, k, c_channels;
  89   gboolean has_alpha;
  90   gint x0, y0, x1, y1, x2, y2;
  91   gint transposed = 0;
  92   gint sum;
  93   gfloat bias;
  94
  95   if (bias_factor == 0)
  96     {
  97       return TRUE;
  98     }
  99
 100   CATCH_CANC (r);
 101   CATCH_F (r->active);
 102   if ((r->w != r->w0) || (r->w_start != r->w0) ||
 103       (r->h != r->h0) || (r->h_start != r->h0))
 104     {
 105       CATCH (lqr_carver_flatten(r));
 106     }
 107   if (r->transposed)
 108     {
 109       transposed = 1;
 110       CATCH (lqr_carver_transpose(r));
 111     }
 112
 113   has_alpha = (channels == 2 || channels >= 4);
 114   c_channels = channels - (has_alpha ? 1 : 0);
 115
 116   x0 = MIN (0, x_off);
 117   y0 = MIN (0, y_off);
 118   x1 = MAX (0, x_off);
 119   y1 = MAX (0, y_off);
 120   x2 = MIN (r->w0, width + x_off);
 121   y2 = MIN (r->h0, height + y_off);
 122
 123   for (y = 0; y < y2 - y1; y++)
 124     {
 125       for (x = 0; x < x2 - x1; x++)
 126         {
 127           sum = 0;
 128           for (k = 0; k < c_channels; k++)
 129             {
 130               sum += rgb[((y - y0) * width + (x - x0)) * channels + k];
 131             }
 132
 133           bias = (gfloat) ((gdouble) bias_factor * sum / (2 * 255 * c_channels));
 134           if (has_alpha)
 135             {
 136               bias *= (gfloat) rgb[((y - y0) * width + (x - x0) + 1) * channels - 1] / 255;
 137             }
 138
 139           r->bias[(y + y1) * r->w0 + (x + x1)] += bias;
 140
 141         }
 142
 143     }
 144
 145   if (transposed)
 146     {
 147       CATCH (lqr_carver_transpose(r));
 148     }
 149
 150   return LQR_OK;
 151 }
 152
 153 LQR_PUBLIC
 154 LqrRetVal
 155 lqr_carver_bias_add_rgb(LqrCarver *r, guchar *rgb, gint bias_factor, gint channels)
 156 {
 157   return lqr_carver_bias_add_rgb_area(r, rgb, bias_factor, channels, r->w0, r->h0, 0, 0);
 158 }
 159
 160
 161 /**** END OF LQR_CARVER_BIAS CLASS FUNCTIONS ****/