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Add polygon area function & tests. These tests catch a single-px bug.

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This commit is contained in:
jaseg 2021-06-02 11:57:00 +02:00
parent 536a34cd59
commit 0530c365ca
3 changed files with 83 additions and 0 deletions
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11
svg-flatten/src/nopencv.cpp
View file

@ -427,3 +427,14 @@ bool gerbolyze::nopencv::Image32::stb_to_internal(uint8_t *data) {
stbi_image_free(data);
return true;
}
double gerbolyze::nopencv::polygon_area(Polygon_i &poly) {
double acc = 0;
size_t prev = poly.size() - 1;
for (size_t cur=0; cur<poly.size(); cur++) {
acc += (poly[prev][0] + poly[cur][0]) * (poly[prev][1] - poly[cur][1]);
prev = cur;
}
return acc / 2;
}

2
svg-flatten/src/nopencv.hpp
View file

@ -102,6 +102,8 @@ namespace gerbolyze {
void find_blobs(Image32 &img, ContourCallback cb);
ContourCallback simplify_contours_teh_chin(ContourCallback cb);
double polygon_area(Polygon_i &poly);
}
}

70
svg-flatten/src/nopencv_test.cpp
View file

@ -226,6 +226,59 @@ MU_TEST(test_round_trip_two_blobs) { testdata_roundtrip("testdata/two-b
MU_TEST(test_round_trip_two_px) { testdata_roundtrip("testdata/two-px.png"); }
MU_TEST(test_round_trip_two_px_inv) { testdata_roundtrip("testdata/two-px-inv.png"); }
static void test_polygon_area(const char *fn) {
cerr << endl << "poly area test " << fn << endl;
Image32 ref_img;
mu_assert(ref_img.load(fn), "Input image failed to load");
ref_img.binarize();
int white_px_count = 0;
int black_px_count = 0;
for (int y=0; y<ref_img.rows(); y++) {
for (int x=0; x<ref_img.cols(); x++) {
if (ref_img.at(x, y)) {
white_px_count += 1;
} else {
black_px_count += 1;
}
}
}
double pos_sum = 0.0;
double neg_sum = 0.0;
gerbolyze::nopencv::find_blobs(ref_img, [fn, white_px_count, black_px_count, &pos_sum, &neg_sum](Polygon_i& poly, ContourPolarity pol) {
double area = polygon_area(poly);
cerr << endl << fn << ": " << area << pos_sum << " / " << neg_sum << " -- " << white_px_count << " / " << black_px_count << endl;
mu_assert(fabs(area) > 0.99, "Polygon smaller than a single pixel");
mu_assert((pol == CP_CONTOUR) == (area >= 0), "Polygon area has incorrect sign");
if (area > 0) {
pos_sum += area;
} else {
neg_sum -= area;
}
});
mu_assert(pos_sum - white_px_count < 0.01, "Calculated area outside tolerance");
mu_assert(neg_sum - black_px_count < 0.01, "Calculated area outside tolerance");
cerr << endl << "poly area test " << fn << " done" << endl;
}
MU_TEST(test_polygon_area_blank) { test_polygon_area("testdata/blank.png"); }
MU_TEST(test_polygon_area_white) { test_polygon_area("testdata/white.png"); }
MU_TEST(test_polygon_area_blob_border_w) { test_polygon_area("testdata/blob-border-w.png"); }
MU_TEST(test_polygon_area_blobs_borders) { test_polygon_area("testdata/blobs-borders.png"); }
MU_TEST(test_polygon_area_blobs_corners) { test_polygon_area("testdata/blobs-corners.png"); }
MU_TEST(test_polygon_area_blobs_crossing) { test_polygon_area("testdata/blobs-crossing.png"); }
MU_TEST(test_polygon_area_cross) { test_polygon_area("testdata/cross.png"); }
MU_TEST(test_polygon_area_letter_e) { test_polygon_area("testdata/letter-e.png"); }
MU_TEST(test_polygon_area_paper_example) { test_polygon_area("testdata/paper-example.png"); }
MU_TEST(test_polygon_area_paper_example_inv) { test_polygon_area("testdata/paper-example-inv.png"); }
MU_TEST(test_polygon_area_single_px) { test_polygon_area("testdata/single-px.png"); }
MU_TEST(test_polygon_area_single_px_inv) { test_polygon_area("testdata/single-px-inv.png"); }
MU_TEST(test_polygon_area_two_blobs) { test_polygon_area("testdata/two-blobs.png"); }
MU_TEST(test_polygon_area_two_px) { test_polygon_area("testdata/two-px.png"); }
MU_TEST(test_polygon_area_two_px_inv) { test_polygon_area("testdata/two-px-inv.png"); }
static void chain_approx_test(const char *fn) {
//cout << endl << "Testing \"" << fn << "\"" << endl;
@ -293,6 +346,7 @@ MU_TEST(chain_approx_test_two_px_inv) { chain_approx_test("testdata/two-
MU_TEST_SUITE(nopencv_contours_suite) {
/*
MU_RUN_TEST(test_complex_example_from_paper);
MU_RUN_TEST(test_round_trip_blank);
MU_RUN_TEST(test_round_trip_white);
@ -325,6 +379,22 @@ MU_TEST_SUITE(nopencv_contours_suite) {
MU_RUN_TEST(chain_approx_test_two_blobs);
MU_RUN_TEST(chain_approx_test_two_px);
MU_RUN_TEST(chain_approx_test_two_px_inv);
*/
MU_RUN_TEST(test_polygon_area_blank);
MU_RUN_TEST(test_polygon_area_white);
MU_RUN_TEST(test_polygon_area_blob_border_w);
MU_RUN_TEST(test_polygon_area_blobs_borders);
MU_RUN_TEST(test_polygon_area_blobs_corners);
MU_RUN_TEST(test_polygon_area_blobs_crossing);
MU_RUN_TEST(test_polygon_area_cross);
MU_RUN_TEST(test_polygon_area_letter_e);
MU_RUN_TEST(test_polygon_area_paper_example);
MU_RUN_TEST(test_polygon_area_paper_example_inv);
MU_RUN_TEST(test_polygon_area_single_px);
MU_RUN_TEST(test_polygon_area_single_px_inv);
MU_RUN_TEST(test_polygon_area_two_blobs);
MU_RUN_TEST(test_polygon_area_two_px);
MU_RUN_TEST(test_polygon_area_two_px_inv);
};
int main(int argc, char **argv) {