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-rw-r--r--svg-flatten/src/nopencv.cpp157
-rw-r--r--svg-flatten/src/nopencv.hpp98
-rw-r--r--svg-flatten/src/nopencv_test.cpp198
3 files changed, 453 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();
+ }
+ }
+ }
+}
+
diff --git a/svg-flatten/src/nopencv.hpp b/svg-flatten/src/nopencv.hpp
new file mode 100644
index 0000000..b749808
--- /dev/null
+++ b/svg-flatten/src/nopencv.hpp
@@ -0,0 +1,98 @@
+/*
+ * This file is part of gerbolyze, a vector image preprocessing toolchain
+ * Copyright (C) 2021 Jan Sebastian Götte <gerbolyze@jaseg.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <array>
+#include <string>
+#include <sstream>
+#include <cmath>
+#include <algorithm>
+#include <assert.h>
+
+#include "geom2d.hpp"
+
+using namespace std;
+
+namespace gerbolyze {
+ namespace nopencv {
+
+ enum ContourPolarity {
+ CP_CONTOUR,
+ CP_HOLE
+ };
+
+ typedef std::function<void(Polygon, ContourPolarity)> ContourCallback;
+
+ class Image32 {
+ public:
+ Image32(int size_x, int size_y, const int32_t *data=nullptr) {
+ assert(size_x > 0 && size_x < 100000);
+ assert(size_y > 0 && size_y < 100000);
+ m_data = new int32_t[size_x * size_y] { 0 };
+ m_rows = size_y;
+ m_cols = size_x;
+ if (data != nullptr) {
+ memcpy(m_data, data, sizeof(int32_t) * size_x * size_y);
+ }
+ }
+
+ Image32(const Image32 &other) : Image32(other.cols(), other.rows(), other.ptr()) {}
+
+ ~Image32() {
+ delete m_data;
+ }
+
+ int32_t &at(int x, int y) {
+ assert(x >= 0 && y >= 0 && x < m_cols && y < m_rows);
+ assert(m_data != nullptr);
+
+ return m_data[y*m_cols + x];
+ };
+
+ const int32_t &at(int x, int y) const {
+ assert(x >= 0 && y >= 0 && x < m_cols && y < m_rows);
+ assert(m_data != nullptr);
+
+ return m_data[y*m_cols + x];
+ };
+
+ int32_t at_default(int x, int y, int32_t default_value=0) const {
+ assert(m_data != nullptr);
+
+ if (x >= 0 && y >= 0 && x < m_cols && y < m_rows) {
+ return at(x, y);
+
+ } else {
+ return default_value;
+ }
+ };
+
+ int rows() const { return m_rows; }
+ int cols() const { return m_cols; }
+ const int32_t *ptr() const { return m_data; }
+
+ private:
+ int32_t *m_data = nullptr;
+ int m_rows=0, m_cols=0;
+ };
+
+ void find_blobs(Image32 img, ContourCallback cb);
+ }
+}
+
diff --git a/svg-flatten/src/nopencv_test.cpp b/svg-flatten/src/nopencv_test.cpp
new file mode 100644
index 0000000..cc1c988
--- /dev/null
+++ b/svg-flatten/src/nopencv_test.cpp
@@ -0,0 +1,198 @@
+
+#include <iostream>
+#include <fstream>
+#include <iomanip>
+#include <cmath>
+#include <filesystem>
+
+#include "nopencv.hpp"
+
+#include <subprocess.h>
+#include <minunit.h>
+
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
+using namespace gerbolyze;
+using namespace gerbolyze::nopencv;
+
+char msg[1024];
+
+MU_TEST(test_complex_example_from_paper) {
+ int32_t img_data[6*9] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 1, 1, 1, 1, 1, 1, 1, 0,
+ 0, 1, 0, 0, 1, 0, 0, 1, 0,
+ 0, 1, 0, 0, 1, 0, 0, 1, 0,
+ 0, 1, 1, 1, 1, 1, 1, 1, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ };
+ Image32 test_img(9, 6, static_cast<int*>(img_data));
+
+ const Polygon expected_polys[3] = {
+ {
+ {1,1}, {1,2}, {1,3}, {1,4}, {1,5},
+ {2,5}, {3,5}, {4,5}, {5,5}, {6,5}, {7,5}, {8,5},
+ {8,4}, {8,3}, {8,2}, {8,1},
+ {7,1}, {6,1}, {5,1}, {4,1}, {3,1}, {2,1}
+ },
+ {
+ {2,2}, {2,3}, {2,4},
+ {3,4}, {4,4},
+ {4,3}, {4,2},
+ {3,2}
+ },
+ {
+ {5,2}, {5,3}, {5,4},
+ {6,4}, {7,4},
+ {7,3}, {7,2},
+ {6,2}
+ }
+ };
+
+ const ContourPolarity expected_polarities[3] = {CP_CONTOUR, CP_HOLE, CP_HOLE};
+
+ int invocation_count = 0;
+ gerbolyze::nopencv::find_blobs(test_img, [&invocation_count, &expected_polarities, &expected_polys](Polygon poly, ContourPolarity pol) {
+ invocation_count += 1;
+ mu_assert((invocation_count <= 3), "Too many contours returned");
+
+ mu_assert(poly.size() > 0, "Empty contour returned");
+ mu_assert_int_eq(pol, expected_polarities[invocation_count-1]);
+
+ d2p last;
+ bool first = true;
+ Polygon exp = expected_polys[invocation_count-1];
+ //cout << "poly: ";
+ for (d2p &p : poly) {
+ //cout << "(" << p[0] << ", " << p[1] << "), ";
+ if (!first) {
+ mu_assert((fabs(p[0] - last[0]) + fabs(p[1] - last[1]) == 1), "Subsequent contour points have distance other than one");
+ mu_assert(find(exp.begin(), exp.end(), p) != exp.end(), "Got unexpected contour point");
+ }
+ last = p;
+ }
+ //cout << endl;
+ });
+ mu_assert_int_eq(3, invocation_count);
+
+ int32_t tpl[6*9] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 2, 2, 2, 2, 2, 2,-2, 0,
+ 0,-3, 0, 0,-4, 0, 0,-2, 0,
+ 0,-3, 0, 0,-4, 0, 0,-2, 0,
+ 0, 2, 2, 2, 2, 2, 2,-2, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ };
+
+
+ for (int y=0; y<6; y++) {
+ for (int x=0; x<9; x++) {
+ int a = test_img.at(x, y), b = tpl[y*9+x];
+ if (a != b) {
+ cout << "Result:" << endl;
+ cout << " ";
+ for (int x=0; x<9; x++) {
+ cout << x << " ";
+ }
+ cout << endl;
+ cout << " ";
+ for (int x=0; x<9; x++) {
+ cout << "---";
+ }
+ cout << endl;
+ for (int y=0; y<6; y++) {
+ cout << y << " | ";
+ for (int x=0; x<9; x++) {
+ cout << setfill(' ') << setw(2) << test_img.at(x, y) << " ";
+ }
+ cout << endl;
+ }
+
+ snprintf(msg, sizeof(msg), "Result does not match template @(%d, %d): %d != %d\n", x, y, a, b);
+ mu_fail(msg);
+ }
+ }
+ }
+}
+
+MU_TEST(test_round_trip) {
+ int x, y;
+ uint8_t *data = stbi_load("testdata/paper-example.png", &x, &y, nullptr, 1);
+ Image32 ref_img(x, y);
+ for (int cy=0; cy<y; cy++) {
+ for (int cx=0; cx<x; cx++) {
+ ref_img.at(cx, cy) = data[cy*x + cx];
+ }
+ }
+ stbi_image_free(data);
+ Image32 ref_img_copy(ref_img);
+
+ filesystem::path tmp_svg = { filesystem::temp_directory_path() /= (std::tmpnam(nullptr) + string(".svg")) };
+ filesystem::path tmp_png = { filesystem::temp_directory_path() /= (std::tmpnam(nullptr) + string(".png")) };
+ ofstream svg(tmp_svg.c_str());
+
+ svg << "<svg width=\"" << x << "px\" height=\"" << y << "px\" viewBox=\"0 0 "
+ << x << " " << y << "\" "
+ << "xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">" << endl;
+ svg << "<rect width=\"100%\" height=\"100%\" fill=\"black\">" << endl;
+
+ gerbolyze::nopencv::find_blobs(ref_img, [&svg](Polygon poly, ContourPolarity pol) {
+ mu_assert(poly.size() > 0, "Empty contour returned");
+ mu_assert(poly.size() > 2, "Contour has less than three points, no area");
+ mu_assert(pol == CP_CONTOUR || pol == CP_HOLE, "Contour has invalid polarity");
+
+ svg << "<path fill=\"" << (pol == CP_HOLE ? "black" : "white") << "\" d=\"";
+ svg << "M " << poly[0][0] << " " << poly[0][1];
+ for (size_t i=1; i<poly.size(); i++) {
+ svg << " L " << poly[i][0] << " " << poly[i][1];
+ }
+ svg << " Z\">" << endl;
+ });
+ svg << "</svg>" << endl;
+ svg.close();
+
+ const char *command_line[] = {"resvg", tmp_svg.c_str(), tmp_png.c_str()};
+ struct subprocess_s subprocess;
+ int rc = subprocess_create(command_line, subprocess_option_inherit_environment, &subprocess);
+ mu_assert_int_eq(rc, 0);
+
+ int resvg_rc = -1;
+ rc = subprocess_join(&subprocess, &resvg_rc);
+ mu_assert_int_eq(rc, 0);
+ mu_assert_int_eq(resvg_rc, 0);
+
+ rc = subprocess_destroy(&subprocess);
+ mu_assert_int_eq(rc, 0);
+
+ int out_x, out_y;
+ uint8_t *out_data = stbi_load(tmp_png.c_str(), &out_x, &out_y, nullptr, 1);
+ mu_assert_int_eq(out_x, x);
+ mu_assert_int_eq(out_y, y);
+
+ for (int cy=0; cy<y; cy++) {
+ for (int cx=0; cx<x; cx++) {
+ int actual = out_data[cy*x + cx];
+ int expected = ref_img_copy.at(x, y);
+ if (actual != expected) {
+ snprintf(msg, sizeof(msg), "Result does not match input @(%d, %d): %d != %d\n", cx, cy, actual, expected);
+ mu_fail(msg);
+ }
+ }
+ }
+ stbi_image_free(out_data);
+}
+
+MU_TEST_SUITE(nopencv_contours_suite) {
+ MU_RUN_TEST(test_complex_example_from_paper);
+// MU_RUN_TEST(test_round_trip);
+}
+
+int main(int argc, char **argv) {
+ (void)argc;
+ (void)argv;
+
+ MU_RUN_SUITE(nopencv_contours_suite);
+ MU_REPORT();
+ return MU_EXIT_CODE;
+}
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