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 #ifdef HAVE_CONFIG_H
  24 #  include <config.h>
  25 #endif
  26
  27 #include <lqr/lqr_all.h>
  28
  29 #ifdef __LQR_DEBUG__
  30 #include <assert.h>
  31 #endif
  32
  33 /**** LQR_CARVER_BIAS STRUCT FUNTIONS ****/
  34
  35 /* LQR_PUBLIC */
  36 void
  37 lqr_carver_bias_clear(LqrCarver *r)
  38 {
  39     g_free(r->bias);
  40     r->bias = NULL;
  41     r->nrg_uptodate = FALSE;
  42 }
  43
  44 /* LQR_PUBLIC */
  45 LqrRetVal
  46 lqr_carver_bias_add_xy(LqrCarver *r, gdouble bias, gint x, gint y)
  47 {
  48     gint xt, yt;
  49
  50     if (bias == 0) {
  51         return LQR_OK;
  52     }
  53
  54     LQR_CATCH_CANC(r);
  55     if (r->nrg_active == FALSE) {
  56         LQR_CATCH(lqr_carver_init_energy_related(r));
  57     }
  58
  59     if ((r->w != r->w0) || (r->w_start != r->w0) || (r->h != r->h0) || (r->h_start != r->h0)) {
  60         LQR_CATCH(lqr_carver_flatten(r));
  61     }
  62     if (r->bias == NULL) {
  63         LQR_CATCH_MEM(r->bias = g_try_new0(gfloat, r->w0 * r->h0));
  64     }
  65
  66     xt = r->transposed ? y : x;
  67     yt = r->transposed ? x : y;
  68
  69     r->bias[yt * r->w0 + xt] += (gfloat) bias / 2;
  70
  71     r->nrg_uptodate = FALSE;
  72
  73     return LQR_OK;
  74 }
  75
  76 /* LQR_PUBLIC */
  77 LqrRetVal
  78 lqr_carver_bias_add_area(LqrCarver *r, gdouble *buffer, gint bias_factor, gint width, gint height, gint x_off,
  79                          gint y_off)
  80 {
  81     gint x, y;
  82     gint xt, yt;
  83     gint wt, ht;
  84     gint x0, y0, x1, y1, x2, y2;
  85     gfloat bias;
  86
  87     LQR_CATCH_CANC(r);
  88
  89     if (bias_factor == 0) {
  90         return LQR_OK;
  91     }
  92
  93     if ((r->w != r->w0) || (r->w_start != r->w0) || (r->h != r->h0) || (r->h_start != r->h0)) {
  94         LQR_CATCH(lqr_carver_flatten(r));
  95     }
  96
  97     if (r->nrg_active == FALSE) {
  98         LQR_CATCH(lqr_carver_init_energy_related(r));
  99     }
 100
 101     if (r->bias == NULL) {
 102         LQR_CATCH_MEM(r->bias = g_try_new0(gfloat, r->w * r->h));
 103     }
 104
 105     wt = r->transposed ? r->h : r->w;
 106     ht = r->transposed ? r->w : r->h;
 107
 108     x0 = MIN(0, x_off);
 109     y0 = MIN(0, y_off);
 110     x1 = MAX(0, x_off);
 111     y1 = MAX(0, y_off);
 112     x2 = MIN(wt, width + x_off);
 113     y2 = MIN(ht, height + y_off);
 114
 115     for (y = 0; y < y2 - y1; y++) {
 116         for (x = 0; x < x2 - x1; x++) {
 117             bias = (gfloat) ((gdouble) bias_factor * buffer[(y - y0) * width + (x - x0)] / 2);
 118
 119             xt = r->transposed ? y : x;
 120             yt = r->transposed ? x : y;
 121
 122             r->bias[(yt + y1) * r->w0 + (xt + x1)] += bias;
 123         }
 124     }
 125
 126     r->nrg_uptodate = FALSE;
 127
 128     return LQR_OK;
 129 }
 130
 131 /* LQR_PUBLIC */
 132 LqrRetVal
 133 lqr_carver_bias_add(LqrCarver *r, gdouble *buffer, gint bias_factor)
 134 {
 135     return lqr_carver_bias_add_area(r, buffer, bias_factor, lqr_carver_get_width(r), lqr_carver_get_height(r), 0, 0);
 136 }
 137
 138 /* LQR_PUBLIC */
 139 LqrRetVal
 140 lqr_carver_bias_add_rgb_area(LqrCarver *r, guchar *rgb, gint bias_factor, gint channels, gint width, gint height,
 141                              gint x_off, gint y_off)
 142 {
 143     gint x, y, k, c_channels;
 144     gboolean has_alpha;
 145     gint xt, yt;
 146     gint wt, ht;
 147     gint x0, y0, x1, y1, x2, y2;
 148     gint sum;
 149     gdouble bias;
 150
 151     LQR_CATCH_CANC(r);
 152
 153     if ((r->w != r->w0) || (r->w_start != r->w0) || (r->h != r->h0) || (r->h_start != r->h0)) {
 154         LQR_CATCH(lqr_carver_flatten(r));
 155     }
 156
 157     if (r->nrg_active == FALSE) {
 158         LQR_CATCH(lqr_carver_init_energy_related(r));
 159     }
 160
 161     if (bias_factor == 0) {
 162         return LQR_OK;
 163     }
 164
 165     if (r->bias == NULL) {
 166         LQR_CATCH_MEM(r->bias = g_try_new0(gfloat, r->w * r->h));
 167     }
 168
 169     has_alpha = (channels == 2 || channels >= 4);
 170     c_channels = channels - (has_alpha ? 1 : 0);
 171
 172     wt = r->transposed ? r->h : r->w;
 173     ht = r->transposed ? r->w : r->h;
 174
 175     x0 = MIN(0, x_off);
 176     y0 = MIN(0, y_off);
 177     x1 = MAX(0, x_off);
 178     y1 = MAX(0, y_off);
 179     x2 = MIN(wt, width + x_off);
 180     y2 = MIN(ht, height + y_off);
 181
 182     for (y = 0; y < y2 - y1; y++) {
 183         for (x = 0; x < x2 - x1; x++) {
 184             sum = 0;
 185             for (k = 0; k < c_channels; k++) {
 186                 sum += rgb[((y - y0) * width + (x - x0)) * channels + k];
 187             }
 188
 189             bias = ((gdouble) bias_factor * sum / (2 * 255 * c_channels));
 190             if (has_alpha) {
 191                 bias *= (gdouble) rgb[((y - y0) * width + (x - x0) + 1) * channels - 1] / 255;
 192             }
 193
 194             xt = r->transposed ? y : x;
 195             yt = r->transposed ? x : y;
 196
 197             r->bias[(yt + y1) * r->w0 + (xt + x1)] += (gfloat) bias;
 198         }
 199     }
 200
 201     r->nrg_uptodate = FALSE;
 202
 203     return LQR_OK;
 204 }
 205
 206 /* LQR_PUBLIC */
 207 LqrRetVal
 208 lqr_carver_bias_add_rgb(LqrCarver *r, guchar *rgb, gint bias_factor, gint channels)
 209 {
 210     return lqr_carver_bias_add_rgb_area(r, rgb, bias_factor, channels, lqr_carver_get_width(r),
 211                                         lqr_carver_get_height(r), 0, 0);
 212 }
 213
 214 /**** END OF LQR_CARVER_BIAS CLASS FUNCTIONS ****/