| 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 | int ff_calculate_bounding_box(FFBoundingBox *bbox, |
| 24 | const uint8_t *data, int linesize, int w, int h, |
| 25 | int min_val) |
| 26 | { |
| 27 | int x, y; |
| 28 | int start_x; |
| 29 | int start_y; |
| 30 | int end_x; |
| 31 | int end_y; |
| 32 | const uint8_t *line; |
| 33 | |
| 34 | /* left bound */ |
| 35 | for (start_x = 0; start_x < w; start_x++) |
| 36 | for (y = 0; y < h; y++) |
| 37 | if ((data[y * linesize + start_x] > min_val)) |
| 38 | goto outl; |
| 39 | outl: |
| 40 | if (start_x == w) /* no points found */ |
| 41 | return 0; |
| 42 | |
| 43 | /* right bound */ |
| 44 | for (end_x = w - 1; end_x >= start_x; end_x--) |
| 45 | for (y = 0; y < h; y++) |
| 46 | if ((data[y * linesize + end_x] > min_val)) |
| 47 | goto outr; |
| 48 | outr: |
| 49 | |
| 50 | /* top bound */ |
| 51 | line = data; |
| 52 | for (start_y = 0; start_y < h; start_y++) { |
| 53 | for (x = 0; x < w; x++) |
| 54 | if (line[x] > min_val) |
| 55 | goto outt; |
| 56 | line += linesize; |
| 57 | } |
| 58 | outt: |
| 59 | |
| 60 | /* bottom bound */ |
| 61 | line = data + (h-1)*linesize; |
| 62 | for (end_y = h - 1; end_y >= start_y; end_y--) { |
| 63 | for (x = 0; x < w; x++) |
| 64 | if (line[x] > min_val) |
| 65 | goto outb; |
| 66 | line -= linesize; |
| 67 | } |
| 68 | outb: |
| 69 | |
| 70 | bbox->x1 = start_x; |
| 71 | bbox->y1 = start_y; |
| 72 | bbox->x2 = end_x; |
| 73 | bbox->y2 = end_y; |
| 74 | return 1; |
| 75 | } |