opencv/modules/imgproc/test/test_contours.cpp

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#include "test_precomp.hpp"
#include <opencv2/highgui.hpp>

namespace opencv_test { namespace {

//rotate/flip a quadrant appropriately
static void rot(int n, int *x, int *y, int rx, int ry)
{
    if (ry == 0) {
        if (rx == 1) {
            *x = n-1 - *x;
            *y = n-1 - *y;
        }

        //Swap x and y
        int t  = *x;
        *x = *y;
        *y = t;
    }
}

static void d2xy(int n, int d, int *x, int *y)
{
    int rx, ry, s, t=d;
    *x = *y = 0;
    for (s=1; s<n; s*=2)
    {
        rx = 1 & (t/2);
        ry = 1 & (t ^ rx);
        rot(s, x, y, rx, ry);
        *x += s * rx;
        *y += s * ry;
        t /= 4;
    }
}

static Mat draw_hilbert(int n = 64, int scale = 10)
{
    int n2 = n*n, w = (n + 2)*scale;
    Point ofs(scale, scale);
    Mat img(w, w, CV_8U);
    img.setTo(Scalar::all(0));

    Point p(0,0);
    for( int i = 0; i < n2; i++ )
    {
        Point q(0,0);
        d2xy(n2, i, &q.x, &q.y);
        line(img, p*scale + ofs, q*scale + ofs, Scalar::all(255));
        p = q;
    }
    dilate(img, img, Mat());
    return img;
}

TEST(Imgproc_FindContours, hilbert)
{
    Mat img = draw_hilbert();
    vector<vector<Point> > contours;

    findContours(img, contours, noArray(), RETR_LIST, CHAIN_APPROX_NONE);
    ASSERT_EQ(1, (int)contours.size());
    ASSERT_EQ(78632, (int)contours[0].size());

    findContours(img, contours, noArray(), RETR_LIST, CHAIN_APPROX_SIMPLE);
    ASSERT_EQ(1, (int)contours.size());
    ASSERT_EQ(9832, (int)contours[0].size());
}

TEST(Imgproc_FindContours, border)
{
    Mat img;
    cv::copyMakeBorder(Mat::zeros(8, 10, CV_8U), img, 1, 1, 1, 1, BORDER_CONSTANT, Scalar(1));

    std::vector<std::vector<cv::Point> > contours;
    findContours(img, contours, RETR_LIST, CHAIN_APPROX_NONE);

    Mat img_draw_contours = Mat::zeros(img.size(), CV_8U);
    for (size_t cpt = 0; cpt < contours.size(); cpt++)
    {
      drawContours(img_draw_contours, contours, static_cast<int>(cpt), cv::Scalar(1));
    }

    ASSERT_EQ(0, cvtest::norm(img, img_draw_contours, NORM_INF));
}

TEST(Imgproc_FindContours, regression_4363_shared_nbd)
{
    // Create specific test image
    Mat1b img(12, 69, (const uchar&)0);

    img(1, 1) = 1;

    // Vertical rectangle with hole sharing the same NBD
    for (int r = 1; r <= 10; ++r) {
        for (int c = 3; c <= 5; ++c) {
            img(r, c) = 1;
        }
    }
    img(9, 4) = 0;

    // 124 small CCs
    for (int r = 1; r <= 7; r += 2) {
        for (int c = 7; c <= 67; c += 2) {
            img(r, c) = 1;
        }
    }

    // Last CC
    img(9, 7) = 1;

    vector< vector<Point> > contours;
    vector<Vec4i> hierarchy;
    findContours(img, contours, hierarchy, RETR_TREE, CHAIN_APPROX_NONE);

    bool found = false;
    size_t index = 0;
    for (vector< vector<Point> >::const_iterator i = contours.begin(); i != contours.end(); ++i)
    {
        const vector<Point>& c = *i;
        if (!c.empty() && c[0] == Point(7, 9))
        {
            found = true;
            index = (size_t)(i - contours.begin());
            break;
        }
    }
    EXPECT_TRUE(found) << "Desired result: point (7,9) is a contour - Actual result: point (7,9) is not a contour";

    if (found)
    {
        ASSERT_EQ(contours.size(), hierarchy.size());
        EXPECT_LT(hierarchy[index][3], 0) << "Desired result: (7,9) has no parent - Actual result: parent of (7,9) is another contour. index = " << index;
    }
}

TEST(Imgproc_DrawContours, regression_26264)
{
    Mat img = draw_hilbert(32);
    img.push_back(~img);

    for (int i = 50; i < 200; i += 17)
    {
        rectangle(img, Rect(i, i, img.cols - (i*2), img.rows - (i*2)), Scalar(0), 7);
        rectangle(img, Rect(i, i, img.cols - (i*2), img.rows - (i*2)), Scalar(255), 1);
    }

    vector<vector<Point> > contours;
    vector<Vec4i> hierarchy;
    findContours(img, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE);
    img.setTo(Scalar::all(0));
    Mat img1 = img.clone();
    Mat img2 = img.clone();
    Mat img3 = img.clone();

    int idx = 0;
    while (idx >= 0)
    {
        drawContours(img, contours, idx, Scalar::all(255), FILLED, LINE_8, hierarchy);
        drawContours(img2, contours, idx, Scalar::all(255), 1, LINE_8, hierarchy);
        idx = hierarchy[idx][0];
    }

    drawContours(img1, contours, -1, Scalar::all(255), FILLED, LINE_8, hierarchy);
    drawContours(img3, contours, -1, Scalar::all(255), 1, LINE_8, hierarchy);
    ASSERT_EQ(0, cvtest::norm(img, img1, NORM_INF));
    ASSERT_EQ(0, cvtest::norm(img2, img3, NORM_INF));
}

TEST(Imgproc_DrawContours, MatListOfMatIntScalarInt)
{
    Mat gray0 = Mat::zeros(10, 10, CV_8U);
    rectangle(gray0, Point(1, 2), Point(7, 8), Scalar(100));
    vector<Mat> contours;
    findContours(gray0, contours, noArray(), RETR_EXTERNAL, CHAIN_APPROX_SIMPLE);
    drawContours(gray0, contours, -1, Scalar(0), FILLED);
    int nz = countNonZero(gray0);
    EXPECT_EQ(nz, 0);
}

}} // namespace
/* End of file. */