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_F (r->active);
  45   if ((r->w != r->w0) || (r->w_start != r->w0) ||
  46       (r->h != r->h0) || (r->h_start != r->h0))
  47     {
  48       CATCH (lqr_carver_flatten(r));
  49     }
  50   if (r->transposed)
  51     {
  52       CATCH (lqr_carver_transpose(r));
  53     }
  54
  55   x1 = MAX (0, x_off);
  56   y1 = MAX (0, y_off);
  57   x2 = MIN (r->w, width + x_off);
  58   y2 = MIN (r->h, height + y_off);
  59
  60   for (y = 0; y < y2 - y1; y++)
  61     {
  62       for (x = 0; x < x2 - x1; x++)
  63         {
  64           bias = (gfloat) ((gdouble) bias_factor * buffer[y * width + x] / 2);
  65
  66           r->bias[(y + y1) * r->w0 + (x + x1)] += bias;
  67
  68         }
  69
  70     }
  71
  72   return LQR_OK;
  73 }
  74
  75
  76 LQR_PUBLIC
  77 LqrRetVal
  78 lqr_carver_bias_add(LqrCarver *r, gdouble *buffer, gint bias_factor)
  79 {
  80   return lqr_carver_bias_add_area(r, buffer, bias_factor, r->w0, r->h0, 0, 0);
  81 }
  82
  83 LQR_PUBLIC
  84 LqrRetVal
  85 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)
  86 {
  87   gint x, y, k, c_channels;
  88   gboolean has_alpha;
  89   gint x0, y0, x1, y1, x2, y2;
  90   gint transposed = 0;
  91   gint sum;
  92   gfloat bias;
  93
  94   if (bias_factor == 0)
  95     {
  96       return TRUE;
  97     }
  98
  99   CATCH_F (r->active);
 100   if ((r->w != r->w0) || (r->w_start != r->w0) ||
 101       (r->h != r->h0) || (r->h_start != r->h0))
 102     {
 103       CATCH (lqr_carver_flatten(r));
 104     }
 105   if (r->transposed)
 106     {
 107       transposed = 1;
 108       CATCH (lqr_carver_transpose(r));
 109     }
 110
 111   has_alpha = (channels == 2 || channels >= 4);
 112   c_channels = channels - (has_alpha ? 1 : 0);
 113
 114   x0 = MIN (0, x_off);
 115   y0 = MIN (0, y_off);
 116   x1 = MAX (0, x_off);
 117   y1 = MAX (0, y_off);
 118   x2 = MIN (r->w0, width + x_off);
 119   y2 = MIN (r->h0, height + y_off);
 120
 121   for (y = 0; y < y2 - y1; y++)
 122     {
 123       for (x = 0; x < x2 - x1; x++)
 124         {
 125           sum = 0;
 126           for (k = 0; k < c_channels; k++)
 127             {
 128               sum += rgb[((y - y0) * width + (x - x0)) * channels + k];
 129             }
 130
 131           bias = (gfloat) ((gdouble) bias_factor * sum / (2 * 255 * c_channels));
 132           if (has_alpha)
 133             {
 134               bias *= (gfloat) rgb[((y - y0) * width + (x - x0) + 1) * channels - 1] / 255;
 135             }
 136
 137           r->bias[(y + y1) * r->w0 + (x + x1)] += bias;
 138
 139         }
 140
 141     }
 142
 143   if (transposed)
 144     {
 145       CATCH (lqr_carver_transpose(r));
 146     }
 147
 148   return LQR_OK;
 149 }
 150
 151 LQR_PUBLIC
 152 LqrRetVal
 153 lqr_carver_bias_add_rgb(LqrCarver *r, guchar *rgb, gint bias_factor, gint channels)
 154 {
 155   return lqr_carver_bias_add_rgb_area(r, rgb, bias_factor, channels, r->w0, r->h0, 0, 0);
 156 }
 157
 158
 159 /**** END OF LQR_CARVER_BIAS CLASS FUNCTIONS ****/