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Sorting 2nd array of points to define four corners

Hi I have a set of 2d dots that can be of any size. By finding the minimum and maximum distance between the origin, I can find out the top left and bottom corner points, but I cannot find the top and bottom left points.

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Perhaps you can use cv::approxPoly()

to find the corners of your set of 2D points. Then you can sort the points in any order you want, like this:



//Sorts a vector of 4 points into top left, top right, bottomleft, bottomright
vector<Point> sortPoints(vector<Point> unsorted) {
    vector<Point> sorted;
    for (int i = 0; i < 4; i++)sorted.push_back(Point(0, 0));
    int middleX = (unsorted[0].x + unsorted[1].x + unsorted[2].x + unsorted[3].x) / 4;
    int middleY = (unsorted[0].y + unsorted[1].y + unsorted[2].y + unsorted[3].y) / 4;
    for (int i = 0; i < unsorted.size(); i++) {
        if (unsorted.at(i).x < middleX && unsorted.at(i).y < middleY)sorted[0] = unsorted.at(i);
        if (unsorted.at(i).x > middleX && unsorted.at(i).y < middleY)sorted[1] = unsorted.at(i);
        if (unsorted.at(i).x < middleX && unsorted.at(i).y > middleY)sorted[2] = unsorted.at(i);
        if (unsorted.at(i).x > middleX && unsorted.at(i).y > middleY)sorted[3] = unsorted.at(i);
    }
    return sorted;
}
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p1 (left, top), p2 (right, bottom) - you know.

Now get the values ​​at the top, left, bottom and right and form other points:



p3 (right, top), p4 (left, bottom).

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