yading@10: /*
yading@10:  * Copyright (c) 2005 Robert Edele <yartrebo@earthlink.net>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "bbox.h"
yading@10: 
yading@10: int ff_calculate_bounding_box(FFBoundingBox *bbox,
yading@10:                               const uint8_t *data, int linesize, int w, int h,
yading@10:                               int min_val)
yading@10: {
yading@10:     int x, y;
yading@10:     int start_x;
yading@10:     int start_y;
yading@10:     int end_x;
yading@10:     int end_y;
yading@10:     const uint8_t *line;
yading@10: 
yading@10:     /* left bound */
yading@10:     for (start_x = 0; start_x < w; start_x++)
yading@10:         for (y = 0; y < h; y++)
yading@10:             if ((data[y * linesize + start_x] > min_val))
yading@10:                 goto outl;
yading@10: outl:
yading@10:     if (start_x == w) /* no points found */
yading@10:         return 0;
yading@10: 
yading@10:     /* right bound */
yading@10:     for (end_x = w - 1; end_x >= start_x; end_x--)
yading@10:         for (y = 0; y < h; y++)
yading@10:             if ((data[y * linesize + end_x] > min_val))
yading@10:                 goto outr;
yading@10: outr:
yading@10: 
yading@10:     /* top bound */
yading@10:     line = data;
yading@10:     for (start_y = 0; start_y < h; start_y++) {
yading@10:         for (x = 0; x < w; x++)
yading@10:             if (line[x] > min_val)
yading@10:                 goto outt;
yading@10:         line += linesize;
yading@10:     }
yading@10: outt:
yading@10: 
yading@10:     /* bottom bound */
yading@10:     line = data + (h-1)*linesize;
yading@10:     for (end_y = h - 1; end_y >= start_y; end_y--) {
yading@10:         for (x = 0; x < w; x++)
yading@10:             if (line[x] > min_val)
yading@10:                 goto outb;
yading@10:         line -= linesize;
yading@10:     }
yading@10: outb:
yading@10: 
yading@10:     bbox->x1 = start_x;
yading@10:     bbox->y1 = start_y;
yading@10:     bbox->x2 = end_x;
yading@10:     bbox->y2 = end_y;
yading@10:     return 1;
yading@10: }