diff options
Diffstat (limited to 'svg-flatten/src/nopencv.cpp')
| -rw-r--r-- | svg-flatten/src/nopencv.cpp | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/svg-flatten/src/nopencv.cpp b/svg-flatten/src/nopencv.cpp new file mode 100644 index 0000000..77c6cc6 --- /dev/null +++ b/svg-flatten/src/nopencv.cpp @@ -0,0 +1,157 @@ + +#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(); + } + } + } +} + |