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#include <iostream>
#include "nopencv.hpp"
using namespace gerbolyze;
using namespace gerbolyze::nopencv;
/* directions:
* 0
* 7 1
* ^
* |
* 6 <--- X ---> 2
* |
* v
* 5 3
* 4
*
*/
enum Direction {
D_N,
D_NE,
D_E,
D_SE,
D_S,
D_SW,
D_W,
D_NW
};
//const char * const dir_str[8] = { "N", "NE", "E", "SE", "S", "SW", "W", "NW" };
static struct {
int x;
int y;
} dir_to_coords[8] = {{0, -1}, {1, -1}, {1, 0}, {1, 1}, {0, 1}, {-1, 1}, {-1, 0}, {-1, -1}};
static Direction flip_direction[8] = {
D_S,
D_SW,
D_W,
D_NW,
D_N,
D_NE,
D_E,
D_SE
};
static void follow(gerbolyze::nopencv::Image32 img, int start_x, int start_y, Direction initial_direction, int nbd, int connectivity, Polygon &poly) {
//cerr << "follow " << start_x << " " << start_y << " | dir=" << dir_str[initial_direction] << " nbd=" << nbd << " conn=" << connectivity << endl;
int dir_inc = (connectivity == 4) ? 2 : 1;
int probe_x, probe_y;
/* homing run: find starting point for algorithm steps below. */
bool found = false;
int k;
for (k=initial_direction; k<initial_direction+8; k += dir_inc) {
probe_x = start_x + dir_to_coords[k % 8].x;
probe_y = start_y + dir_to_coords[k % 8].y;
if (img.at_default(probe_x, probe_y) != 0) {
found = true;
break;
}
}
if (!found) { /* No nonzero pixels found. This is a single-pixel contour */
img.at(start_x, start_y) = nbd;
poly.emplace_back(d2p{(double)start_x, (double)start_y});
poly.emplace_back(d2p{(double)start_x+1, (double)start_y});
poly.emplace_back(d2p{(double)start_x+1, (double)start_y+1});
poly.emplace_back(d2p{(double)start_x, (double)start_y+1});
return;
}
/* starting point found. */
int current_direction = k % 8;
int start_direction = current_direction;
int center_x = start_x, center_y = start_y;
//cerr << " init: " << center_x << " " << center_y << " / " << dir_str[current_direction] << endl;
do {
bool flag = false;
for (k = current_direction + 8 - dir_inc; k >= current_direction; k -= dir_inc) {
probe_x = center_x + dir_to_coords[k % 8].x;
probe_y = center_y + dir_to_coords[k % 8].y;
if (k%8 == D_E)
flag = true;
if (img.at_default(probe_x, probe_y) != 0) {
break;
}
}
int set_val = 0;
if (flag && img.at_default(center_x+1, center_y) == 0) {
img.at(center_x, center_y) = -nbd;
set_val = -nbd;
} else if (img.at(center_x, center_y) == 1) {
img.at(center_x, center_y) = nbd;
set_val = nbd;
}
for (int l = (current_direction + 8 - 2 + 1) / 2 * 2; l > k; l -= dir_inc) {
switch (l%8) {
case 0: poly.emplace_back(d2p{(double)center_x, (double)center_y}); break;
case 2: poly.emplace_back(d2p{(double)center_x+1, (double)center_y}); break;
case 4: poly.emplace_back(d2p{(double)center_x+1, (double)center_y+1}); break;
case 6: poly.emplace_back(d2p{(double)center_x, (double)center_y+1}); break;
}
}
center_x = probe_x;
center_y = probe_y;
current_direction = flip_direction[k % 8];
//cerr << " " << center_x << " " << center_y << " / " << dir_str[current_direction] << " -> " << set_val << endl;
} while (center_x != start_x || center_y != start_y || current_direction != start_direction);
}
void gerbolyze::nopencv::find_blobs(gerbolyze::nopencv::Image32 img, gerbolyze::nopencv::ContourCallback cb) {
int nbd = 1;
Polygon poly;
for (int y=0; y<img.rows(); y++) {
for (int x=0; x<img.cols(); x++) {
int val_xy = img.at(x, y);
/* Note: outer borders are followed with 8-connectivity, hole borders with 4-connectivity. This prevents
* incorrect results in this case:
*
* 1 1 1 | 0 0 0
* |
* 1 1 1 | 0 0 0
* ----------+---------- <== Here
* 0 0 0 | 1 1 1
* |
* 0 0 0 | 1 1 1
*/
if (img.at_default(x-1, y) == 0 && val_xy == 1) { /* outer border starting point */
nbd += 1;
follow(img, x, y, D_W, nbd, 8, poly);
cb(poly, CP_CONTOUR);
poly.clear();
} else if (val_xy >= 1 && img.at_default(x+1, y) == 0) { /* hole border starting point */
nbd += 1;
follow(img, x, y, D_E, nbd, 4, poly);
cb(poly, CP_HOLE);
poly.clear();
}
}
}
}
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