/*
* Copyright (c) 2005 Robert Edele
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "bbox.h"
int ff_calculate_bounding_box(FFBoundingBox *bbox,
const uint8_t *data, int linesize, int w, int h,
int min_val)
{
int x, y;
int start_x;
int start_y;
int end_x;
int end_y;
const uint8_t *line;
/* left bound */
for (start_x = 0; start_x < w; start_x++)
for (y = 0; y < h; y++)
if ((data[y * linesize + start_x] > min_val))
goto outl;
outl:
if (start_x == w) /* no points found */
return 0;
/* right bound */
for (end_x = w - 1; end_x >= start_x; end_x--)
for (y = 0; y < h; y++)
if ((data[y * linesize + end_x] > min_val))
goto outr;
outr:
/* top bound */
line = data;
for (start_y = 0; start_y < h; start_y++) {
for (x = 0; x < w; x++)
if (line[x] > min_val)
goto outt;
line += linesize;
}
outt:
/* bottom bound */
line = data + (h-1)*linesize;
for (end_y = h - 1; end_y >= start_y; end_y--) {
for (x = 0; x < w; x++)
if (line[x] > min_val)
goto outb;
line -= linesize;
}
outb:
bbox->x1 = start_x;
bbox->y1 = start_y;
bbox->x2 = end_x;
bbox->y2 = end_y;
return 1;
}