git.sesse.net Git - ffmpeg/blob - libavfilter/bbox.c

   1 /*
   2  * Copyright (c) 2005 Robert Edele <yartrebo@earthlink.net>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "bbox.h"
  22
  23 #define BBOX(type, name)                                             \
  24 static int bbox_##name(FFBoundingBox *bbox,                          \
  25                        const type *data, int linesize, int w, int h, \
  26                        int min_val)                                  \
  27 {                                                                    \
  28     int x, y;                                                        \
  29     int start_x;                                                     \
  30     int start_y;                                                     \
  31     int end_x;                                                       \
  32     int end_y;                                                       \
  33     const type *line;                                                \
  34                                                                      \
  35     /* left bound */                                                 \
  36     for (start_x = 0; start_x < w; start_x++)                        \
  37         for (y = 0; y < h; y++)                                      \
  38             if ((data[y * linesize + start_x] > min_val))            \
  39                 goto outl;                                           \
  40 outl:                                                                \
  41     if (start_x == w) /* no points found */                          \
  42         return 0;                                                    \
  43                                                                      \
  44     /* right bound */                                                \
  45     for (end_x = w - 1; end_x >= start_x; end_x--)                   \
  46         for (y = 0; y < h; y++)                                      \
  47             if ((data[y * linesize + end_x] > min_val))              \
  48                 goto outr;                                           \
  49 outr:                                                                \
  50                                                                      \
  51     /* top bound */                                                  \
  52     line = data;                                                     \
  53     for (start_y = 0; start_y < h; start_y++) {                      \
  54         for (x = 0; x < w; x++)                                      \
  55             if (line[x] > min_val)                                   \
  56                 goto outt;                                           \
  57         line += linesize;                                            \
  58     }                                                                \
  59 outt:                                                                \
  60                                                                      \
  61     /* bottom bound */                                               \
  62     line = data + (h-1)*linesize;                                    \
  63     for (end_y = h - 1; end_y >= start_y; end_y--) {                 \
  64         for (x = 0; x < w; x++)                                      \
  65             if (line[x] > min_val)                                   \
  66                 goto outb;                                           \
  67         line -= linesize;                                            \
  68     }                                                                \
  69 outb:                                                                \
  70                                                                      \
  71     bbox->x1 = start_x;                                              \
  72     bbox->y1 = start_y;                                              \
  73     bbox->x2 = end_x;                                                \
  74     bbox->y2 = end_y;                                                \
  75     return 1;                                                        \
  76 }
  77
  78 BBOX(uint8_t, 8)
  79 BBOX(uint16_t, 16)
  80
  81 int ff_calculate_bounding_box(FFBoundingBox *bbox,
  82                               const uint8_t *data, int linesize,
  83                               int w, int h,
  84                               int min_val, int depth)
  85 {
  86     if (depth <= 8)
  87         return bbox_8(bbox, data, linesize, w, h, min_val);
  88     else
  89         return bbox_16(bbox, (const uint16_t *)data, linesize / 2, w, h, min_val);
  90 }